# Steel Standart — full data (edition September 2026)

## 080M40 — Unalloyed medium-carbon engineering steel (British standard)
URL: https://steelstandart.com/grade/080m40/
System: BS (superseded British) | Family: Carbon steel | Standard: BS 970 | Verified against: BS 970-1:1991
Aliases: 080m40, 080 m 40, en8, en 8, en8 steel, en8 equivalent, bs 970 080m40, 080m40 equivalent, en8 vs en19, 080a40, en8d

080M40 is the medium-carbon engineering steel that British machine shops have run on for seventy years, and almost nobody calls it that. Its name is EN8 — a designation from BS 970:1955 that was formally withdrawn in 1970 and is still what the bar is ordered, stocked and drawn as from Birmingham to Bangalore.

The modern designation is readable once the pattern is known. 080 places the steel in the carbon-manganese group, M means it is supplied to *mechanical property* requirements, and 40 is the nominal carbon in hundredths of a per cent. The same steel ordered to chemical analysis alone is 080A40, with no guaranteed strength — a distinction that matters on a purchase order and is routinely lost.

A warning about the name: the EN in EN8 has nothing to do with the European EN standards. It stands for *Emergency Number*, from the wartime British specification series. EN8 is not an EN 10025 or EN 10083 grade, and the coincidence has caused a great many mis-specified orders.

What the steel actually offers is a good balance for general machined parts: 550–700 MPa tensile normalised, rising to 700–850 MPa hardened and tempered, with clean machining and straightforward through-hardening in small sections. What it does not offer is hardenability in thick sections or guaranteed toughness. Both of those are the reason 709M40 (EN19) and 817M40 (EN24) exist above it.

Chemical composition (mass %): C 0.36 – 0.44; Si 0.1 – 0.4; Mn 0.6 – 1; P ≤ 0.05; S ≤ 0.05 (080A40 is the same analysis ordered to chemical composition only; 212M36 is the free-cutting variant with added sulphur)
BS 970-1:1991 ladle analysis. The designation encodes it: **080** places the steel in the carbon-manganese group with manganese around 1 %, **M** means the bar is supplied to mechanical property requirements, and **40** is the nominal carbon in hundredths of a per cent. Change the letter and the meaning changes with it — **080A40** is the same chemistry supplied to analysis only, with no guaranteed mechanical properties.

Mechanical properties:
- Condition R — normalised, ≤ 63 mm ruling section: yield 280 MPa; tensile 550–700 MPa; elongation 16 %; hardness 152–207 HB
- Condition S — hardened and tempered, ≤ 63 mm: yield 355 MPa; tensile 625–775 MPa; elongation 16 %; hardness 179–229 HB
- Condition T — hardened and tempered, ≤ 63 mm: yield 385 MPa; tensile 700–850 MPa; elongation 15 %; hardness 201–255 HB
- Condition U — hardened and tempered, ≤ 30 mm: yield 450 MPa; tensile 775–925 MPa; elongation 13 %; hardness 223–277 HB
- As-supplied bright drawn bar: yield — MPa; tensile typically 600–750 MPa; elongation — %; hardness ≈ 180–230 HB
BS 970 guarantees properties against a **limiting ruling section** — the largest diameter for which the stated band applies. The values above are for the common small and medium sections; the same condition letter on a 100 mm bar guarantees less, because the core of a thick bar cannot be cooled fast enough. Always read the condition letter and the ruling section together, and note that bright drawn bar is cold-worked rather than heat-treated, so its strength comes from the drawing and not from a specified condition.
Impact:  J at  °C (not a standard requirement)

Equivalents:
- C45 (EN (European)) — near: C45 (1.0503) is 0.42–0.50 % C against 080M40's 0.36–0.44 %, so it sits slightly above — closer to 080M46. For general shafting the substitution is routine, but C45 will through-harden marginally deeper and machine marginally harder.
- 1045 (AISI / SAE) — functional: AISI 1045 is 0.43–0.50 % C — the American counterpart of 080M46. Against 080M40 it is one carbon step higher; AISI 1040 is the true match, at 0.37–0.44 % C.
- 42CrMo4 (EN (European)) — functional: The alloy step up, equivalent to 709M40 (EN19). Substitute where hardenability in sections above about 60 mm or genuine toughness is required — 080M40 cannot deliver either.

Superseded names:
- En8 — BS 970:1955 (withdrawn): The name almost everyone still uses. En8 became 080M40 in the 1970 revision, and more than half a century later the old name has not gone away — suppliers, drawings and stock lists across Britain, Ireland, India, Australia and the Gulf all still say EN8.
- En8D — BS 970:1955 (withdrawn): The letter suffix marked a tighter sulphur and phosphorus limit for better ductility; closest modern equivalent is 080A40 ordered to analysis.
- 080M46 — BS 970-1: The next grade up in the same family: 0.42–0.50 % carbon, the British counterpart of AISI 1045 rather than 1040. Frequently confused with 080M40 in cross-reference tables.

Product forms: bright drawn and turned round bar; hot-rolled black bar and billet; flat, square and hexagon bar; forging stock; hollow bar and tube for machining
Tolerances: bright bar: BS EN 10278 (h9, h11); hot-rolled round: BS EN 10060; hot-rolled flat and square: BS EN 10058 / 10059; straightness and decarburisation per BS 970-1 Annex

### 080M40 mechanical properties
Normalised (condition R): 550–700 MPa tensile, 280 MPa yield, 152–207 HB. Hardened and tempered: 625–775 MPa (condition S), 700–850 MPa (T) or 775–925 MPa (U), with hardness rising to 277 HB. Each band is guaranteed only up to its limiting ruling section.

### What the limiting ruling section means
BS 970 does not guarantee a strength for a grade; it guarantees a strength for a grade in a stated maximum diameter. A 25 mm bar in condition T reaches 700–850 MPa through its section; a 100 mm bar in the same condition does not, because the quench cannot cool its core fast enough. Ordering condition T without stating the section is ordering something the standard cannot supply.

### EN8 does not mean European EN
The En series came from the British wartime *Emergency Number* specifications and was made permanent by BS 970:1955. EN8, EN19, EN24 and EN31 are British legacy names, unrelated to EN 10025, EN 10083 or any CEN document. A drawing calling for "EN8" wants 080M40; a drawing calling for "EN 10083-2 C40E" wants something else.

### 080M40 heat treatment
Normalise at 830–860 °C, air cool. Harden from 830–860 °C, quench in oil or water depending on section — oil for thin, water for thicker, with the crack risk rising accordingly. Temper between 550 and 660 °C to reach conditions S, T or U; the higher the tempering temperature, the lower the strength and the higher the ductility. Stress-relieve machined parts at 550–600 °C.

### 080M40 against C45
C45 (1.0503) is the grade most often offered against an EN8 enquiry in Europe, and for general shafting it works. The difference is one carbon step: C45 is 0.42–0.50 % against 0.36–0.44 %, so it hardens a little deeper, machines a little harder and sits closer to 080M46 than to 080M40. Where the part is heat-treated to a specified band, check which grade the band was written for.

### Where 080M40 runs out
Three limits. Section size: above roughly 60 mm the quench does not reach the core and the properties fall away. Toughness: no impact requirement, and a plain carbon steel at 0.40 % C has little to offer at low temperature. Fatigue under shock: shafts with keyways and shoulders in duty cycles belong in 709M40 (EN19) or 817M40 (EN24). 080M40 is a general-purpose steel, not a highly stressed one.

### Weldability
080M40 is weldable with care and is not a welding grade. At 0.36–0.44 % carbon the carbon equivalent runs around 0.55–0.65, well above the 0.45 threshold at which cold cracking becomes a real risk, so welding requires preheat of 150–250 °C by section, low-hydrogen consumables, and a post-weld stress relief at 550–660 °C wherever the joint is restrained. Weld the material in the normalised condition where possible; welding onto hardened and tempered bar destroys the temper locally and leaves a hard, untempered zone at the fusion boundary. For assemblies that must be welded rather than machined from solid, a low-carbon structural grade or a weldable alloy steel is the right specification from the start.

### Machining, forming, heat treatment
This is the grade's strength. In the normalised condition 080M40 machines cleanly and predictably with a machinability index around 60 % of free-cutting steel, giving good surface finish and manageable tool wear — it is the default choice for turned shafts, studs, pins and spacers precisely because it behaves. Bright drawn bar machines better still but carries residual stress from the drawing, so parts machined unevenly from it can move; where dimensional stability matters, use turned-and-polished bar or stress-relieve before finish machining. Where chip control dominates, 212M36 is the free-cutting version with added sulphur, at the cost of transverse ductility.

Applications: Turned shafts, spindles, axles and drive pins; Studs, bolts, keys and general machined fasteners; Gears and sprockets in light duty, often flame or induction hardened on the teeth; Machine tool components, jigs, fixtures and tooling bodies; Hydraulic rams and rods in the hardened and tempered conditions; General engineering bar stock across Britain, Ireland, India, Australia and the Gulf

Q: What is EN8 steel?
A: EN8 is the common name for 080M40, the British medium-carbon engineering steel of BS 970 with 0.36–0.44 % carbon. It is supplied normalised at 550–700 MPa tensile or hardened and tempered up to 925 MPa, and it is the default bar stock for turned shafts and general machined parts.

Q: Is EN8 the same as 080M40?
A: Yes. EN8 is the 1955 designation and 080M40 the one that replaced it in 1970. The old name never stopped being used, so suppliers, drawings and stock lists carry both, and they refer to the same steel.

Q: Does the EN in EN8 mean European standard?
A: No, and this is a common and expensive confusion. EN in EN8 stands for Emergency Number, from the British wartime specification series. It has no connection to EN 10025, EN 10083 or any other CEN standard.

Q: What is the equivalent of EN8 in European standards?
A: C45 (1.0503) is the grade normally offered, though it is one carbon step higher at 0.42–0.50 % and is strictly closer to 080M46. C40E is the nearer match on carbon. In the American system, AISI 1040 matches 080M40 and 1045 matches 080M46.

Q: What is the difference between 080M40 and 080A40?
A: The letter. M means the bar is supplied to guaranteed mechanical properties in a stated condition and ruling section; A means it is supplied to chemical analysis only, with no guaranteed strength. Ordering A when the drawing assumed M is a real and recurring problem.

Q: Can EN8 be hardened?
A: Yes, by quench and temper: austenitise at 830–860 °C, quench in oil or water by section, temper at 550–660 °C to the required condition. It through-hardens reliably only in small sections — above roughly 60 mm diameter the core will not reach the specified band and an alloy grade such as EN19 is needed.

Q: What is the difference between EN8 and EN19?
A: Alloy content and therefore hardenability. EN19 is 709M40, a chromium-molybdenum steel equivalent to 42CrMo4, which hardens right through much larger sections and holds far better toughness after tempering. EN8 is the plain carbon grade for general work; EN19 is for highly stressed shafts and gears.

Q: Can EN8 be welded?
A: With preheat, low-hydrogen consumables and post-weld stress relief — and preferably not at all. The carbon equivalent is around 0.55–0.65, well into the cold-cracking range. Weld in the normalised condition if you must; welding hardened and tempered bar leaves an untempered zone at the fusion line.

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## 09G2S — Low-alloy structural steel of increased strength (GOST / CIS)
URL: https://steelstandart.com/grade/09g2s/
System: GOST (Russia/CIS) | Family: Structural steel | Standard: GOST 19281 | Verified against: GOST 19281-2014
Aliases: 09g2s, 09 g2s, 09г2с, 09g2s steel, 09g2s equivalent, gost 19281, 09g2s vs s355, 10khsnd, 17g1s

09G2S is the low-alloy structural steel that does in the CIS what S355 does in Europe — and it does one thing better. Defined in GOST 19281, it delivers 345 MPa yield with only 0.12 % carbon, buying its strength from 1.3–1.7 % manganese and 0.5–0.8 % silicon instead. The consequence is a steel that is strong, tough at very low temperature and unusually forgiving to weld.

The designation is literally the recipe: 09 is the nominal carbon in hundredths of a per cent, Г is the Cyrillic letter for manganese (*marganets*), 2 is roughly its percentage, and С is silicon (*kremniy*, written with S in the Russian alloy code). Anyone who can read that pattern can read most GOST alloy names.

The feature that sells it is the cold. Depending on the category ordered, 09G2S is impact-tested at −40 °C, −60 °C or −70 °C, and after mechanical ageing as well. That is the reason it dominates structures in Siberia, Kazakhstan and the Russian north, and the reason it turns up in export enquiries for cold-climate projects where a European J2 grade would be the obvious alternative.

Against S355J2 the substitution works on strength and needs care on the test. 09G2S is 345 MPa against 355 at the first step — a 3 % difference that a design check will usually absorb — but GOST states impact energy as KCU in J/cm² on a U-notch while EN states KV in joules on a V-notch. The U-notch test is the gentler of the two and the numbers do not convert. Where the design depends on toughness, the V-notch test has to be ordered explicitly.

Chemical composition (mass %): C ≤ 0.12; Si 0.5 – 0.8; Mn 1.3 – 1.7; P ≤ 0.035; S ≤ 0.04; Cr ≤ 0.3 (residual); Ni ≤ 0.3 (residual); Cu ≤ 0.3 (residual); N ≤ 0.008
GOST 19281-2014 ladle analysis. The name is the composition read aloud: **09** is 0.09 % carbon nominal, **Г** (G) is manganese, **2** is roughly 2 % of it, and **С** (S) is silicon. Low carbon with high manganese and silicon is a classic solid-solution strengthening recipe — the strength comes from the alloy, not from carbon, which is why the grade welds far better than its yield would suggest.

Mechanical properties:
- ≤ 10 mm: yield 345 MPa; tensile ≥ 490 MPa; elongation 21 %; hardness ≈ 150–190 HB (typical)
- > 10 ≤ 20 mm: yield 325 MPa; tensile ≥ 470 MPa; elongation 21 %; hardness —
- > 20 ≤ 32 mm: yield 305 MPa; tensile ≥ 460 MPa; elongation 21 %; hardness —
- > 32 ≤ 60 mm: yield 285 MPa; tensile ≥ 450 MPa; elongation 21 %; hardness —
- > 60 ≤ 80 mm: yield 275 MPa; tensile ≥ 440 MPa; elongation 21 %; hardness —
- > 80 ≤ 160 mm: yield 265 MPa; tensile ≥ 430 MPa; elongation 21 %; hardness —
Strength class 325 or 345 depending on the product and thickness; GOST 19281 organises the grades by strength class rather than by name, so a certificate may read "09G2S, class 345". Elongation is 21 % across the range. Unlike GOST 380, this standard carries its own mechanical table — 09G2S is a complete specification in one document.
Impact: 29 J at -70 °C (KCU 29 J/cm² at −70 °C, category dependent; also tested after mechanical ageing)

Equivalents:
- A572 Grade 50 (ASTM / ASME) — near: ASTM A572 Grade 50 is 345 MPa yield and 450 MPa minimum tensile — the same strength class, achieved with vanadium or niobium microalloying rather than manganese and silicon, and with no low-temperature requirement as standard.
- S355J2 (EN (European)) — near: The usual counterpart: 345 MPa yield against 355 at the first thickness step and a 490 MPa tensile floor against 470. 09G2S is tested colder than S355J2 but reports KCU on a U-notch rather than KV on a V-notch.
- S355JR (EN (European)) — near: Matches on strength; S355JR is tested only at +20 °C, so 09G2S exceeds it comfortably on toughness.
- P355NH (EN (European)) — near: GOST 5520 09G2S vessel plate: yield 305–345 MPa, Rm 460–490 MPa.
- Q355 (GB/T (China)) — near: The CIS grade of the same tier: 345 MPa yield, 490 MPa tensile floor, tested far colder but reporting KCU on a U-notch rather than KV on a V-notch.
- S355MC (EN (European)) — functional: Similar yield, different route: S355MC is thermomechanically rolled for forming, with much tighter carbon and a bend requirement. Substitute only where the design is about strength rather than about forming.

Superseded names:
- 09G2S per GOST 19282-73 — GOST 19282-73 (withdrawn): Thick plate was specified separately until the 1989 revision merged 19282 into 19281.
- 09G2 — GOST 19281: The same steel without the silicon addition: lower strength class, still in the standard. 09G2S is the silicon-bearing, higher-strength member of the family.
- 10KhSND / 15KhSND — GOST 19281: The weathering members of the same standard — chromium, silicon, nickel and copper — used where atmospheric corrosion resistance is wanted alongside the strength.

Product forms: heavy plate to GOST 19281 and GOST 5520 (boiler and vessel duty); hot-rolled sections: I beam, channel, angle; hot-rolled coil and strip; seamless pipe to GOST 8731 / 8732 and welded pipe to GOST 10706; round and flat bar
Tolerances: heavy plate: GOST 19903; thin sheet and coil: GOST 19903 / 19904; I beam: GOST 8239, wide-flange GOST 26020; seamless pipe: GOST 8732

### 09G2S yield strength
345 MPa minimum up to 10 mm, then 325 MPa to 20 mm, 305 MPa to 32 mm, 285 MPa to 60 mm, 275 MPa to 80 mm and 265 MPa to 160 mm. The steps are closer together than in EN 10025-2, where S355 holds 345 MPa all the way to 40 mm — so in the 10–40 mm band the European grade is nominally the stronger of the two.

### 09G2S tensile strength
490 MPa minimum up to 32 mm, falling to 470, 460, 450, 440 and 430 MPa through the thickness bands. GOST sets a floor with no ceiling, where EN 10025-2 gives S355 a 470–630 MPa band. A 09G2S plate can therefore be stronger at the top end than any conforming S355 plate.

### 09G2S chemical composition
C ≤ 0.12 %, Si 0.50–0.80 %, Mn 1.30–1.70 %, P ≤ 0.035 %, S ≤ 0.040 %, N ≤ 0.008 %, with Cr, Ni and Cu each ≤ 0.30 % as residuals. The carbon equivalent works out around 0.37–0.42, comparable with S355J2 and low enough that preheat is rarely needed below 30 mm.

### Low-temperature toughness
This is the grade's reason for existing. Categories in GOST 19281 set the impact temperature at −40 °C, −60 °C or −70 °C, with a further requirement after mechanical ageing. Few commodity structural steels anywhere are routinely certified at −70 °C, and the fine grain produced by the manganese-silicon chemistry is what makes it possible at this carbon level.

### The GOST 19281 family
09G2S sits in a family organised by strength class from 265 to 590 MPa. 09G2 is the same steel without silicon and one class lower. 17G1S is the higher-carbon, higher-strength member used for pipe. 10KhSND and 15KhSND add chromium, nickel and copper for atmospheric corrosion resistance — the CIS weathering steels, comparable with S355J2W.

### Accepting 09G2S against S355J2
Four checks. Yield at the governing thickness, since the ladders step differently between 10 and 40 mm. The impact test: temperature, category and whether a V-notch result is available. The tensile ceiling, because GOST sets none and a weld procedure written for a capped band may not cover the material. And the delivery condition — GOST 19281 allows as-rolled, normalised and controlled-rolled, and the certificate should say which.

### Weldability
09G2S is one of the more forgiving high-strength structural steels to weld, and that is a direct consequence of its chemistry: at 0.12 % carbon maximum, the hardenability that produces cold cracking simply is not there. Carbon equivalent typically runs 0.37–0.42, so preheat is normally unnecessary below about 30 mm at ordinary ambient temperature, and 100–150 °C is enough above it. All arc processes apply. CIS practice uses UONI-13/55 electrodes and Sv-08G2S wire — the latter being the near-identical filler composition, which is why it is also the standard consumable for welding ordinary carbon steel throughout the region. For joints that must hold the low-temperature guarantee, match the consumable's certified impact temperature to the plate's, not to the room's.

### Machining, forming, heat treatment
Machinability is moderate and noticeably tougher than St3sp: the manganese and silicon that provide the strength also make the steel gummy and raise cutting forces by roughly a quarter over a plain carbon steel of the same hardness. Sharp tooling, positive rake and adequate feed are the usual answers. Cold forming is good for the strength class — elongation is 21 % across the whole thickness range — and the grade bends and rolls well, but spring-back is higher than on a 235 MPa steel and the absence of a tensile ceiling means it varies between heats.

Applications: Structural steelwork for cold climates: Siberia, the Russian north, Kazakhstan, Mongolia; Bridges, gantries, crane runways and heavy welded frames; Tank, silo and pressure-vessel shells (with GOST 5520 for vessel duty); Oil and gas structures, pipe racks and offshore module steelwork; Railway wagon and heavy vehicle structures; Seamless and welded pipe for structural and low-temperature service

Q: What is 09G2S steel?
A: 09G2S is the low-alloy structural steel of GOST 19281, used across Russia and the CIS where S355 would be used in Europe. It delivers 345 MPa yield and a 490 MPa tensile floor from 0.12 % carbon with 1.3–1.7 % manganese and 0.5–0.8 % silicon, and it is impact-tested down to −70 °C.

Q: Is 09G2S equivalent to S355J2?
A: It is the accepted counterpart. Yield is 345 MPa against 355 at the first step and the tensile floor is 490 against 470. The difference that needs attention is the impact test: GOST reports KCU in J/cm² on a U-notch, EN reports KV in joules on a V-notch, and the two do not convert.

Q: What does the name 09G2S mean?
A: It is the composition: 09 is 0.09 % nominal carbon, Г is manganese at roughly 2 %, and С is silicon. Russian alloy designations are read this way throughout — the number in front is carbon in hundredths of a per cent, the letters are the alloying elements.

Q: How cold can 09G2S be used?
A: Depending on the category ordered, it is certified at −40 °C, −60 °C or −70 °C, and additionally after mechanical ageing. That routine −70 °C certification is unusual for a commodity structural steel and is the main reason the grade is specified.

Q: Does 09G2S need preheat for welding?
A: Usually not below about 30 mm at normal ambient temperature. The carbon equivalent is typically 0.37–0.42, low for a 345 MPa steel, because the strength comes from manganese and silicon rather than carbon. Above 30 mm or in cold shop conditions, 100–150 °C is the usual figure.

Q: What is the difference between 09G2S and St3sp?
A: Strength class and toughness. St3sp is the 245 MPa ordinary-quality carbon grade of GOST 380; 09G2S is the 345 MPa low-alloy grade of GOST 19281 with guaranteed sub-zero impact values. The step between them mirrors S235 to S355.

Q: Is 09G2S the same as 17G1S?
A: No. 17G1S is a higher-carbon member of the same standard — about 0.17 % C with around 1.5 % manganese — used mainly for large-diameter pipe. It is stronger in the as-rolled state and less tough at low temperature than 09G2S.

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## 1.2311 (1.2311) — Plastic mould steel, pre-hardened and tempered
URL: https://steelstandart.com/grade/1-2311/
System: EN (European) | Family: Tool steel | Standard: EN ISO 4957 | Verified against: EN ISO 4957:2018
Aliases: 40CrMnMo7, 40 CrMnMo 7, P20, AISI P20, P20 tool steel, 1.2311 tool steel, 1.2311 mould steel, GS-711, M200, Impax, 40CrMnMo8, 3Cr2Mo

1.2311 (40CrMnMo7) is the steel most plastic moulds are built from, and the thing to understand about it is not its analysis but how it is sold: already hardened. A block arrives quenched and tempered to 28–34 HRC, the cavity is cut into it at that hardness, and the mould goes into the press without ever seeing a heat-treatment furnace. Nothing moves, nothing cracks, nothing needs re-grinding to size — which on a 600 kg mould base is worth far more than the extra hardness a through-hardened tool could offer.

The analysis exists to serve that trick. At 0.40 % carbon the steel reaches 28–34 HRC after tempering at around 600 °C, which is soft enough to machine with ordinary carbide tooling and hard enough to resist the clamping, injection and ejection loads of a few hundred thousand cycles. The 1.5 % manganese and 2 % chromium give it enough hardenability to come out of the quench uniformly at 250 mm section without nickel; above that the core falls away, which is exactly where 1.2738 with its 1 % nickel takes over.

The third member of the family is the one toolrooms actually buy most of. 1.2312 is the same steel with sulphur added: it machines about 20 % faster and costs the same, but the sulphide stringers that do the lubricating also ruin a polished surface and make welding unreliable. The division of labour is settled practice — 1.2312 for mould bases and bolsters, 1.2311 for cavities that will be polished, textured or welded, and 1.2738 for anything large.

AISI P20 is the North American counterpart; it is leaner on manganese, so a thick P20 block reads lower in the core than a 1.2311 block of the same size. For mould bases they are interchangeable, but the hardness certificate is what should be compared, not the designation.

Chemical composition (mass %): C 0.35 – 0.45; Si 0.2 – 0.4; Mn 1.3 – 1.6; P ≤ 0.03; S ≤ 0.03; Cr 1.8 – 2.1; Mo 0.15 – 0.25
EN ISO 4957:2018, plastic mould steels (40CrMnMo7). AISI P20 to ASTM A681 is leaner on manganese: C 0.28–0.40, Mn 0.60–1.00, Cr 1.40–2.00, Mo 0.30–0.55. The high manganese of 1.2311 substitutes for part of the molybdenum and is what gives a 400 mm block a usable core hardness without nickel.

Mechanical properties:
- +QT as delivered, section ≤ 250 mm: yield ≈ 800–900 MPa; tensile 1000–1100 MPa; elongation ≈ 13 %; hardness 280–325 HB (29–34 HRC)
- +QT as delivered, section 250–400 mm (core): yield ≈ 700–800 MPa; tensile 900–1000 MPa; elongation ≈ 14 %; hardness 260–300 HB (26–31 HRC)
- Re-hardened 840–870 °C oil, as-quenched: yield — MPa; tensile — MPa; elongation — %; hardness 52–54 HRC
- Re-hardened and tempered 550 °C: yield ≈ 1150 MPa; tensile ≈ 1350 MPa; elongation ≈ 10 %; hardness 42–44 HRC
- Nitrided surface (480–520 °C): yield — MPa; tensile — MPa; elongation — %; hardness 600–700 HV
- Flame or induction hardened surface: yield — MPa; tensile — MPa; elongation — %; hardness 50–54 HRC
EN ISO 4957 specifies the chemistry and the delivery hardness range; the tensile figures are the normal correlation for a quenched and tempered 0.40 % C low-alloy steel at that hardness, not standardised values. The only number on the certificate that matters in practice is the **delivery hardness**, and it is measured on the surface — on a block over 250 mm the core will read lower.

Equivalents:
- P20 (AISI / SAE) — near: AISI P20 (ASTM A681): C 0.28–0.40, Mn 0.60–1.00, Cr 1.40–2.00, Mo 0.30–0.55. The same pre-hardened mould steel concept, but leaner on manganese and richer on molybdenum, so a thick P20 block has a lower core hardness than a 1.2311 block of the same size. Interchangeable for mould bases; check the hardness certificate, not the name.
- 1.2312 (EN (European)) — near: 40CrMnMoS8-6: the same steel with 0.05–0.10 % sulphur added. Machines about 20 % faster and is the standard choice for mould bases, but the sulphide stringers make it unsuitable for polishing, texturing or welding.
- 1.2738 (EN (European)) — near: 40CrMnNiMo8-6-4: 1.2311 with 1 % nickel added. Holds 28–34 HRC in blocks up to 600 mm and above, where 1.2311 drops below 28 HRC in the core. The default for large moulds.
- 3Cr2Mo (GB/T (China)) — near: GB/T 1299 3Cr2Mo is the Chinese P20 transcription: C 0.28–0.40, Cr 1.40–2.00, Mo 0.30–0.55. 3Cr2MnNiMo corresponds to 1.2738.
- 40KhGM (GOST (Russia/CIS)) — near: GOST 4543 40KhGM: C 0.37–0.45, Mn 0.90–1.20, Cr 0.90–1.20, Mo 0.20–0.30 — the closest Russian analysis, with less chromium.
- 42CrMo4 (EN (European)) — functional: 1.7225: the general-purpose quenched and tempered engineering steel. Similar hardness at delivery and cheaper, but supplied in bar rather than mould-block sizes and without the cleanliness and flatness guarantees a mould base needs.
- 1-2083 (EN (European)) — functional: X40Cr14: the stainless mould steel. Chosen when the moulded polymer is corrosive (PVC, fluoropolymers, flame-retardant compounds) or the mould must survive condensation; harder to machine and a step up in price.
- SCM440 / 42CrMo (JIS (Japan)) — functional: JIS has no dedicated pre-hardened mould grade; Japanese mould bases are commonly SCM440 (42CrMo4 class) supplied quenched and tempered to 28–33 HRC, which performs the same job with lower manganese and 0.20 % more molybdenum.

Superseded names:
- 40CrMnMo7 — DIN 17350 (withdrawn): Same number and name; the plastic mould steels moved into EN ISO 4957.
- GS-711 — older German trade usage: Still seen on drawings as a synonym for 1.2311.
- 40CrMnMo8 — older designation: Occasionally used for the same steel; the modern short name is 40CrMnMo7.
- M200 / Impax — Böhler / Uddeholm trade names: Thyroplast 2311, Cryodur 2311. Impax Supreme is the remelted, higher-cleanliness version.

Product forms: blocks and plate, pre-hardened and tempered (+QT); flat bar, pre-hardened; round bar, pre-hardened; machined mould bases and bolsters
Tolerances: pre-hardened blocks: supplier tolerances, normally +3/+6 mm per face for finish machining; ground or milled all over on request; plate thickness: EN 10029 class B where supplied as plate; flatness and parallelism on machined mould bases: supplier specification, typically 0.05 mm/m

### 1.2311 delivery hardness
Supplied pre-hardened and tempered to 280–325 HB, that is 29–34 HRC. Typical guaranteed bands are 300 ± 20 HB. The hardness is measured on the surface; a block above 250 mm thick reads 260–300 HB at the core and the drop is normal, not a defect. Specify the hardness at the depth that matters if the cavity is cut deep into a thick plate.

### Why it is not hardened further
The mould steel compromise: at 30 HRC a cavity can be milled, drilled, tapped and EDM-cut in the delivered state and will hold its dimensions for the life of the mould. Re-hardening to 42–44 HRC is possible (oil quench from 840–870 °C, temper at 550 °C) and occasionally done for small inserts, but it means distortion, re-grinding and the risk of cracking a machined cavity — so it is almost never done to a finished mould. Where a harder surface is needed, it is added locally by nitriding or flame hardening, not by re-quenching the block.

### Surface hardening
Gas or plasma nitriding at 480–520 °C gives 600–700 HV to a depth of 0.2–0.4 mm with no measurable distortion and no loss of core hardness — the tempering temperature of the delivered block is above the nitriding temperature, which is why it works. Used on slides, guides, gate areas and ejector holes. Flame or induction hardening reaches 50–54 HRC locally. Hard chrome plating, PVD CrN and nickel plating are all applied on 1.2311 cavities for wear and release.

### Polishing and texturing
1.2311 polishes to a mirror finish (Ra < 0.05 µm) and takes photo-etched textures cleanly — this is the single reason to pay for it instead of the free-machining 1.2312. Standard practice is to stone, then paper down to 1200 grit, then diamond paste. Remelted versions (Impax Supreme and equivalents) are bought where the moulding is optically critical, because ordinary continuously cast material carries enough inclusions to show pinholes at high polish.

### Section size and hardenability
Uniform 28–34 HRC up to about 250 mm section; from 250 to 400 mm the core typically falls to 26–31 HRC, and beyond 400 mm it is below the useful band. The remedy is nickel: 1.2738 holds the same hardness to 600 mm and beyond. Do not solve it by specifying a higher delivery hardness — a 38 HRC block is noticeably harder to machine and gains nothing where the load is clamping, not wear.

### Physical properties
Density 7.85 g/cm³, E = 205 GPa, thermal conductivity ≈ 34 W/m·K at 20 °C — better than any of the high-alloy tool steels, which matters directly for cycle time. Expansion 12.3 × 10⁻⁶/K (20–200 °C). Maximum sensible service temperature about 500 °C; in a mould the limit is set by the polymer, not the steel.

### Weldability
Weldable, and mould repair welding is routine — this is the main advantage over the sulphur-bearing 1.2312. Preheat to 200–300 °C, TIG or micro-TIG with a matching filler (or a slightly softer filler where the weld will be polished), keep interpass temperature above 200 °C, cool slowly and temper at 500–550 °C, which is below the original tempering temperature so the block keeps its hardness. Laser cladding is used for small cavity corrections because the heat-affected zone stays under 0.5 mm and no post-weld temper is needed. A weld that will be polished must be made with matching filler, or it will show as a different-coloured patch after polishing.

### Machining, forming, heat treatment
Machined in the delivered pre-hardened condition at 30 HRC: machinability ≈ 55–60 % relative to 1 % C free-cutting steel, entirely routine with coated carbide at moderate speeds. Deep cavities are milled dry or with air blast; tapping at 30 HRC needs quality taps and correct hole sizes. Drilling for conformal cooling lines is the usual difficulty on large blocks — use a through-coolant drill. EDM is standard for ribs and sharp corners; the white layer should be stoned off a surface that will be polished. If a cavity is to be stress-relieved after heavy rough machining, do it at 500–550 °C, never higher, or the delivered hardness is lost.

Applications: Plastic injection mould cavities, cores and inserts; Mould bases, bolsters and support plates (more often 1.2312); Blow-moulding and extrusion-blow tooling; Die casting holder blocks, frames and bolsters for zinc; Rubber and compression moulds; Hydroforming and foam tooling; Jigs, fixtures and machine parts needing 30 HRC without heat treatment

Q: Is 1.2311 the same as P20?
A: They are counterparts, not identical. AISI P20 carries 0.28–0.40 % carbon, 0.60–1.00 % manganese and 0.30–0.55 % molybdenum; 1.2311 carries 0.35–0.45 % carbon, 1.30–1.60 % manganese and 0.15–0.25 % molybdenum. Both are sold pre-hardened at around 30 HRC and both are used for the same moulds, but the higher manganese of 1.2311 gives a thick block a better core hardness. Compare the hardness certificate rather than the designation.

Q: What hardness is 1.2311 supplied at?
A: 280–325 HB, which is 29–34 HRC, quenched and tempered by the mill. It is machined in that condition and needs no further heat treatment. On blocks above 250 mm the core reads 260–300 HB; that drop is expected and is the reason 1.2738 exists.

Q: What is the difference between 1.2311 and 1.2312?
A: Sulphur. 1.2312 (40CrMnMoS8-6) carries 0.05–0.10 % sulphur, which forms manganese sulphide stringers that act as internal lubricant: it machines roughly 20 % faster at the same price. The same stringers open up as pinholes when the surface is polished and make welds porous, so 1.2312 is used for mould bases and bolsters while 1.2311 is kept for cavities that will be polished, textured or repair welded.

Q: When should I use 1.2738 instead of 1.2311?
A: When the block is thicker than about 250 mm. 1.2738 is the same steel with roughly 1 % nickel added, which keeps the core in the 28–34 HRC band out to 600 mm and beyond. For small and medium moulds there is no benefit and 1.2311 is cheaper.

Q: Can 1.2311 be hardened to a higher hardness?
A: It can — oil quench from 840–870 °C and temper at 550 °C gives 42–44 HRC — but it is rarely worth doing to a machined cavity, because the quench distorts it and the dimensions have to be recovered by grinding. Where a harder surface is needed the normal answer is nitriding to 600–700 HV or local flame hardening to 50–54 HRC, neither of which moves the block.

Q: Can 1.2311 be polished to a mirror finish?
A: Yes, down to Ra 0.05 µm or better, and it takes photo-etched textures cleanly. For optically critical mouldings a remelted version is specified, because the inclusion content of ordinary material shows as pinholes at the highest polish. The free-machining variant 1.2312 cannot be polished to this level.

Q: Is 1.2311 corrosion resistant?
A: No. Two per cent chromium is far short of what a passive layer needs. Moulds rust in cooling channels, in humid storage and under condensation, and corrosive polymers such as PVC attack the cavity. Where that is the operating condition the answer is the stainless mould steel 1.2083 (X40Cr14) or a plated 1.2311 cavity.

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## 1.2344 (1.2344) [T20813] — Hot-work tool steel, 5 % Cr secondary-hardening
URL: https://steelstandart.com/grade/1-2344/
System: EN (European) | Family: Tool steel | Standard: EN ISO 4957 | Verified against: EN ISO 4957:2018
Aliases: X40CrMoV5-1, X 40 CrMoV 5 1, H13, AISI H13, H13 tool steel, H13 EN, 1.2344 tool steel, SKD61, 4Cr5MoSiV1, 4Kh5MFS, BH13, W302, Orvar Supreme, Thyrotherm 2344

1.2344 is the hot-work tool steel the whole industry calls H13. Its 5 % chromium, 1.3 % molybdenum and 1 % vanadium form fine alloy carbides that only precipitate when the steel is tempered above 500 °C — the secondary-hardening reaction that lets a tool keep 44–52 HRC while its surface cycles to 600 °C and back thousands of times. Nearly every aluminium die casting die, extrusion die and hot forging insert in the world is made of this steel or a remelted version of it.

The rule that governs its use has nothing to do with maximum hardness. The tempering temperature must be at least 30–50 °C above the working temperature of the tool. A die tempered at 520 °C and then run at 540 °C tempers itself in service: it softens, distorts and cracks, and no amount of extra hardness at delivery prevents it. That is why the standard cycle is two tempers at 550–620 °C and why delivery hardness for die casting sits around 44–48 HRC rather than the 54 HRC the steel can reach.

The second thing to understand is the failure mode. Hot-work dies rarely wear out; they heat-check — a network of thermal-fatigue cracks on the cavity surface from repeated expansion and contraction. Toughness, cleanliness and thermal conductivity therefore decide die life more than hardness does, which is why premium 1.2344 is electro-slag remelted and bought against NADCA #207 instead of against EN ISO 4957 alone. Two blocks can both be legitimate X40CrMoV5-1 and still differ by a factor of three in die life.

1.2344 and AISI H13 are the same steel; JIS SKD61 and GB 4Cr5MoSiV1 are too. Its close relative 1.2343 (H11) carries a third of the vanadium, trading wear resistance for toughness, and is the European preference for large die casting dies.

Chemical composition (mass %): C 0.37 – 0.43; Si 0.9 – 1.2; Mn 0.3 – 0.5; P ≤ 0.03; S ≤ 0.02; Cr 4.8 – 5.5; Mo 1.1 – 1.5; V 0.9 – 1.1
EN ISO 4957:2018 Table 5 (X40CrMoV5-1). AISI H13 to ASTM A681 is wider: C 0.32–0.45, Si 0.80–1.20, Cr 4.75–5.50, Mo 1.10–1.75, V 0.80–1.20. The silicon content near 1 % is deliberate — it raises the tempering resistance and is what separates the hot-work 5 % Cr family from the cold-work 5 % Cr grade 1.2363.

Mechanical properties:
- +A soft annealed (delivery): yield — MPa; tensile ≈ 760–850 (typ.) MPa; elongation — %; hardness ≤ 229 HB
- Hardened 1020–1050 °C, air/vacuum, as-quenched: yield — MPa; tensile — MPa; elongation — %; hardness 52–56 HRC
- Tempered 2 × 550 °C: yield ≈ 1450 MPa; tensile ≈ 1700 MPa; elongation — %; hardness 50–52 HRC
- Tempered 2 × 600 °C: yield ≈ 1250 MPa; tensile ≈ 1500 MPa; elongation — %; hardness 44–46 HRC
- Tempered 2 × 650 °C: yield ≈ 1000 MPa; tensile ≈ 1200 MPa; elongation — %; hardness 38–40 HRC
- At 46 HRC, tested at 500 °C: yield ≈ 1050 MPa; tensile ≈ 1200 MPa; elongation — %; hardness —
EN ISO 4957 specifies chemistry and annealed hardness only; everything below the annealed row is typical for a 100 mm block and depends on the heat-treater. Room-temperature strength matters less than the hot yield and the thermal-fatigue resistance, which is why hot-work dies are specified by hardness band and by impact energy from the supplier's own test, not by a standard mechanical table.

Equivalents:
- H13 (AISI / SAE) — identical: AISI H13 (UNS T20813, ASTM A681): C 0.32–0.45, Cr 4.75–5.50, Mo 1.10–1.75, V 0.80–1.20. Same steel; the ASTM window is wider at both ends, so a certificate to A681 can sit outside the EN ISO 4957 limits while still being correctly labelled H13.
- 4Cr5MoSiV1 (GB/T (China)) — identical: GB/T 1299 4Cr5MoSiV1 is the direct H13 transcription; 4Cr5MoSiV is the older lower-vanadium grade equivalent to H11.
- SKD61 (JIS (Japan)) — identical: JIS G4404 SKD61: C 0.35–0.42, Si 0.80–1.20, Cr 4.80–5.50, Mo 1.00–1.50, V 0.80–1.15. For die casting work the two are interchangeable.
- 1.2343 (EN (European)) — near: X37CrMoV5-1 (H11): the same steel with vanadium at 0.30–0.50 instead of 1.00. Lower wear and temper resistance, noticeably higher toughness — the European default for large aluminium die casting dies, where heat checking rather than erosion ends the tool.
- 1.2363 (EN (European)) — near: X40CrMoV5-1 (H13): nearly the same alloy content with 0.40 % C and 1 % Si. The low carbon makes it a hot-work steel — it cannot reach 60 HRC, but it holds 45 HRC at 550 °C.
- 4Kh5MFS (GOST (Russia/CIS)) — near: GOST 5950 4Kh5MFS: C 0.32–0.40, Cr 4.50–5.50, Mo 1.20–1.50, V 0.30–0.50 — vanadium is roughly half, so tempering resistance is lower.
- 1.2367 (EN (European)) — functional: X38CrMoV5-3: molybdenum raised to 2.8–3.3 %. Better high-temperature strength and thermal-fatigue resistance for large dies and extrusion tooling; it is the usual upgrade when 1.2344 heat-checks too early.
- 1.2365 (EN (European)) — functional: 32CrMoV12-28: 3 % Mo, 0.30 % C hot-work steel for hot extrusion mandrels and die holders where toughness outranks hardness.
- 1.2714 (EN (European)) — functional: 55NiCrMoV7 (L6): the nickel hot-work forging-die steel. Tougher and used pre-hardened at 38–44 HRC, but it loses hardness above about 500 °C and is not a die casting steel.
- 1.2738 (EN (European)) — functional: X40CrMoV5-1 (H13) at 48–52 HRC: the choice when the mould runs hot or abrasively filled polymers erode the cavity. Far more expensive, must be heat treated after machining, and an unnecessary step for ordinary thermoplastics.

Superseded names:
- X40CrMoV5-1 — DIN 17350 (withdrawn): Same number and same short name; only the standard changed to EN ISO 4957.
- BH13 — BS 4659 (withdrawn): The British designation of the same steel.
- Z40CDV5 — NF A 35-590: The French designation.
- W302 / Orvar Supreme — Böhler / Uddeholm trade names: Thyrotherm 2344, Cryodur 2344, Vidar Superior. Premium versions are remelted and sold against NADCA #207 rather than against EN ISO 4957 alone.

Product forms: blocks and flat bar (annealed); round bar (annealed, rough-turned); plate; forgings and die blanks; ESR / remelted premium quality for die casting
Tolerances: annealed blocks and flat: supplier tolerances, typically +2/+5 mm machining allowance per face; rough-turned round: DIN 7527-6 forging allowance; die casting dies: NADCA #207 dimensional and cleanliness requirements ordered in addition to EN ISO 4957

### 1.2344 hardness
Annealed ≤ 229 HB on delivery. As-quenched 52–56 HRC. Working hardness is set by the temper: 50–52 HRC at 550 °C, 44–46 HRC at 600 °C, 38–40 HRC at 650 °C. Typical specifications are 44–48 HRC for aluminium die casting, 46–50 HRC for extrusion dies, 48–52 HRC for plastic moulds and cold-running tooling.

### Heat treatment
Soft anneal 750–800 °C, slow cool. Stress relieve at 650 °C after rough machining — on a deep cavity this step is the difference between a usable die and a distorted one. Preheat 650 and 850 °C, austenitise 1020–1050 °C (30 min at temperature per 25 mm), quench in air, vacuum gas or hot oil; interrupt at 50–70 °C, do not cool to room temperature before tempering. Temper twice, 2 h minimum each, at 550–650 °C; a third temper is normal practice on large dies. Ms ≈ 320 °C.

### Tempering above the service temperature
The temper curve has a secondary-hardening peak near 520 °C and falls away above it. Tempering on the rising side of that peak looks attractive because the hardness number is higher, but the die then continues to temper in service. Set the temper 30–50 °C above the highest surface temperature the tool will see: 550 °C minimum for zinc, 580–620 °C for aluminium die casting and hot extrusion.

### Heat checking and thermal fatigue
The dominant failure mode. Cracking is driven by the temperature swing at the surface, so preheating the die to 200–250 °C before the first shot and keeping the cooling steady matter more than hardness. Lower hardness (44–46 HRC) resists heat checking better; higher hardness (50 HRC) resists erosion and washout better. Remelted (ESR) material with low sulphur and isotropic toughness extends life several-fold on the same hardness.

### Nitriding — where it helps and where it hurts
Gas or plasma nitriding at 480–520 °C gives 1000–1200 HV and resists aluminium erosion, but the brittle compound layer initiates heat-check cracks. Practice splits accordingly: nitride extrusion dies, mandrels and forging dies, where erosion dominates; do not nitride a die casting cavity surface unless the compound layer is suppressed and the depth kept below about 0.1 mm. PVD CrN or duplex coatings are the alternative for cores and pins.

### Physical properties
Density 7.80 g/cm³, E = 210 GPa at 20 °C and 180 GPa at 500 °C. Thermal conductivity ≈ 25 W/m·K at 20 °C rising to 30 W/m·K at 500 °C — about 20 % better than the cold-work 12 % Cr grades, which is part of why it survives thermal cycling. Expansion 11.5 × 10⁻⁶/K (20–200 °C), 12.6 × 10⁻⁶/K (20–600 °C).

### Weldability
Weldable for repair with care, and repair welding is routine on die casting dies. Preheat and hold at 350–450 °C, weld with a matching 1.2344-type filler (or a slightly softer H11-type filler on highly stressed cavities), keep the interpass temperature above 350 °C, cool slowly to 100 °C and temper immediately 20–30 °C below the original tempering temperature. Welding a hardened die without preheat cracks it. Laser and micro-TIG cladding are used for small cavity repairs because the heat-affected zone stays shallow.

### Machining, forming, heat treatment
Annealed machinability ≈ 55–60 % relative to 1 % C free-cutting steel: easier than the 12 % Cr cold-work grades because there is no carbide network, but the 1 % silicon makes the chip gummy and promotes built-up edge, so use positive geometry and keep speeds up. Rough machine, stress relieve at 650 °C, then finish — this is the single most skipped step and the most common cause of a die that moves during hardening. Hard milling at 44–52 HRC is standard practice for cavities with coated carbide and light radial engagement. EDM leaves a re-hardened white layer that must be stoned or ground off and the die re-tempered, otherwise the layer cracks on the first thermal cycle. Polishing to Ra < 0.2 µm is achievable; remelted material polishes noticeably better.

Applications: Aluminium, zinc and magnesium die casting dies, cores and inserts; Hot extrusion dies, die holders, mandrels and liners; Hot forging dies and trimming tools; Plastic injection moulds for abrasive or corrosive compounds; Shear blades for hot cutting, hot punches and piercing tools; Die casting shot sleeves and plunger tips; Hot-work rolls and guide tooling

Q: Is 1.2344 the same as H13?
A: Yes. 1.2344 (X40CrMoV5-1, EN ISO 4957) and AISI H13 (UNS T20813, ASTM A681) are the same steel. The ASTM composition window is wider — carbon 0.32–0.45 % against 0.37–0.43 %, molybdenum up to 1.75 % against 1.50 % — so material correctly certified as H13 can be outside the EN limits. If a drawing calls for X40CrMoV5-1, ask for the analysis, not just the trade name.

Q: What hardness should a 1.2344 die casting die be?
A: Typically 44–48 HRC for aluminium, 46–50 HRC for zinc and small inserts. Lower hardness resists heat checking, higher hardness resists washout and erosion. The hardness is a consequence of the tempering temperature, which must sit 30–50 °C above the die surface temperature — that constraint comes first and the hardness follows.

Q: What is the difference between 1.2343 and 1.2344?
A: Vanadium: 0.30–0.50 % in 1.2343 (H11) against 0.90–1.10 % in 1.2344 (H13). Less vanadium means fewer hard carbides, so 1.2343 is tougher and more resistant to heat checking, while 1.2344 holds its hardness better at temperature and resists erosion. European die makers favour 1.2343 for large aluminium dies, North American practice favours H13 almost everywhere.

Q: Why does 1.2344 have to be tempered twice?
A: The first temper transforms the retained austenite left after quenching; the fresh martensite that forms as it cools is untempered and brittle. The second temper tempers it. On blocks over 150 mm a third temper is standard. Each temper is held for at least two hours at temperature, counted from when the core reaches it.

Q: Can 1.2344 be nitrided?
A: Yes, at 480–520 °C, and it is standard practice for extrusion dies and forging tools where aluminium erosion or abrasion is the problem. It is deliberately avoided on die casting cavity surfaces, because the brittle compound layer starts thermal-fatigue cracks. If nitriding is used there, the compound layer is suppressed and depth held below about 0.1 mm.

Q: Is 1.2344 a stainless steel?
A: No. The 5 % chromium raises tempering resistance and scaling resistance, not corrosion resistance; a passive layer needs around 11 %. Dies rust in humid storage and in water-cooled channels, which is why cooling lines are treated and dies are oiled when idle.

Q: What does NADCA #207 add over EN ISO 4957?
A: EN ISO 4957 fixes the chemistry and the annealed hardness. NADCA #207 is a purchasing specification for premium die casting steel on top of that: microstructural cleanliness, maximum annealed hardness, segregation and banding limits, and a minimum impact energy measured on specified test pieces. Two blocks can both meet EN ISO 4957 and differ by a factor of three in die life; #207 is how that difference is bought.

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## 1.2363 (1.2363) [T30102] — Cold-work tool steel, 5 % Cr air-hardening
URL: https://steelstandart.com/grade/1-2363/
System: EN (European) | Family: Tool steel | Standard: EN ISO 4957 | Verified against: EN ISO 4957:2018
Aliases: X100CrMoV5, X100CrMoV5-1, X 100 CrMoV 5 1, A2, AISI A2, A2 tool steel, A2 EN, 1.2363 tool steel, SKD12, Cr5Mo1V, Kh12MF A2, BA2, K305, Rigor

1.2363 (X100CrMoV5) is the steel that sits between the two extremes of cold-work tooling. With 1 % carbon and 5 % chromium it hardens fully in still air, reaching 63–65 HRC as-quenched and settling at 58–62 HRC after a low temper. Compared with the 12 % chromium grade 1.2379 it gives up a large part of the abrasive wear resistance and gets back roughly double the toughness — and that trade is the whole reason to specify it.

The practical consequences of air hardening are what make it popular in toolrooms. There is no quench medium to manage, distortion is small and predictable, long slender tools stay straight, and a finished die can be hardened without a salt bath. Against that, the hardenable section is limited to about 100 mm and the carbide content is modest, so a punch running millions of hits on thin, hard sheet will outlast a 1.2363 tool if it is made of 1.2379 instead.

The selection rule most toolrooms use is the nature of the load, not the number of parts. Continuous cuts on thin sheet reward wear resistance — use 1.2379. Interrupted cuts, thick sheet, hard material, shock and bending loads reward toughness — use 1.2363. A punch that chips is a toughness failure and will not be fixed by a harder steel.

AISI A2, JIS SKD12 and GB Cr5Mo1V are the same steel; Böhler K305 and Uddeholm Rigor are proprietary versions. The carbon content is what separates it from the hot-work grade 1.2344, whose alloy analysis is otherwise almost identical.

Chemical composition (mass %): C 0.95 – 1.05; Si 0.1 – 0.4; Mn 0.4 – 0.8; P ≤ 0.03; S ≤ 0.03; Cr 4.8 – 5.5; Mo 0.9 – 1.2; V 0.15 – 0.35
EN ISO 4957:2018 Table 4 (X100CrMoV5). AISI A2 to ASTM A681 allows Mn up to 1.00, Mo to 1.40 and V to 0.50, so an A2 certificate can carry noticeably more vanadium than the EN grade. Note how close the analysis is to the hot-work grade 1.2344 — the difference is carbon (1.0 % against 0.40 %) and the near-absence of silicon.

Mechanical properties:
- +A soft annealed (delivery): yield — MPa; tensile ≈ 700–800 (typ.) MPa; elongation — %; hardness ≤ 241 HB
- Hardened 940–980 °C air/vacuum, as-quenched: yield — MPa; tensile — MPa; elongation — %; hardness 63–65 HRC
- Tempered 180–200 °C (2×): yield — MPa; tensile — MPa; elongation — %; hardness 60–62 HRC
- Tempered 400 °C (2×): yield — MPa; tensile — MPa; elongation — %; hardness 57–59 HRC
- Tempered 500–520 °C (2×, secondary hardening): yield — MPa; tensile — MPa; elongation — %; hardness 57–58 HRC
- Compressive yield at 60 HRC (typical): yield ≈ 2200 MPa; tensile ≈ 3400 (bend strength) MPa; elongation — %; hardness —
Specified by chemistry and annealed hardness; the hardened values are typical for a 25 mm section and come from the heat-treater, not from the standard. The number worth asking for is unnotched impact energy: roughly 40–80 J at 60 HRC against 20–40 J for 1.2379 in the same condition, measured on the same test piece. That ratio, not hardness, is the reason this grade exists.

Equivalents:
- A2 (AISI / SAE) — identical: AISI A2 (UNS T30102, ASTM A681): C 0.95–1.05, Cr 4.75–5.50, Mo 0.90–1.40, V 0.15–0.50. Same steel with a wider molybdenum and vanadium window.
- Cr5Mo1V (GB/T (China)) — identical: GB/T 1299 Cr5Mo1V is the A2 transcription.
- SKD12 (JIS (Japan)) — identical: JIS G4404 SKD12: C 0.95–1.05, Cr 4.75–5.50, Mo 0.90–1.20, V 0.15–0.35 — effectively the EN analysis.
- 1.2344 (EN (European)) — near: X40CrMoV5-1 (H13): nearly the same alloy content with 0.40 % C and 1 % Si. The low carbon makes it a hot-work steel — it cannot reach 60 HRC, but it holds 45 HRC at 550 °C.
- 1.2379 (EN (European)) — functional: X153CrMoV12 (D2): 12 % Cr and 1.5 % C give far higher abrasive wear resistance and roughly half the toughness. The pair is chosen against each other for every blanking die — see the comparison below.
- 1.2842 (EN (European)) — functional: 90MnCrV8 (O2): oil-hardening, cheaper, similar toughness but much lower wear resistance and more distortion. Used for short runs and simple tools.
- 1.2767 (EN (European)) — functional: 45NiCrMo16: the nickel cold-work steel for heavy blanking and cold forging where impact dominates — tougher still, at 54–58 HRC.
- 1.2510 (EN (European)) — functional: X100CrMoV5 (A2): air-hardening, far less distortion and better wear resistance at a higher price. The standard upgrade when oil-quench distortion becomes the problem.
- Kh6VF (GOST (Russia/CIS)) — functional: GOST 5950 has no direct 5 % Cr air-hardening grade; Kh6VF (C 1.05–1.15, Cr 5.5–6.5, W 1.1–1.5, V 0.5–0.8) fills the same slot with tungsten instead of molybdenum.

Superseded names:
- X100CrMoV5-1 — DIN 17350 (withdrawn): Same number 1.2363; EN ISO 4957 shortened the name to X100CrMoV5.
- BA2 — BS 4659 (withdrawn): The British designation.
- Z100CDV5 — NF A 35-590: The French designation.
- K305 / Rigor — Böhler / Uddeholm trade names: Cryodur 2363, Thyrodur 2363.

Product forms: flat bar and round bar (annealed); ground flat stock (precision); blocks and plate; forgings
Tolerances: annealed flat and round: supplier tolerances, typically +1/+3 mm machining allowance; ground flat stock: DIN 59350 precision sizes, +0.1/+0.3 mm on thickness

### 1.2363 hardness
Annealed ≤ 241 HB. As-quenched 63–65 HRC; working hardness 58–62 HRC after a 180–200 °C temper. There is a weak secondary-hardening plateau around 500–520 °C holding 57–58 HRC, which allows PVD coating without dropping below 57 HRC.

### Heat treatment
Soft anneal 800–840 °C, slow cool. Stress relieve 650 °C after rough machining. Preheat 650 °C, austenitise 940–980 °C (20–30 min at temperature), cool in still air, forced air or vacuum gas; sections above 50 mm benefit from forced cooling to avoid grain-boundary carbide. Temper twice for at least 2 h at 180–200 °C for maximum hardness, or 500–520 °C where coating or extra dimensional stability is needed. Ms ≈ 180 °C.

### Air hardening and distortion
The whole appeal: typical size change after hardening and a low temper is −0.02 to +0.05 %, against the much larger and less predictable movement of an oil-quenched grade such as 1.2510. Long punches, thin blades and finished dies can be hardened without warping. Hardenable section is about 100 mm in air; above that the core drops below 58 HRC.

### Wear resistance and toughness
Carbide volume is around 6–8 %, against roughly 15 % in 1.2379 — abrasive wear resistance is clearly lower. Unnotched impact energy at 60 HRC is about 40–80 J against 20–40 J for 1.2379 on the same test piece. The 5 % Cr matrix is also less prone to chipping at sharp edges, which is why 1.2363 survives fine-blanking and thick-sheet work that chips D2 punches.

### Physical properties
Density 7.86 g/cm³, E = 210 GPa, thermal conductivity ≈ 25 W/m·K, expansion 11.5 × 10⁻⁶/K (20–100 °C), 12.3 × 10⁻⁶/K (20–400 °C). Maximum service temperature about 200 °C before hardness starts to fall.

### Weldability
Poor weldability, repair only. Weld in the annealed condition where possible; otherwise preheat to 300–400 °C, TIG with a matching or 1.2363-type filler, keep interpass above 300 °C, cool slowly and re-temper at the original tempering temperature immediately. The air-hardening character means the heat-affected zone hardens even on slow cooling, so an un-tempered repair will crack.

### Machining, forming, heat treatment
Annealed machinability ≈ 45–55 % relative to 1 % C free-cutting steel — easier than the 12 % Cr grades because there is far less carbide, and this is a real cost advantage on deep cavities. Carbide or coated carbide tooling, moderate speeds. Rough machine, stress relieve at 650 °C, then finish. Grinding is straightforward with conventional wheels; grinding cracks are much less of a problem than on 1.2379. Hard machining at 58–62 HRC with CBN is practical. EDM is routine; remove the white layer and re-temper. Surface treatments: nitriding at 480–520 °C, PVD TiN/TiCN/CrN after a 510 °C temper.

Applications: Blanking and piercing punches for thick or high-strength sheet; Fine-blanking tools and shear blades for interrupted cuts; Cold forming, swaging and coining dies; Thread-rolling and knurling tools; Long slender punches and trim steels where distortion must stay small; Plastic-mould inserts and gauges; Woodworking and paper knives, slitter blades

Q: Is 1.2363 the same as A2?
A: Yes. 1.2363 (X100CrMoV5, EN ISO 4957) and AISI A2 (UNS T30102, ASTM A681) are the same air-hardening 5 % chromium cold-work steel. ASTM allows more manganese, molybdenum and vanadium, so an A2 heat can be slightly more wear resistant and slightly less tough than an EN heat.

Q: 1.2363 or 1.2379 — which one should I use?
A: Choose by load, not by production volume. 1.2379 (D2) wins on continuous cuts in thin sheet where abrasive wear ends the tool. 1.2363 (A2) wins when the tool sees shock, interrupted cuts, thick or high-strength sheet, or has slender sections that chip — its toughness is roughly double at the same hardness. A punch that chips rather than wears is telling you to move to 1.2363.

Q: What hardness does 1.2363 reach?
A: 63–65 HRC as-quenched, and 58–62 HRC in service after tempering at 180–200 °C. Tempering at 500–520 °C holds 57–58 HRC and is used before PVD coating or where maximum dimensional stability is needed.

Q: Does 1.2363 really harden in air?
A: Yes, in still air up to about 50 mm and in forced air or vacuum gas up to roughly 100 mm section. That is the grade's main advantage: no quench medium, small and predictable distortion, and finished tools can be hardened. Above 100 mm the core falls below 58 HRC and a different grade is needed.

Q: Is 1.2363 stainless?
A: No. Five per cent chromium improves scaling and tempering resistance but is far short of the roughly 11 % needed for a passive layer, and much of it is tied into carbides. The steel rusts in humid storage and must be oiled.

Q: What is the maximum working temperature of 1.2363?
A: About 200 °C for a tool that must hold 58 HRC. Above that it tempers in service. For warm or hot work the almost identically alloyed 1.2344 is the grade to use — it carries only 0.40 % carbon, so it tops out near 52 HRC but keeps about 45 HRC at 550 °C.

---

## 1.2379 (1.2379) — Cold-work tool steel, 12 % Cr ledeburitic
URL: https://steelstandart.com/grade/1-2379/
System: EN (European) | Family: Tool steel | Standard: EN ISO 4957 | Verified against: EN ISO 4957:2018
Aliases: X153CrMoV12, X155CrVMo12-1, X 155 CrVMo 12 1, D2 EN, 1.2379 tool steel, K110, Sverker 21, D2, AISI D2, D2 tool steel, SKD11, Cr12Mo1V1, Kh12MF, BD2

1.2379 (X153CrMoV12) is the ledeburitic 12 % chromium cold-work steel known everywhere as D2. With 1.5 % carbon and 12 % chromium it solidifies with a network of hard chromium carbides (M₇C₃) that, after hardening to 58–62 HRC, give the best wear resistance of any conventional tool steel below the powder-metallurgy grades. Molybdenum and vanadium refine the carbides and allow air or vacuum hardening with minimal distortion — the reason 1.2379 is the default steel for blanking and punching dies, shear blades and forming rolls.

Its weaknesses are the ones that come with coarse carbides: moderate toughness, difficult grinding, and heavy machining allowances in the annealed state (≤ 255 HB but abrasive). Tempering at 500–530 °C gives secondary hardening and allows PVD coating (TiN, TiCN) without losing hardness; the low-temperature temper (180–220 °C) gives maximum hardness for short-run tools.

AISI D2, JIS SKD11, GB Cr12Mo1V1 and BS BD2 are the same steel; Böhler K110, Uddeholm Sverker 21 and Buderus Cryodur 2379 are proprietary versions. The powder-metallurgy alternatives (1.2380 / Vanadis 4E, K390) are cross-referenced as functional upgrades.

Chemical composition (mass %): C 1.45 – 1.6; Si 0.1 – 0.6; Mn 0.2 – 0.6; P ≤ 0.03; S ≤ 0.03; Cr 11 – 13; Mo 0.7 – 1; V 0.7 – 1
EN ISO 4957:2018 Table 4 (X153CrMoV12). The former DIN name X155CrVMo12-1 is the same steel. AISI D2 allows C 1.40–1.60, Mo 0.70–1.20, V ≤ 1.10, Co ≤ 1.00.

Mechanical properties:
- +A soft annealed (delivery): yield — MPa; tensile ≈ 750–850 (typ.) MPa; elongation — %; hardness ≤ 255 HB
- Hardened 1020–1040 °C oil/air, as-quenched: yield — MPa; tensile — MPa; elongation — %; hardness 62–64 HRC
- Tempered 180–220 °C (1×): yield — MPa; tensile — MPa; elongation — %; hardness 60–62 HRC
- Tempered 500–530 °C (2×, secondary hardening): yield — MPa; tensile — MPa; elongation — %; hardness 58–60 HRC
- Tempered 550 °C (2×): yield — MPa; tensile — MPa; elongation — %; hardness 55–57 HRC
- Compressive yield at 60 HRC (typical): yield ≈ 2200 MPa; tensile ≈ 2500 (bend strength ≈ 3000) MPa; elongation — %; hardness —
Tool steels are specified by chemistry and annealed hardness only; hardness after heat treatment is the working property. Values are typical for a 25 mm section. Toughness (unnotched impact) ≈ 20–40 J at 60 HRC — moderate; 1.2379 is chosen for wear, not shock.

Equivalents:
- D2 (AISI / SAE) — identical: AISI D2 (UNS T30402, ASTM A681): C 1.40–1.60, Cr 11–13, Mo 0.70–1.20, V 0.50–1.10. Same steel; 1.2379 has a slightly tighter V/Mo window.
- BD2 (BS (superseded British)) — identical: BS 4659 BD2.
- Cr12Mo1V1 (GB/T (China)) — identical: GB/T 1299 Cr12Mo1V1 (D2 type): C 1.40–1.60, Cr 11–13, Mo 0.70–1.20, V 0.50–1.10. Cr12MoV is the older lower-Mo Chinese grade.
- SKD11 (JIS (Japan)) — identical: JIS G4404 SKD11: C 1.40–1.60, Cr 11–13, Mo 0.80–1.20, V 0.20–0.50 — vanadium lower; hardenability and wear resistance close.
- 1.2436 (EN (European)) — near: X210CrW12 (D6): tungsten-bearing 12 % Cr, slightly higher wear resistance, lower toughness.
- Kh12MF (GOST (Russia/CIS)) — near: GOST 5950 Kh12MF: C 1.45–1.65, Cr 11–12.5, Mo 0.40–0.60, V 0.15–0.30 — lower Mo and V.
- 1.2363 (EN (European)) — functional: X100CrMoV5 (A2): 5 % Cr air-hardening steel with better toughness, lower wear resistance.
- 1.2842 (EN (European)) — functional: 90MnCrV8 (O2) oil-hardening steel for less demanding dies.
- 1.2510 (EN (European)) — functional: X153CrMoV12 (D2): many times the abrasive wear resistance, air hardening, higher cost. Used where tool life rather than cost or edge sharpness governs.

Superseded names:
- X155CrVMo12-1 — DIN 17350 (withdrawn): Same number 1.2379; renamed X153CrMoV12 in EN ISO 4957.
- X210Cr12 (1.2080) — DIN 17350: The older 2 % C / 12 % Cr steel (D3) it replaced — harder but more brittle.
- BD2 — BS 4659
- Z160CDV12 — NF A 35-590
- K110 — Böhler trade name: Sverker 21 (Uddeholm), Cryodur 2379 (Buderus), Thyrodur 2379.

Product forms: flat bar and round bar (annealed); plate and blocks; ground flat stock (precision); forgings
Tolerances: annealed flat/round: EN ISO 4957 Annex / supplier tolerances (typically +1/+3 mm oversize for machining); ground flat stock: DIN 59350 / ISO 4957 precision

### 1.2379 hardness
Annealed ≤ 255 HB; as-quenched 62–64 HRC; working hardness 58–62 HRC after tempering. Secondary hardening peak 60–61 HRC at ~520 °C (for PVD coating), 55–57 HRC at 550 °C.

### Heat treatment
Soft anneal 800–850 °C, slow cool (≤ 10 K/h to 600 °C). Stress relieve 600–650 °C. Harden 1020–1040 °C (preheat 650 and 850 °C), oil, air or vacuum gas quench; hold 20–40 min at temperature. Temper twice for ≥ 2 h: 180–220 °C for maximum hardness, or 500–540 °C for secondary hardening and coating. Deep freeze (−80 °C) after quenching reduces retained austenite. Ms ≈ 200 °C.

### Dimensional change
Air/vacuum hardening from 1030 °C with 520 °C temper: typically +0.05 to +0.10 % length change; low-temperature temper: 0 to +0.05 %. Allow grinding stock of 0.15–0.30 mm.

### Wear resistance and toughness
Abrasive wear resistance among the highest of conventional cold-work steels (carbide volume ≈ 15 %); adhesive wear moderate. Unnotched impact ≈ 20–40 J at 60 HRC — choose 1.2363 (A2) or 1.2767 for shock loads.

### Physical properties
Density 7.70 g/cm³, E = 210 GPa, thermal conductivity ≈ 20 W/m·K, expansion 10.5 × 10⁻⁶/K (20–100 °C), 11.5 × 10⁻⁶/K (20–500 °C).

### Weldability
Poor weldability. Repair welding only: preheat 300–450 °C (or weld in the annealed state), TIG with matching or 1.2379-type rods, peen, and re-temper immediately at the previous tempering temperature. Hardened tools should be pre-warmed and post-tempered; cracks are common without these steps.

### Machining, forming, heat treatment
Machinability in the annealed state ≈ 30–40 % (abrasive carbides): carbide tooling, moderate speeds, generous allowances. Hard machining after hardening is possible with CBN/ceramic at 58–62 HRC. Grinding requires soft, open wheels and light passes to avoid grinding cracks (dry grinding forbidden). EDM (wire or sink) is the standard route for complex dies; remove the white layer by grinding or by a further temper. Surface treatments: PVD TiN/TiCN/CrN after 520 °C temper, nitriding (500–520 °C) for extra surface hardness.

Applications: Blanking, punching and fine-blanking dies for sheet up to ~6 mm; Shear blades, slitting knives, rotary cutters; Cold forming, drawing and bending dies, thread-rolling dies; Profile rolls and roll-forming tools; Plastic-moulding tools for abrasive filled polymers (with PVD); Wear parts, gauges, measuring tools; Ceramic and powder-compaction dies

Q: Is 1.2379 the same as D2?
A: Yes. 1.2379 (X153CrMoV12, EN ISO 4957) and AISI D2 (T30402) share the 1.5 % C / 12 % Cr / 1 % Mo / 1 % V analysis; the EN specification is marginally tighter on Mo and V. JIS SKD11 and GB Cr12Mo1V1 are also identical for tooling purposes.

Q: What hardness does 1.2379 reach?
A: 62–64 HRC as-quenched, 58–62 HRC in service after tempering. Tempering at 500–540 °C gives a secondary-hardening peak of about 60 HRC and is the standard cycle before PVD coating.

Q: Is 1.2379 stainless?
A: No. Although it contains 12 % chromium, most of it is tied up in carbides, leaving too little in solution for a passive layer. It rusts in humid storage and must be oiled.

Q: 1.2379 or 1.2363 (A2) — which should I use?
A: 1.2379 for maximum wear resistance and long runs on thin sheet; 1.2363 when the tool sees impact, thick sheet or interrupted cuts, because its 5 % Cr structure is roughly twice as tough. Both air-harden with low distortion.

Q: Can 1.2379 be nitrided or coated?
A: Yes. Temper at ≥ 520 °C first, then PVD (TiN, TiCN, CrN at 450–500 °C) or gas/plasma nitride at 500–520 °C. Coating extends punch life several-fold on galvanized or stainless sheet.

---

## 1.2510 (1.2510) [T31501] — Cold-work tool steel, oil-hardening manganese-chromium-tungsten
URL: https://steelstandart.com/grade/1-2510/
System: EN (European) | Family: Tool steel | Standard: EN ISO 4957 | Verified against: EN ISO 4957:2018
Aliases: 100MnCrW4, 100 MnCrW 4, O1, AISI O1, O1 tool steel, O1 EN, 1.2510 tool steel, SKS3, SKS31, 9CrWMn, 9KhVG, BO1, K460, Arne

1.2510 (100MnCrW4) is the classic oil-hardening toolroom steel, AISI O1 — a 1 % carbon steel with just enough manganese, chromium and tungsten to harden right through in oil instead of water. It is the cheapest tool steel that reaches a dependable 60 HRC, it takes and holds a very sharp edge, and it machines and grinds more easily than any of the alloy-rich grades. For hand tools, small dies, gauges, reamers and knives it remains the default after a century.

The limits follow directly from the lean analysis. Through-hardening stops at about 30 mm in a plain oil quench, so a large block is hard on the outside and softer in the middle. There is no secondary hardening: hardness drops in a straight line above 200 °C and the steel is finished as a cutting tool by about 250 °C, which rules out any warm work and most coating cycles. And an oil quench from 800 °C moves the part — more than an air-hardening grade and much less predictably, so complex shapes crack and slender tools bow.

That makes the selection question simple. Use 1.2510 for small, simple, sharp tools where cost and edge quality matter. Move to 1.2363 (A2) when distortion must be controlled or the section is large, and to 1.2379 (D2) when abrasive wear ends the tool. The step from 1.2510 to 1.2363 typically doubles the price of the blank and removes most of the heat-treatment risk.

AISI O1, JIS SKS3, GB 9CrWMn and GOST 9KhVG are the same steel; Böhler K460 and Uddeholm Arne are proprietary versions. It is most often bought as ground flat stock in precision thicknesses, ready to machine and harden without further grinding.

Chemical composition (mass %): C 0.9 – 1.05; Si 0.1 – 0.4; Mn 1 – 1.2; P ≤ 0.03; S ≤ 0.03; Cr 0.5 – 0.7; W 0.5 – 0.7; V 0.05 – 0.15
EN ISO 4957:2018 Table 4 (100MnCrW4). AISI O1 to ASTM A681 is a looser specification: C 0.85–1.00, Mn 1.00–1.40, Cr 0.40–0.70, W 0.40–0.60, V ≤ 0.30. The manganese is the active ingredient — it is what makes a 1 % carbon steel harden right through in oil rather than needing water.

Mechanical properties:
- +A soft annealed (delivery): yield — MPa; tensile ≈ 650–750 (typ.) MPa; elongation — %; hardness ≤ 229 HB
- Hardened 790–820 °C oil, as-quenched: yield — MPa; tensile — MPa; elongation — %; hardness 63–65 HRC
- Tempered 180 °C: yield — MPa; tensile — MPa; elongation — %; hardness 61–63 HRC
- Tempered 200–250 °C: yield — MPa; tensile — MPa; elongation — %; hardness 58–60 HRC
- Tempered 300 °C: yield — MPa; tensile — MPa; elongation — %; hardness 54–56 HRC
- Tempered 400 °C: yield — MPa; tensile — MPa; elongation — %; hardness 48–50 HRC
Chemistry and annealed hardness are the only specified properties. Hardened values are typical for a 25 mm section quenched in oil; a 60 mm section loses 2–4 HRC at the core. Note how fast hardness falls above 250 °C — there is no secondary-hardening reaction in this grade, so every degree of tempering costs hardness directly.

Equivalents:
- O1 (AISI / SAE) — identical: AISI O1 (UNS T31501, ASTM A681): C 0.85–1.00, Mn 1.00–1.40, Cr 0.40–0.70, W 0.40–0.60. The same oil-hardening steel; the ASTM carbon window starts lower, so an O1 bar can be marginally softer at the same temper.
- 9CrWMn (GB/T (China)) — identical: GB/T 1299 9CrWMn is the direct O1 transcription; 9Mn2V is the cheaper manganese-only version.
- 9KhVG (GOST (Russia/CIS)) — identical: GOST 5950 9KhVG: C 0.85–0.95, Mn 0.90–1.20, Cr 0.50–0.80, W 0.50–0.80.
- SKS3 (JIS (Japan)) — identical: JIS G4404 SKS3: C 0.90–1.00, Mn 0.90–1.20, Cr 0.50–1.00, W 0.50–1.00. SKS31 is the higher-tungsten variant.
- 1.2842 (EN (European)) — near: 90MnCrV8 (O2): the same idea without tungsten, 0.90 % C and 2 % Mn. Slightly lower hardness, cheaper, somewhat more distortion — the commonest substitute when 1.2510 is unavailable.
- 1095 (AISI / SAE) — functional: Plain 0.95 % carbon steel: the same hardness at the surface but no hardenability — it must be water quenched and does not harden through beyond a few millimetres.
- 1.2363 (EN (European)) — functional: X100CrMoV5 (A2): air-hardening, far less distortion and better wear resistance at a higher price. The standard upgrade when oil-quench distortion becomes the problem.
- 1.2379 (EN (European)) — functional: X153CrMoV12 (D2): many times the abrasive wear resistance, air hardening, higher cost. Used where tool life rather than cost or edge sharpness governs.

Superseded names:
- 100MnCrW4 — DIN 17350 (withdrawn): Same number and name; only the governing standard changed.
- BO1 — BS 4659 (withdrawn): The British designation of the same steel.
- 90MnWCrV5 — older German practice: A closely related oil-hardening grade, 1.2516, with slightly lower carbon.
- K460 / Arne — Böhler / Uddeholm trade names: Cryodur 2510, Thyrodur 2510, Olympic O1.

Product forms: flat bar and round bar (annealed); ground flat stock (precision); drawn and peeled bar; plate up to about 100 mm
Tolerances: annealed flat and round: supplier tolerances, typically +1/+3 mm machining allowance; ground flat stock: DIN 59350 precision sizes — the usual way this grade is bought

### 1.2510 hardness
Annealed ≤ 229 HB. As-quenched 63–65 HRC from an oil quench — the highest as-quenched hardness of the common cold-work grades. Working hardness 58–62 HRC after tempering at 180–250 °C. At 300 °C it is down to 54–56 HRC and at 400 °C to 48–50 HRC.

### Heat treatment
Soft anneal 710–750 °C, slow cool. Stress relieve 650 °C after rough machining. Preheat 500–600 °C, austenitise 790–820 °C (10–20 min at temperature — short, because grain coarsening is a real risk at this low alloy content), quench in oil to 50–70 °C, then temper immediately for 1–2 h at 180–250 °C. Do not let the part reach room temperature before tempering; quench cracks in 1.2510 almost always happen in that gap. Ms ≈ 220 °C.

### Hardenable section and the oil quench
Full hardness through about 25–30 mm in oil; by 60 mm the core is 4 HRC or more below the surface. Hardening a large or complex part means either accepting a soft core or interrupting the quench, which raises the distortion further. Size change after hardening and a 200 °C temper is typically +0.05 to +0.15 % and direction depends on geometry — allow grinding stock of 0.3 mm or more on a part that must hold tolerance.

### Edge quality and wear resistance
The fine, evenly distributed carbide of a plain 1 % carbon matrix takes a cleaner and sharper edge than any high-carbide grade; this is why knives, plane irons and paper knives are still made from it. Abrasive wear resistance, however, is the lowest of the common tool steels — carbide volume is only 2–3 % against roughly 15 % in 1.2379. On an abrasive sheet or a long production run it will be worn out while a D2 tool is still cutting.

### No secondary hardening
Unlike the 5 % and 12 % Cr grades, 1.2510 has no secondary-hardening peak: tempering resistance ends around 200 °C and hardness falls monotonically above it. The practical limits: maximum service temperature about 200 °C; PVD coating at 450–500 °C is impossible without ruining the tool; nitriding is likewise out of reach.

### Physical properties
Density 7.80 g/cm³, E = 210 GPa, thermal conductivity ≈ 33 W/m·K — markedly higher than the alloy-rich grades. Expansion 11.5 × 10⁻⁶/K (20–100 °C), 13.0 × 10⁻⁶/K (20–300 °C).

### Weldability
Poor weldability and rarely welded. If a repair is unavoidable: anneal first, or preheat to 250–350 °C, TIG with a matching filler, keep interpass temperature up, cool slowly in vermiculite and re-temper immediately at the original temperature. The high carbon content means the heat-affected zone is brittle martensite on any cooling rate above very slow.

### Machining, forming, heat treatment
The easiest of the cold-work tool steels: annealed machinability ≈ 85–90 % relative to 1 % C free-cutting steel, with HSS tooling entirely practical. That is a large part of its attraction for one-off toolroom work. Grinding is straightforward with conventional aluminium-oxide wheels and the low carbide content means little wheel loading. Rough machine, stress relieve at 650 °C, finish, then harden with 0.3 mm grinding stock. EDM is possible but the re-hardened white layer is brittle at this carbon level and must be removed. Not suitable for hard machining — at 62 HRC only grinding works.

Applications: Blanking, piercing and trimming dies for short runs and thin sheet; Gauges, jigs, templates and measuring tools; Reamers, broaches, taps, thread chasers and milling cutters for light work; Woodworking tools, plane irons, chisels, paper and leather knives; Shear blades for thin sheet, slitter knives; Punches, stamps and marking tools; Spindles, guide bushes and simple wear parts

Q: Is 1.2510 the same as O1?
A: Yes. 1.2510 (100MnCrW4, EN ISO 4957) and AISI O1 (UNS T31501, ASTM A681) are the same oil-hardening cold-work tool steel. The ASTM window starts at 0.85 % carbon against 0.90 % for the EN grade and allows up to 1.40 % manganese, so an O1 bar may be slightly deeper hardening and slightly softer at the surface.

Q: What hardness does 1.2510 reach?
A: 63–65 HRC as-quenched from oil, and 58–62 HRC in service after tempering at 180–250 °C. It has the highest as-quenched hardness of the common cold-work grades, but no tempering resistance: by 300 °C it is down to 55 HRC.

Q: How thick a section will 1.2510 harden through?
A: About 25–30 mm in a plain oil quench. At 60 mm the core is typically 4 HRC or more below the surface. For a large block that must be hard throughout, use an air-hardening grade such as 1.2363 (A2) or 1.2379 (D2).

Q: 1.2510 or 1.2363 — which should I use?
A: 1.2510 for small, simple tools where cost, machinability and edge sharpness matter and distortion can be ground out afterwards. 1.2363 when the part is large, slender or complex, when the tolerance after hardening must hold, or when the tool will see abrasive wear. The blank costs roughly twice as much and most of the heat-treatment risk disappears.

Q: Can 1.2510 be nitrided or PVD coated?
A: No. Both processes run at 450–520 °C, well above the point at which this steel starts to lose hardness — the tool would come out of the coating chamber at about 45 HRC. Coating a 1 % carbon oil-hardening steel requires moving to a grade with secondary hardening, such as 1.2363 or 1.2379.

Q: Why does 1.2510 crack during hardening?
A: Almost always because the part was allowed to cool to room temperature in the oil, or because tempering was delayed. Pull the part out of the oil at 50–70 °C — while it is still too warm to hold — and put it straight into the tempering furnace. Sharp internal corners, abrupt section changes and un-relieved machining stresses are the other causes; stress relieve at 650 °C before the final cut.

Q: Is 1.2510 a good knife steel?
A: For a working knife, yes, and it has been used for exactly that for a century: it takes a very fine edge because the carbides are small and evenly spread, it hardens to 60 HRC without exotic equipment, and it is easy to grind and re-sharpen. It is not stainless and has low abrasive wear resistance, so the edge needs more frequent attention and the blade needs oiling.

---

## 1.2738 (1.2738) — Plastic mould steel, nickel-alloyed, pre-hardened
URL: https://steelstandart.com/grade/1-2738/
System: EN (European) | Family: Tool steel | Standard: EN ISO 4957 | Verified against: EN ISO 4957:2018
Aliases: 40CrMnNiMo8-6-4, 40 CrMnNiMo 8 6 4, P20+Ni, P20 Ni, AISI P20+Ni, 1.2738 tool steel, 1.2738 mould steel, 1.2738HH, 1.2738 HH, M238, Impax Supreme, GS-738, 3Cr2MnNiMo, 3Cr2NiMnMo

1.2738 is 1.2311 with about 1 % nickel, and that single addition is bought for one reason: it keeps the hardness in the middle of a big block. A mould plate 600 mm thick cannot be cooled fast enough at its core for a nickel-free analysis to reach 30 HRC there; the nickel shifts the transformation curves far enough to the right that the core transforms to the same tempered structure as the surface. A 1.2311 block of that size reads 240–270 HB in the middle. A 1.2738 block reads 275–315 HB.

That is the whole engineering argument, and it sets the selection rule precisely. Below about 250 mm section, 1.2738 offers nothing over 1.2311 and costs 15–25 % more. Above 400 mm, it is the only one of the two that works. Large automotive bumper and dashboard moulds, appliance housings, crate and pallet tools and thick-walled blow moulds are where it belongs.

The nickel brings two secondary effects worth knowing. It raises the impact energy at the same hardness, so a deep cavity with sharp internal corners is less likely to crack in service — and in a mould base the dominant load is clamping and cycling, not wear, so toughness is the property that ends the tool. It also makes repair welding more exacting: a nickel-alloyed weld pool is more sensitive to hydrogen and the filler must match, or the repair shows up after polishing as a different shade of grey.

A note on the designation. 1.2738HH is not a different steel. It is the same analysis delivered at 38–42 HRC instead of 29–34 HRC, achieved by tempering lower. It gives a harder cavity surface and better texture retention for long production runs, in exchange for slower machining and much less latitude for later stress relief — and its tempering temperature is now close to the nitriding temperature, so the two cannot always be combined.

Chemical composition (mass %): C 0.35 – 0.45; Si 0.2 – 0.4; Mn 1.3 – 1.6; P ≤ 0.03; S ≤ 0.03; Cr 1.8 – 2.1; Mo 0.15 – 0.25; Ni 0.9 – 1.2
EN ISO 4957:2018, plastic mould steels (40CrMnNiMo8-6-4). The analysis is 1.2311 with nickel added at 0.90–1.20 %; nothing else changes. AISI has no separate designation — the material is sold as P20+Ni or P20 modified, and the nickel content on a North American certificate may be anywhere from 0.5 to 1.2 %.

Mechanical properties:
- +QT as delivered, section ≤ 400 mm: yield ≈ 850–950 MPa; tensile 1000–1150 MPa; elongation ≈ 13 %; hardness 280–325 HB (29–34 HRC)
- +QT as delivered, section 400–700 mm (core): yield ≈ 800–900 MPa; tensile 980–1100 MPa; elongation ≈ 13 %; hardness 275–315 HB (28–33 HRC)
- +QT HH variant as delivered: yield ≈ 1050–1150 MPa; tensile 1250–1400 MPa; elongation ≈ 11 %; hardness 360–400 HB (38–42 HRC)
- Nitrided surface (480–520 °C): yield — MPa; tensile — MPa; elongation — %; hardness 650–750 HV
- Flame or induction hardened surface: yield — MPa; tensile — MPa; elongation — %; hardness 52–56 HRC
- Impact energy at delivery hardness, longitudinal (typical): yield — MPa; tensile — MPa; elongation — %; hardness 25–40 J (KV, +20 °C)
EN ISO 4957 fixes the chemistry and the delivery hardness band only; tensile and impact figures are the usual correlation for this class at that hardness, not standardised minima. The figure that should be on the order is **the hardness and where it is measured** — on a 700 mm block the difference between a surface reading and a mid-thickness reading is what distinguishes a well-made block from a badly quenched one.

Equivalents:
- 3Cr2MnNiMo (GB/T (China)) — identical: GB/T 1299 3Cr2MnNiMo (also written 3Cr2NiMnMo) is the direct transcription: C 0.32–0.40, Mn 1.10–1.50, Cr 1.70–2.00, Ni 0.85–1.15, Mo 0.25–0.40.
- P20 (AISI / SAE) — near: AISI P20 modified with nickel is sold as P20+Ni and is the direct counterpart. Base P20 (C 0.28–0.40, Mn 0.60–1.00, Mo 0.30–0.55, no nickel) does not hold the band in large sections. North American certificates do not standardise the nickel level — ask for the analysis.
- 1.2311 (EN (European)) — near: 40CrMnMo7: the same steel without nickel. Identical in use up to about 250 mm section and cheaper; above 400 mm its core hardness drops out of the band, which is exactly the gap 1.2738 fills.
- 1.2311 (EN (European)) — near: 40CrMnNiMo8-6-4: 1.2311 with 1 % nickel added. Holds 28–34 HRC in blocks up to 600 mm and above, where 1.2311 drops below 28 HRC in the core. The default for large moulds.
- 40KhNM (GOST (Russia/CIS)) — near: GOST 4543 40KhNMA: C 0.37–0.44, Cr 0.60–0.90, Ni 1.25–1.75, Mo 0.15–0.25 — a nickel-chromium-molybdenum steel supplied quenched and tempered; less manganese and chromium than 1.2738.
- 4140 (AISI / SAE) — functional: The general-purpose quenched and tempered engineering steel at a similar hardness. Sold as bar and plate without mould-block sizes, cleanliness grading or guaranteed through-hardness, so it is used for frames and fixtures rather than cavities.
- 1.2312 (EN (European)) — functional: 40CrMnMoS8-6: free-machining mould base steel. Cuts faster and costs less, but the sulphide stringers make it unsuitable for polishing, texturing or welding and it has no nickel, so it is used for plates rather than cavities.
- 1-2083 (EN (European)) — functional: X40Cr14: the stainless mould steel for corrosive polymers and cooling-channel corrosion, hardened to 48–52 HRC. Different purpose — it is bought for corrosion resistance, not for section size.
- 1.2344 (EN (European)) — functional: X40CrMoV5-1 (H13) at 48–52 HRC: the choice when the mould runs hot or abrasively filled polymers erode the cavity. Far more expensive, must be heat treated after machining, and an unnecessary step for ordinary thermoplastics.

Superseded names:
- 40CrMnNiMo8-6-4 — DIN 17350 (withdrawn): Same number and name; the plastic mould steels moved into EN ISO 4957.
- GS-738 — older German trade usage: Still found on older mould drawings.
- M238 / Impax Supreme — Böhler / Uddeholm trade names: Thyroplast 2738, Cryodur 2738. Impax Supreme and M238 are remelted with controlled cleanliness; ordinary 1.2738 is not.
- 1.2738HH — supplier designation: Not a separate EN grade — the same analysis delivered at 38–42 HRC instead of 29–34 HRC.

Product forms: large blocks, pre-hardened and tempered (+QT); heavy plate, pre-hardened; machined and ground mould plates; +QT ESR / remelted quality for optical and textured cavities
Tolerances: pre-hardened blocks: supplier tolerances, normally +3/+8 mm per face on large sizes; plate thickness: EN 10029 class B; six-sided machined blocks: typically ±0.1 mm on size and 0.05 mm/m on parallelism, supplier specification

### 1.2738 hardness by section
Delivered 280–325 HB (29–34 HRC) and uniform out to roughly 400 mm. From 400 to 700 mm the core typically reads 275–315 HB — within a few points of the surface, which is the entire point of the grade. Compare that with 1.2311, where the same 700 mm block falls to 240–270 HB in the middle. Specify where the hardness is to be checked when ordering large blocks; a surface reading on a poorly quenched block tells you nothing about the cavity depth.

### The HH variant
1.2738HH is the same steel tempered to 360–400 HB (38–42 HRC). It resists surface deformation and holds photo-etched textures longer on runs above a million cycles, and it is sold mainly as remelted material. Costs: machinability drops noticeably, drilling and tapping become slower, and because the tempering temperature is now around 500 °C, a later stress-relief or nitriding cycle has far less headroom. Use it where the cavity surface itself is the wearing part, not as a general upgrade.

### Toughness and why it matters here
At delivery hardness, longitudinal impact energy is typically 25–40 J (KV, +20 °C), roughly a third higher than the nickel-free grade at the same hardness, and the transverse-to-longitudinal ratio is better. In a large mould the failure mode is cracking from a sharp internal corner, a cooling-line intersection or an ejector hole under repeated clamping — not wear. Toughness, not hardness, is what keeps a 600 mm plate in service.

### Nitriding and surface treatment
Gas or plasma nitriding at 480–520 °C gives 650–750 HV to 0.2–0.4 mm with no distortion; the nickel makes no practical difference to the result. Standard on slides, guide bushes, gate inserts and ejector plates. Flame or induction hardening reaches 52–56 HRC locally. Hard chrome, nickel plating and PVD CrN are all used on cavities for release and wear. For the HH variant, check the tempering temperature against the nitriding temperature before committing — there may be only 20–30 °C of margin.

### Polishing, texturing and cleanliness
Polishes to Ra < 0.05 µm and etches cleanly, but at high polish the limit is the inclusion content, not the steel's analysis. Ordinary continuously cast 1.2738 shows pinholes on a mirror cavity; remelted material (ESR) is what is specified for optical, high-gloss or fine-textured surfaces and is sold under names such as Impax Supreme and M238. For a textured interior panel mould the difference is visible on the moulded part, not just on the steel.

### Physical properties
Density 7.85 g/cm³, E = 205 GPa, thermal conductivity ≈ 33 W/m·K at 20 °C. Expansion 12.4 × 10⁻⁶/K (20–200 °C), 13.3 × 10⁻⁶/K (20–400 °C). The conductivity is high for an alloy steel and is the reason mould cycle times are set by the cooling layout rather than by the steel.

### Weldability
Weldable and routinely repair welded, but less forgiving than the nickel-free grade. Preheat to 250–325 °C and hold it, use a matching nickel-bearing filler — a mismatched filler polishes to a visibly different shade and etches differently, which ruins a textured cavity — keep interpass temperature above 250 °C, cool slowly under insulation and temper at 500–540 °C, below the original tempering temperature. Hydrogen control matters more here than in 1.2311: dry the filler and keep the joint clean. Micro-TIG and laser cladding are preferred for cavity corrections because the heat-affected zone stays shallow and no full-block temper is needed; on an HH block laser cladding is effectively the only option, because there is no room to temper afterwards.

### Machining, forming, heat treatment
Machined in the delivered condition at 30 HRC, machinability ≈ 50–55 % relative to 1 % C free-cutting steel — slightly tougher-cutting than 1.2311 because of the nickel, and the chip is more adhesive. Coated carbide, moderate speeds, rigid set-ups. On blocks of this size the real work is deep-hole drilling for cooling lines: use through-coolant drills and expect to peck, and plan the drill pattern before the cavity is cut. Heavy rough machining on a large plate releases enough residual stress to move it — rough, stress relieve at 500–540 °C, then finish. EDM is standard; stone the white layer off any surface that will be polished. At 38–42 HRC in the HH condition, allow roughly 30 % more cycle time and use rigid tooling.

Applications: Large plastic injection moulds — bumpers, dashboards, interior panels, appliance housings; Crate, pallet and bin moulds, thick-walled technical mouldings; Mould plates, bolsters and support blocks above 250 mm; Blow-moulding tooling and extrusion-blow moulds; Rubber and compression moulds in large sizes; Die casting holder blocks and frames; Heavy jigs, fixtures and press structures needing 30 HRC through section

Q: What is the difference between 1.2311 and 1.2738?
A: Nickel: 0.90–1.20 % in 1.2738, none in 1.2311. Everything else in the analysis is the same. The nickel increases hardenability, so the core of a thick block reaches the same 28–34 HRC as the surface. Below roughly 250 mm section there is no benefit and 1.2311 is 15–25 % cheaper; above 400 mm only 1.2738 holds the hardness band.

Q: Is 1.2738 the same as P20+Ni?
A: Yes, that is exactly what P20+Ni means — AISI P20 modified with nickel. But P20+Ni is a trade description rather than a standardised grade, and the nickel level on a North American certificate can be anywhere from about 0.5 to 1.2 %. EN ISO 4957 fixes 1.2738 at 0.90–1.20 %. If the section is large, ask for the analysis.

Q: What is 1.2738HH?
A: The same steel delivered at a higher hardness: 360–400 HB (38–42 HRC) instead of 280–325 HB, achieved by tempering lower. It holds textures and resists surface deformation better on very long runs. The costs are slower machining and almost no headroom for a later stress relief or nitriding cycle, because the tempering temperature is now close to those process temperatures.

Q: What hardness does 1.2738 hold in a 600 mm block?
A: Typically 275–315 HB at the core against 280–325 HB at the surface — a difference of a few Brinell points. A nickel-free 1.2311 block of the same thickness falls to around 240–270 HB in the middle. State on the order where the hardness is to be measured.

Q: Does 1.2738 need heat treatment after machining?
A: No. It is delivered quenched and tempered and the cavity is cut at that hardness, which is the point of the whole mould-steel class — nothing distorts and nothing needs re-grinding. If heavy rough machining has released enough stress to move a large plate, stress relieve at 500–540 °C before finishing; never above that, or the delivered hardness is lost.

Q: Can 1.2738 be polished and textured?
A: Yes, to Ra 0.05 µm or better, and it photo-etches cleanly. For high-gloss or fine-textured cavities, specify remelted material — the limit at high polish is inclusion content rather than analysis, and ordinary continuously cast material shows pinholes on the moulded part.

Q: Is 1.2738 corrosion resistant?
A: No. Two per cent chromium does not make a passive layer, and the nickel does not change that. Cooling channels corrode, cavities rust in storage, and corrosive polymers such as PVC attack the surface. Where that is the operating condition, the answer is the stainless mould steel 1.2083 or a plated cavity.

Q: Can 1.2738 cavities be welded without showing afterwards?
A: Only with a matching nickel-bearing filler. A non-matching filler polishes to a visibly different shade and etches differently, so the repair appears on the moulded part. Preheat to 250–325 °C, hold interpass above 250 °C, cool slowly and temper at 500–540 °C. For small corrections laser cladding is preferred because the affected zone stays under half a millimetre.

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## 1.3343 (1.3343) [T11302] — High-speed steel, tungsten-molybdenum
URL: https://steelstandart.com/grade/1-3343/
System: EN (European) | Family: Tool steel | Standard: EN ISO 4957 | Verified against: EN ISO 4957:2018
Aliases: HS6-5-2C, HS 6-5-2 C, HS6-5-2, M2, AISI M2, M2 HSS, M2 high speed steel, M2 tool steel, 1.3343 HSS, 1.3343 tool steel, SKH51, W6Mo5Cr4V2, R6M5, BM2, S600, S 6-5-2

1.3343 (HS6-5-2C) is the general-purpose high-speed steel — AISI M2 — and it is the steel most drills, taps, end mills, reamers, hobs, broaches and band-saw teeth in the world are made of. With 6 % tungsten, 5 % molybdenum, 4 % chromium and 2 % vanadium it hardens to 64–66 HRC and, crucially, holds about 50 HRC at 600 °C. That is the property that separates a high-speed steel from every other tool steel: not what it reads cold, but what it still reads when the cutting edge is glowing.

The price of that property is a hardening process with no margin for error. Austenitising is at 1190–1230 °C — within roughly ±10 °C of the chosen set point, barely below the melting range, held for two to five minutes only. Too cold and the alloy carbides do not dissolve, so the secondary hardening never happens; too hot or too long and the grain coarsens and the tool is brittle. Then come three tempers at 550–560 °C, each one transforming the retained austenite that the previous one released. A high-speed steel tool is a heat-treatment product in a way a cold-work tool is not; vacuum or salt-bath furnaces with tight pyrometry are the minimum, and this is not toolroom work.

Two things are commonly misread about the designation. The C in HS6-5-2C is the carbon level, not a quality mark: 0.86–0.94 % against 0.78–0.88 % for plain HS6-5-2, worth about one point of hardness and a useful gain in wear resistance. And M2 is not a cheap version of a carbide tool — it is the tougher one. Carbide holds its hardness far higher and cuts far faster, but it chips where M2 bends, which is why hand taps, long drills, thin saw blades and interrupted-cut tooling are still high-speed steel.

Where M2 runs out, the upgrades are well defined: 1.3243 (M35) adds 5 % cobalt for another 50 °C of hot hardness, 1.3344 (M3:2) adds vanadium for abrasive wear, and the powder-metallurgy high-speed steels sit above both. For most drilling, tapping and milling of carbon and alloy steel, none of that is needed.

Chemical composition (mass %): C 0.86 – 0.94; Si ≤ 0.45; Mn ≤ 0.4; P ≤ 0.03; S ≤ 0.03; Cr 3.8 – 4.5; Mo 4.7 – 5.2; W 5.9 – 6.7; V 1.7 – 2.1
EN ISO 4957:2018, high-speed steels (HS6-5-2C). The **C suffix is the carbon level, not a quality grade**: HS6-5-2C carries 0.86–0.94 % C where plain HS6-5-2 carries 0.78–0.88 %. The extra carbon gives 1 HRC more working hardness and better abrasive wear resistance, at the cost of a little toughness, and it is the version normally supplied for drills, end mills and form tools. AISI M2 to ASTM A600 spans both: C 0.78–1.05, W 5.50–6.75, Mo 4.50–5.50, V 1.75–2.20.

Mechanical properties:
- +A soft annealed (delivery): yield — MPa; tensile ≈ 800–900 (typ.) MPa; elongation — %; hardness ≤ 269 HB
- Hardened 1210–1230 °C, as-quenched: yield — MPa; tensile — MPa; elongation — %; hardness 63–65 HRC
- Tempered 3 × 550–560 °C: yield — MPa; tensile — MPa; elongation — %; hardness 64–66 HRC
- Tempered 3 × 580 °C: yield — MPa; tensile — MPa; elongation — %; hardness 62–64 HRC
- At 64 HRC, hot hardness at 600 °C: yield — MPa; tensile — MPa; elongation — %; hardness ≈ 50 HRC
- Compressive yield at 64 HRC (typical): yield ≈ 3000 MPa; tensile ≈ 4000 (bend strength) MPa; elongation — %; hardness —
EN ISO 4957 specifies the chemistry and the maximum annealed hardness; everything else is a heat-treatment result. The property that defines a high-speed steel is in the fifth row: **it still reads about 50 HRC at 600 °C**, where every cold-work and hot-work tool steel on this site is soft. That is what 'high speed' means — not the hardness at room temperature, which a plain 1 % carbon steel can almost match, but the hardness retained at the cutting edge while it is glowing.

Equivalents:
- M2 (AISI / SAE) — identical: AISI M2 (UNS T11302, ASTM A600): C 0.78–1.05, W 5.50–6.75, Mo 4.50–5.50, Cr 3.75–4.50, V 1.75–2.20. The same steel. Because the ASTM carbon range covers both the plain and the high-carbon European versions, an M2 certificate should be read for its carbon level before it is matched to 1.3343 or to 1.3339.
- W6Mo5Cr4V2 (GB/T (China)) — identical: GB/T 9943 W6Mo5Cr4V2 is the direct transcription and the most widely produced high-speed steel in China. W6Mo5Cr4V2Al adds aluminium for higher hot hardness.
- R6M5 (GOST (Russia/CIS)) — identical: GOST 19265 R6M5: C 0.82–0.90, W 5.50–6.50, Mo 4.80–5.30, Cr 3.80–4.40, V 1.70–2.10. R6M5K5 is the 5 % cobalt version corresponding to M35.
- SKH51 (JIS (Japan)) — identical: JIS G4403 SKH51: C 0.80–0.88, W 5.90–6.70, Mo 4.70–5.20, Cr 3.80–4.50, V 1.70–2.10 — the plain-carbon version, so about 1 HRC below HS6-5-2C at the same temper.
- 1.3243 (EN (European)) — near: HS6-5-2-5 (M35): the same steel with 4.5–5.0 % cobalt. Cobalt raises hot hardness by about 50 °C and is the standard upgrade for stainless and high-temperature alloy machining; slightly more brittle and more expensive.
- 1.3344 (EN (European)) — near: HS6-5-3 (M3:2): vanadium raised to 2.7–3.2 % and carbon to 1.15–1.25 %. Markedly better abrasive wear resistance for form tools and gear hobs, harder to grind.
- 1.3355 (EN (European)) — functional: HS18-0-1 (T1): the original 18 % tungsten high-speed steel. Equivalent performance for general turning, but tungsten is heavier and dearer than molybdenum, so T1 has been displaced almost everywhere by M2.
- 1.2379 (EN (European)) — functional: X153CrMoV12 (D2): comparable room-temperature hardness and abrasive wear resistance at a fraction of the cost, but it is soft by 300 °C. The right choice for cold blanking and the wrong one for any tool that cuts at speed.

Superseded names:
- S 6-5-2 — DIN 17350 (withdrawn): The German short designation; same number 1.3343. The letters give the alloy content in order — 6 % W, 5 % Mo, 2 % V.
- BM2 — BS 4659 (withdrawn): The British designation.
- Z85WDCV — NF A 35-590: The French designation of the same steel.
- S600 / HS6-5-2 — Böhler / trade names: Böhler S600, Erasteel EM2, Thyrapid 3343. Powder-metallurgy equivalents (ASP 2023, Böhler S390 class) are different steels, not versions of this one.

Product forms: round bar (annealed, rolled or peeled); flat bar and strip; hollow bar and tube for hollow tooling; finished cutting tools (drills, taps, end mills, hobs, broaches); saw strip and bi-metal band-saw edge wire
Tolerances: annealed round bar: EN 10060 or supplier tolerances, typically +0.5/+2 mm grinding allowance; ground stock: h6/h7 as agreed; finished cutting tools: tolerances from the relevant tool standard (ISO 235 for drills, ISO 529 for taps and so on), not from EN ISO 4957

### 1.3343 hardness and red hardness
Annealed ≤ 269 HB. As-quenched 63–65 HRC; after triple tempering at 550–560 °C the working hardness is 64–66 HRC — a secondary-hardening gain, so the steel comes out of tempering harder than it went in. Hot hardness is the real specification: roughly 62 HRC at 400 °C, 58 HRC at 500 °C and 50 HRC at 600 °C. Compare the cold-work grade 1.2379, which is below 45 HRC by 400 °C.

### Heat treatment — the narrow window
Soft anneal 820–870 °C, very slow cool (≤ 15 K/h). Preheat in two stages, 450–500 °C and 850–900 °C. Austenitise 1190–1230 °C, held only 2–5 minutes at temperature, in vacuum, a neutral salt bath or a protective atmosphere; the window is about ±10 °C around the set point. Quench in oil, salt at 500–550 °C, or vacuum gas; interrupt at 50–70 °C. Temper three times for at least 1 h at 550–560 °C, cooling to room temperature between tempers. Deep freezing after the quench is sometimes used but does not replace the third temper. Ms ≈ 220 °C.

### Why three tempers
A quenched high-speed steel contains 20–30 % retained austenite. Each temper converts part of it to fresh, untempered martensite on cooling; the next temper tempers that martensite and converts more austenite. After three cycles the retained austenite is below a few per cent. Skipping the third temper leaves an unstable structure that changes dimension in storage and chips in service — the classic cause of a tool that was correct on inspection and failed in the first hour.

### Coating
Nearly all production high-speed steel tooling is coated. TiN (gold, 2300 HV, deposited at 450–500 °C) is the general case; TiCN for abrasive work, TiAlN/AlTiN for dry and high-speed cutting because its oxide layer insulates the edge, and CrN for aluminium and copper alloys. PVD temperatures sit below the 550 °C tempering temperature, so the substrate keeps its hardness — that compatibility is a direct consequence of the secondary-hardening temper and is why high-speed steel takes coatings while oil-hardening grades cannot. Coating a tool typically doubles to quadruples its life; it does not repair a bad edge geometry.

### Wear resistance and grinding
Carbide volume is around 10 %, including hard MC vanadium carbides. That makes the steel abrasion resistant in service and difficult to grind: use soft, open aluminium-oxide wheels or CBN, generous coolant, light passes, and watch for grinding burn — a blue edge is a soft edge, because the surface has been tempered past 600 °C. Re-sharpening a coated tool removes the coating on the ground face; the edge still works, but the gain is partly lost unless it is re-coated.

### Physical properties
Density 8.10 g/cm³ — noticeably heavier than ordinary tool steel because of the tungsten. E = 230 GPa, higher than any other steel on this site, which is part of why high-speed steel drills deflect less than their stiffness-to-diameter ratio suggests. Thermal conductivity ≈ 19 W/m·K, low, so heat stays at the edge and coolant matters. Expansion 10.1 × 10⁻⁶/K (20–100 °C), 11.5 × 10⁻⁶/K (20–600 °C).

### Weldability
Not a weldable steel in any structural sense, but flash and friction welding of a high-speed steel tip to a plain-steel shank is standard industrial practice — most drills above about 13 mm diameter and every bi-metal band saw are made this way, which is why a cheap long drill has a hardened flute section and a soft shank. Repair welding of a damaged tool is uneconomic and unreliable: preheat 500 °C, matching filler, immediate triple temper, and the result is still a crack risk. Do not weld a hardened high-speed steel tool as a repair.

### Machining, forming, heat treatment
Annealed machinability ≈ 35–40 % relative to 1 % C free-cutting steel: the hard carbides are abrasive even in the annealed state, so carbide tooling, moderate speeds and rigid set-ups are required. Finished tool geometry is almost always produced by grinding after hardening, not by machining before it — flutes, lands and reliefs are ground on CNC tool grinders, which is why a high-speed steel cutter is a ground product. EDM is possible and used for form tools; the white layer must be removed because it is untempered. Hard turning at 64 HRC is impractical. Nitriding (steam or salt, 'blue' finish) at 480–520 °C is applied to taps and some drills for extra surface hardness and lubricity.

Applications: Twist drills, centre drills and reamers; Hand and machine taps, thread chasers and thread-rolling tools; End mills, slot drills, side-and-face cutters and slitting saws; Gear hobs, shaper cutters and shaving tools; Broaches and keyway cutters; Bi-metal band-saw and hacksaw blades (edge wire); Turning and planing tool bits for interrupted or low-speed work; Cold-work punches needing red hardness, hot shear blades

Q: Is 1.3343 the same as M2?
A: Yes. 1.3343 (HS6-5-2C, EN ISO 4957) and AISI M2 (UNS T11302, ASTM A600) are the same tungsten-molybdenum high-speed steel. The ASTM carbon range, 0.78–1.05 %, covers both the standard and the high-carbon European versions, so an M2 certificate should be read for its actual carbon content: 1.3343 is the high-carbon one at 0.86–0.94 %, and 1.3339 is the plain version.

Q: What does the C in HS6-5-2C mean?
A: Carbon. HS6-5-2C carries 0.86–0.94 % carbon against 0.78–0.88 % for plain HS6-5-2, which is worth roughly one point of working hardness — 64–66 HRC instead of 63–65 — and a useful gain in abrasive wear resistance for a small loss of toughness. It is not a quality or purity designation. The numbers in the name are the tungsten, molybdenum and vanadium contents.

Q: What hardness does M2 reach?
A: 64–66 HRC after hardening from 1210–1230 °C and triple tempering at 550–560 °C. More to the point, it retains about 58 HRC at 500 °C and 50 HRC at 600 °C, which no cold-work or hot-work tool steel does. The room-temperature number is not what the steel is bought for.

Q: Why does high-speed steel need three tempers?
A: Because a quenched high-speed steel holds 20–30 % retained austenite. Each tempering cycle converts part of it to fresh untempered martensite as it cools, which the next cycle then tempers. Three cycles bring the retained austenite down to a few per cent. A tool tempered only once or twice is dimensionally unstable and chips in service, even though it measures correctly on inspection.

Q: M2 or carbide — which should I use?
A: Carbide cuts several times faster and holds hardness far higher, so for stable, rigid, high-volume machining it wins on cost per part. M2 is tougher: it bends where carbide chips. Hand taps, small and long drills, thin slitting saws, interrupted cuts, unstable set-ups, old low-speed machines and anything that may be shock-loaded are still high-speed steel for that reason, and coating closes part of the speed gap.

Q: What is the difference between M2 and M35?
A: Cobalt. M35 (1.3243, HS6-5-2-5) is the same steel with 4.5–5.0 % cobalt, which raises hot hardness by roughly 50 °C and makes it the standard choice for drilling stainless steel, nickel alloys and titanium. It is slightly more brittle and more expensive, and it brings no benefit on ordinary carbon steel.

Q: Can M2 tools be re-sharpened?
A: Yes, and they are designed to be — that is part of the economics of high-speed steel tooling. Grind with soft open wheels or CBN, with plenty of coolant and light passes, and watch the colour: a blue edge has been tempered above 600 °C and is soft, so it must be ground back further. Re-sharpening removes the coating on the ground face, so a re-ground coated tool performs between the coated and uncoated levels unless it is re-coated.

Q: Why is a cheap long drill hard at the tip and soft at the shank?
A: Because it is two steels friction or flash welded together: a high-speed steel cutting section joined to a plain-steel shank. It is normal manufacturing practice above about 13 mm diameter, not a defect, and the same construction gives bi-metal band-saw blades a hard tooth edge on a flexible backing.

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## 1.4301 (1.4301) — Austenitic Cr-Ni stainless steel
URL: https://steelstandart.com/grade/1-4301/
System: EN (European) | Family: Stainless steel | Standard: EN 10088-2 | Verified against: EN 10088-2:2014
Aliases: X5CrNi18-10, X5 CrNi 18 10, V2A, 1.4301 stainless, Edelstahl 1.4301, 18/10, 18/8

1.4301 is the material number of X5CrNi18-10, the 18/8 (18/10) austenitic stainless steel that accounts for roughly half of all stainless produced in Europe. In German-speaking industry it is simply "V2A". EN 10088 sets 17.5–19.5 % Cr, 8–10.5 % Ni and ≤ 0.07 % C; solution-annealed sheet has 210–230 MPa yield, 520–750 MPa tensile and 45 % elongation, and the steel is non-magnetic and tough down to cryogenic temperatures.

The pitting resistance equivalent (PREN ≈ 18–19) makes it suitable for kitchens, food processing, architecture and mild chemical service, but not for warm chloride environments — swimming pools and coastal facades move to 1.4404 or 1.4571. Carbon at 0.07 % keeps sensitization low in thin welded sections; heavier welded plate is ordered as 1.4307 (304L).

For cross-referencing, 1.4301 and AISI/ASTM 304 are treated as the same grade: the American limits are a shade wider (C ≤ 0.08, S ≤ 0.030), so 1.4301 material always meets 304, and virtually all coil is dual-certified. The table lists JIS, GB, GOST and old BS/DIN names with the same grading.

Chemical composition (mass %): C ≤ 0.07; Si ≤ 1; Mn ≤ 2; P ≤ 0.045; S ≤ 0.015 (EN 10088-2 flat products; 0.030 for EN 10088-3 long products); N ≤ 0.1; Cr 17.5 – 19.5; Ni 8 – 10.5
EN 10088-2:2014 Table 3. Compare ASTM A240 304: C ≤ 0.08, Cr 17.5–19.5, Ni 8.0–10.5, S ≤ 0.030 — 1.4301 is slightly tighter on carbon and sulphur.

Mechanical properties:
- Cold-rolled strip/sheet (C), ≤ 8 mm, +AT: yield ≥ 230 MPa; tensile 540–750 MPa; elongation 45 %; hardness ≤ 215 HB
- Hot-rolled strip (H), ≤ 13.5 mm, +AT: yield ≥ 210 MPa; tensile 520–720 MPa; elongation 45 %; hardness ≤ 215 HB
- Hot-rolled plate (P), ≤ 75 mm, +AT: yield ≥ 210 MPa; tensile 520–720 MPa; elongation 45 %; hardness ≤ 215 HB
- Bar ≤ 160 mm, +AT (EN 10088-3): yield ≥ 190 MPa; tensile 500–700 MPa; elongation 45 %; hardness ≤ 215 HB
- Rp1.0 (all forms, for design): yield ≥ 250 (C) / ≥ 250 (P) MPa; tensile — MPa; elongation — %; hardness —
Values at +20 °C, solution annealed (+AT, 1050 ± 50 °C, quenched). Transverse for flat products. Work-hardened conditions (+C700, +C850…) available for strip and wire.
Impact: 60 J at -196 °C (typical, not a standard requirement)

Equivalents:
- 304 (AISI / SAE) — identical: AISI 304 / UNS S30400 (ASTM A240): same Cr/Ni window; C ≤ 0.08 vs 0.07, S ≤ 0.030 vs 0.015. Dual-certified 1.4301/304 is the norm.
- 304S31 (BS (superseded British)) — identical: BS 1449 304S31: C ≤ 0.07, Cr 17–19, Ni 8–11.
- 06Cr19Ni10 (GB/T (China)) — identical: GB/T 20878 06Cr19Ni10 (formerly 0Cr18Ni9): C ≤ 0.08, Cr 18.0–20.0, Ni 8.0–11.0.
- 08Kh18N10 (GOST (Russia/CIS)) — identical: GOST 5632 08Kh18N10: C ≤ 0.08, Cr 17–19, Ni 9–11.
- SUS304 (JIS (Japan)) — identical: JIS G4304/G4305 SUS304: C ≤ 0.08, Cr 18.0–20.0, Ni 8.0–10.5.
- 304L (AISI / SAE) — near: UNS S30403: C ≤ 0.03 — the low-carbon version; EN equivalent is 1.4307 (X2CrNi18-9).
- 1.4307 (EN (European)) — near: X2CrNi18-9, C ≤ 0.03 — the low-carbon variant for welded heavy sections (304L).
- 1.4404 (EN (European)) — functional: X2CrNiMo17-12-2 (316L) with 2 % Mo: substitute when chloride pitting resistance is needed.
- 1.4305 (EN (European)) — functional: Non-free-machining base grade: better corrosion resistance and weldability, poorer machinability.

Superseded names:
- X5CrNi18-10 — EN 10088 (current name): The name and number are used together; 1.4301 is the number, X5CrNi18-10 the symbolic name.
- X5CrNi18 9 — DIN 17440 (withdrawn 1996): Same number 1.4301.
- V2A — Krupp trade name (1912): Colloquial German name for 18/8 austenitic; V4A = 1.4401/1.4571.
- 304S15 / 304S31 — BS 1449 / BS 970: 304S31 is the closer match (C ≤ 0.07).
- Z7CN18-09 — NF A 35-573

Product forms: cold-rolled sheet and coil (2B, 2R/BA, brushed); hot-rolled plate (1D); bar, wire and profiles (EN 10088-3); welded and seamless tube (EN 10217-7 / EN 10216-5); fittings, flanges, fasteners
Tolerances: cold-rolled: EN ISO 9445-2; hot-rolled plate: EN 10029; bar: EN 10278 / EN 10060; tube: EN ISO 1127

### 1.4301 yield strength
Rp0.2 ≥ 210 MPa (hot-rolled plate, 30 ksi) and ≥ 230 MPa (cold-rolled strip); Rp1.0 ≥ 250 MPa. Design codes (EN 1993-1-4) use fy = 210 MPa for plate and 230 MPa for cold-rolled sheet.

### 1.4301 tensile strength
520–720 MPa (plate) / 540–750 MPa (cold-rolled). Work-hardened strip is available at 700, 850 and 1000 MPa minimum (+C700 … +C1000).

### 1.4301 hardness
Solution annealed max 215 HB (≈ 230 HV, ≈ 92 HRB). Cannot be hardened by heat treatment; cold work raises hardness to 300–400 HV.

### Corrosion resistance
PREN = Cr + 3.3 Mo + 16 N ≈ 18–19. Critical pitting temperature in 6 % FeCl₃ ≈ 5–10 °C. Resists nitric acid, organic acids, food media and atmospheric exposure inland; pits in warm chloride solutions above ~200 ppm Cl⁻.

### Physical properties
Density 7.9 g/cm³, E = 200 GPa, thermal expansion 16 × 10⁻⁶/K (20–100 °C), thermal conductivity 15 W/m·K, electrical resistivity 0.73 Ω·mm²/m, magnetic permeability ≈ 1.005 (annealed; increases after cold work).

### Heat treatment
Solution anneal 1000–1100 °C, rapid cooling (water or forced air). Avoid holding at 500–800 °C (chromium carbide precipitation → sensitization). No stress-relief below 900 °C unless followed by re-annealing.

### Weldability
Excellent weldability with all arc processes without preheat; filler 19 9 L / ER308L (EN ISO 14343). Limit heat input and interpass to ≤ 150 °C to reduce distortion (expansion is 50 % higher than carbon steel). Heavy sections (> 6 mm) that will see corrosive service should be ordered as 1.4307 or post-weld pickled. Back-purge with argon for tube roots.

### Machining, forming, heat treatment
Machinability index ≈ 45 % (work-hardens; use sharp positive-rake tooling, low speed, high feed). 1.4305 (303) is the free-machining alternative. Deep drawing and spinning are excellent (that is why 1.4301 dominates sinks and cookware); spring-back is higher than carbon steel. Polishing, brushing, bead blasting and electropolishing are all standard finishes.

Applications: Kitchen sinks, cookware, cutlery, catering equipment; Food, beverage and dairy processing vessels and piping; Architectural cladding, handrails, street furniture (inland); Tanks and containers for mild chemicals, water treatment; Automotive trim and exhaust components (as 1.4301 or 1.4512); Fasteners A2-70 (ISO 3506 = 1.4301/1.4307 group)

Q: Is 1.4301 the same as 304?
A: Yes in practice. 1.4301 (EN 10088) and 304 (ASTM A240 / UNS S30400) have the same 18 % Cr / 8–10.5 % Ni base; 1.4301 caps carbon at 0.07 % and sulphur at 0.015 % versus 0.08 % and 0.030 % for 304, so 1.4301 material always satisfies 304. Sheet and coil are routinely dual-certified.

Q: What does V2A mean?
A: V2A is a Krupp trade name from 1912 ("Versuchsschmelze 2 Austenit") that became the colloquial German term for 18/8 chromium-nickel stainless — today 1.4301. V4A refers to the molybdenum-bearing 1.4401/1.4571 group.

Q: Is 1.4301 magnetic?
A: No in the annealed state (austenitic, permeability ≈ 1.005). Cold forming — bending, deep drawing, machining — produces some martensite and a weak magnetic response, which is normal and not a sign of a wrong grade.

Q: Can 1.4301 be used outdoors or near the sea?
A: Inland and urban atmospheres: yes, with occasional washing. Coastal or de-icing-salt exposure: expect tea staining and pitting; specify 1.4404/1.4571 (316) or 1.4462 (duplex).

Q: What is the difference between 1.4301 and 1.4307?
A: 1.4307 (X2CrNi18-9, 304L) limits carbon to 0.03 %, preventing sensitization in thick welded sections. Its strength minimums are 10–20 MPa lower. Most mills supply 1.4301/1.4307 dual-certified with C ≤ 0.03 %.

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## 1.4305 (1.4305) — Austenitic free-machining stainless steel (sulphur-bearing)
URL: https://steelstandart.com/grade/1-4305/
System: EN (European) | Family: Stainless steel | Standard: EN 10088-3 | Verified against: EN 10088-3:2014
Aliases: X8CrNiS18-9, X8 CrNiS 18 9, 303 EN, 1.4305 stainless, Automatenstahl 1.4305, 303, AISI 303, SS303, 303 stainless steel, SUS303, Y12Cr18Ni9, 303S31, 12Kh18N10E

1.4305 (X8CrNiS18-9) is 18/8 stainless deliberately made dirty: 0.15–0.35 % sulphur forms manganese-sulphide inclusions that break chips and lubricate the tool, giving roughly 80 % of the machinability of free-cutting carbon steel and about double that of 1.4301. It is the grade of every automatic lathe shop that turns stainless fittings, nuts, shafts, valve stems and pins.

The sulphides cost something: pitting resistance drops (PREN nominally the same, but sulphide sites initiate attack), weldability is poor (hot-cracking and porosity), and transverse ductility is low, so 1.4305 is supplied only as bar, wire and hexagons — never as sheet. It is used for parts that see mild environments (indoor, fresh water, food-grade with cleaning) and no welding.

AISI 303, JIS SUS303 and GB Y12Cr18Ni9 are the same steel; the EN specification is slightly tighter on carbon (0.10 vs 0.15 %). For chloride service the free-machining 316 variant is 1.4570 (316F).

Chemical composition (mass %): C ≤ 0.1; Si ≤ 1; Mn ≤ 2; P ≤ 0.045; S 0.15 – 0.35 (manganese sulphide inclusions break the chip); N ≤ 0.11; Cr 17 – 19; Ni 8 – 10; Cu ≤ 1
EN 10088-3:2014 Table 3. Compared with 1.4301: higher C (0.10) and, above all, 0.15–0.35 % S — which is why corrosion resistance and weldability are lower.

Mechanical properties:
- Bar ≤ 160 mm, +AT solution annealed: yield ≥ 190 MPa; tensile 500–750 MPa; elongation 35 %; hardness ≤ 230 HB
- Bright bar ≤ 16 mm, cold-drawn (+C): yield ≥ 400 (typ.) MPa; tensile 600–850 (typ.) MPa; elongation 20 %; hardness ≈ 190–260 HB
- Wire (EN 10088-3), +AT: yield ≥ 190 MPa; tensile 500–750 MPa; elongation 35 %; hardness —
Solution annealed 1010–1110 °C. Cold-drawn values are typical supplier data, not standard minima. Elongation is lower than 1.4301 because of sulphide stringers; transverse ductility is markedly reduced.

Equivalents:
- 303 (AISI / SAE) — identical: UNS S30300 (ASTM A582): C ≤ 0.15, Cr 17–19, Ni 8–10, S ≥ 0.15, Mo ≤ 0.60. 1.4305 caps C at 0.10 and S at 0.35; dual-certified.
- 303S31 (BS (superseded British)) — identical: BS 970 303S31: C ≤ 0.12, S 0.15–0.35.
- Y12Cr18Ni9 (GB/T (China)) — identical: GB/T 1220 Y12Cr18Ni9 (formerly Y1Cr18Ni9): free-machining 18/8 with S 0.15–0.35.
- SUS303 (JIS (Japan)) — identical: JIS G4303 SUS303: C ≤ 0.15, Cr 17–19, Ni 8–10, S ≥ 0.15.
- 1.4570 (EN (European)) — near: X6CrMoNiS17-12-2 — the free-machining 316 (316F) for chloride service.
- 1.4301 (EN (European)) — functional: Non-free-machining base grade: better corrosion resistance and weldability, poorer machinability.

Superseded names:
- X10CrNiS18 9 — DIN 17440 (withdrawn): Same number 1.4305.
- 303S31 / 303S21 — BS 970: 303S31 is the closer match.
- Z8CNF18-09 — NF A 35-574

Product forms: round, hexagon and square bar (bright drawn, peeled, ground); wire and profiles; forgings (limited); not produced as sheet or plate
Tolerances: bright bar: EN 10278 (h9, h10, h11); hot-rolled bar: EN 10060

### 1.4305 yield strength
Rp0.2 ≥ 190 MPa (27.6 ksi) solution annealed; cold-drawn bright bar typically 400–500 MPa.

### 1.4305 tensile strength
500–750 MPa annealed; 600–850 MPa cold-drawn in small diameters.

### 1.4305 hardness
Max 230 HB annealed (≈ 95 HRB); cold-drawn bar 190–260 HB. Not hardenable by heat treatment.

### Machinability
Index ≈ 75–80 % relative to 1.0715 (11SMn30) versus ≈ 45 % for 1.4301. Recommended: carbide, 100–160 m/min turning, generous coolant; chips break short.

### Corrosion resistance
Reduced relative to 1.4301: suitable for indoor, dry and mildly humid atmospheres, fresh water and food contact with regular cleaning. Not for chlorides, marine air or acids. Passivation (nitric acid) after machining is recommended.

### Physical properties
Density 7.9 g/cm³, E = 200 GPa, expansion 16 × 10⁻⁶/K, non-magnetic annealed (slightly magnetic after cold drawing).

### Weldability
Not recommended. High sulphur causes hot cracking and porosity; if unavoidable, use 19 9 L / ER308L or 312 filler, low heat input, short welds, and accept reduced corrosion resistance. Design machined 1.4305 parts for mechanical joining (threads, press fits).

### Machining, forming, heat treatment
This is what 1.4305 is for: automatic lathes, CNC turning, drilling, tapping and threading. Use sharp positive geometry, higher speeds than for 1.4301 (100–160 m/min carbide), and avoid dwelling. Threads and knurls come out clean; surface finish after turning is excellent. Cold forming is poor (sulphides); hot forging 1150–950 °C followed by solution anneal is possible but rarely economic.

Applications: Turned fittings, adapters, nipples and unions; Nuts, bolts and threaded studs (non-structural); Valve stems, spindles and shafts for pumps (mild media); Electrical and instrument components, pins, bushings; Gears and worm shafts in food and packaging machinery (dry); Dental and laboratory hardware (non-implant)

Q: Is 1.4305 the same as 303?
A: Yes. 1.4305 (EN 10088-3) and AISI 303 (UNS S30300) are the sulphur-bearing free-machining versions of 18/8; the EN grade limits carbon to 0.10 % (303: 0.15 %) and sulphur to 0.35 %. Bar is routinely dual-certified.

Q: Can 1.4305 be welded?
A: Only with difficulty. The 0.15–0.35 % sulphur causes hot cracks and porosity. For welded assemblies use 1.4301 or 1.4307 and accept slower machining.

Q: Is 1.4305 food-safe?
A: It is used for food-machinery parts that are cleaned regularly and not exposed to chlorides or acidic media for long periods. For product-contact vessels and piping, 1.4301 or 1.4404 are the normal choices.

Q: Why is 1.4305 slightly magnetic?
A: Cold drawing of bar produces a small amount of strain-induced martensite. Annealed 1.4305 is non-magnetic like other austenitic grades.

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## 1.4404 (1.4404) — Austenitic Cr-Ni-Mo stainless steel, low carbon
URL: https://steelstandart.com/grade/1-4404/
System: EN (European) | Family: Stainless steel | Standard: EN 10088-2 | Verified against: EN 10088-2:2014
Aliases: X2CrNiMo17-12-2, X2 CrNiMo 17 12 2, 1.4404 stainless, V4A, 316L EN

1.4404 (X2CrNiMo17-12-2) is the European name for 316L: an austenitic stainless steel with 17 % Cr, 11 % Ni and 2–2.5 % molybdenum, carbon held to 0.03 % so that welded joints stay free of chromium-carbide sensitization. The Mo addition roughly triples the resistance to chloride pitting compared with 1.4301 (PREN 24 vs 18), which is why 1.4404 is the default grade for coastal architecture, chemical and pharmaceutical process equipment, swimming-pool fittings and marine hardware.

Mechanically it is close to 1.4301 — 220 MPa yield, 520–670 MPa tensile, 40 % elongation — and equally non-magnetic and cryogenic-tough. It is not hardenable by heat treatment; strength is raised only by cold work.

EN 10088 makes 1.4404 a subset of ASTM 316L (S31603): the EN Mo window (2.0–2.5 %) sits at the low end of ASTM's 2.0–3.0 %, so material certified 1.4404 automatically meets 316L, and most plate and coil is dual-certified 1.4404/316L. In German industry the group is called "V4A". The related grades — 1.4401 (316, higher carbon), 1.4571 (316Ti, titanium-stabilized) and 1.4432/1.4436 (higher Mo) — are cross-referenced below.

Chemical composition (mass %): C ≤ 0.03; Si ≤ 1; Mn ≤ 2; P ≤ 0.045; S ≤ 0.015 (0.030 for long products (EN 10088-3)); N ≤ 0.1; Cr 16.5 – 18.5; Mo 2 – 2.5; Ni 10 – 13
EN 10088-2:2014 Table 3. Compare ASTM 316L (S31603): Cr 16.0–18.0, Ni 10.0–14.0, Mo 2.00–3.00 — the ASTM Mo window is wider on the high side.

Mechanical properties:
- Cold-rolled strip/sheet (C), ≤ 8 mm, +AT: yield ≥ 240 MPa; tensile 530–680 MPa; elongation 40 %; hardness ≤ 215 HB
- Hot-rolled strip (H), ≤ 13.5 mm, +AT: yield ≥ 220 MPa; tensile 520–670 MPa; elongation 40 %; hardness ≤ 215 HB
- Hot-rolled plate (P), ≤ 75 mm, +AT: yield ≥ 220 MPa; tensile 520–670 MPa; elongation 40 %; hardness ≤ 215 HB
- Bar ≤ 160 mm, +AT (EN 10088-3): yield ≥ 200 MPa; tensile 500–700 MPa; elongation 40 %; hardness ≤ 215 HB
- Rp1.0 (design): yield ≥ 260 (P) / ≥ 270 (C) MPa; tensile — MPa; elongation — %; hardness —
Solution annealed (+AT, 1030–1110 °C, quenched), +20 °C, transverse for flat products.
Impact: 60 J at -196 °C (typical)

Equivalents:
- 316L (AISI / SAE) — identical: UNS S31603 (ASTM A240): C ≤ 0.03, Cr 16–18, Ni 10–14, Mo 2–3; 1.4404 sits inside the 316L window and is dual-certified.
- 316S11 (BS (superseded British)) — identical: BS 1449 316S11: C ≤ 0.03, Cr 16.5–18.5, Ni 10–13, Mo 2–2.5.
- 022Cr17Ni12Mo2 (GB/T (China)) — identical: GB/T 20878 022Cr17Ni12Mo2 (formerly 00Cr17Ni14Mo2).
- SUS316L (JIS (Japan)) — identical: JIS G4304 SUS316L: C ≤ 0.03, Cr 16–18, Ni 12–15, Mo 2–3.
- 316 (AISI / SAE) — near: S31600 allows C ≤ 0.08; 1.4401 is the EN counterpart. 1.4404 meets 316 mechanicals only at the low end (316 requires Rp0.2 ≥ 205 MPa — satisfied).
- 1.4401 (EN (European)) — near: X5CrNiMo17-12-2 (316): C ≤ 0.07; higher strength minimums (Rp0.2 ≥ 240 MPa plate).
- 1.4571 (EN (European)) — near: X6CrNiMoTi17-12-2 (316Ti): Ti-stabilized instead of low-carbon; same corrosion class, slightly higher strength, poorer polish.
- 1.4432 / 1.4436 (EN (European)) — near: 2.5–3.0 % Mo versions (316L high-Mo) for slightly higher PREN.
- 03Kh17N14M3 (GOST (Russia/CIS)) — near: GOST 5632 03Kh17N14M3: C ≤ 0.03, Mo 2.5–3.0, Ni 13–15 — richer than 1.4404.
- 1.4301 (EN (European)) — functional: Non-Mo 304: cheaper, lower pitting resistance.
- 1.4462 (EN (European)) — functional: Austenitic 316L: half the yield strength, PREN 24; the grade 1.4462 usually replaces.

Superseded names:
- X2CrNiMo17 13 2 — DIN 17440 (withdrawn): Same number 1.4404; name changed to 17-12-2 in EN 10088.
- V4A — Krupp trade name: German colloquial name for the Mo-bearing austenitics (1.4401, 1.4404, 1.4571).
- 316S11 — BS 1449 / BS 970
- Z3CND17-12-02 — NF A 35-573

Product forms: cold-rolled sheet and coil (2B, 2R, brushed); hot-rolled plate; bar, wire, profiles (EN 10088-3); welded and seamless tube and pipe (EN 10217-7, EN 10216-5); fittings, flanges, fasteners (A4-70)
Tolerances: cold-rolled: EN ISO 9445-2; plate: EN 10029; bar: EN 10278 / EN 10060; tube: EN ISO 1127

### 1.4404 yield strength
Rp0.2 ≥ 220 MPa plate (32 ksi), ≥ 240 MPa cold-rolled sheet; Rp1.0 ≥ 260 MPa. EN 1993-1-4 design values: fy = 220 MPa (plate) / 240 MPa (cold-rolled).

### 1.4404 tensile strength
520–670 MPa (plate, 75–97 ksi), 530–680 MPa (cold-rolled). Bar 500–700 MPa.

### 1.4404 hardness
Max 215 HB annealed (≈ 95 HRB). Not heat-treatable; cold-worked strip up to 350–400 HV.

### Corrosion resistance
PREN = Cr + 3.3 Mo + 16 N ≈ 23.5–25. Critical pitting temperature (6 % FeCl₃) ≈ 15–20 °C. Resistant to seawater splash, de-icing salts, dilute sulphuric and phosphoric acids, most organic acids; not resistant to hot concentrated chlorides (use 1.4462 duplex or 1.4539/904L).

### Physical properties
Density 8.0 g/cm³, E = 200 GPa, expansion 16 × 10⁻⁶/K, conductivity 15 W/m·K, resistivity 0.75 Ω·mm²/m, non-magnetic (μr ≈ 1.005 annealed).

### Heat treatment
Solution anneal 1030–1110 °C, water or forced-air quench. Because C ≤ 0.03 %, 1.4404 can be welded in any thickness without post-weld annealing for corrosion reasons.

### Weldability
Excellent weldability by TIG, MIG, MMA, SAW and laser; filler 19 12 3 L / ER316L. No preheat; interpass ≤ 150 °C. Low carbon eliminates sensitization in the HAZ, so post-weld heat treatment is not required. Pickle or electropolish welds exposed to chlorides to restore the passive layer.

### Machining, forming, heat treatment
Machinability index ≈ 40 % (slightly worse than 1.4301 because of Mo and work hardening). Forming, deep drawing and spinning are very good; spring-back is high. Finishes: 2B, 2R (BA), brushed (grit 240–320), electropolished for pharma and food contact.

Applications: Chemical, pharmaceutical and food process vessels, piping and heat exchangers; Coastal and urban architecture: facades, handrails, roofing; Swimming-pool and spa fittings (with regular cleaning; 1.4462 for indoor pools); Marine hardware, deck fittings, boat rails; Water treatment, desalination pre-treatment, brewery and dairy equipment; Medical implants and instruments (as ASTM F138 1.4441 variant); Fasteners A4-70 / A4-80 (ISO 3506)

Q: Is 1.4404 the same as 316L?
A: Yes. 1.4404 (EN 10088) and 316L (UNS S31603, ASTM A240) are dual-certified; the EN Mo window (2.0–2.5 %) lies inside the ASTM window (2.0–3.0 %), so 1.4404 always satisfies 316L.

Q: What is the difference between 1.4404 and 1.4401?
A: Carbon: 1.4404 ≤ 0.03 % (316L), 1.4401 ≤ 0.07 % (316). 1.4401 has slightly higher strength minimums (Rp0.2 ≥ 240 MPa plate) but can sensitize when welded in thick sections. Most suppliers stock 1.4401/1.4404 dual-certified.

Q: 1.4404 or 1.4571 — which is better?
A: Same corrosion class (PREN ≈ 24). 1.4571 (316Ti) has ~10 % higher strength and better creep resistance to 550 °C, but the titanium carbides leave streaks when polished. Choose 1.4404 for polished, hygienic and welded sheet; 1.4571 for hot-service and heavy plate in German-spec projects.

Q: Is 1.4404 suitable for seawater?
A: For splash zones, boat fittings and intermittent exposure, yes with cleaning. For continuous immersion in warm seawater it will crevice-corrode; use 1.4462 (duplex), 1.4539 (904L) or 6 % Mo grades.

Q: Is 1.4404 magnetic?
A: No when annealed. Heavy cold work induces a slight magnetic response, less than in 1.4301 because the higher Ni stabilizes the austenite.

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## 1.4462 (1.4462) — Ferritic-austenitic (duplex) stainless steel
URL: https://steelstandart.com/grade/1-4462/
System: EN (European) | Family: Stainless steel | Standard: EN 10088-2 | Verified against: EN 10088-2:2014
Aliases: X2CrNiMoN22-5-3, X2 CrNiMoN 22 5 3, 2205 EN, duplex 1.4462, 1.4462 stainless, F51 EN, F51, UNS S31803 EN

1.4462 (X2CrNiMoN22-5-3) is the standard duplex stainless steel — the grade the world calls 2205. Its microstructure is half ferrite, half austenite, and that balance gives twice the yield strength of 316L (460 MPa vs 220 MPa), better chloride stress-corrosion cracking resistance and a pitting index PREN of about 35 against 24 for 1.4404. Nitrogen (0.10–0.22 %) is the key alloying element: it stabilizes the austenite, raises PREN and speeds re-formation of austenite in weld metal.

Because designers can halve the wall thickness compared with austenitic steel, 1.4462 is the economic choice for pressure vessels, storage tanks, heat exchangers, offshore piping, desalination and pulp-and-paper digesters. The limits are temperature: intermetallic phases (sigma, chi) form on holding at 700–950 °C and 475 °C embrittlement occurs on long exposure at 350–500 °C, so the practical service window is −50 to +280 °C (EN 13445 / ASME: 315 °C).

Since 2000 most 2205 is melted to the tighter UNS S32205 window, which 1.4462 plate normally meets; the older S31803 window is wider on the low side. The table grades both, plus the JIS, GB and forging (F51/F60) designations.

Chemical composition (mass %): C ≤ 0.03; Si ≤ 1; Mn ≤ 2; P ≤ 0.035; S ≤ 0.015; N 0.1 – 0.22; Cr 21 – 23; Mo 2.5 – 3.5; Ni 4.5 – 6.5
EN 10088-2:2014 Table 4. ASTM S32205 ("2205" since 2000) requires Cr 22–23, Mo 3.0–3.5, N 0.14–0.20 — a tighter, higher-PREN window inside the EN range; older S31803 is wider (Cr 21–23, Mo 2.5–3.5, N 0.08–0.20).

Mechanical properties:
- Cold-rolled sheet (C), ≤ 8 mm, +AT: yield ≥ 500 MPa; tensile 700–950 MPa; elongation 20 %; hardness ≤ 270 HB
- Hot-rolled strip (H), ≤ 13.5 mm, +AT: yield ≥ 460 MPa; tensile 700–950 MPa; elongation 25 %; hardness ≤ 270 HB
- Hot-rolled plate (P), ≤ 75 mm, +AT: yield ≥ 460 MPa; tensile 640–840 MPa; elongation 25 %; hardness ≤ 270 HB
- Bar ≤ 160 mm, +AT (EN 10088-3): yield ≥ 450 MPa; tensile 650–880 MPa; elongation 25 %; hardness ≤ 270 HB
- Rp1.0 (design): yield ≥ 500 (P) / ≥ 530 (C) MPa; tensile — MPa; elongation — %; hardness —
Solution annealed 1020–1100 °C, water quenched. Roughly 50/50 ferrite/austenite; ferromagnetic. Impact ≥ 100 J at +20 °C and ≥ 40 J at −40 °C typical for plate.
Impact: 40 J at -40 °C (typical plate; EN 10028-7 requires ≥ 60 J at −40 °C for pressure plate ≤ 30 mm)

Equivalents:
- 2205 (S32205) (AISI / SAE) — identical: UNS S32205 (ASTM A240/A790): Cr 22–23, Ni 4.5–6.5, Mo 3–3.5, N 0.14–0.20. Modern 1.4462 plate is melted to S32205 and dual-certified.
- 2205 (AISI / SAE) — identical: X2CrNiMoN22-5-3: EN window covers both S31803 and S32205; modern 1.4462 plate is dual-certified S32205.
- F51 / F60 (ASTM / ASME) — identical: ASTM A182 forging grades: F51 = S31803, F60 = S32205.
- 022Cr23Ni5Mo3N (GB/T (China)) — identical: GB/T 20878 022Cr23Ni5Mo3N (formerly 00Cr22Ni5Mo3N).
- SUS329J3L (JIS (Japan)) — identical: JIS G4304 SUS329J3L: Cr 21–24, Ni 4.5–6.5, Mo 2.5–3.5, N 0.08–0.20.
- 2205 (AISI / SAE) — near: Original 2205 window (Cr 21–23, Mo 2.5–3.5, N 0.08–0.20): 1.4462 material with N ≥ 0.10 fits, but low-N heats have lower PREN. S32205 is the safer equivalence.
- 03Kh22N5AM3 (GOST (Russia/CIS)) — near: GOST R 55374 / TU designations for 2205-type duplex; not a classic GOST 5632 grade.
- 1.4362 (EN (European)) — functional: Lean duplex 2304 (23 % Cr, 4 % Ni, no Mo): cheaper, PREN ≈ 25.
- 1.4410 (EN (European)) — functional: Super-duplex 2507 (25 % Cr, 7 % Ni, 4 % Mo, PREN ≥ 40) for hot seawater.
- 1.4404 (EN (European)) — functional: Austenitic 316L: half the yield strength, PREN 24; the grade 1.4462 usually replaces.

Superseded names:
- X2CrNiMoN22 5 3 — DIN 17440 / SEW 400: Same number 1.4462.
- 318S13 — BS 1449
- Z3CND22-05Az — NF A 35-573
- SAF 2205 — Sandvik trade name: Generic 2205 designation now used industry-wide.

Product forms: hot-rolled plate (dominant); cold-rolled sheet and coil; bar and forgings (EN 10088-3, EN 10222-5); seamless and welded pipe (EN 10216-5, EN 10217-7); fittings and flanges
Tolerances: plate: EN 10029; cold-rolled: EN ISO 9445-2; bar: EN 10278 / EN 10060

### 1.4462 yield strength
Rp0.2 ≥ 460 MPa hot-rolled plate (67 ksi), ≥ 500 MPa cold-rolled sheet, ≥ 450 MPa bar; Rp1.0 ≥ 500 MPa. EN 1993-1-4 uses fy = 460 MPa (plate).

### 1.4462 tensile strength
640–840 MPa plate (93–122 ksi), 700–950 MPa strip and cold-rolled sheet.

### 1.4462 hardness
Max 270 HB (≈ 28 HRC) solution annealed; NACE MR0175 limits to 28 HRC / 36 HRC depending on product form for sour service. Not hardenable by heat treatment.

### Corrosion resistance
PREN = Cr + 3.3 Mo + 16 N ≈ 34–36 (S32205 heats ≥ 35). CPT (ASTM G48 A) ≈ 35–50 °C; CCT ≈ 20 °C. Resistant to chloride SCC up to ~150 °C where 316L fails at 60 °C. Suitable for seawater at ambient temperature with flow; crevices need super-duplex.

### Physical properties
Density 7.8 g/cm³, E = 200 GPa, expansion 13 × 10⁻⁶/K (20–100 °C — closer to carbon steel than austenitics), conductivity 15 W/m·K, ferromagnetic.

### Heat treatment
Solution anneal 1020–1100 °C, water quench. Never stress-relieve at 350–950 °C (embrittlement). Hot forming 1200–950 °C followed by full re-anneal.

### Weldability
Weldable by TIG, MIG, MMA, SAW and FCAW with over-alloyed filler 22 9 3 N L (ER2209, 9 % Ni) to keep the weld metal ≥ 30 % austenite. Heat input 0.5–2.5 kJ/mm, interpass ≤ 150 °C (100 °C for thick sections), no preheat, no PWHT. Purge roots with argon + 2 % N₂. Autogenous welding without filler produces a ferritic, brittle bead and is not permitted for pressure parts.

### Machining, forming, heat treatment
Machinability ≈ 30 % (high yield strength and work hardening): rigid set-ups, carbide with sharp positive geometry, low speed / high feed, abundant coolant. Cold forming requires ~50 % higher press force than 316L and generous bend radii (≥ 2 t); spring-back is large. Hot forming 1200–950 °C then solution anneal.

Applications: Pressure vessels, columns and storage tanks (EN 13445, ASME VIII with S32205); Heat exchangers, condensers and evaporators in chloride-containing water; Offshore process piping, risers, firewater systems, umbilical tubes; Desalination (SWRO) high-pressure piping and vessels; Pulp and paper digesters, bleach plant, white-liquor tanks; Chemical tankers cargo tanks, road tankers; Bridges, walkways and rebar in marine or de-icing environments; Flue-gas desulphurization and wet scrubbers

Q: Is 1.4462 the same as 2205?
A: Yes. 2205 is the common name for UNS S31803/S32205, the ASTM counterpart of EN 1.4462. Modern plate is melted to the tighter S32205 limits (Cr ≥ 22, Mo ≥ 3, N ≥ 0.14) and dual-certified as 1.4462 / S32205 / S31803.

Q: What is the maximum service temperature of 1.4462?
A: About 280 °C in European pressure codes (EN 13445) and 315 °C (600 °F) in ASME; above that 475 °C embrittlement and sigma phase reduce toughness. The lower limit is around −50 °C.

Q: Is 1.4462 magnetic?
A: Yes. The 50 % ferrite phase makes duplex steels ferromagnetic — a simple way to distinguish them from 316L on site.

Q: What is the difference between 1.4462 and 1.4404?
A: 1.4462 has double the yield strength (460 vs 220 MPa), higher pitting resistance (PREN 35 vs 24) and far better chloride stress-corrosion resistance, but it is magnetic, harder to form, and limited to −50/+280 °C. 1.4404 is the choice for cryogenic, high-temperature and deep-drawn parts.

Q: Can 1.4462 be welded to carbon steel or 316L?
A: Yes, with 22 9 3 N L (2209) or 23 12 2 L (309LMo) filler and controlled heat input. Dissimilar joints are common in vessel nozzles and pipe transitions.

---

## 1.4571 (1.4571) — Austenitic Cr-Ni-Mo stainless steel, titanium-stabilized
URL: https://steelstandart.com/grade/1-4571/
System: EN (European) | Family: Stainless steel | Standard: EN 10088-2 | Verified against: EN 10088-2:2014
Aliases: X6CrNiMoTi17-12-2, X6 CrNiMoTi 17 12 2, 316Ti, V4A Ti, 1.4571 stainless

1.4571 (X6CrNiMoTi17-12-2) is the titanium-stabilized member of the 316 family and, with 1.4404, one of the two grades German engineers mean by "V4A". Instead of driving carbon down to 0.03 %, the mill adds titanium at five times the carbon content; the carbon precipitates as harmless TiC during hot rolling, so the 17 % Cr / 2.2 % Mo matrix keeps its full corrosion resistance after welding or after service at 400–550 °C.

That heat stability is the reason 1.4571 remains the specified grade in German, Austrian and Eastern-European pressure-vessel, exhaust, flue-gas and chemical plant drawings (EN 10028-7, AD 2000). Strength is 10–20 MPa above 1.4404, creep strength is markedly better, and PREN is the same ≈ 24.

The price is surface quality: titanium carbonitride stringers show as fine streaks after bright polishing and can nucleate pits in thin sheet, so hygienic and decorative applications moved to 1.4404. Outside Europe, 316Ti is rare — ASTM lists it as S31635 but US mills stock 316L — and the cross-reference table explains what to accept as a substitute.

Chemical composition (mass %): C ≤ 0.08; Si ≤ 1; Mn ≤ 2; P ≤ 0.045; S ≤ 0.015; Cr 16.5 – 18.5; Mo 2 – 2.5; Ni 10.5 – 13.5; Ti 5 × C – 0.7 (stabilizing ratio Ti ≥ 5×C, max 0.70 %)
EN 10088-2:2014 Table 3. Titanium ties up carbon as TiC so the steel cannot sensitize at 500–800 °C — the alternative to lowering carbon (1.4404).

Mechanical properties:
- Cold-rolled sheet (C), ≤ 8 mm, +AT: yield ≥ 240 MPa; tensile 540–690 MPa; elongation 40 %; hardness ≤ 215 HB
- Hot-rolled strip (H), ≤ 13.5 mm, +AT: yield ≥ 220 MPa; tensile 520–670 MPa; elongation 40 %; hardness ≤ 215 HB
- Hot-rolled plate (P), ≤ 75 mm, +AT: yield ≥ 220 MPa; tensile 520–670 MPa; elongation 40 %; hardness ≤ 215 HB
- Bar ≤ 160 mm, +AT (EN 10088-3): yield ≥ 200 MPa; tensile 500–700 MPa; elongation 40 %; hardness ≤ 215 HB
- Rp0.2 at 300 °C (EN 10028-7): yield ≥ 145 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 500 °C (EN 10028-7): yield ≥ 125 MPa; tensile — MPa; elongation — %; hardness —
Solution annealed 1020–1120 °C. Elevated-temperature minimums per EN 10028-7 (pressure-vessel plate).
Impact: 60 J at -196 °C (typical)

Equivalents:
- 316Ti (AISI / SAE) — identical: UNS S31635 (ASTM A240 316Ti): C ≤ 0.08, Cr 16–18, Ni 10–14, Mo 2–3, Ti 5×(C+N)–0.70. Rarely stocked in the USA.
- 320S31 (BS (superseded British)) — identical: BS 1449 320S31.
- 06Cr17Ni12Mo2Ti (GB/T (China)) — identical: GB/T 20878 06Cr17Ni12Mo2Ti (formerly 0Cr18Ni12Mo2Ti).
- 10Kh17N13M2T (GOST (Russia/CIS)) — identical: GOST 5632 10Kh17N13M2T: C ≤ 0.10, Cr 16–18, Ni 12–14, Mo 2–3, Ti 5×C–0.7 — the Russian workhorse Mo grade.
- SUS316Ti (JIS (Japan)) — identical: JIS G4304 SUS316Ti: C ≤ 0.08, Cr 16–18, Ni 10–14, Mo 2–3, Ti ≥ 5×C.
- 316L (AISI / SAE) — near: Same corrosion class; 316L achieves weld-zone stability by low carbon instead of Ti. Usual substitute outside Europe.
- 316 (AISI / SAE) — near: 316Ti — Ti-stabilized; equivalent corrosion class, better at 400–550 °C.
- 1.4404 (EN (European)) — near: Low-carbon route to the same stability; better polish, slightly lower strength.
- 1.4401 (EN (European)) — near: Unstabilized 316; sensitizes in thick welds.

Superseded names:
- X10CrNiMoTi18 10 — DIN 17440 (withdrawn): Same number 1.4571; name changed in EN 10088.
- 320S31 — BS 1449: British 316Ti.
- Z6CNDT17-12 — NF A 35-573

Product forms: hot-rolled plate (dominant form); cold-rolled sheet; bar, forgings, profiles; seamless and welded pipe (EN 10216-5 / 10217-7); fittings and flanges
Tolerances: plate: EN 10029; cold-rolled: EN ISO 9445-2; bar: EN 10278 / EN 10060

### 1.4571 yield strength
Rp0.2 ≥ 220 MPa plate, ≥ 240 MPa cold-rolled (≈ 32–35 ksi); at 300 °C ≥ 145 MPa, at 500 °C ≥ 125 MPa (EN 10028-7).

### 1.4571 tensile strength
520–670 MPa plate, 540–690 MPa cold-rolled.

### 1.4571 hardness
Max 215 HB solution annealed; not hardenable by heat treatment.

### Corrosion and heat resistance
PREN ≈ 24; intergranular corrosion resistant in the as-welded and 500–800 °C-exposed condition (EN ISO 3651-2 passes without sensitization). Maximum continuous service ≈ 550 °C for pressure parts; scaling resistance in air to ~850 °C.

### Physical properties
Density 8.0 g/cm³, E = 200 GPa, expansion 16.5 × 10⁻⁶/K, conductivity 15 W/m·K, non-magnetic annealed.

### Heat treatment
Solution anneal 1020–1120 °C, quench in water or air. Stabilizing anneal (870–900 °C) is possible for maximum intergranular resistance.

### Weldability
Very good weldability; filler 19 12 3 Nb (ER318) or 19 12 3 L (ER316L). Titanium does not transfer across the arc, so unstabilized filler is acceptable when C ≤ 0.03 %. No preheat, interpass ≤ 150 °C, no PWHT required. Pickle welds for corrosive service.

### Machining, forming, heat treatment
Machinability ≈ 40 %; TiC particles increase tool wear slightly relative to 1.4404. Forming and bending excellent; polishing to mirror finish is difficult (streaking). Preferred for heavy plate, forged flanges and machined pressure parts rather than decorative sheet.

Applications: Pressure vessels, columns and heat exchangers to EN 10028-7 / AD 2000 (German-spec projects); Chemical and petrochemical piping and valves; Exhaust systems, flue-gas ducting and scrubbers; Textile, paper and pulp equipment; Food industry heavy equipment (non-polished); Structural parts in warm marine and de-icing environments

Q: Is 1.4571 the same as 316L?
A: Not identical but equivalent in corrosion class. 1.4571 (316Ti) is titanium-stabilized with up to 0.08 % C; 316L is low-carbon (≤ 0.03 %). Both resist weld sensitization. 316L can generally replace 1.4571 for ambient service; for service above 400 °C, 1.4571 is superior.

Q: What is the ASTM equivalent of 1.4571?
A: UNS S31635 / ASTM A240 Type 316Ti. Because it is seldom stocked in North America, specifications usually allow 316L (S31603) as an alternative.

Q: Why does 1.4571 not polish well?
A: Titanium combines with carbon and nitrogen into hard TiC/TiN particles that appear as streaks and pin-holes on a bright-polished surface. For mirror or hygienic finishes use 1.4404.

Q: What is 1.4571 used for?
A: Pressure equipment and piping in the chemical, petrochemical and power industries, exhaust and flue-gas systems, heat exchangers, and heavy plate structures in corrosive environments — especially in projects built to German standards (AD 2000, EN 13445 with EN 10028-7).

Q: What does V4A mean?
A: V4A is a Krupp trade name from the early years of stainless steel and is used colloquially in German-speaking industry for the molybdenum-bearing group — 1.4401, 1.4404 and 1.4571. V2A refers to the group without molybdenum, around 1.4301.

---

## SAE 1010 (1.0301) [G10100] — Low-carbon steel for cold forming, welding and case hardening
URL: https://steelstandart.com/grade/1010/
System: ASTM / ASME | Family: Carbon steel | Standard: ASTM A29 | Verified against: ASTM A29/A29M-20
Aliases: AISI 1010, C10, CK10, S10C, UNS G10100

SAE 1010 sits at the bottom of the plain-carbon ladder, and that is exactly why it is everywhere. With 0.10 % carbon the steel is soft, ductile and completely weldable; it cold heads into bolts, roll forms into tube, draws into wire and takes a carburized case when a hard surface is needed on a soft core. It is not a strength grade and was never meant to be — a hot-rolled 1010 bar yields around 180 MPa, less than structural S235.

The designation comes from the SAE-AISI four-digit system: the first two digits describe the alloy family (10 = plain carbon, no alloying), the last two the nominal carbon content in hundredths of a percent. So 1010 is a plain carbon steel with about 0.10 % C. ASTM A29 is the standard that governs bar; sheet and strip in the same chemistry are ordered against A1011 or A1008 by forming class rather than by the 1010 number, which is a frequent source of confusion in enquiries.

The European equivalent is C10 (1.0301) under EN 10084, a case-hardening standard, and the Japanese equivalent is S10C under JIS G4051. Both are close enough on chemistry to be treated as the same steel; what differs is the surrounding standard's requirements for hardenability and case depth.

Chemical composition (mass %): C 0.08 – 0.13; Mn 0.3 – 0.6; P ≤ 0.03; S ≤ 0.05
That is the whole specification — four elements. Silicon is not specified for 10xx bar grades unless the steel is killed, in which case 0.15–0.35 % is usual. The 10xx family means plain carbon: the last two digits are the carbon content in hundredths of a percent, so 1010 is nominally 0.10 % C.

Mechanical properties:
- hot rolled bar: yield 180 MPa; tensile 325 MPa; elongation 28 %; hardness 95 HB
- cold drawn bar: yield 305 MPa; tensile 365 MPa; elongation 20 %; hardness 105 HB
- annealed: yield 170 MPa; tensile 310 MPa; elongation 32 %; hardness 90 HB
- normalized (925 °C): yield 205 MPa; tensile 365 MPa; elongation 30 %; hardness 110 HB
Typical values — ASTM A29 does not guarantee mechanical properties for bar, only chemistry. Sheet and strip carry mechanical requirements through A1011 and A1008.
Impact: 0 J at 20 °C °C (not specified)

Equivalents:
- C10 (EN (European)) — near: EN 10084 C10 / 1.0301: 0.07–0.13 % C, 0.30–0.60 % Mn — the same steel in European designation, used as a case-hardening grade. The EN standard adds hardenability and case-depth requirements that SAE 1010 does not carry.
- S10C (JIS (Japan)) — near: JIS G4051 S10C: 0.08–0.13 % C, 0.30–0.60 % Mn, Si 0.15–0.35. Practically identical chemistry with silicon specified.
- 1008 (ASTM / ASME) — functional: SAE 1008 (0.10 % C max) is one step softer and is preferred for the deepest drawing and for wire that will be cold headed. 1010 is the better compromise when the part also has to hold a thread or a form.
- 1015 / 1018 (ASTM / ASME) — functional: One and two steps up in carbon. 1018 (0.15–0.20 % C) is the usual choice when 1010 is too soft to hold a machined feature — it is the most common carburizing and general machining bar in the US.
- DC01 (EN (European)) — functional: For cold-rolled sheet the practical European counterpart is DC01 rather than C10, because sheet is specified by forming behaviour, not by bar chemistry.

Superseded names:
- C10 — EN 10084 / DIN 17210: the European case-hardening equivalent, 1.0301
- CK10 — DIN 17210: the cleaner (low P and S) version
- S10C — JIS G4051: Japanese machine structural carbon steel

Product forms: hot-rolled bar and coil; cold-drawn bar; hot- and cold-rolled sheet and strip; welded tube; wire and fasteners
Tolerances: Bar to ASTM A29; cold-drawn to A108. Sheet products are usually ordered against A1011 (hot) or A1008 (cold) rather than by the 1010 number.

### SAE 1010 tensile strength
325 MPa (47 ksi) hot rolled, 365 MPa (53 ksi) cold drawn. Yield 180 MPa hot rolled, 305 MPa cold drawn — cold work nearly doubles the yield while cutting elongation from 28 % to 20 %.

### Hardness
95 HB hot rolled, 105 HB cold drawn, 90 HB annealed. After carburizing and quenching the case reaches 58–62 HRC with a core that stays around 150 HB.

### Carburizing
The main heat treatment for this grade. Carburize at 900–925 °C, direct quench or reheat to 780–820 °C and quench in oil or water, then temper at 150–200 °C. Case depths of 0.5–1.5 mm are routine; core strength stays low, which is what makes it a *case-hardening* rather than a through-hardening steel.

### Cold forming
Excellent. Bends flat on itself in sheet, cold heads without intermediate annealing in wire, and deep draws when supplied as sheet to a drawing class. Work hardening is modest, so multi-stage forming rarely needs an anneal between operations.

### Physical data
Density 7.87 kg/dm³; modulus 205 GPa; thermal conductivity 49.8 W/mK at 20 °C; specific heat 448 J/kgK; electrical resistivity 0.143 µΩ·m.

### Weldability
Among the most weldable steels in production. Carbon equivalent is about 0.20, so no preheat, no interpass control and no post-weld heat treatment are needed at any thickness normally supplied. MIG, TIG, stick, resistance and laser welding all work with standard mild-steel consumables (ER70S-6, E7018). The one caution is that the weld metal is usually stronger than the base metal, so a welded joint in 1010 fails in the parent plate rather than the weld — which matters when designing a test coupon.

### Machining, forming, heat treatment
Machinability rating about 55 % of B1112, and the difficulty is softness rather than hardness: 1010 tears and builds up on the tool edge rather than chipping cleanly. Use sharp positive-rake tooling, high surface speeds and plenty of coolant, or specify a resulfurized grade (1117, 12L14) where the part is machined rather than formed. Cold-drawn bar machines noticeably better than hot-rolled because the surface is harder and the chip breaks earlier.

Applications: Cold-headed fasteners, rivets, nails and wire products; Welded tube and roll-formed sections; Carburized pins, bushings, shafts and small gears; Pressed and deep-drawn sheet parts, enclosures and covers; Automotive brackets, clips and non-structural body parts; Chain, wire mesh and general low-stress fabrication

Q: What is SAE 1010 steel?
A: A plain low-carbon steel with 0.08–0.13 % carbon and 0.30–0.60 % manganese, used for cold forming, welding and case hardening. Tensile strength is about 325 MPa hot rolled and 365 MPa cold drawn.

Q: What is the equivalent of SAE 1010?
A: EN 10084 C10 / 1.0301 in Europe and JIS G4051 S10C in Japan; both share the chemistry. For cold-rolled sheet the practical European counterpart is DC01, because sheet is specified by forming class rather than bar chemistry.

Q: What is the difference between 1010 and 1018?
A: Carbon: 1010 has 0.08–0.13 %, 1018 has 0.15–0.20 %. 1018 is stronger, machines better and is the default general-purpose bar in the US; 1010 forms and cold heads better and is the better carburizing base when core strength does not matter.

Q: Can SAE 1010 be hardened?
A: Not through-hardened — the carbon is too low. It is case hardened by carburizing at 900–925 °C followed by quench and low temper, giving a 58–62 HRC case over a soft core.

Q: Is 1010 steel weldable?
A: Yes, exceptionally. The carbon equivalent is around 0.20, so no preheat or post-weld heat treatment is required by any common process.

Q: What does the number 1010 mean?
A: In the SAE-AISI system the first two digits give the alloy family — 10 means plain carbon with no alloying — and the last two give the nominal carbon content in hundredths of a percent, so 1010 is about 0.10 % C.

---

## 1018 [G10180] — Low-carbon steel, cold-finished bar (case-hardenable)
URL: https://steelstandart.com/grade/1018/
System: AISI / SAE | Family: Carbon steel | Standard: ASTM A29 | Verified against: ASTM A29/A29M-20 (SAE J403 chemistry)
Aliases: AISI 1018, SAE 1018, 1018 steel, 1018 mild steel, 1018 CRS, 1018 cold rolled, C1018, G10180, 1018 carbon steel, 1018 bar

AISI 1018 is the general-purpose low-carbon steel of North American machine shops: 0.15–0.20 % carbon and 0.6–0.9 % manganese, UNS G10180, sold overwhelmingly as cold-drawn bar ('1018 CRS') in rounds, squares, hexes and flats with a smooth, close-tolerance surface. Cold drawing raises the yield from about 220 MPa (hot-rolled) to 350–400 MPa and gives a bright finish that often needs no further machining — which is why 1018 is the default for shafts, spacers, pins, keys, fixtures, brackets and prototype parts that will not be heat-treated.

Its other role is case hardening: the low carbon core stays tough while carburizing produces a 58–62 HRC skin, so 1018 is used for pins, gears and cam followers in light service. Through-hardening is not possible. Weldability is excellent (CE ≈ 0.3) and it forms, bends and machines easily, though the low carbon makes it 'gummy' with built-up edge on tools.

There is no exact EN grade: C15 (lower Mn) is the case-hardening match, S235JRC or C22 the bright-bar substitute; JIS S17C/S20C, GB 20 and BS 080A17 are near or identical. When a drawing says 1018 for a plate, the buyer usually receives A36 or A1011 CS.

Chemical composition (mass %): C 0.15 – 0.2; Mn 0.6 – 0.9; P ≤ 0.04; S ≤ 0.05
SAE J403 / ASTM A29 (G10180). Si is not specified for 10xx bar (typically 0.15–0.30). Compare EN C15 (C 0.12–0.18, Mn 0.30–0.60), C20 / C22 (C 0.17–0.24, Mn 0.40–0.70) — 1018 sits between them with higher Mn.

Mechanical properties:
- Cold drawn (as drawn), 16–22 mm — typical: yield ≈ 370 MPa; tensile ≈ 440 MPa; elongation 15 %; hardness ≈ 126 HB
- Cold drawn, 22–32 mm — typical: yield ≈ 345 MPa; tensile ≈ 420 MPa; elongation 15 %; hardness ≈ 121 HB
- Cold drawn, 32–50 mm — typical: yield ≈ 310 MPa; tensile ≈ 400 MPa; elongation 15 %; hardness ≈ 116 HB
- Cold drawn + stress relieved (A108 SR) — typical: yield ≈ 400 MPa; tensile ≈ 450 MPa; elongation 18 %; hardness ≈ 130 HB
- Hot rolled — typical: yield ≈ 220 MPa; tensile ≈ 400 MPa; elongation 25 %; hardness ≈ 116 HB
- Normalized (925 °C) — typical: yield ≈ 235 MPa; tensile ≈ 420 MPa; elongation 28 %; hardness ≈ 121 HB
- Annealed (870 °C) — typical: yield ≈ 205 MPa; tensile ≈ 385 MPa; elongation 30 %; hardness ≈ 111 HB
- Carburized & hardened — surface: yield — MPa; tensile — MPa; elongation — %; hardness 58–62 HRC (case), core ≈ 20 HRC
AISI 1018 is specified by chemistry; mechanical values are typical (ASM / A108 guidance) and vary with bar size and reduction. ASTM A108 gives no strength minimums unless a special condition (e.g. SR) is ordered.
Impact: 80 J at 20 °C (typical, hot rolled / normalized)

Equivalents:
- 080A17 (BS (superseded British)) — identical: BS 970 080A17: C 0.15–0.20, Mn 0.70–0.90.
- 1020 (AISI / SAE) — near: C 0.18–0.23, Mn 0.30–0.60: slightly higher carbon, lower Mn; used interchangeably for many parts.
- 1015 / 1010 (AISI / SAE) — near: Lower-carbon cold-heading grades.
- C15 / C15E (EN (European)) — near: C 0.12–0.18, Mn 0.30–0.60 — lower Mn; the case-hardening equivalent. C16E (1.1148) and C20/C22 are also quoted.
- S235JRC / C22 (EN (European)) — near: EN 10277 bright bar S235JRC (1.0122) is the general-purpose cold-drawn substitute; C22 (C 0.17–0.24) the closer chemistry.
- C15 (EN (European)) — near: C 0.15–0.20, Mn 0.60–0.90; the US stock grade most often supplied against a C15 request.
- 20 (GB/T (China)) — near: GB/T 699 grade 20 (20#): C 0.17–0.23, Mn 0.35–0.65 — slightly higher C, lower Mn.
- 20 / 18kp (GOST (Russia/CIS)) — near: GOST 1050 Steel 20: C 0.17–0.24, Mn 0.35–0.65.
- S15C / S17C / S20C (JIS (Japan)) — near: JIS G4051 S17C (C 0.15–0.20, Mn 0.30–0.60) is closest on carbon; S20C on strength.
- 12L14 (AISI / SAE) — functional: Free-machining leaded steel for high-volume screw-machine parts (not weldable, not case-hardenable).
- A36 (ASTM / ASME) — functional: Structural plate/shape with guaranteed 250 MPa yield — the alternative for welded structures; 1018 is a bar product with no guaranteed properties.

Superseded names:
- C1018 — AISI (pre-1960s prefix): C = basic open-hearth; still used in catalogues.
- G10180 — UNS
- 080A17 / 080M15 — BS 970
- C15 / C20 — EN 10084 / 10083: Bracketing European grades.
- St 37-3 K (bright bar) — DIN 1652 (withdrawn): German bright-bar equivalent, now EN 10277 S235JRC / C15.

Product forms: cold-finished (cold-drawn) bar — round, square, hex, flat (ASTM A108): the signature form ('1018 CRS'); hot-rolled bar (A29 / A575 / A576); seamless DOM tube (A513 type 5), welded tube (A513); forgings, wire, cold-heading wire (A510); plate and sheet are usually A36 / A1011 / A1008 rather than '1018'
Tolerances: cold-finished bar: ASTM A108 (typ. −0.05 mm on rounds ≤ 25 mm; h10–h11); hot-rolled bar: ASTM A29 / A6; DOM tube: ASTM A513

### 1018 steel yield strength
Cold-drawn ≈ 370 MPa (54 ksi) in 16–22 mm rounds (decreasing to ≈ 310 MPa at 50 mm); stress-relieved cold-drawn ≈ 400 MPa; hot-rolled ≈ 220 MPa (32 ksi); annealed ≈ 205 MPa.

### 1018 tensile strength
Cold-drawn ≈ 440 MPa (64 ksi); hot-rolled ≈ 400 MPa (58 ksi); annealed ≈ 385 MPa; carburized core ≈ 500–600 MPa.

### 1018 hardness
Cold-drawn ≈ 126 HB (≈ 71 HRB); hot-rolled ≈ 116 HB; annealed ≈ 111 HB. Carburized case 58–62 HRC (0.5–1.5 mm typical); through-hardening not possible (as-quenched ≈ 35–40 HRC in very thin sections only).

### Heat treatment
Anneal 870–900 °C, furnace cool. Normalize 900–925 °C (1650–1700 °F), air. Stress relieve cold-drawn bar 500–600 °C (A108 condition SR). Carburize 900–930 °C, direct or single quench in water/brine from 790–820 °C (oil for distortion-sensitive parts), temper 150–200 °C. Ac1 ≈ 725 °C, Ac3 ≈ 845 °C.

### Machinability
≈ 70–78 % of B1112 (cold-drawn) — good but gummy; sharp tools, positive rake, higher feeds to avoid built-up edge. 1117/1141 or 12L14 are the free-machining alternatives; 1018 machines better than 1020 hot-rolled thanks to the cold-drawn surface.

### Physical properties
Density 7.87 g/cm³ (0.284 lb/in³), E = 205 GPa (29.7 × 10⁶ psi), expansion 11.7 × 10⁻⁶/K (20–100 °C), conductivity 51.9 W/m·K, specific heat 486 J/kg·K.

### Weldability
Excellent weldability by all processes (CE ≈ 0.30): MIG (ER70S-6), TIG, stick (E6013/E7018), resistance and laser, no preheat, no PWHT. Cold-drawn bar loses its cold-work strength in the HAZ (reverts to ≈ 220 MPa yield) — design welded 1018 assemblies on hot-rolled properties. Do not weld carburized surfaces.

### Machining, forming, heat treatment
Good machinability with HSS or carbide; typical turning 60–90 m/min HSS, 150–250 m/min carbide. Chip control is poor (long stringy chips) — use chip breakers. Cold forming, bending (1 t radius), swaging and cold heading are excellent in the annealed or hot-rolled condition; cold-drawn bar has reduced ductility and may crack on sharp bends. Surface treatments: carburizing/carbonitriding, zinc/nickel/chrome plating, black oxide, phosphate.

Applications: Shafts, spacers, pins, dowels, keys, studs for machinery and fixtures; Prototype and low-stress machined parts, jigs and tooling bodies; Case-hardened pins, gears, ratchets, cam followers in light service; Hydraulic and pneumatic cylinder tubes (DOM, A513 type 5); Cold-headed bolts and rivets, tie rods, anchor bolts; Welded brackets, frames and general fabrication (hot-rolled); Chain links, agricultural and lawn-equipment parts

Q: What is the difference between 1018 and A36?
A: 1018 is an AISI bar grade defined by chemistry (0.15–0.20 % C) and sold mainly cold-drawn with ~370 MPa yield; A36 is an ASTM structural specification for plate and shapes with a guaranteed 250 MPa minimum yield and looser chemistry (C ≤ 0.25–0.29 %). Use 1018 for machined bar parts, A36 for welded structures and plate.

Q: Which is stronger, 1018 or 4140?
A: 4140 by a wide margin: even annealed 4140 (≈ 415 MPa yield) exceeds cold-drawn 1018 (≈ 370 MPa), and heat-treated 4140 reaches 900–1600 MPa. 1018 cannot be through-hardened. Choose 1018 for cheap, weldable, low-stress parts; 4140 for strength.

Q: Can 1018 be hardened?
A: Only on the surface by carburizing or carbonitriding (58–62 HRC case). Its 0.18 % carbon is too low for through-hardening; quenching alone gives at most 35–40 HRC in very thin sections.

Q: What does 1018 CRS mean?
A: Cold-Rolled Steel — strictly cold-drawn bar (ASTM A108): pickled hot-rolled bar pulled through a die, giving a bright surface, tight tolerance and higher yield strength (≈ 370 MPa vs 220 MPa hot-rolled).

Q: Is 1018 weldable?
A: Yes, one of the most weldable steels — no preheat, any process, ER70S-6 or E7018. The heat-affected zone loses the strength gained by cold drawing, so welded joints should be designed on hot-rolled strength.

Q: What is 1018 equivalent to in EN?
A: No exact match. C15/C15E (1.0401/1.1141) for case-hardening use, C22 or S235JRC (EN 10277 bright bar) for general machining. JIS S17C/S20C, GB 20 and BS 080A17 are the closest.

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## 1045 [G10450] — Medium-carbon steel, hardenable
URL: https://steelstandart.com/grade/1045/
System: AISI / SAE | Family: Carbon steel | Standard: ASTM A29 | Verified against: ASTM A29/A29M-20 (SAE J403 chemistry)
Aliases: AISI 1045, SAE 1045, 1045 steel, 1045 carbon steel, C1045, G10450, 1045 medium carbon, 1045 TGP, 1045 CRS, 1045 HR, 080M46, S45C AISI, 45 GB, 45 GOST

AISI 1045 is the medium-carbon workhorse: 0.43–0.50 % carbon, 0.6–0.9 % manganese, no alloying, UNS G10450 — the American twin of EN C45, JIS S45C and GB/GOST 45. It is the cheapest steel that can be usefully hardened: through-hardening in water works up to about 20–25 mm, and flame or induction hardening gives a 55–58 HRC wear surface on shafts, gears and rollers of any size while the core stays at ~180 HB. Most 1045 is used either as-rolled/cold-drawn for shafting, or surface-hardened.

Cold-drawn 1045 bar reaches roughly 530 MPa yield and 625 MPa tensile — about 40 % above 1018 — and it is the standard material for turned-ground-and-polished (TGP) and induction-hardened chrome-plated shafting used in linear bearings and hydraulic cylinders. Normalized or Q&T it serves for axles, bolts (SAE Grade 5), crankshafts in small engines, spindles, gears, sprockets and machine parts of moderate size.

The price of the higher carbon is weldability: 1045 needs 200–300 °C preheat and post-weld tempering, and it is more prone to quench cracking than 1040. Machinability is still good (≈ 55–60 %).

Chemical composition (mass %): C 0.43 – 0.5; Mn 0.6 – 0.9; P ≤ 0.04; S ≤ 0.05
SAE J403 / ASTM A29 (G10450). Si typically 0.15–0.35 (not specified). Compare EN C45 (C 0.42–0.50, Mn 0.50–0.80, Cr/Mo/Ni capped) and C45E (P ≤ 0.030).

Mechanical properties:
- Hot rolled — typical: yield ≈ 310 MPa; tensile ≈ 565 MPa; elongation 16 %; hardness ≈ 163 HB
- Cold drawn, 16–22 mm — typical: yield ≈ 530 MPa; tensile ≈ 625 MPa; elongation 12 %; hardness ≈ 179 HB
- Cold drawn, 22–32 mm — typical: yield ≈ 485 MPa; tensile ≈ 600 MPa; elongation 12 %; hardness ≈ 170 HB
- Annealed (790 °C) — typical: yield ≈ 310 MPa; tensile ≈ 565 MPa; elongation 20 %; hardness ≈ 163 HB
- Normalized (900 °C) — typical: yield ≈ 410 MPa; tensile ≈ 620 MPa; elongation 22 %; hardness ≈ 187 HB
- Q&T (water), tempered 540 °C, 25 mm — typical: yield ≈ 530 MPa; tensile ≈ 760 MPa; elongation 18 %; hardness ≈ 220 HB
- Q&T (water), tempered 425 °C — typical: yield ≈ 620 MPa; tensile ≈ 850 MPa; elongation 15 %; hardness ≈ 255 HB
- Q&T (water), tempered 315 °C — typical: yield ≈ 700 MPa; tensile ≈ 960 MPa; elongation 12 %; hardness ≈ 290 HB
- As-quenched (water), surface: yield — MPa; tensile — MPa; elongation — %; hardness 55–60 HRC
Typical values (ASM), 25 mm rounds; hardenability is low so Q&T figures apply to the surface and to sections ≤ 20–25 mm. Induction/flame-hardened surface 55–58 HRC with soft core ≈ 165–190 HB.
Impact: 30 J at 20 °C (typical, normalized; ≈ 15 J cold drawn)

Equivalents:
- 080M46 (BS (superseded British)) — identical: BS 970 080M46: C 0.42–0.50, Mn 0.60–1.00.
- C45 (EN (European)) — identical: 1.0503: C 0.42–0.50, Mn 0.50–0.80; C45E (1.1191) the cleaner version — dual-certified 1045/C45 bar is standard.
- 45 (GOST (Russia/CIS)) — identical: GOST 1050 Steel 45: C 0.42–0.50, Mn 0.50–0.80.
- S45C (JIS (Japan)) — identical: JIS G4051 S45C: C 0.42–0.48, Mn 0.60–0.90.
- 1050 (AISI / SAE) — near: C 0.48–0.55: slightly higher carbon and hardness for the same treatments.
- 1040 (AISI / SAE) — near: C 0.37–0.44: slightly lower carbon, better weldability.
- 4140 (AISI / SAE) — functional: Alloyed alternative with deep hardenability for sections > 25 mm and higher toughness.
- 1144 (AISI / SAE) — functional: Resulfurized 0.44 % C free-machining bar ('Stressproof') for high-volume screw-machine shafts.
- 080M40 (BS (superseded British)) — functional: AISI 1045 is 0.43–0.50 % C — the American counterpart of 080M46. Against 080M40 it is one carbon step higher; AISI 1040 is the true match, at 0.37–0.44 % C.

Superseded names:
- C1045 — AISI (pre-1960s)
- G10450 — UNS: 1045H = H10450 hardenability band.
- 080M46 / 080A47 — BS 970: 080M46 ≈ 1045 (Mn 0.60–1.00).
- C45 / Ck45 / C45E — EN 10083 / DIN 17200: European twins.
- XC45 / XC48 — NF A 35-552

Product forms: hot-rolled and cold-drawn bar (ASTM A29, A108, A576); turned, ground & polished (TGP) shafting; induction-hardened chrome-plated shafting; plate (A830 1045), forgings (A29 / A521), seamless tube (A519); wire, rail-type sections
Tolerances: cold-finished bar: ASTM A108; hot-rolled bar: ASTM A29 / A6; TGP shafting: ASTM A108 + supplier tolerance (typ. h6–h8)

### 1045 steel yield strength
Hot-rolled ≈ 310 MPa (45 ksi); cold-drawn ≈ 530 MPa (77 ksi) in 16–22 mm rounds; normalized ≈ 410 MPa; Q&T tempered 540 °C ≈ 530 MPa, 425 °C ≈ 620 MPa, 315 °C ≈ 700 MPa (≤ 25 mm).

### 1045 tensile strength
Hot-rolled ≈ 565 MPa (82 ksi); cold-drawn ≈ 625 MPa (91 ksi); normalized ≈ 620 MPa; Q&T 760–960 MPa depending on temper (≤ 25 mm).

### 1045 hardness
Hot-rolled / annealed ≈ 163 HB; cold-drawn ≈ 179 HB; normalized ≈ 187 HB; Q&T 220–290 HB; as-quenched (water) 55–60 HRC at the surface; flame/induction-hardened surface 55–58 HRC, case depth 1.5–5 mm.

### Heat treatment
Anneal 790–870 °C, furnace cool. Normalize 870–925 °C (1600–1700 °F), air. Harden 820–850 °C (1500–1560 °F), water or brine quench (oil for thin, simple shapes); temper 205–650 °C, avoid 230–370 °C. Induction/flame harden to 55–58 HRC, temper 150–200 °C. Stress relieve 550–650 °C. Ac1 ≈ 725 °C, Ac3 ≈ 780 °C, Ms ≈ 340 °C. Ideal critical diameter ≈ 20–25 mm (water).

### Machinability
≈ 55–60 % of B1112 (hot-rolled / cold-drawn) — good with carbide; better chip control than 1018. 1144 / 1146 are the free-machining alternatives.

### Physical properties
Density 7.85 g/cm³, E = 205 GPa, expansion 11.7 × 10⁻⁶/K, conductivity 49.8 W/m·K, specific heat 486 J/kg·K.

### Weldability
Limited weldability (CE ≈ 0.55–0.65): preheat 200–300 °C, low-hydrogen consumables (E7018 / ER70S-6), interpass control, slow cooling, temper or stress-relieve at 550–650 °C afterwards. Weld before hardening; never weld induction-hardened surfaces. For welded assemblies use 1020/A36 for the structure and 1045 only for the machined insert.

### Machining, forming, heat treatment
Turning, milling, drilling and threading with HSS or carbide are all routine; cold-drawn and normalized conditions give the best finish. Machine before hardening. Cold forming is limited (annealed condition, generous radii); hot forging 1200–850 °C followed by normalizing. Surface treatments: induction/flame hardening, hard chrome plating (shafting), nitriding (shallow), black oxide, zinc plating.

Applications: TGP shafting, induction-hardened chrome-plated shafts for linear bearings and hydraulic cylinders; Axles, spindles, drive shafts, pump shafts in general machinery; Gears, sprockets, ratchets and pinions with induction-hardened teeth; Bolts and studs SAE Grade 5, threaded rod, U-bolts; Crankshafts and connecting rods for small engines, compressors; Hand tools, hammers, wrenches (forged), agricultural wear parts (flame-hardened); Rolls, rams, couplings, keys and machine parts up to ~60 mm

Q: Is 1045 the same as C45?
A: Yes. AISI 1045 (C 0.43–0.50, Mn 0.60–0.90) and EN C45 (C 0.42–0.50, Mn 0.50–0.80) overlap almost completely; mills dual-certify 1045/C45/S45C. C45E is the cleaner, guaranteed-impact version.

Q: Which is stronger, 1045 or 4140?
A: 4140. Both have ~0.45 % C, but 4140's Cr and Mo let it through-harden in sections up to 50–75 mm and temper to a tougher structure; heat-treated 4140 reaches 900–1600 MPa versus 700–960 MPa for 1045 in thin sections. In the as-rolled condition the difference is smaller (≈ 655 vs 565 MPa tensile). 1045 is cheaper and slightly easier to machine.

Q: Can 1045 be hardened?
A: Yes: water-quench from 820–850 °C for 55–60 HRC at the surface, through-hardening only to about 20–25 mm; or flame/induction-harden the surface to 55–58 HRC on any size. Temper afterwards (150–200 °C for surface hardening, higher for Q&T).

Q: Is 1045 weldable?
A: With precautions: 200–300 °C preheat, low-hydrogen filler and post-weld tempering. Without preheat the heat-affected zone hardens and cracks. Use lower-carbon steel where welding is the main joining method.

Q: What is 1045 used for?
A: Shafts (especially TGP and induction-hardened chrome-plated shafting), axles, gears, bolts, spindles, hand tools and any medium-strength machine part that will be surface-hardened rather than through-hardened.

Q: What is 1045 equivalent to in JIS and GB?
A: JIS S45C and GB/T 699 grade 45 (45#) are identical; GOST Steel 45 and BS 080M46 as well.

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## 1095 [G10950] — High-carbon steel (spring / knife / blade steel)
URL: https://steelstandart.com/grade/1095/
System: AISI / SAE | Family: Spring steel | Standard: ASTM A29 | Verified against: ASTM A29/A29M-20 (SAE J403 chemistry)
Aliases: AISI 1095, SAE 1095, 1095 steel, 1095 high carbon steel, 1095 knife steel, 1095 spring steel, C1095, G10950, 1095 blue temper, C100S, 1.1274, CS100, SK4

AISI 1095 is the highest-carbon member of the plain-carbon 10xx series: 0.90–1.03 % carbon with only 0.3–0.5 % manganese, UNS G10950. Above the eutectoid composition it forms excess cementite, which gives excellent edge retention and wear resistance after hardening to 64–66 HRC — the reason 1095 has been the standard American knife, sword, saw-blade and spring-clip steel for a century. Blades are tempered to 56–62 HRC; springs, clock springs and blue-tempered strip to 44–50 HRC.

Because it contains no alloying elements, hardenability is very low: a fast quench (brine or a fast quench oil) and thin sections (< 6 mm) are needed for full hardness, and the steel is unforgiving of slow quenches (pearlite forms in about one second). This makes 1095 easy to differentially harden — a clay-coated back stays soft while the edge hardens — but it also means 1095 is not a through-hardening steel for thick parts. Toughness is modest and corrosion resistance nil (blades rust without oil).

EN C100S (1.1274), JIS SK95 (SK4) and BS CS100 are the same steel; W1 tool steel is the tool-quality version; 1084 and 5160 are the tougher alternatives.

Chemical composition (mass %): C 0.9 – 1.03; Mn 0.3 – 0.5; P ≤ 0.04; S ≤ 0.05
SAE J403 / ASTM A29 (G10950). Si ≈ 0.15–0.30 typical (not specified). Compare EN C100S (1.1274): C 0.95–1.05, Mn 0.30–0.60, Si 0.15–0.35; JIS SK4 (SK95): C 0.90–1.00; DIN Ck101.

Mechanical properties:
- Annealed (spheroidized) strip — typical: yield ≈ 380 MPa; tensile ≈ 650 MPa; elongation 13 %; hardness ≈ 190 HB (max 210)
- Hot rolled bar — typical: yield ≈ 460 MPa; tensile ≈ 965 MPa; elongation 9 %; hardness ≈ 293 HB
- Normalized (900 °C) — typical: yield ≈ 500 MPa; tensile ≈ 1015 MPa; elongation 9 %; hardness ≈ 293 HB
- Blue-tempered spring strip (A682), 44–50 HRC — typical: yield ≈ 1100–1300 MPa; tensile ≈ 1400–1700 MPa; elongation 3 %; hardness 44–50 HRC
- Q&T, tempered 540 °C (1000 °F) — typical: yield ≈ 690 MPa; tensile ≈ 1000 MPa; elongation 13 %; hardness ≈ 300 HB
- Q&T, tempered 315 °C (600 °F) — typical: yield ≈ 950 MPa; tensile ≈ 1250 MPa; elongation 10 %; hardness ≈ 375 HB
- Knife blade, tempered 175–230 °C (350–450 °F): yield — MPa; tensile — MPa; elongation — %; hardness 58–62 HRC
- As-quenched (brine/fast oil, 800 °C): yield — MPa; tensile — MPa; elongation — %; hardness 64–66 HRC
Typical values (ASM / strip-producer data). 1095 has very low hardenability (ideal critical diameter ≈ 15–20 mm in water); full hardness requires thin sections and fast quench (brine, Parks 50 or equivalent fast oil). Strip products are ordered by hardness (HRC / HV) rather than strength.
Impact: 10 J at 20 °C (typical, Q&T 300 HB; blades at 60 HRC ≈ 5–10 J unnotched)

Equivalents:
- CS100 (BS (superseded British)) — identical: BS 1449 CS100 carbon spring strip.
- C100S (EN (European)) — identical: 1.1274 (EN 10132-4 spring strip): C 0.95–1.05, Mn 0.30–0.60, Si 0.15–0.35.
- SK95 (SK4) (JIS (Japan)) — identical: JIS G4401 SK95: C 0.90–1.00, Mn 0.10–0.50 — the Japanese knife/saw grade; SK85 (SK5) is the 0.85 % C step.
- W1 (AISI / SAE) — near: AISI W1 water-hardening tool steel at 0.95–1.05 % C is chemically the same, supplied to tool-steel cleanliness (ASTM A686).
- 1084 / 1084 (AISI / SAE) — near: 0.84 % C: near-eutectoid, more forgiving heat treatment, slightly tougher — the beginner knifemaker's alternative.
- C90S / C98S (EN (European)) — near: 1.1217 / 1.1233 — adjacent carbon steps in EN spring-strip grades.
- T9A / T10A (GB/T (China)) — near: GB/T 1298 T10A: C 0.95–1.04, Mn ≤ 0.40 — Chinese carbon tool steel; T9A at 0.85–0.94.
- U9A / U10A (GOST (Russia/CIS)) — near: GOST 1435 U10A: C 0.95–1.09, Mn 0.17–0.33 (tool steel); 65G/70S2A are the spring steels.
- 5160 (AISI / SAE) — functional: 0.6 % C, 0.8 % Cr spring steel: far tougher, less edge retention — for swords, leaf springs and choppers.
- O1 (AISI / SAE) — functional: Oil-hardening tool steel (1.2510): deeper hardening, better wear, easier quench — the tool-shop upgrade.
- 52100 (AISI / SAE) — functional: Plain 0.95 % C: similar hardness, much lower hardenability, no chromium carbides — cheaper knife/spring alternative.
- 9260 (AISI / SAE) — functional: Plain 0.95 % carbon steel. Harder at the surface and much cheaper, but it has essentially no hardenability and no silicon, so it takes a permanent set where 9260 springs back.
- 1.2510 (EN (European)) — functional: Plain 0.95 % carbon steel: the same hardness at the surface but no hardenability — it must be water quenched and does not harden through beyond a few millimetres.

Superseded names:
- C1095 — AISI (pre-1960s): Still printed on knife blanks and saw blades.
- G10950 — UNS
- CS95 / CS100 — BS 1449 (withdrawn): Carbon spring strip.
- Ck101 / C100S — DIN 17222 / EN 10132-4: Cold-rolled spring strip.
- SK4 / SK95 — JIS G4401: SK4 (old) = SK95 (2000+).
- W1 (near) — AISI tool steel: W1 (0.6–1.4 % C water-hardening tool steel) — the same steel with tool-steel quality control.

Product forms: cold-rolled strip and flat stock (ASTM A684 / A682) — annealed or blue-tempered (hardened & tempered spring strip); hot-rolled and cold-drawn bar (A29, A108) — knife billets; wire (A228 music wire is a 0.8–0.95 C relative), plate (limited); flat ground stock for knifemakers
Tolerances: strip: ASTM A684 (annealed) / A682 (tempered); thickness commonly ±0.025 mm; bar: ASTM A29 / A108

### 1095 hardness
As-quenched 64–66 HRC (thin sections, fast quench); knives tempered 175–230 °C → 58–62 HRC; springs and blue-tempered strip → 44–50 HRC; annealed (spheroidized) ≈ 190 HB (max 210); hot-rolled ≈ 293 HB.

### 1095 yield and tensile strength
Annealed ≈ 380 / 650 MPa; hot-rolled ≈ 460 / 965 MPa; Q&T tempered 540 °C ≈ 690 / 1000 MPa; tempered 315 °C ≈ 950 / 1250 MPa; blue-tempered spring strip ≈ 1100–1300 / 1400–1700 MPa.

### Heat treatment
Spheroidize anneal 730–760 °C slow cool (for machining/forming). Normalize 870–900 °C (grain refinement after forging). Harden 790–815 °C (1450–1500 °F) — do not overheat (retained austenite, grain growth) — quench in brine or fast oil; thin blades can be water-quenched with care. Temper immediately: 175–230 °C for blades (58–62 HRC), 260–315 °C for chisels/punches (54–58 HRC), 370–450 °C for springs (44–50 HRC). Ac1 ≈ 725 °C, Acm ≈ 800 °C, Ms ≈ 215 °C. Quench must reach < 540 °C within ~1 s for full hardness.

### Edge retention and toughness
Wear resistance among the best of the plain-carbon steels (fine cementite); toughness low (≈ 5–10 J unnotched at 60 HRC), improving markedly at 56–58 HRC. Differential hardening (clay/hamon) or a soft spine gives sword-grade toughness with a hard edge.

### Corrosion resistance
None — plain carbon steel. Blades develop a patina and rust in humid storage; oil, wax or force a patina (vinegar/mustard) for protection.

### Physical properties
Density 7.85 g/cm³, E = 205 GPa, expansion 11.4 × 10⁻⁶/K, conductivity ≈ 50 W/m·K.

### Weldability
Not recommended (CE ≈ 1.0+). If unavoidable: preheat 300–400 °C, low-hydrogen filler, post-weld anneal at 730–760 °C, then re-harden. Forge-welding (damascus, san-mai) at 1100–1200 °C with flux is common in knifemaking; arc-welding of blades causes cracking.

### Machining, forming, heat treatment
Machinability ≈ 40–45 % of B1112 in the spheroidized condition (hard cementite wears tools; use carbide, low speed). Machine, grind and drill in the annealed state only; after hardening only grinding (with coolant to avoid burning) and EDM are practical. Cold forming: bending of annealed strip to ≥ 2 t; hot forging 1050–850 °C followed by normalizing and spheroidizing. Surface treatments: black oxide, parkerizing, cerakote; no plating on hardened blades without hydrogen bake.

Applications: Knife blades (fixed-blade, machetes, kukris), swords and axes; Saw blades: hand saws, band and circular saw bodies, scrapers; Flat and clock springs, spring clips, retaining rings, snap rings (blue-tempered strip); Cutting tools: chisels, punches, wood-working blades, shear blades (light duty); Agricultural blades: sickles, cutter bars, mower blades; Music wire relatives (A228) for coil springs; needles, pins, feeler gauges; Shim stock, doctor blades, feeler-gauge stock

Q: Is 1095 a good knife steel?
A: Yes for fixed-blade working knives: easy to sharpen, excellent edge retention among carbon steels, takes a very keen edge at 58–62 HRC and can be differentially hardened. Downsides: it rusts, has modest toughness at high hardness, and needs a fast quench that thin blades tolerate but thick ones do not.

Q: What is the difference between 1095 and 1084?
A: Carbon: 0.95 vs 0.84 %. 1084 is near-eutectoid, so it hardens fully with a slower (safer) quench and is slightly tougher; 1095 holds an edge a little longer and reaches higher maximum hardness (66 vs 65 HRC) but is less forgiving in heat treatment. Beginners usually start with 1084.

Q: How hard does 1095 get?
A: 64–66 HRC as-quenched in thin sections with a brine or fast-oil quench. Knives are tempered to 58–62 HRC, springs to 44–50 HRC. Thick sections (> 6–8 mm) will not through-harden because of the very low hardenability.

Q: What temperature do you heat-treat 1095 at?
A: Austenitize 790–815 °C (a dull cherry / just past non-magnetic), quench in brine or fast oil (must cool below ~540 °C within a second), temper immediately at 175–230 °C for blades (twice, 1–2 h each). Overheating above 850 °C causes grain growth and retained austenite.

Q: What is 1095 equivalent to in EN and JIS?
A: EN C100S (1.1274, spring strip) and JIS SK95 (formerly SK4) are the same steel; DIN Ck101 and BS CS100 as well. AISI W1 tool steel is the tool-quality version.

Q: Does 1095 rust?
A: Yes, readily — it has no chromium. Keep blades dry and oiled, or let them develop a stable patina; for corrosion resistance choose a stainless blade steel (440C, 154CM, VG-10, N690).

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## 16MnCr5 (1.7131) — Alloy case-hardening steel
URL: https://steelstandart.com/grade/16mncr5/
System: EN (European) | Family: Case-hardening steel | Standard: EN 10084 | Verified against: EN 10084:2008
Aliases: 16MnCrS5, 1.7139, 16 MnCr 5, 1.7131, 16MnCr5+A, 16MnCr5+FP, SCr415, 20CrMn, 18KhG, 527M17

16MnCr5 is the standard European case-hardening steel for gears: 0.16 % carbon for a tough core, 1.15 % Mn and 0.95 % Cr for hardenability, Werkstoff number 1.7131, specified in EN 10084. After carburizing to 0.8 % surface carbon and quenching, the case reaches 58–62 HRC while the core stays at roughly 780–1080 MPa tensile in small sections.

It occupies the middle of the EN 10084 hardenability ladder: above C15/C16E and 16MnCr5's own lower-band variants, below 20MnCr5, 18CrNiMo7-6 and the Ni-bearing grades used for large, heavily loaded gears. That makes it the economical choice for automotive gearbox gears, small pinions, camshafts, piston pins, bushings and any part that needs a hard, wear-resistant surface over a ductile core.

The usual delivery condition is +A (soft annealed) or +FP (treated to ferrite–pearlite for machining). AISI 5115/5120, JIS SCr420 and GB 20CrMn are the nearest matches; none is identical, and the differences are explained in the table.

Chemical composition (mass %): C 0.14 – 0.19; Si ≤ 0.4; Mn 1 – 1.3; P ≤ 0.025; S ≤ 0.035 (16MnCrS5 (1.7139): S 0.020–0.040); Cr 0.8 – 1.1
EN 10084:2008 Table 3. Hardenability band (+H) available as 16MnCr5H; +HH / +HL for restricted upper/lower bands.

Mechanical properties:
- Core after carburize, quench & temper, 11 mm ref. bar: yield ≥ 590 MPa; tensile 780–1080 MPa; elongation 10 %; hardness —
- Core, 30 mm ref. bar: yield ≥ 490 MPa; tensile 690–890 MPa; elongation 11 %; hardness —
- Core, 63 mm ref. bar: yield ≥ 440 MPa; tensile 640–840 MPa; elongation 12 %; hardness —
- Surface after carburizing: yield — MPa; tensile — MPa; elongation — %; hardness 58–62 HRC (≈ 700–780 HV)
- +A soft annealed (delivery): yield — MPa; tensile ≤ 700 (typ. 500–650) MPa; elongation — %; hardness ≤ 207 HB
- +FP ferrite-pearlite (delivery): yield — MPa; tensile — MPa; elongation — %; hardness 140–187 HB
Core values from EN 10084 Annex F (informative) for blank-hardened reference bars; the standard itself specifies only chemistry, hardenability and delivery hardness. Jominy J9 hardenability: 30–43 HRC for 16MnCr5H.

Equivalents:
- 5115 (AISI / SAE) — near: SAE 5115 (UNS G51150): C 0.13–0.18, Mn 0.70–0.90, Cr 0.70–0.90 — lower Mn and Cr, somewhat lower hardenability. SAE 5120 is closer on hardenability.
- 590M17 (BS (superseded British)) — near: BS 970 590M17: C 0.14–0.20, Mn 1.00–1.30, Cr 0.60–1.00 (Cr window slightly lower).
- 20MnCr5 (EN (European)) — near: 1.7147: C 0.17–0.22, same Mn/Cr; higher core strength (900–1200 MPa) for larger gears.
- 16MnCrS5 (EN (European)) — near: Free-machining variant with 0.020–0.040 % S; same case/core response.
- 16CrMn / 20CrMn (GB/T (China)) — near: GB/T 3077 20CrMn: C 0.17–0.23, Mn 0.90–1.20, Cr 0.90–1.20; 16MnCr5 sits at the low-carbon end.
- 18KhG (GOST (Russia/CIS)) — near: GOST 4543 18KhG: C 0.15–0.21, Mn 0.90–1.20, Cr 0.90–1.20.
- SCr415 / SCr420 (JIS (Japan)) — near: JIS G4053 SCr415: C 0.13–0.18, Mn 0.60–0.90, Cr 0.90–1.20; Mn lower than 16MnCr5.
- 8620 (AISI / SAE) — functional: Ni-Cr-Mo case-hardening steel, better toughness and hardenability; the US default for the same parts.
- C15 (EN (European)) — functional: Unalloyed case-hardening steel for small, lightly loaded parts.

Superseded names:
- 16MnCr5 (1.7131) — DIN 17210 (withdrawn): Name and number unchanged; standard replaced by EN 10084.
- 590M17 / 527M17 — BS 970
- 16MC5 — NF A 35-551
- 16MnCr5 — UNI 7846

Product forms: round bar (hot-rolled, peeled, drawn); forgings; seamless tube; wire rod for cold heading
Tolerances: hot-rolled round: EN 10060; bright bar: EN 10278; forgings: EN 10250-3

### 16MnCr5 core strength
After carburizing and hardening, core tensile is about 780–1080 MPa in an 11 mm reference bar, 690–890 MPa at 30 mm and 640–840 MPa at 63 mm (EN 10084 Annex F). Core hardness ≈ 25–35 HRC.

### 16MnCr5 surface hardness
Carburized case: 58–62 HRC (700–780 HV) at a typical case depth (CHD) of 0.6–1.5 mm. Carbonitriding gives similar hardness at shallower depth for small parts.

### Delivery hardness
+A soft-annealed max 207 HB; +FP 140–187 HB; +S (treated for shearability) max 255 HB.

### Heat treatment
Carburize 880–980 °C; direct or single quench from 820–860 °C in oil; core-refine at 860–900 °C where required; temper 150–200 °C. Normalize 880–920 °C; soft anneal 650–700 °C. Ac1 ≈ 740 °C, Ac3 ≈ 840 °C.

### Hardenability
Jominy end-quench (16MnCr5H): J1.5 = 39–47 HRC, J9 = 30–43 HRC, J15 = 22–37 HRC. Sufficient for gears up to roughly module 5 / 50 mm section.

### Why the H in the name matters
Without the H only the chemical limits apply, and two conforming heats can harden differently. 16MnCr5H is supplied against a guaranteed hardenability band and verified by the Jominy end-quench test. For series production with a fixed case depth and a tight distortion tolerance, that is the ordering detail that decides whether the parts come out alike.

### Weldability
Weldable in the soft-annealed condition with preheat 150–250 °C and low-hydrogen consumables (CEV ≈ 0.50 %). Carburized surfaces must be removed or masked before welding. Post-weld stress relief 550–650 °C. Welding is uncommon; parts are usually machined from bar or forged.

### Machining, forming, heat treatment
Machinability is good in the +FP or +A condition (index ≈ 65–70 %); 16MnCrS5 with controlled S is preferred for high-volume turning and hobbing. Machine to finish size allowing for carburizing distortion (grinding stock 0.1–0.3 mm on gear flanks). Cold heading and cold extrusion are possible after spheroidize annealing (+AC). Hot forging 1100–850 °C then normalize.

Applications: Automotive gearbox gears, synchronizer rings and shafts; Small pinions, worms and sprockets; Camshafts and rocker arms; Piston pins, bushings and sleeves; Ball-screw nuts, guide rails and cam followers; Cold-headed parts requiring a hard case (rivets, pins)

Q: What is 16MnCr5 equivalent to in AISI?
A: The nearest SAE grades are 5115 and 5120 (Cr steels with 0.15–0.20 % C). 8620 is the functional US equivalent in gear practice because it is what American mills stock, but it is a Ni-Cr-Mo steel with different hardenability.

Q: What hardness does 16MnCr5 reach after case hardening?
A: Surface 58–62 HRC with a case depth of typically 0.6–1.5 mm; core around 25–35 HRC (780–1080 MPa in thin sections).

Q: What is the difference between 16MnCr5 and 20MnCr5?
A: 20MnCr5 (1.7147) has 0.17–0.22 % carbon versus 0.14–0.19 %, giving a stronger core (about 900–1200 MPa) and slightly higher hardenability. Choose 20MnCr5 for larger gears and higher torque.

Q: Can 16MnCr5 be through-hardened instead of carburized?
A: Not usefully. With 0.16 % C the as-quenched hardness is only about 40–45 HRC. Use 42CrMo4 or C45 if you need a through-hardened part.

---

## 16Mo3 (1.5415) — Molybdenum-alloyed steel for pressure purposes at elevated temperature
URL: https://steelstandart.com/grade/16mo3/
System: EN (European) | Family: Pressure vessel steel | Standard: EN 10028-2 | Verified against: EN 10028-2:2017
Aliases: 16 Mo 3, 15Mo3, 1.5415, 16Mo3+N, 16Mo3 steel, 15 Mo 3

16Mo3 is the first alloy step above carbon steel in the European pressure-vessel range: 0.3 % molybdenum in a 0.16 % carbon matrix, Werkstoff number 1.5415, specified in EN 10028-2 (plate), EN 10216-2 (seamless tube), EN 10222-2 (forgings) and EN 10273 (bar). The old DIN 17155 name 15Mo3 is still heard daily.

Molybdenum does two things: it raises the yield strength that can be guaranteed at 400–500 °C (148 MPa at 500 °C, versus P265GH's table ending at 400 °C) and it slows creep, so 16Mo3 is the economical choice for boiler tubes, superheater headers, steam drums, hot-gas ducting and refinery vessels operating between roughly 400 and 530 °C. Room-temperature values are 275 MPa yield, 440–590 MPa tensile, 24 % elongation, 27 J at −20 °C.

The ASME counterparts are C-½Mo grades — A204 (plate), A335 P1 (pipe), A182 F1 (forgings) — which carry 0.45–0.60 % Mo, so the match is 'near'; note that ASME has restricted C-½Mo in hydrogen service (API 941), a caution that applies equally to 16Mo3.

Chemical composition (mass %): C 0.12 – 0.2; Si ≤ 0.35; Mn 0.4 – 0.9; P ≤ 0.025; S ≤ 0.01; N ≤ 0.012; Cr ≤ 0.3; Cu ≤ 0.3; Mo 0.25 – 0.35; Ni ≤ 0.3
EN 10028-2:2017 Table 1. Al is not deliberately added (Al ≤ 0.040 % — fine Al-nitrides would reduce creep strength). CEV max 0.45 %.

Mechanical properties:
- ≤ 16 mm, +N: yield 275 MPa; tensile 440–590 MPa; elongation 24 %; hardness ≈ 130–170 HB (typ.)
- > 16 ≤ 40 mm: yield 270 MPa; tensile 440–590 MPa; elongation 24 %; hardness —
- > 40 ≤ 60 mm: yield 260 MPa; tensile 440–590 MPa; elongation 24 %; hardness —
- > 60 ≤ 100 mm: yield 240 MPa; tensile 430–580 MPa; elongation 23 %; hardness —
- > 100 ≤ 150 mm: yield 220 MPa; tensile 420–570 MPa; elongation 22 %; hardness —
- Rp0.2 at 100 °C (≤ 60 mm): yield 243 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 200 °C: yield 218 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 300 °C: yield 193 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 400 °C: yield 169 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 450 °C: yield 159 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 500 °C: yield 148 MPa; tensile — MPa; elongation — %; hardness —
EN 10028-2 Tables 2–4; transverse for plate. Creep-rupture strength (mean, 100 000 h): ≈ 122 MPa at 450 °C, 74 MPa at 500 °C, 41 MPa at 530 °C (EN 10028-2 Annex, informative).
Impact: 27 J at -20 °C (transverse; 40 J longitudinal; also 31 J at 0 °C, 34 J at +20 °C transverse)

Equivalents:
- 16Mo (GB/T (China)) — identical: GB/T 713 16Mo (formerly 16MnMoR-type usage); GB adopted the EN name for Mo pressure plate.
- A204 Gr. A (ASTM / ASME) — near: ASTM/ASME A204 Grade A (SA-204-A): C ≤ 0.18, Mo 0.45–0.60, yield 255 MPa, Rm 450–585 MPa. Higher Mo than 16Mo3; Grade B (yield 275) is closer on strength.
- A204 Gr. B (ASTM / ASME) — near: Yield 275 MPa, Rm 485–620 MPa, Mo 0.45–0.60.
- A335 P1 (ASTM / ASME) — near: Seamless pipe: C 0.10–0.20, Mo 0.44–0.65, yield 205 MPa — the ASME C-½Mo pipe grade corresponding to 16Mo3 tube (EN 10216-2).
- A182 F1 (ASTM / ASME) — near: C-½Mo forging grade (flanges, fittings).
- 15KhM / 16M (GOST (Russia/CIS)) — near: GOST 20072 / 5520 grade 16M (Mo 0.25–0.35) is close; 15KhM adds Cr.
- STPA12 / SB450M (JIS (Japan)) — near: JIS G3462 STPA12 (0.5 Mo pipe) and G3103 SB450M (Mo boiler plate).
- P265GH (EN (European)) — functional: Non-alloy grade below 400–450 °C; 16Mo3 is the step up.
- 13CrMo4-5 (EN (European)) — functional: 1.7335 Cr-Mo grade for 500–570 °C and hydrogen service.
- P355GH (EN (European)) — functional: Molybdenum-alloyed creep-resistant grade for service above 400 °C, where P355GH's guaranteed proof strength table ends.

Superseded names:
- 15Mo3 — DIN 17155 (withdrawn 1992): Same number 1.5415; still widely used name. Renamed 16Mo3 with the EN edition.
- 16Mo3 — DIN 17175 (tubes)
- 1503-243B / 1501-240 — BS 1501 / BS 3059: BS 3059 Part 2 grade 243 (tubes).
- 15D3 — NF A 36-205

Product forms: plate (EN 10028-2); seamless tube and pipe (EN 10216-2); welded tube (EN 10217-2); forgings (EN 10222-2); fittings (EN 10253-2); bar for flanges and bolting (EN 10273)
Tolerances: plate: EN 10029; tube: EN 10216-2 / EN ISO 1127; forgings: EN 10222-1

### 16Mo3 yield strength
275 MPa (39.9 ksi) ≤ 16 mm, 270 to 40 mm, 260 to 60 mm, 240 to 100 mm, 220 to 150 mm. Elevated temperature (≤ 60 mm): 243 MPa at 100 °C, 218 at 200, 193 at 300, 169 at 400, 159 at 450 and 148 MPa at 500 °C.

### 16Mo3 tensile strength
440–590 MPa (64–86 ksi) to 60 mm; 430–580 MPa to 100 mm; 420–570 MPa to 150 mm.

### 16Mo3 creep strength
Mean creep-rupture strength for 100 000 h: ≈ 122 MPa at 450 °C, 74 MPa at 500 °C, 41 MPa at 530 °C. 1 % creep strain limits are about 70 % of these. Practical upper service limit ≈ 530 °C.

### 16Mo3 hardness
Not specified; normalized plate ≈ 130–170 HB. Weld HAZ can reach 250–300 HV without PWHT.

### Physical properties
Density 7.85 g/cm³, E = 212 GPa (20 °C), 190 GPa (400 °C); expansion 12.4 × 10⁻⁶/K (20–100 °C), 14.0 (20–500 °C); conductivity ≈ 45 W/m·K.

### Heat treatment
Delivery condition normalized (+N) at 900–950 °C, air cooled; stress relief / PWHT 570–650 °C. Ac1 ≈ 730 °C, Ac3 ≈ 850 °C.

### Weldability
Good weldability with matching Mo consumables (E Mo B / G Mo Si, EN ISO 3580 / 21952 — e.g. E 7018-A1 / ER70S-A1 type). Preheat 100–150 °C above ~15 mm thickness; PWHT 570–620 °C is normally required by EN 13445 / AD 2000 for pressure parts above about 15–20 mm and for all creep-range service. Avoid welding with unalloyed filler in creep service (weld would be the weak point).

### Machining, forming, heat treatment
Machinability similar to P265GH/P295GH (index ≈ 65 %). Cold forming within code strain limits followed by normalizing when strain exceeds ~5 %; hot forming 1050–900 °C then re-normalize. Flame cutting with 100 °C preheat above 30 mm. Not intended for hardening; surface treatments uncommon.

Applications: Boiler drums, headers, economizer and evaporator tubes (EN 10216-2 16Mo3); Superheater and reheater tubes up to ~500 °C metal temperature; Refinery and petrochemical vessels, columns and heat exchangers 400–500 °C; Hot-gas ducts, flue-gas and waste-heat boilers; Steam piping, flanges (EN 10273 16Mo3) and fittings; Hydrocracker and reformer components below API 941 C-½Mo limits

Q: Is 16Mo3 the same as 15Mo3?
A: Yes. 15Mo3 was the DIN 17155 name; EN 10028-2 renamed it 16Mo3 (nominal carbon 0.16 %) in 1992 with the same number 1.5415 and effectively the same limits.

Q: What is the ASTM equivalent of 16Mo3?
A: C-½Mo grades: A204 Grade A/B (plate), A335 P1 (seamless pipe), A182 F1 (forgings), A217 WC1 (castings). They contain 0.45–0.60 % Mo versus 0.25–0.35 % in 16Mo3, so strength and creep values are close but not identical.

Q: What is the maximum working temperature of 16Mo3?
A: Design tables give yield to 500 °C; creep-rupture data support use to about 530 °C. Above that, 13CrMo4-5 (≈ 570 °C) or 10CrMo9-10 (≈ 600 °C) are used.

Q: Does 16Mo3 need preheat and PWHT?
A: Preheat 100–150 °C above ~15 mm; PWHT at 570–620 °C is required by European vessel codes for most pressure-retaining welds in 16Mo3, and is always advisable for creep service.

Q: Can 16Mo3 be used in hydrogen service?
A: Only within the C-½Mo limits of API RP 941 (Nelson curves); many operators now specify 13CrMo4-5 instead because of hydrogen attack incidents in C-½Mo steels.

---

## 17-4 PH [S17400] — Martensitic precipitation-hardening stainless steel
URL: https://steelstandart.com/grade/17-4ph/
System: AISI / SAE | Family: Stainless steel | Standard: ASTM A564 | Verified against: ASTM A564/A564M-19
Aliases: 17-4PH, 17-4 PH stainless steel, 17-4, 630, Type 630, S17400, 1.4542, X5CrNiCuNb16-4, 1.4548, SUS630, AMS 5643, 17-4 H900, 17-4 H1150

17-4 PH is the most-used precipitation-hardening stainless steel: a martensitic 17 % Cr / 4 % Ni matrix strengthened by copper precipitates formed during a simple single-step ageing at 480–620 °C. Because the steel is delivered soft-ish (Condition A, ≈ 35 HRC, fully machinable) and hardened afterwards at low temperature with almost no distortion (≈ 0.05 % contraction), it lets shops machine complex parts to size and then age them to 1170 MPa (170 ksi) yield and 44–47 HRC in the H900 condition — or to a tougher 725 MPa / 28 HRC at H1150. UNS S17400, AISI Type 630, EN 1.4542.

Corrosion resistance is close to 304 in most media (better than any conventional martensitic grade), which is why 17-4 is the material of pump shafts and impellers, valve stems and balls, aircraft fittings and landing-gear parts, gears, fasteners, nuclear-reactor components, oil-and-gas downhole tools and, increasingly, additively manufactured parts. The ageing temperature is chosen against the environment: H900 for maximum strength in benign service, H1025–H1150 for toughness and resistance to stress-corrosion and hydrogen embrittlement, H1150M for NACE MR0175 sour service (≤ 33 HRC).

JIS SUS630, GB 05Cr17Ni4Cu4Nb and EN 1.4542 are identical; 15-5 PH is the cleaner, ferrite-free variant preferred for transverse-loaded aerospace forgings.

Chemical composition (mass %): C ≤ 0.07; Mn ≤ 1; P ≤ 0.04; S ≤ 0.03; Si ≤ 1; Cr 15 – 17.5; Ni 3 – 5; Cu 3 – 5; Nb 0.15 – 0.45 (Nb + Ta)
ASTM A564/A564M-19 (S17400). EN 1.4542 (X5CrNiCuNb16-4): C ≤ 0.07, Cr 15–17, Ni 3–5, Cu 3–5, Nb 5×C–0.45 — identical. 15-5 PH (S15500 / 1.4545) is the remelted, ferrite-free variant with better transverse toughness.

Mechanical properties:
- Condition A (solution annealed 1040 °C) — as supplied: yield ≈ 760 (typ.) MPa; tensile ≈ 1030 (typ.) MPa; elongation 10 %; hardness ≤ 363 HB / ≤ 38 HRC
- H900 (482 °C, 1 h, air) — peak hardness: yield ≥ 1170 MPa; tensile ≥ 1310 MPa; elongation 10 %; hardness ≥ 40 HRC (388 HB); typ. 44–47 HRC
- H925 (496 °C, 4 h): yield ≥ 1070 MPa; tensile ≥ 1170 MPa; elongation 10 %; hardness ≥ 38 HRC (375 HB)
- H1025 (552 °C, 4 h): yield ≥ 1000 MPa; tensile ≥ 1070 MPa; elongation 12 %; hardness ≥ 35 HRC (331 HB)
- H1075 (580 °C, 4 h): yield ≥ 860 MPa; tensile ≥ 1000 MPa; elongation 13 %; hardness ≥ 32 HRC (311 HB)
- H1100 (593 °C, 4 h): yield ≥ 795 MPa; tensile ≥ 965 MPa; elongation 14 %; hardness ≥ 31 HRC (302 HB)
- H1150 (621 °C, 4 h) — max toughness: yield ≥ 725 MPa; tensile ≥ 930 MPa; elongation 16 %; hardness ≥ 28 HRC (277 HB)
- H1150M (760 °C 2 h + 621 °C 4 h) — NACE: yield ≥ 520 MPa; tensile ≥ 795 MPa; elongation 18 %; hardness ≤ 33 HRC (255–311 HB)
- H1150D (double 621 °C): yield ≥ 725 MPa; tensile ≥ 860 MPa; elongation 16 %; hardness ≥ 26 HRC (255 HB)
ASTM A564 Table 4, bar ≤ 200 mm (8 in). Impact (Charpy, longitudinal, typical): H900 ≈ 20 J, H1025 ≈ 40 J, H1150 ≈ 70 J. Condition A is not a service condition — it must be aged.
Impact: 20 J at 20 °C (typical H900; ≈ 70 J at H1150)

Equivalents:
- 1.4542 (EN (European)) — identical: X5CrNiCuNb16-4 (EN 10088-3): same analysis; delivery conditions +P800/+P930/+P960/+P1070 correspond to H1150/H1075/H1025/H900.
- 05Cr17Ni4Cu4Nb (GB/T (China)) — identical: GB/T 20878 05Cr17Ni4Cu4Nb (formerly 0Cr17Ni4Cu4Nb).
- SUS630 (JIS (Japan)) — identical: JIS G4303 SUS630: C ≤ 0.07, Cr 15.5–17.5, Ni 3–5, Cu 3–5, Nb 0.15–0.45.
- 15-5 PH (AISI / SAE) — near: S15500 / 1.4545: Cr 14–15.5, Ni 3.5–5.5 — vacuum-remelted, ferrite-free, better transverse ductility and toughness; often substituted in aerospace.
- 07Kh16N4B / 09Kh16N4B (GOST (Russia/CIS)) — near: GOST martensitic Nb-bearing 16-4 grades without copper; the closest Russian analogues, not true PH steels.
- 13-8 Mo (AISI / SAE) — functional: S13800: higher strength and toughness, more expensive; for critical aerospace parts.
- 410 (AISI / SAE) — functional: Conventional martensitic 12 % Cr: cheaper, lower strength (≤ 1200 MPa), poorer corrosion resistance, needs quench hardening.
- 316 (AISI / SAE) — functional: Austenitic: similar corrosion resistance, one-quarter of the yield strength; 17-4 replaces it where strength matters.

Superseded names:
- Type 630 — AISI / ASTM: The numeric AISI designation for 17-4 PH.
- 1.4542 / X5CrNiCuNb16-4 — EN 10088-3: 1.4548 is the same steel for pressure purposes (EN 10088 older number / SEW).
- 17-4 PH — Armco trade name (1948): Precipitation Hardening; 15-5 PH, 13-8 Mo and Custom 450 are later relatives.
- AMS 5643 / 5604 / 5622 — SAE Aerospace: Bar/forgings, sheet, and consumable-remelted bar.
- CB7Cu-1 — ACI / ASTM A747: Cast equivalent.

Product forms: bar, wire and forgings (ASTM A564 / A705, AMS 5643); plate, sheet and strip (A693); seamless tube (A511 limited); castings CB7Cu-1 (A747); investment castings, powder-metallurgy and additive-manufactured parts
Tolerances: bar: ASTM A484 / A564; plate/sheet: ASTM A480 / A693; aerospace: AMS 5643 (bar), AMS 5604 (sheet)

### 17-4 PH yield strength by condition
H900 ≥ 1170 MPa (170 ksi); H925 ≥ 1070; H1025 ≥ 1000; H1075 ≥ 860; H1100 ≥ 795; H1150 ≥ 725 MPa (105 ksi); H1150M ≥ 520; Condition A ≈ 760 MPa typical (not for service).

### 17-4 PH tensile strength
H900 ≥ 1310 MPa (190 ksi); H1025 ≥ 1070; H1150 ≥ 930 MPa (135 ksi); H1150M ≥ 795 MPa.

### 17-4 PH hardness
Condition A ≤ 38 HRC (typ. 33–36); H900 40–47 HRC (typ. 44); H925 ≥ 38; H1025 ≥ 35; H1075 ≥ 32; H1100 ≥ 31; H1150 ≥ 28; H1150M 255–311 HB (≤ 33 HRC, NACE).

### Heat treatment
Solution anneal (Condition A) 1025–1055 °C (1875–1925 °F), air or oil cool to below 32 °C to complete the martensite transformation. Age: H900 = 482 °C (900 °F) 1 h; H925 = 496 °C 4 h; H1025 = 552 °C 4 h; H1075 = 580 °C 4 h; H1100 = 593 °C 4 h; H1150 = 621 °C 4 h; H1150M = 760 °C 2 h + 621 °C 4 h; H1150D = 621 °C 4 h twice. Air cool after ageing. Dimensional change on ageing ≈ −0.04 to −0.06 % (H900) to −0.10 % (H1150).

### Corrosion resistance
Comparable to 304 in most atmospheric, fresh-water, mild chemical and food environments (better than 410/420); inferior to 316 in chlorides. Stress-corrosion cracking resistance improves with ageing temperature — avoid H900/H925 in chloride or H₂S service; use ≥ H1025, or H1150M/H1150D for NACE MR0175.

### Service temperature
Use up to about 315 °C (600 °F) for long-term strength (over-ageing above that); short excursions to 425 °C. Down to −40 °C for H1025 and softer; H900 is notch-sensitive below ~0 °C.

### Physical properties
Density 7.8 g/cm³, E = 196 GPa (H900), expansion 10.8 × 10⁻⁶/K (0–100 °C), conductivity 18 W/m·K, resistivity 0.80 µΩ·m, ferromagnetic.

### Weldability
Weldable in Condition A or over-aged (H1150) with matching ER630 / E630 filler or, for less critical joints, ER308L/ER309L. No preheat for thin sections; for > 12 mm preheat 100–150 °C. After welding, re-solution-anneal and age, or at minimum age the assembly (H900–H1150) to harden the weld and HAZ. Welding in the aged condition produces a soft HAZ and possible cracking. Resistance and laser welding are common for thin parts.

### Machining, forming, heat treatment
Machine in Condition A (≈ 35 HRC; index ≈ 45 % of B1112) or, better, in H1150 (≈ 28 HRC, more uniform chips) and then re-age to the final condition; finish-machining after H900 requires carbide/CBN at 44 HRC. Threads should be rolled or cut before ageing. Cold forming is limited to gentle bends in Condition A; hot forging 1150–980 °C followed by solution treatment. Surface treatments: passivation (nitric or citric), shot peening for fatigue, PVD coatings after ageing ≤ 480 °C.

Applications: Pump shafts, impellers, wear rings and valve stems, balls and seats; Aircraft fittings, landing-gear components, actuator parts, fasteners (AMS 5643); Gears, shafts, couplings in food, chemical and marine equipment; Nuclear reactor internals, control-rod components; Oil and gas: wellhead and downhole tools, subsea parts (H1150M/H1150D per NACE); Firearm components, golf-club heads, surgical and dental instruments; Additive-manufactured (L-PBF) structural parts — the standard PH stainless powder; Paper-mill and turbine components exposed to moderate corrosion and high stress

Q: What does H900 or H1150 mean for 17-4 PH?
A: The ageing (precipitation-hardening) temperature in °F: H900 = 900 °F (482 °C) for 1 h → maximum strength, ≈ 44 HRC; H1150 = 1150 °F (621 °C) for 4 h → maximum toughness, ≈ 28–33 HRC. Intermediate conditions (H925, H1025, H1075, H1100) trade strength for toughness; H1150M and H1150D are double treatments for sour service.

Q: Is 17-4 PH magnetic?
A: Yes — it is martensitic in all conditions and strongly ferromagnetic, unlike austenitic 304/316.

Q: How does 17-4 PH compare with 316 for corrosion?
A: Roughly equal to 304 and below 316 in chloride environments. 17-4 is chosen when strength (3–5× the yield of 316) is needed with 'good enough' corrosion resistance; in seawater or hot chlorides use 316, duplex or over-aged 17-4 with cathodic protection.

Q: Can 17-4 PH be machined after hardening?
A: Yes with carbide or CBN tooling at 40–47 HRC, but it is slow. Standard practice is to rough and semi-finish in Condition A or H1150, age, then finish-grind or lightly finish-machine; the 0.05 % shrinkage on ageing is predictable.

Q: What is 17-4 PH equivalent to in EN and JIS?
A: EN 1.4542 (X5CrNiCuNb16-4) and JIS SUS630 — identical compositions. EN delivery conditions +P1070, +P960, +P930 and +P800 correspond to H900, H1025, H1075 and H1150.

Q: What is the difference between 17-4 PH and 15-5 PH?
A: 15-5 PH (S15500) is a vacuum-remelted, slightly lower-chromium version designed to be free of delta ferrite, giving better transverse toughness and ductility in forgings. Strength levels and heat treatments are the same; 15-5 costs more and is preferred in aerospace.

---

## 2205 [S32205] — Ferritic-austenitic (duplex) stainless steel
URL: https://steelstandart.com/grade/2205/
System: AISI / SAE | Family: Stainless steel | Standard: ASTM A240 | Verified against: ASTM A240/A240M-22
Aliases: 2205 duplex, duplex 2205, 2205 stainless steel, S32205, S31803, UNS S31803, F51, F60, SAF 2205, duplex stainless steel, 2205 stainless, SUS329J3L, 022Cr23Ni5Mo3N, 03Kh22N5AM3, S32205 EN

2205 is the standard duplex stainless steel — the alloy most often specified when 316L is not strong or corrosion-resistant enough but super-duplex or nickel alloys are unnecessary. Its microstructure is roughly 50 % ferrite and 50 % austenite, which gives it about twice the yield strength of 316L (450 vs 205 MPa), a pitting resistance equivalent of 35 or more (316L: 24), excellent resistance to chloride stress-corrosion cracking, and good weldability in modern nitrogen-balanced heats. Two UNS numbers apply: S31803 (the original 1980s window) and S32205 (from 2000, guaranteeing Cr ≥ 22, Mo ≥ 3, N ≥ 0.14 and therefore PREN ≥ 35). Nearly all current production meets both and is dual-certified; specify S32205 for new work. ASTM A182 forgings are F51 (S31803) and F60 (S32205).

The high strength lets designers cut vessel and pipe wall thickness by 30–50 % versus austenitic steel, which is why 2205 dominates in chemical tankers, storage tanks, pressure vessels, heat exchangers, desalination plant, pulp-and-paper digesters, offshore piping and, increasingly, structural applications such as bridges and rebar in marine environments.

Limits: a service window of about −50 to +300 °C (sigma-phase and 475 °C embrittlement outside it), ferromagnetism, and higher forming loads. EN 1.4462, JIS SUS329J3L and GB 022Cr23Ni5Mo3N are the same grade.

Chemical composition (mass %): C ≤ 0.03; Mn ≤ 2; P ≤ 0.03; S ≤ 0.02; Si ≤ 1; Cr 22 – 23 (S31803: 21.0–23.0); Ni 4.5 – 6.5; Mo 3 – 3.5 (S31803: 2.5–3.5); N 0.14 – 0.2 (S31803: 0.08–0.20)
ASTM A240/A240M-22 Table 1 (S32205). S31803 is the original, wider 2205 window; S32205 (introduced 2000) guarantees the higher-Cr/Mo/N end and PREN ≥ 35. Most modern plate is dual-certified S31803/S32205. EN 1.4462 (X2CrNiMoN22-5-3): Cr 21–23, Ni 4.5–6.5, Mo 2.5–3.5, N 0.10–0.22.

Mechanical properties:
- S32205 plate, sheet, strip — annealed (A240): yield ≥ 450 MPa; tensile ≥ 655 MPa; elongation 25 %; hardness ≤ 293 HB / ≤ 31 HRC
- S31803 plate, sheet, strip — annealed (A240): yield ≥ 450 MPa; tensile ≥ 620 MPa; elongation 25 %; hardness ≤ 293 HB / ≤ 31 HRC
- Bar — annealed (A276 / A479): yield ≥ 450 MPa; tensile ≥ 620 MPa; elongation 25 %; hardness ≤ 290 HB
- Seamless/welded pipe (A790 / A789): yield ≥ 450 MPa; tensile ≥ 620 MPa; elongation 25 %; hardness ≤ 290 HB / ≤ 30 HRC
- Forgings F51 / F60 (A182): yield ≥ 450 MPa; tensile ≥ 620 / ≥ 655 MPa; elongation 25 %; hardness ≤ 290 HB
- EN 1.4462 hot-rolled plate +AT (for comparison): yield ≥ 460 MPa; tensile 640–840 MPa; elongation 25 %; hardness ≤ 270 HB
Minimums per ASTM A240/A276/A790/A182. Typical plate: yield 500–560 MPa, tensile 720–780 MPa, elongation 30–35 %. Charpy typical ≥ 100 J at +20 °C, ≥ 40 J at −40 °C; ASME requires impact testing below −29 °C for some product forms.
Impact: 40 J at -40 °C (typical; ASTM A923 test method C for intermetallic detection)

Equivalents:
- 318S13 (BS (superseded British)) — identical: BS 1449 318S13 (withdrawn).
- 1.4462 (EN (European)) — identical: X2CrNiMoN22-5-3: EN window covers both S31803 and S32205; modern 1.4462 plate is dual-certified S32205.
- 022Cr23Ni5Mo3N (GB/T (China)) — identical: GB/T 20878 022Cr23Ni5Mo3N (formerly 00Cr22Ni5Mo3N).
- SUS329J3L (JIS (Japan)) — identical: JIS G4304 SUS329J3L: Cr 21–24, Ni 4.5–6.5, Mo 2.5–3.5, N 0.08–0.20 (S31803 window).
- 03Kh22N5AM3 (GOST (Russia/CIS)) — near: Russian TU/GOST R designations for 2205-type duplex; not in the classic GOST 5632 list.
- 2304 (S32304 / 1.4362) (AISI / SAE) — functional: Lean duplex: 23 Cr, 4 Ni, no Mo, PREN ≈ 25 — cheaper, for less aggressive service.
- 2507 (S32750 / 1.4410) (AISI / SAE) — functional: Super-duplex: 25 Cr, 7 Ni, 4 Mo, PREN ≥ 40 — for hot seawater and sour service.
- 316L (AISI / SAE) — functional: Austenitic 316L: half the yield, PREN 24 — the grade 2205 usually replaces to save wall thickness.
- 316 (AISI / SAE) — functional: Duplex S32205: double the yield, PREN 35 — the upgrade for warm chloride service.

Superseded names:
- S31803 — UNS (1980s): Original 2205 designation; wider Cr/Mo/N window. Still valid; most material meets both.
- F51 / F60 — ASTM A182: Forging grades: F51 = S31803, F60 = S32205.
- 1.4462 / X2CrNiMoN22-5-3 — EN 10088: European designation.
- SAF 2205 — Sandvik trade name: Origin of the generic name; Uranus 45N, Avesta 2205, Outokumpu 2205 are equivalents.
- CD3MN / 4A — ACI / ASTM A890, A995: Cast equivalents.

Product forms: plate, sheet and strip (ASTM A240); bar and forgings (A276, A479, A182 F51/F60); seamless and welded pipe and tube (A790, A789, A928); fittings (A815 WP-S), flanges; castings CD3MN / 4A (A890, A995), wire and fasteners
Tolerances: plate/sheet: ASTM A480; bar: ASTM A484; pipe: ASTM A999 / ASME B36.19

### 2205 yield strength
Minimum 450 MPa (65 ksi) in all wrought product forms (ASTM A240, A276, A790); typical 500–560 MPa. Design codes: ASME uses 65 ksi; EN 1993-1-4 uses 460 MPa.

### 2205 tensile strength
S32205: ≥ 655 MPa (95 ksi); S31803: ≥ 620 MPa (90 ksi); typical 720–780 MPa.

### 2205 hardness
Annealed max 293 HB / 31 HRC (plate), 290 HB (bar, pipe); typical 250–270 HB. NACE MR0175: ≤ 28 HRC for solution-annealed wrought 2205 in sour service (36 HRC for cold-worked tubing under specific limits). Not hardenable by heat treatment.

### Corrosion resistance
PREN = Cr + 3.3 Mo + 16 N: ≥ 35 for S32205 (typ. 35–37), 31–35 for low-end S31803. Critical pitting temperature (ASTM G48 A) ≈ 40–50 °C; critical crevice temperature ≈ 20–25 °C. Resists chloride SCC in boiling 25 % NaCl (316L fails), organic acids, dilute sulphuric acid, alkalis, and seawater at ambient temperature with flow. Not for hot stagnant seawater or strong reducing acids.

### Service temperature
−50 °C to +300 °C (ASME −40 °F to 600 °F / 315 °C; EN 13445 to 250–280 °C). Above 300 °C: 475 °C embrittlement; 700–950 °C: sigma/chi phases form within minutes at 850 °C. Never use as a high-temperature alloy.

### Physical properties
Density 7.8 g/cm³, E = 200 GPa, expansion 13.7 × 10⁻⁶/K (20–100 °C — between carbon and austenitic steel), conductivity 19 W/m·K, resistivity 0.80 µΩ·m, ferromagnetic.

### Heat treatment
Solution anneal 1020–1100 °C (1870–2010 °F), rapid water quench — the only permitted heat treatment. No stress relief (350–950 °C is forbidden). Hot forming 1230–950 °C followed by full re-anneal and quench; verify absence of intermetallics per ASTM A923.

### Weldability
Weldable by GTAW, GMAW, SMAW, SAW, FCAW and plasma with over-alloyed ER2209 / E2209 filler (≈ 9 % Ni) so the weld metal solidifies to a balanced ferrite/austenite ratio. Heat input 0.5–2.5 kJ/mm, interpass ≤ 150 °C (≤ 100 °C for thick sections), no preheat, no PWHT. Argon + 2–5 % N₂ shielding/backing preserves nitrogen; autogenous welds are not permitted for pressure parts. Qualify procedures with ferrite measurement (30–70 %) and ASTM A923 or G48 corrosion tests. Dissimilar joints to carbon steel or 316L: ER2209 or ER309LMo.

### Machining, forming, heat treatment
Machinability ≈ 30 % of B1112 — high strength and work hardening: rigid setups, sharp carbide (positive rake), low speed / high feed, flood coolant. Cold forming needs ~50 % more force than 316L and generous bend radii (≥ 2 t); spring-back is large. Deep drawing is limited. Hot forming 1230–950 °C then anneal. Abrasive cutting, plasma and laser cutting are routine; keep cut edges cool.

Applications: Chemical tankers cargo tanks, road and rail tankers; Pressure vessels, columns, storage tanks (ASME VIII, EN 13445) — thinner walls than 316L; Heat exchangers, condensers, evaporators with brackish or chloride-bearing cooling water; Desalination: SWRO high-pressure piping, MSF evaporator shells; Offshore: process piping, firewater systems, risers, umbilical tubes, subsea manifolds; Pulp and paper: digesters, bleach plant, white-liquor and black-liquor equipment; Oil and gas: flowlines, OCTG (cold-worked), sour-service equipment within NACE limits; Structural: bridges, walkways, rebar, marine architecture; biogas and FGD plant

Q: What is the difference between S31803 and S32205?
A: Both are called 2205. S31803 (1980s) allows Cr 21–23, Mo 2.5–3.5, N 0.08–0.20; S32205 (2000) narrows this to Cr 22–23, Mo 3.0–3.5, N 0.14–0.20 to guarantee PREN ≥ 35 and better weldability. Nearly all modern material meets both and is dual-certified — specify S32205 for new designs.

Q: Is 2205 duplex magnetic?
A: Yes. The 50 % ferrite phase makes it ferromagnetic — a quick field check distinguishing it from 316L.

Q: What is the maximum temperature for 2205?
A: About 300 °C (ASME 315 °C / 600 °F; European codes 250–280 °C). Above that, 475 °C embrittlement and, at 700–950 °C, sigma phase destroy toughness and corrosion resistance. Minimum is about −50 °C.

Q: How much stronger is 2205 than 316?
A: Minimum yield 450 MPa vs 205 MPa — more than double — and tensile 655 vs 515 MPa. Vessel walls can typically be 30–50 % thinner, which often offsets the higher price per tonne.

Q: Can 2205 be welded without filler?
A: Not for pressure or corrosion-critical parts: autogenous welds solidify almost fully ferritic and are brittle with poor corrosion resistance. Use ER2209 filler and nitrogen-bearing shielding gas; if autogenous welding is unavoidable (thin tube), a full solution anneal afterwards is required.

Q: What is 2205 equivalent to in EN?
A: EN 1.4462 (X2CrNiMoN22-5-3). Modern 1.4462 plate is melted to the S32205 window and dual-certified; ASTM forgings F51 (S31803) and F60 (S32205) both map to 1.4462.

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## 304 [S30400] — Austenitic chromium-nickel stainless steel
URL: https://steelstandart.com/grade/304/
System: AISI / SAE | Family: Stainless steel | Standard: ASTM A240 | Verified against: ASTM A240/A240M-22
Aliases: AISI 304, SS304, SS 304, Type 304, 304 stainless steel, 304 stainless, S30400, 18-8, 304 SS, A240 304, TP304, 1.4301 AISI, SUS304, 06Cr19Ni10, 0Cr18Ni9, 08Kh18N10, 12Kh18N10, 304S31, S30400 EN, X5CrNi18-10

Type 304 is the world's default stainless steel: an austenitic alloy of 18 % chromium and 8 % nickel (hence '18-8'), with carbon held at 0.08 % max, listed as UNS S30400 in ASTM A240 (plate), A276 (bar), A312 (pipe) and a dozen other product standards. It resists oxidizing acids, food media, most organic chemicals and ordinary atmospheres; it forms, draws and welds easily; it is non-magnetic, hygienic and tough to cryogenic temperatures. Roughly half of all stainless steel made is 304 or its low-carbon twin 304L.

Minimum properties are modest — 205 MPa (30 ksi) yield and 515 MPa (75 ksi) tensile — but the alloy work-hardens strongly, so cold-rolled tempers up to 1275 MPa are available, and typical annealed sheet actually tests at 260–300 MPa yield. Strength is retained to about 800 °C (oxidation limit ≈ 870 °C continuous), and there is no ductile-to-brittle transition.

Its limits are chloride pitting and stress-corrosion cracking above ~60 °C in chloride solutions — the reasons 316 exists — and sensitization when slowly cooled through 500–800 °C after welding thick sections, which is why 304L (C ≤ 0.03 %) is specified for heavy weldments. EN 1.4301, JIS SUS304, GB 06Cr19Ni10 and GOST 08Kh18N10 are identical for procurement.

Chemical composition (mass %): C ≤ 0.08; Mn ≤ 2; P ≤ 0.045; S ≤ 0.03; Si ≤ 0.75; Cr 18 – 20; Ni 8 – 10.5; N ≤ 0.1
ASTM A240/A240M-22 Table 1 (S30400). Bar per A276 uses the same limits with Si ≤ 1.00. Compare EN 1.4301: Cr 17.5–19.5, C ≤ 0.07, S ≤ 0.015.

Mechanical properties:
- Plate, sheet, strip — annealed (A240): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 40 %; hardness ≤ 201 HB / ≤ 92 HRB
- Bar — annealed (A276): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 40 %; hardness —
- Bar — cold finished ≤ 12.7 mm (A276 condition B): yield ≥ 310 MPa; tensile ≥ 620 MPa; elongation 30 %; hardness —
- Pipe TP304 (A312): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 35 %; hardness —
- Sheet ¼ hard (A666): yield ≥ 515 MPa; tensile ≥ 860 MPa; elongation 10 %; hardness —
- Sheet full hard (A666): yield ≥ 965 MPa; tensile ≥ 1275 MPa; elongation 3 %; hardness —
ASTM A240 Table 2; A276 Table 2; A666 for temper-rolled sheet. Minimum values; typical annealed 2B sheet tests at 260–300 MPa yield and 600–650 MPa tensile.
Impact: 100 J at -196 °C (typical)

Equivalents:
- 304S31 / 304S15 (BS (superseded British)) — identical: BS 1449 / BS 970 (withdrawn); 304S31 has C ≤ 0.07.
- 1.4301 (EN (European)) — identical: X5CrNi18-10: Cr 17.5–19.5, Ni 8–10.5, C ≤ 0.07 — inside the 304 window; dual-certified worldwide.
- 06Cr19Ni10 (GB/T (China)) — identical: GB/T 20878 06Cr19Ni10 (formerly 0Cr18Ni9): C ≤ 0.08, Cr 18–20, Ni 8–11.
- 08Kh18N10 (GOST (Russia/CIS)) — identical: GOST 5632 08Kh18N10: C ≤ 0.08, Cr 17–19, Ni 9–11.
- IS 6911 X04Cr19Ni9 (IS (India)) — identical: Indian designation for 304 (IS 6911 wrought stainless).
- SUS304 (JIS (Japan)) — identical: JIS G4304/G4305 SUS304: C ≤ 0.08, Cr 18–20, Ni 8–10.5 — the same limits as ASTM.
- 304L (AISI / SAE) — near: S30403: C ≤ 0.030, yield ≥ 170 MPa, tensile ≥ 485 MPa. Same corrosion resistance, preferred for welded sections > 6 mm. Dual-certified 304/304L coil is standard.
- 304H (AISI / SAE) — near: S30409: C 0.04–0.10 for creep strength above 525 °C; grain size ≥ ASTM 7.
- 316 (AISI / SAE) — functional: Adds 2–3 % Mo for chloride pitting resistance (PREN 24 vs 18); replaces 304 in marine and chemical service.
- 430 (AISI / SAE) — functional: Ferritic 17 % Cr without Ni: cheaper, magnetic, lower corrosion resistance — the substitute in appliances and trim.
- 316L (AISI / SAE) — functional: The same austenitic family without molybdenum. Adequate in most atmospheres, not in chlorides — the substitution runs one way only.

Superseded names:
- 18-8 — Trade/colloquial: Generic name for the 18 % Cr / 8 % Ni austenitic family (301, 302, 304).
- 302 — AISI (S30200): The higher-carbon (≤ 0.15 %) predecessor; 304 replaced it for weldability.
- S30400 — UNS: The unified number used in ASTM/ASME; 304L = S30403, 304H = S30409, 304N = S30451.
- CF8 — ASTM A351 / ACI: Cast equivalent (CF3 = 304L).

Product forms: sheet, strip and plate (ASTM A240); bar and shapes (A276, A479); seamless and welded pipe (A312 TP304), tube (A269, A249); fittings (A403), flanges (A182 F304), forgings; wire, fasteners (F593), castings as CF8 (A351)
Tolerances: sheet/plate: ASTM A480 (thickness, flatness, finish Nos. 1, 2B, 2D, BA, 3, 4, 7, 8); bar: ASTM A484; pipe: ASTM A999 / ASME B36.19

### 304 stainless steel yield strength
Minimum 205 MPa (30 ksi) annealed; typical 260–300 MPa. Cold-finished bar ≥ 310 MPa; temper-rolled sheet ¼ hard ≥ 515 MPa, ½ hard ≥ 760 MPa, full hard ≥ 965 MPa (A666).

### 304 tensile strength
Minimum 515 MPa (75 ksi); typical 600–650 MPa annealed; up to 1275 MPa (185 ksi) full-hard sheet.

### 304 hardness
Annealed max 201 HB / 92 HRB (≈ 210 HV); typical 150–180 HB. Cold work raises it to 30–40 HRC. Not hardenable by heat treatment.

### Corrosion resistance
PREN = Cr + 3.3 Mo + 16 N ≈ 18–20. Resists nitric acid to 65 %, organic acids, alkalis, fresh water, food and dairy media; pits in chloride solutions above ~200 ppm at elevated temperature and is susceptible to chloride SCC above 60 °C. Atmospheric: excellent inland, tea-staining near the coast.

### High-temperature use
Continuous oxidation limit ≈ 870 °C (925 °C intermittent). For creep-rated service above 525 °C, ASME requires 304H (C ≥ 0.04 %). Sensitization risk on long exposure at 425–860 °C for 304 (not 304L).

### Physical properties
Density 8.0 g/cm³ (0.289 lb/in³), E = 193 GPa (28 × 10⁶ psi), thermal expansion 17.2 × 10⁻⁶/K (0–100 °C), conductivity 16.2 W/m·K, resistivity 0.72 µΩ·m, specific heat 500 J/kg·K, magnetic permeability 1.02 max annealed.

### Heat treatment
Solution anneal 1010–1120 °C (1850–2050 °F), water quench or rapid air cool. Stress relief 400–450 °C for cold-worked parts (below the sensitization range). Never slow-cool through 500–800 °C.

### Weldability
Excellent weldability by GTAW, GMAW, SMAW, SAW, laser and resistance welding without preheat; filler ER308/ER308L (AWS A5.9) or E308L-16. Interpass ≤ 150 °C (300 °F); keep heat input moderate to limit distortion (expansion 50 % above carbon steel). For sections > 6 mm in corrosive service use 304L base and 308L filler, or solution-anneal after welding. Purge pipe roots with argon.

### Machining, forming, heat treatment
Machinability ≈ 45 % of B1112 (work-hardens; use sharp positive-rake carbide, 60–120 m/min, steady feed, no dwelling); 303 is the free-machining alternative. Forming: outstanding deep-drawability and stretch formability; spring-back and required press force are about 1.5× carbon steel; use lubricants to avoid galling. Finishes per A480: No. 1 (hot-rolled), 2D, 2B (standard cold-rolled), BA, No. 3/4 (brushed), No. 7/8 (polished).

Applications: Kitchen sinks, cookware, cutlery, food-service and restaurant equipment; Food, beverage, dairy and pharmaceutical process equipment, tanks and piping; Architectural panels, handrails, column covers (inland and urban); Chemical containers, water tanks, heat exchangers for non-chloride service; Automotive and truck trim, exhaust components, fuel tanks; Cryogenic vessels and LNG equipment (with 304L); Fasteners (A2-70 / ASTM F593 Group 1), springs (temper-rolled 301/304)

Q: What is the difference between 304 and 316 stainless steel?
A: 316 adds 2–3 % molybdenum and slightly more nickel, raising pitting resistance (PREN ≈ 24 vs 18) so it survives salt water, de-icing salts and many chemicals that pit 304. 304 is cheaper (Mo and Ni are the cost drivers) and is the choice wherever chlorides are not a factor. Strength and formability are nearly the same.

Q: What is the difference between 304 and 304L?
A: 304L (S30403) limits carbon to 0.03 % (vs 0.08 %) to prevent chromium-carbide precipitation in the heat-affected zone of welds thicker than about 6 mm. Its strength minimums are lower (170/485 MPa vs 205/515), but most coil today is dual-certified 304/304L, meeting both.

Q: Is 304 stainless steel magnetic?
A: Not in the annealed condition (fully austenitic). Cold working — bending, deep drawing, machining, cold rolling — forms some martensite and gives a mild magnetic response, which is normal. If a part is strongly magnetic it is likely ferritic 430 or a martensitic grade.

Q: Is 304 stainless food-safe?
A: Yes. 304 (and 316) are the standard food-contact stainless steels approved under FDA, EU 1935/2004 and NSF/3-A sanitary standards, provided surfaces are properly finished and passivated.

Q: Does 304 stainless steel rust?
A: It can, under chlorides (coastal air, road salt, pool water), when contaminated by carbon-steel particles, or after sensitization. In normal indoor, food and inland outdoor service it stays bright indefinitely; near the sea specify 316.

Q: What is the European equivalent of 304?
A: EN 1.4301 (X5CrNi18-10). The EN limits are slightly tighter (C ≤ 0.07 %, S ≤ 0.015 %), so 1.4301 material always meets 304; mills dual-certify.

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## 304L (1.4307) [S30403] — Low-carbon austenitic chromium-nickel stainless steel
URL: https://steelstandart.com/grade/304l/
System: AISI / SAE | Family: Stainless steel | Standard: ASTM A240 | Verified against: EN 10088-2:2014 · ASTM A240/A240M
Aliases: 304L, AISI 304L, SS304L, SS 304L, Type 304L, 304L stainless steel, 304L stainless, S30403, 1.4307, X2CrNi18-9, 304L vs 304, A240 304L, TP304L, SUS304L, 022Cr19Ni10, 00Cr19Ni10, 03Kh18N11, 304S11

304L is not a different alloy from 304. It is the same 18 % chromium, 8–10.5 % nickel austenitic stainless with carbon capped at 0.030 % instead of 0.08 %, and that single change is the entire specification.

The reason is welding. At ordinary carbon levels, the heat of welding holds the zone beside the weld in the 500–800 °C range long enough for chromium carbides to precipitate at the grain boundaries. Those carbides take their chromium from the metal immediately around them, leaving a depleted band that is no longer stainless — sensitisation, and the corrosion that follows it runs along the grain boundaries, invisibly, until the part falls apart. Below 0.030 % carbon there is not enough carbon for that to happen in normal welding times.

The cost is strength. 304L's proof stress runs 10 to 40 MPa below 304 depending on product form, and in a design governed by yield that is a real deduction. The cost is also availability in one direction only: because 304L satisfies a 304 specification on every count except the strength minimum, mills dual-certify most coil as 304/304L and the distinction disappears at the stockholder.

When to insist on it: welded section above roughly 6 mm, any welded assembly that will see a corrosive medium, and anything that cannot be solution-annealed after welding. When not to: thin sheet, unwelded parts, and designs where the extra proof stress of 304 is being used.

Chemical composition (mass %): C ≤ 0.03 (the definition of the grade; 304 allows 0.08 %); Cr 17.5 – 19.5; Ni 8 – 10.5 (EN 10088-2 for 1.4307; ASTM A240 allows 8.0–12.0); Mn ≤ 2; Si ≤ 1; P ≤ 0.045; S ≤ 0.015 (0.030 % under ASTM A240); N ≤ 0.11
EN 10088-2:2014 for 1.4307 and ASTM A240 for S30403. The grades are dual-certified routinely; the EN limits on sulphur and nickel are the tighter pair, so EN material satisfies ASTM while the reverse needs checking on the certificate. Nothing else distinguishes 304L from 304 — there is no extra alloying, only less carbon.

Mechanical properties:
- sheet/plate, annealed (ASTM A240): yield ≥ 170 MPa; tensile ≥ 485 MPa; elongation 40 %; hardness ≤ 201 HB / ≤ 92 HRB
- cold-rolled strip ≤ 8 mm, +AT (EN 10088-2): yield ≥ 220 MPa; tensile 520–700 MPa; elongation 45 %; hardness ≤ 215 HB
- hot-rolled plate ≤ 75 mm, +AT (EN 10088-2): yield ≥ 200 MPa; tensile 500–700 MPa; elongation 45 %; hardness ≤ 215 HB
- bar ≤ 160 mm, +AT (EN 10088-3): yield ≥ 175 MPa; tensile 450–680 MPa; elongation 45 %; hardness ≤ 215 HB
- Rp1.0 for design (EN 1993-1-4): yield ≥ 250 (strip) / ≥ 235 (plate) MPa; tensile — MPa; elongation — %; hardness —
- welded pipe TP304L (ASTM A312): yield ≥ 170 MPa; tensile ≥ 485 MPa; elongation 35 %; hardness —
Values in the solution-annealed condition (+AT, 1000–1100 °C, rapidly cooled). The lower carbon costs roughly 10–40 MPa of proof stress against 304 depending on product form — the price paid for weld stability. Work-hardened strip conditions (+C700 and above) are available and are a different material for design purposes.
Impact: 60 J at -196 °C (typical, not a standard requirement)

Equivalents:
- 022Cr19Ni10 (GB/T (China)) — identical: GB/T 20878 022Cr19Ni10, formerly 00Cr19Ni10: C ≤ 0.030, Cr 18.0–20.0, Ni 8.0–12.0.
- 03Kh18N11 (GOST (Russia/CIS)) — identical: GOST 5632 03Kh18N11: the Russian low-carbon 18/10 austenitic grade.
- SUS304L (JIS (Japan)) — identical: JIS G4304/G4305 SUS304L: C ≤ 0.030, Cr 18.0–20.0, Ni 9.0–13.0 — the same grade under the Japanese designation.
- 304 (AISI / SAE) — near: UNS S30400 allows carbon to 0.08 %. Mechanically a little stronger, and the usual choice where the part is not welded in heavy section. Most coil is dual-certified 304/304L.
- 1.4301 (EN (European)) — near: X5CrNi18-10 is the standard-carbon version at C ≤ 0.07 %. Same alloy and same corrosion class; 1.4301 sensitises in thick welded section where 1.4307 does not.
- 1.4301 (EN (European)) — near: UNS S30403: C ≤ 0.03 — the low-carbon version; EN equivalent is 1.4307 (X2CrNi18-9).
- 316L (AISI / SAE) — functional: UNS S31603 adds 2–2.5 % molybdenum for chloride resistance. Specify it instead of 304L near the sea, in de-icing salt or in pool environments — the low-carbon logic is identical.
- 321 (AISI / SAE) — functional: Low-carbon route to weld stability; not suitable above ~425 °C for strength.
- 1-4541 (EN (European)) — functional: X6CrNiTi18-10 (321) reaches weld stability by titanium stabilisation rather than by low carbon, and holds it at 400–550 °C where 304L does not.

Superseded names:
- X2CrNi18-9 — EN 10088 (current symbolic name): The name and the number 1.4307 are used together; EN 10088-2 lists both.
- X2CrNi19-11 — EN 10088 (older designation): The composition window was restated in a later edition; the material number stayed 1.4307.
- 304S11 — BS 1449 (withdrawn): The British low-carbon 18/8 flat product grade.
- Z3CN18-10 — NF A 35-573 (withdrawn): The French designation for the same alloy.

Product forms: sheet, plate and coil (ASTM A240 / EN 10088-2); bar and section (A276 / EN 10088-3); welded and seamless pipe (A312 TP304L); tube for instrumentation and hygienic service (A269, A270); fittings, flanges and A2-class fasteners
Tolerances: sheet and plate: ASTM A480 / EN ISO 9445; bar: ASTM A484 / EN 10278; pipe: ASTM A999 general requirements; surface finishes: 2B, BA, No. 4, No. 8 to ASTM A480 Table A1.1

### 304L yield strength
Rp0.2 ≥ 170 MPa (25 ksi) for plate under ASTM A240, ≥ 220 MPa for cold-rolled strip and ≥ 200 MPa for hot-rolled plate under EN 10088-2. Rp1.0, which EN 1993-1-4 uses for design, is ≥ 250 MPa for strip and ≥ 235 MPa for plate.

### 304L tensile strength
≥ 485 MPa (70 ksi) under ASTM A240; 520–700 MPa cold-rolled and 500–700 MPa hot-rolled under EN 10088-2. Elongation is 40–45 %, which is what makes the grade deep-drawable.

### 304L hardness
Annealed, ≤ 201 HB under ASTM A240 and ≤ 215 HB under EN. It cannot be hardened by heat treatment — only by cold work, which raises hardness to 300–400 HV and introduces a weak magnetic response.

### Why the L exists: sensitisation
Between 500 and 800 °C, chromium combines with carbon to form Cr₂₃C₆ at the grain boundaries and strips those boundaries of chromium. The depleted band corrodes intergranularly in service and the failure is not visible from outside. Capping carbon at 0.030 % removes the mechanism; the alternative route is titanium stabilisation (321 / 1.4541).

### 304L against 304 on a certificate
Most mill coil is dual-certified 304/304L: it meets the low carbon of 304L and the strength minimum of 304 at the same time. Where a certificate names only 304, the carbon can legitimately be 0.08 % and the material is not 304L. Where it names only 304L, check the proof stress if the design used the 304 figure.

### Corrosion resistance
PREN ≈ 18–19, identical to 304 — the carbon change does nothing for pitting resistance. Good against nitric and organic acids, food media and inland atmospheres; pits in warm chloride above roughly 200 ppm. Coastal facades, pool halls and de-icing salt require 316L or 1.4404.

### Weldability
This is the grade's reason for existing, and it welds by all arc processes without preheat. Filler is ER308L / 19 9 L (EN ISO 14343) — the filler carries extra chromium and nickel to compensate for dilution, and its own carbon is already low. Interpass temperature should stay below about 150 °C to limit distortion, since austenitic stainless expands roughly 50 % more than carbon steel. Back-purge tube roots with argon. No post-weld heat treatment is required, and none should be applied casually: a stress-relief cycle through 500–800 °C would reintroduce exactly the problem the low carbon was bought to prevent. For heavy welded section in aggressive media, the next step is 1.4404 or 316L rather than a thicker 304L.

### Machining, forming, heat treatment
Machinability index around 45 % of free-cutting steel, and marginally worse than 304 because the lower carbon makes the matrix gummier. The grade work-hardens rapidly, so the rules are the usual austenitic ones: sharp positive-rake tooling, heavy and uninterrupted feed, low surface speed and no dwelling — a tool that rubs instead of cutting hardens the surface and the next pass has to cut through it. Where a machined part needs no welding, 1.4305 (303) is the free-machining alternative at the cost of weldability and pitting resistance. Deep drawing, spinning and bending are excellent; spring-back is higher than carbon steel.

Applications: Welded tanks, vessels and process piping in food, dairy, brewing and pharmaceutical plant; Heavy-section welded fabrications that cannot be solution annealed afterwards; Cryogenic vessels and lines, where austenite stays tough and the weld must stay stable; Architectural handrails, cladding and street furniture inland; Heat-exchanger shells and tube sheets in non-chloride service; A2-class fasteners and welded wire products

Q: What is the difference between 304 and 304L?
A: Carbon only. 304 allows up to 0.08 % and 304L caps it at 0.030 %. The low carbon prevents chromium carbides forming at the grain boundaries during welding, at the cost of 10–40 MPa of proof stress. Composition, corrosion resistance and appearance are otherwise identical.

Q: Is 304L stronger than 304?
A: No, slightly weaker. ASTM A240 requires 205 MPa proof stress for 304 and 170 MPa for 304L, with the same 485 MPa tensile minimum. If a design was calculated on the 304 figure, substituting 304L needs the calculation re-checked.

Q: What does dual-certified 304/304L mean?
A: The heat meets both specifications at once: carbon at or below 0.030 % as 304L requires, and proof stress at or above the 304 minimum. Most mill coil is produced this way, which is why a stockholder rarely has to choose between them.

Q: When do I actually need 304L instead of 304?
A: Welded section above roughly 6 mm, welded assemblies that will see a corrosive medium, and anything that cannot be solution annealed after welding. Thin sheet, unwelded parts and strength-governed designs are better served by 304.

Q: What is 1.4307?
A: The EN 10027-2 material number for 304L, with the symbolic name X2CrNi18-9. The EN grade caps sulphur at 0.015 % against 0.030 % in ASTM A240, so EN material always satisfies the American specification.

Q: Is 304L magnetic?
A: Not when annealed — the austenitic structure is essentially non-magnetic. Cold forming, machining and deep drawing transform some austenite into martensite and produce a weak magnetic response, which is normal and is not evidence of the wrong grade.

Q: Can 304L be used in seawater?
A: No. Its PREN of about 18–19 is the same as 304 and the low carbon does nothing for chloride resistance. Marine, coastal and de-icing-salt exposure needs 316L (1.4404) at minimum, and 1.4462 duplex where the chloride load is high.

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## 310 [S31000] — Austenitic heat-resisting stainless steel (25 % Cr, 20 % Ni)
URL: https://steelstandart.com/grade/310/
System: AISI / SAE | Family: Stainless steel | Standard: ASTM A240 | Verified against: ASTM A240/A240M-22
Aliases: AISI 310, SS310, Type 310, 310 stainless steel, 310 stainless, S31000, 310S, S31008, 1.4845, X8CrNi25-21, SUS310S, 25-20, TP310

Type 310 is the heat-resisting austenitic stainless steel: 25 % chromium and 20 % nickel give a scale that stays adherent in air to about 1100 °C (2000 °F) continuous and 1150 °C intermittent — roughly 250 °C beyond 304 or 321. It also resists carburizing, nitriding and sulphur-bearing atmospheres better than the 18-8 grades, and its high nickel keeps the structure fully austenitic and ductile through repeated heating and cooling. That combination puts it in furnace muffles, radiant tubes, kiln linings, heat-treatment baskets, burner parts, thermowells and fluidized-bed components. UNS S31000; the low-carbon 310S (S31008, C ≤ 0.08 %) is the grade actually stocked as plate and pipe, and 310H (S31009) is the creep-rated version for ASME pressure parts.

Room-temperature minimums are the familiar 205/515 MPa; at 800 °C the alloy still holds about 120 MPa yield. The main service limitation is sigma-phase formation after long exposure at 650–900 °C, which embrittles the steel at room temperature — parts that cycle through that range should be inspected for cracking on cooling. Corrosion resistance in aqueous service is moderate (PREN ≈ 25) and rarely the reason for choosing 310.

EN 1.4845, JIS SUS310S, GB 06Cr25Ni20 and BS 310S24 are the same grade; the higher-silicon EN 1.4841 and the cast HK-40 are near relatives for furnace work.

Chemical composition (mass %): C ≤ 0.25 (310S (S31008): ≤ 0.08; 310H (S31009): 0.04–0.10); Mn ≤ 2; P ≤ 0.045; S ≤ 0.03; Si ≤ 1.5; Cr 24 – 26; Ni 19 – 22
ASTM A240/A240M-22 (S31000, S31008). EN 1.4845 (X8CrNi25-21): C ≤ 0.10, Cr 24–26, Ni 19–22, Si ≤ 1.5 — corresponds to 310S. EN 1.4841 (X15CrNiSi25-21, Si 1.5–2.5) is the higher-Si heat-resisting version of EN 10095.

Mechanical properties:
- 310S plate, sheet, strip — annealed (A240): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 40 %; hardness ≤ 217 HB / ≤ 95 HRB
- 310 bar — annealed (A276): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 40 %; hardness —
- TP310S pipe (A312): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 35 %; hardness —
- TP310H boiler tube (A213): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 35 %; hardness ≤ 192 HB
- Typical Rp0.2 at 600 °C: yield ≈ 150 MPa; tensile ≈ 420 MPa; elongation — %; hardness —
- Typical Rp0.2 at 800 °C: yield ≈ 120 MPa; tensile ≈ 230 MPa; elongation — %; hardness —
- Typical Rp0.2 at 1000 °C: yield ≈ 50 MPa; tensile ≈ 80 MPa; elongation — %; hardness —
Minimums per ASTM A240/A276/A312/A213. Typical annealed: yield 270–310 MPa, tensile 600–650 MPa. 100 000 h creep-rupture strength (310H, typical): ≈ 35 MPa at 700 °C, 15 MPa at 800 °C, 6 MPa at 900 °C.
Impact: 80 J at -196 °C (typical, annealed)

Equivalents:
- 310S24 (BS (superseded British)) — identical: BS 1449 310S24 / 310S31.
- 1.4845 (EN (European)) — identical: X8CrNi25-21: C ≤ 0.10, Cr 24–26, Ni 19–22 — corresponds to 310S; dual-certified.
- 06Cr25Ni20 (GB/T (China)) — identical: GB/T 20878 06Cr25Ni20 (formerly 0Cr25Ni20).
- SUS310S (JIS (Japan)) — identical: JIS G4304 SUS310S: C ≤ 0.08, Cr 24–26, Ni 19–22, Si ≤ 1.5.
- 309 / 309S (AISI / SAE) — near: S30900/S30908 (22–24 Cr, 12–15 Ni): the intermediate heat-resisting grade to ~1000 °C; cheaper, less oxidation and carburization resistance.
- 1.4841 (EN (European)) — near: X15CrNiSi25-21 (EN 10095): C ≤ 0.20, Si 1.5–2.5 — the higher-carbon, high-Si heat-resisting version closer to plain 310.
- 10Kh23N18 / 20Kh23N18 (GOST (Russia/CIS)) — near: GOST 5632 20Kh23N18: C ≤ 0.20, Cr 22–25, Ni 17–20 — the Russian 25-20 type; 10Kh23N18 is the lower-carbon version.
- 321 (AISI / SAE) — functional: Stabilized 18-8 for service to ~870 °C; 310 takes over above that.
- 253MA / 1.4835 (EN (European)) — functional: S30815: rare-earth/N-alloyed 21-11 grade with higher creep strength at 850–1100 °C at lower Ni cost.

Superseded names:
- 1.4845 / X8CrNi25-21 — EN 10088 / EN 10095: Older DIN name X12CrNi25 21.
- S31000 / S31008 / S31009 — UNS: 310 / 310S / 310H.
- 310S24 / 310S31 — BS 1449 / BS 970
- 25-20 — Colloquial: Named for its Cr/Ni content.
- HK-40 / CK-20 — ACI / ASTM A297, A351: Cast 25-20 grades (HK has 0.4 % C for creep).

Product forms: sheet, strip, plate (ASTM A240 — 310S is the usual flat-product grade); bar and forgings (A276, A479); seamless and welded pipe and tube (A312 TP310S, A213 TP310H, A269); fittings (A403 WP310S), wire; castings HK-40 / CK-20 (A297, A351)
Tolerances: sheet/plate: ASTM A480; bar: ASTM A484; pipe: ASTM A999

### 310 stainless steel yield strength
Minimum 205 MPa (30 ksi) annealed; typical 270–310 MPa. Typical at 600 °C ≈ 150 MPa, 800 °C ≈ 120 MPa, 1000 °C ≈ 50 MPa.

### 310 tensile strength
Minimum 515 MPa (75 ksi); typical 600–650 MPa annealed; ≈ 230 MPa at 800 °C.

### 310 hardness
Annealed max 217 HB / 95 HRB; typical 160–190 HB. Not hardenable by heat treatment.

### Maximum service temperature
Oxidation in air: 1100 °C continuous, 1150 °C intermittent (thermal cycling is tolerated better than by ferritic 446 because expansion is uniform). ASME creep design: 310H to 816 °C (1500 °F). Resists dry sulphur-bearing gases to ~1000 °C (reducing atmospheres lower this), carburizing and nitriding atmospheres moderately well; poor in molten metals and salts.

### Creep strength
100 000 h rupture (310H, typical): ≈ 35 MPa at 700 °C, 15 MPa at 800 °C, 6 MPa at 900 °C. For higher creep strength at 900–1100 °C use 253MA, 314, or cast HK/HP alloys.

### Physical properties
Density 7.9 g/cm³, E = 200 GPa, expansion 15.9 × 10⁻⁶/K (0–100 °C), 18.5 (0–800 °C), conductivity 14.2 W/m·K, resistivity 0.78 µΩ·m, non-magnetic.

### Heat treatment
Solution anneal 1040–1150 °C (1900–2100 °F), water quench or rapid air cool. Do not stress-relieve at 650–900 °C. Sigma-phase embrittlement can be reversed by re-annealing above 1050 °C.

### Weldability
Good weldability with matching ER310 / E310-16 filler (fully austenitic weld metal — keep heat input low, ≤ 1.5 kJ/mm, and interpass ≤ 150 °C to avoid hot cracking; ER312 for dissimilar or highly restrained joints). No preheat; no PWHT for corrosion reasons. 310 welds are prone to micro-fissuring in thick multi-pass joints — use stringer beads.

### Machining, forming, heat treatment
Machinability ≈ 35–40 % of B1112 (tough, high work-hardening, high nickel); rigid setups, sharp carbide, low speed / positive feed, flood coolant. Forming is good in the annealed state (bending, spinning, drawing) with about 20 % higher loads than 304. Hot forming 1150–980 °C followed by solution annealing.

Applications: Furnace muffles, retorts, radiant tubes, kiln and oven linings; Heat-treatment trays, baskets, fixtures and conveyor belts; Burner components, flare tips, combustion chambers; Thermowells, thermocouple protection tubes, sight glasses frames; Fluidized-bed components, incinerator and waste-heat boiler parts; Refinery tube supports and hangers, coke-oven equipment; Cryogenic parts requiring stable austenite (secondary use)

Q: What is the difference between 310 and 310S?
A: Carbon: 310 allows up to 0.25 %, 310S only 0.08 %. Lower carbon improves weldability and reduces carbide precipitation; 310S is what mills actually stock as plate, sheet and pipe. 310H (0.04–0.10 % C, controlled grain size) is the creep-rated version for ASME pressure parts.

Q: What is the maximum temperature for 310 stainless steel?
A: About 1100 °C (2000 °F) continuous and 1150 °C intermittent in air. For pressure-retaining parts ASME rates 310H to 816 °C. Beyond 1100 °C nickel-base alloys or ceramics are needed.

Q: 310 vs 309 stainless — which to choose?
A: 309 (23 % Cr / 13 % Ni) is rated to about 1000 °C and is cheaper; 310 (25/20) adds ~100 °C of oxidation resistance and better resistance to carburizing and sulphidizing atmospheres. Choose 310 above 1000 °C or for aggressive furnace atmospheres.

Q: Why does 310 become brittle after service?
A: Sigma phase forms during long exposure at 650–900 °C, embrittling the steel at room temperature (cracks on cooling or handling). Re-annealing above 1050 °C dissolves sigma and restores ductility.

Q: What is 310 equivalent to in EN?
A: EN 1.4845 (X8CrNi25-21) corresponds to 310S. EN 1.4841 (X15CrNiSi25-21, EN 10095) is the higher-carbon, higher-silicon heat-resisting version closer to plain 310.

Q: Is 310 stainless magnetic?
A: No — with 20 % nickel it is one of the most stable austenitic grades and stays non-magnetic even after cold work.

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## 316 [S31600] — Austenitic chromium-nickel-molybdenum stainless steel
URL: https://steelstandart.com/grade/316/
System: AISI / SAE | Family: Stainless steel | Standard: ASTM A240 | Verified against: ASTM A240/A240M-22
Aliases: AISI 316, SS316, SS 316, Type 316, 316 stainless steel, 316 stainless, S31600, 316L, S31603, 316 SS, marine grade stainless, TP316, A4 stainless, 1.4401, X5CrNiMo17-12-2, SUS316, 06Cr17Ni12Mo2, 0Cr17Ni12Mo2, 08Kh17N13M2, 316S31

Type 316 is the second most common stainless steel and the first choice where 304 pits: an 18-8 austenitic base with 2–3 % molybdenum and 10–14 % nickel, UNS S31600 (316) or S31603 (316L, carbon ≤ 0.03 %). Molybdenum raises the pitting resistance equivalent from about 18 to 24, which is the difference between tea-staining and staying bright in coastal air, de-icing salt, brackish water and most acidic process streams. That is why 316 is called 'marine grade' and why A4 stainless fasteners, boat fittings, pharmaceutical equipment and chemical piping are made from it.

Mechanically 316 is a twin of 304: 205 MPa (30 ksi) yield and 515 MPa (75 ksi) tensile minimum, 40 % elongation, non-magnetic, no low-temperature transition, hardenable only by cold work. It is slightly stronger than 304 at elevated temperature and has better creep resistance; 316H is the creep-rated version above 525 °C.

Most coil, plate and pipe today is dual-certified 316/316L — carbon ≤ 0.03 % with the higher 316 strength minimums — so a specification for either is normally satisfied by the same stock. EN 1.4401/1.4404, JIS SUS316/316L and GB 06Cr17Ni12Mo2 are identical for procurement; the table also grades the high-Mo (1.4436) and Ti-stabilized (1.4571) European variants.

Chemical composition (mass %): C ≤ 0.08 (316L (S31603): ≤ 0.030; 316H (S31609): 0.04–0.10); Mn ≤ 2; P ≤ 0.045; S ≤ 0.03; Si ≤ 0.75; Cr 16 – 18; Ni 10 – 14; Mo 2 – 3; N ≤ 0.1
ASTM A240/A240M-22 Table 1 (S31600 / S31603). Compare EN 1.4401 (316): Cr 16.5–18.5, Ni 10–13, Mo 2.0–2.5, C ≤ 0.07; EN 1.4404 (316L): same with C ≤ 0.030.

Mechanical properties:
- 316 plate/sheet/strip — annealed (A240): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 40 %; hardness ≤ 217 HB / ≤ 95 HRB
- 316L plate/sheet/strip — annealed (A240): yield ≥ 170 MPa; tensile ≥ 485 MPa; elongation 40 %; hardness ≤ 217 HB / ≤ 95 HRB
- 316 bar — annealed (A276): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 40 %; hardness —
- 316 bar — cold finished ≤ 12.7 mm (A276 cond. B): yield ≥ 310 MPa; tensile ≥ 620 MPa; elongation 30 %; hardness —
- TP316 pipe (A312): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 35 %; hardness —
- 316 at 300 °C (typical Rp0.2): yield ≈ 140 MPa; tensile ≈ 430 MPa; elongation — %; hardness —
Minimum values, ASTM A240 Table 2 / A276 Table 2. Typical annealed 2B sheet: yield 270–310 MPa, tensile 580–620 MPa. Dual-certified 316/316L material meets the 316 minimums with 316L carbon.
Impact: 100 J at -196 °C (typical)

Equivalents:
- 316S31 / 316S11 (BS (superseded British)) — identical: BS 1449 designations for 316 / 316L.
- 1.4401 (EN (European)) — identical: X5CrNiMo17-12-2: Cr 16.5–18.5, Ni 10–13, Mo 2.0–2.5, C ≤ 0.07 — within the 316 window (Mo at the low end).
- 1.4404 (EN (European)) — identical: X2CrNiMo17-12-2 = 316L: C ≤ 0.030, Mo 2.0–2.5. Dual-certified 1.4404/316L is the norm.
- 06Cr17Ni12Mo2 / 022Cr17Ni12Mo2 (GB/T (China)) — identical: GB/T 20878 (formerly 0Cr17Ni12Mo2 / 00Cr17Ni14Mo2).
- SUS316 / SUS316L (JIS (Japan)) — identical: JIS G4304 SUS316: C ≤ 0.08, Cr 16–18, Ni 10–14, Mo 2–3.
- 316L (AISI / SAE) — near: Identical alloy with carbon to 0.08 % and slightly higher strength minima. Most material sold today is dual certified to both.
- 1.4436 / 1.4432 (EN (European)) — near: Mo 2.5–3.0 % versions (316 / 316L 'high-Mo') covering the upper half of the ASTM Mo range.
- 1.4571 (EN (European)) — near: 316Ti — Ti-stabilized; equivalent corrosion class, better at 400–550 °C.
- 08Kh17N13M2T / 03Kh17N14M3 (GOST (Russia/CIS)) — near: GOST 5632 Mo grades; 10Kh17N13M2T (Ti-stabilized) is the common Russian 316 equivalent.
- 304 (AISI / SAE) — functional: Non-Mo 18-8: same strength and formability, PREN 18; substitute where chlorides are absent.
- 2205 (AISI / SAE) — functional: Duplex S32205: double the yield, PREN 35 — the upgrade for warm chloride service.
- 17-4 PH (AISI / SAE) — functional: Austenitic: similar corrosion resistance, one-quarter of the yield strength; 17-4 replaces it where strength matters.

Superseded names:
- S31600 / S31603 / S31609 — UNS: 316 / 316L / 316H.
- 316Ti (S31635) — ASTM A240: Titanium-stabilized variant; EN 1.4571 — rarely stocked in the USA.
- CF8M / CF3M — ASTM A351 / ACI: Cast equivalents of 316 / 316L.
- 316S31 / 316S11 — BS 1449 / BS 970: 316S31 = 316, 316S11 = 316L.
- A4 — ISO 3506 (fasteners): A4-70 / A4-80 stainless bolts are 316-class.

Product forms: sheet, strip and plate (ASTM A240); bar and shapes (A276, A479); seamless and welded pipe (A312 TP316/TP316L), tube (A269, A249); fittings (A403 WP316), flanges and forgings (A182 F316); wire, fasteners (F593 Group 2), castings CF8M / CF3M (A351)
Tolerances: sheet/plate: ASTM A480; bar: ASTM A484; pipe: ASTM A999 / ASME B36.19

### 316 stainless steel yield strength
316: minimum 205 MPa (30 ksi); 316L: 170 MPa (25 ksi); typical annealed 270–310 MPa. Cold-finished bar ≥ 310 MPa; ¼-hard sheet ≥ 515 MPa.

### 316 tensile strength
316: ≥ 515 MPa (75 ksi); 316L: ≥ 485 MPa (70 ksi); typical 580–620 MPa annealed.

### 316 hardness
Annealed max 217 HB / 95 HRB (≈ 225 HV); typical 150–190 HB. Not hardenable by heat treatment; cold-worked up to ~40 HRC.

### Corrosion resistance
PREN ≈ 23–26 (Mo-dependent). Resists seawater splash, marine atmospheres, sulphuric acid to ~5 % at ambient, phosphoric, acetic and most organic acids, chloride solutions to ~1000 ppm at ambient. Susceptible to chloride SCC above ~60 °C and to crevice corrosion in stagnant warm seawater (use 2205 or 6 % Mo).

### High-temperature use
Oxidation limit ≈ 870 °C continuous (925 °C intermittent); ASME creep design above 525 °C requires 316H. Sigma-phase embrittlement on long exposure at 550–900 °C (worse than 304 because of Mo).

### Physical properties
Density 8.0 g/cm³, E = 193 GPa, expansion 16 × 10⁻⁶/K (0–100 °C), conductivity 16.2 W/m·K, resistivity 0.74 µΩ·m, non-magnetic (μr ≤ 1.02 annealed).

### Heat treatment
Solution anneal 1040–1120 °C (1900–2050 °F), water quench. Avoid 425–860 °C exposure for 316 (sensitization); 316L is immune in practical weld thicknesses.

### Weldability
Excellent weldability by all arc, laser and resistance processes without preheat; filler ER316L / E316L-16 (AWS A5.9 / A5.4). Interpass ≤ 150 °C. Use 316L base for welded sections > 6 mm in corrosive service, or solution-anneal 316 after welding. Pickle/passivate welds for chloride exposure. Weld to carbon steel with ER309L.

### Machining, forming, heat treatment
Machinability ≈ 40 % of B1112 (slightly gummier than 304); use sharp carbide, positive rake, rigid setups; 316F (free-machining, S31620) exists but is uncommon. Forming, deep drawing and spinning are excellent; slightly higher press loads than 304. Standard finishes per ASTM A480 (2B, BA, No. 4, No. 8); electropolishing widely used for pharma and semiconductor tubing.

Applications: Marine hardware, boat fittings, deck rails, coastal architecture; Chemical, petrochemical, pulp-and-paper process equipment and piping; Pharmaceutical, biotech and semiconductor high-purity tubing and vessels (316L, electropolished); Food processing in salty or acidic media (brine, pickles, sauces); Medical instruments and implants (316LVM / ASTM F138); Heat exchangers, condensers and evaporators with brackish cooling water; Fasteners A4-70/A4-80, ASTM F593 Group 2; springs and wire; Pool and spa fittings (with maintenance), water treatment, desalination pre-treatment

Q: What is the difference between 316 and 316L?
A: Carbon: 316 allows up to 0.08 %, 316L only 0.03 %. Low carbon prevents chromium-carbide formation in weld heat-affected zones, so 316L is specified for welded equipment > 6 mm and for corrosive service after welding. 316L's strength minimums are 15–35 MPa lower, but dual-certified 316/316L material meets both.

Q: Is 316 stainless steel magnetic?
A: No in the annealed state, and even less after cold work than 304 because its higher nickel content stabilizes the austenite. A strong magnetic response indicates a different grade.

Q: Is 316 suitable for seawater?
A: For marine atmosphere, splash zones and intermittent immersion with cleaning — yes; it is the standard marine grade. For continuous immersion in warm, stagnant seawater it suffers crevice corrosion; use duplex 2205, super-duplex or 6 % Mo austenitics.

Q: What is the European equivalent of 316?
A: EN 1.4401 (X5CrNiMo17-12-2) for 316 and 1.4404 (X2CrNiMo17-12-2) for 316L. The EN Mo window (2.0–2.5 %) sits inside the ASTM 2.0–3.0 %, so EN material always meets ASTM; 1.4436/1.4432 cover the high-Mo end and 1.4571 is the Ti-stabilized 316Ti.

Q: Why is 316 more expensive than 304?
A: Molybdenum (2–3 %) and the extra nickel (10–14 % vs 8–10.5 %) are the costliest alloying elements; together they add roughly 20–40 % to the price depending on the Ni/Mo market.

Q: What temperature can 316 withstand?
A: Continuous service in air to about 870 °C (1600 °F) for oxidation; for pressure parts ASME limits 316 to 425 °C unless it is 316H (carbon ≥ 0.04 %), which is rated to ~815 °C. Avoid long holds at 550–900 °C (sigma phase).

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## 316L (1.4404) [S31603] — Low-carbon austenitic chromium-nickel-molybdenum stainless steel
URL: https://steelstandart.com/grade/316l/
System: AISI / SAE | Family: Stainless steel | Standard: ASTM A240 | Verified against: EN 10088-2:2014 · ASTM A240/A240M
Aliases: 316l, 316l stainless steel, 1.4404, s31603, 316l vs 316, a4 stainless, SUS316L, 022Cr17Ni12Mo2, 00Cr17Ni14Mo2, 03Kh17N14M3, 316S11

316L is 316 with the carbon taken out, and that is the whole specification: 0.030 % maximum against 0.08 %. Chromium, nickel and molybdenum are unchanged, so the corrosion resistance of the base metal is unchanged too.

The carbon matters in one place — beside a weld. Held between roughly 425 and 815 °C, chromium and carbon combine at the grain boundaries; the chromium locked into those carbides is no longer available to protect the steel, and a narrow band parallel to the weld corrodes while the weld itself and the plate beyond it stay sound. That is sensitisation, and less carbon means less of it. It is why 316L is the default for welded fabrication and why 316 is not.

The 2 to 2.5 % molybdenum is what separates the 316 family from 304 and is the reason anyone pays for it: molybdenum resists pitting by chlorides, which is the failure mode in seawater, de-icing salt, swimming pools, brine and most food processing.

One practical note that settles most enquiries: the great majority of material on the market is dual certified 316/316L — carbon below 0.030 % while still meeting the higher 316 mechanical minima — so a single certificate satisfies both specifications.

Chemical composition (mass %): C ≤ 0.03 (the definition of the grade; 316 allows 0.08 %); Cr 16.5 – 18.5; Ni 10 – 13; Mo 2 – 2.5 (the pitting resistance that separates 316 from 304); Mn ≤ 2; Si ≤ 1; P ≤ 0.045; S ≤ 0.015; N ≤ 0.11
EN 10088-2 for 1.4404; the ASTM A240 ranges for S31603 are close but not identical (Ni 10.0–14.0, N ≤ 0.10). PREN, calculated as Cr + 3.3 Mo + 16 N, lands at roughly 24–25 — comfortably above 304's 18–19 and well below a duplex or super-austenitic grade.

Mechanical properties:
- sheet/plate, annealed (ASTM A240): yield ≥ 170 MPa; tensile ≥ 485 MPa; elongation 40 %; hardness ≤ 217 HB / ≤ 95 HRB
- cold-rolled sheet, annealed (EN 10088-2): yield ≥ 240 MPa; tensile 530–680 MPa; elongation 40 %; hardness —
- hot-rolled plate, annealed (EN 10088-2): yield ≥ 220 MPa; tensile 520–670 MPa; elongation 45 %; hardness —
- bar, annealed (A276): yield ≥ 170 MPa; tensile ≥ 485 MPa; elongation 40 %; hardness —
- TP316L pipe (A312): yield ≥ 170 MPa; tensile ≥ 485 MPa; elongation 35 %; hardness —
- 316 for comparison (A240): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 40 %; hardness —
The ASTM and EN minima differ and both are correct: ASTM A240 sets a 170 MPa floor for S31603 while EN 10088-2 sets 240 MPa for cold-rolled 1.4404 sheet. A design that quotes '316L yield strength' without naming the standard and the product form is quoting an incomplete number.
Impact:  J at -196 °C (austenitic — no ductile-to-brittle transition)

Equivalents:
- 1-4404 (EN (European)) — identical: 1.4404 is the EN material number for this grade; X2CrNiMo17-12-2 is its descriptive name.
- 1.4404 (EN (European)) — identical: UNS S31603 (ASTM A240): C ≤ 0.03, Cr 16–18, Ni 10–14, Mo 2–3; 1.4404 sits inside the 316L window and is dual-certified.
- 316 (AISI / SAE) — near: Identical alloy with carbon to 0.08 % and slightly higher strength minima. Most material sold today is dual certified to both.
- 1.4571 (EN (European)) — near: Same corrosion class; 316L achieves weld-zone stability by low carbon instead of Ti. Usual substitute outside Europe.
- 304 (AISI / SAE) — functional: The same austenitic family without molybdenum. Adequate in most atmospheres, not in chlorides — the substitution runs one way only.
- 304L (AISI / SAE) — functional: UNS S31603 adds 2–2.5 % molybdenum for chloride resistance. Specify it instead of 304L near the sea, in de-icing salt or in pool environments — the low-carbon logic is identical.
- A333 Grade 6 (ASTM / ASME) — functional: Austenitic stainless steel has no ductile-to-brittle transition, so it needs no impact test at cryogenic temperature and is often the alternative to a nickel steel below about −100 °C. It costs several times more and has a much higher thermal expansion.
- 2205 (EN (European)) — functional: Duplex with roughly twice the yield and a PREN around 35. Specified when 316L pits or when wall thickness has to come down.

Superseded names:
- X2CrNiMo17-12-2 — EN 10088-2 name: The descriptive EN designation: 0.02 % C, 17 % Cr, 12 % Ni, 2 % Mo.
- SUS 316L — JIS G4304 / G4305: The Japanese designation; ranges are effectively the same.
- 1.4435 — EN 10088-2: Not the same grade — a higher-molybdenum, higher-nickel variant (2.5–3.0 % Mo) often specified for pharmaceutical service and sometimes confused with 1.4404.

Product forms: sheet, plate and coil (ASTM A240 / EN 10088-2); bar and section (A276 / EN 10088-3); welded and seamless pipe (A312 TP316L); tube for instrumentation and hygienic service (A269, A270); fittings, flanges and A4-class fasteners
Tolerances: sheet and plate: ASTM A480 / EN ISO 9445; bar: ASTM A484 / EN 10278; pipe: ASTM A999 general requirements; surface finishes: 2B, BA, No. 4, No. 8 to ASTM A480 Table A1.1

### 316L chemical composition
C ≤ 0.030 %, Cr 16.5–18.5 %, Ni 10.0–13.0 %, Mo 2.0–2.5 %, Mn ≤ 2.0 %, Si ≤ 1.0 %, N ≤ 0.11 % (EN 10088-2 for 1.4404). ASTM A240 allows nickel to 14.0 %. The molybdenum is the working element; the carbon ceiling is the name.

### 316L yield and tensile strength
ASTM A240 requires 170 MPa yield and 485 MPa tensile minimum; EN 10088-2 requires 240 MPa yield and 530–680 MPa tensile for cold-rolled sheet. Real annealed material usually runs well above both. The grade work-hardens steeply, so a cold-worked section tests far harder than an annealed one.

### 316L corrosion resistance
PREN ≈ 24–25, against 18–19 for 304. That buys real chloride tolerance — coastal atmosphere, food brines, chlorinated water at moderate temperature — but not immunity. In warm seawater, in concentrated brine or under deposits, 316L pits, and the step up is duplex 2205 or a 6 % molybdenum super-austenitic grade.

### 316L vs 316
Same alloy, carbon 0.030 % against 0.08 %, and ASTM minima 35 MPa lower on yield. Use 316L for anything welded and not solution annealed afterwards; use 316 for sustained service above about 500 °C, where the higher carbon carries better creep strength, or 316H where a code allows it.

### 316L in fasteners: A4
The A4 property class in ISO 3506 is the 316/316L family, most commonly A4-70 for bolts. A4 is specified for marine and chloride service where A2 (the 304 class) corrodes; the number after the dash is the strength class, set by cold work, not by the alloy.

### Weldability
316L is the reason the L grades exist and it welds by every standard process — TIG, MIG, MMA, plasma and laser — without preheat and without post-weld heat treatment at normal thicknesses. Use 316L filler (ER316L / E316L-16), or 309L for a dissimilar joint to carbon steel. Heat input should be kept moderate and interpass temperature controlled, not because of sensitisation but because austenitic steel distorts: its thermal expansion is around 60 % greater than carbon steel's while its conductivity is a third. Back-purge with argon on pipe to prevent oxide on the root, and pickle or passivate afterwards — heat tint is chromium-depleted and corrodes, which is the single most common cause of 'the stainless rusted' on a new installation.

### Machining, forming, heat treatment
Machinability is poor by carbon-steel standards, roughly 35–45 % of a free-cutting reference, and the reasons are gumminess and work hardening rather than hardness. Use sharp tooling, positive rake, rigid setups, generous coolant and — critically — a feed heavy enough to cut under the work-hardened layer rather than rubbing on it. Cold forming is excellent: 40 % elongation and steep work hardening make it a deep-drawing material, at the cost of high press loads and springback. Interstage annealing is normal on severe draws.

Applications: Welded process pipework and vessels in food, dairy, brewing and pharmaceutical plant; Marine and coastal fittings, balustrade, fasteners (A4) and architectural components; Heat exchangers and tanks handling chloride-bearing water; Chemical and pulp plant where 304 pits and duplex is not justified; Hygienic tube and fittings with orbital-welded joints; Cryogenic service down to −196 °C, where austenitic toughness is the requirement

Q: What does the L in 316L mean?
A: Low carbon: a maximum of 0.030 % against 0.08 % for 316. Chromium, nickel and molybdenum are unchanged, so the L affects welding behaviour rather than the corrosion resistance of the base metal.

Q: Is 316L better than 316?
A: For welded fabrication, yes — it will not sensitise in the heat-affected zone. For sustained service above about 500 °C, no: the lower carbon means lower creep strength, and 316 or 316H is the correct choice there.

Q: What is the difference between 316L and 304?
A: Molybdenum. 316L carries 2.0–2.5 % of it and 304 has none, which lifts the pitting resistance number from about 18–19 to about 24–25. In dry or mildly wet service they behave alike; in chlorides — sea air, brine, pool water, de-icing salt — 304 pits and 316L does not.

Q: What is the yield strength of 316L?
A: It depends on which standard and which product form. ASTM A240 sets a minimum of 170 MPa for annealed sheet and plate; EN 10088-2 sets 240 MPa for cold-rolled sheet of the same grade. Both are correct, so the standard has to be named alongside the number.

Q: Is 316L magnetic?
A: Not in the annealed condition — it is austenitic, with a relative permeability close to 1.0. Heavy cold work such as deep drawing or severe bending induces some martensite and a part can then register weakly magnetic, which is normal and not a sign of the wrong grade.

Q: What is dual certified 316/316L?
A: Material whose carbon is below 0.030 %, satisfying 316L, while its mechanical properties still meet the higher 316 minima. One certificate then covers both specifications, which is how most 316 is supplied today.

Q: Can 316L be used in seawater?
A: In moving, aerated seawater at ambient temperature it performs for a time; in warm, stagnant or deposit-covered seawater it pits and crevice-corrodes. For sustained seawater duty the specification steps up to duplex 2205, super duplex or a 6 % molybdenum austenitic grade.

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## 321 [S32100] — Austenitic Cr-Ni stainless steel, titanium-stabilized
URL: https://steelstandart.com/grade/321/
System: AISI / SAE | Family: Stainless steel | Standard: ASTM A240 | Verified against: ASTM A240/A240M-22
Aliases: AISI 321, SS321, Type 321, 321 stainless steel, 321 stainless, S32100, 1.4541, X6CrNiTi18-10, SUS321, 321H, S32109, TP321, 06Cr18Ni11Ti, 0Cr18Ni10Ti, 12Kh18N10T, 321S31

Type 321 is 18-8 stainless stabilized with titanium (≥ 5 × carbon) so that, when the steel sits in the 425–870 °C range — in an exhaust manifold, an expansion bellows, a furnace part or a refinery heater — the carbon precipitates as harmless titanium carbide instead of chromium carbide at the grain boundaries. 304 in the same service sensitizes and corrodes intergranularly; 304L runs out of strength. 321 does neither, which makes it the standard austenitic for intermediate-temperature service and for welded equipment that cannot be annealed after welding. UNS S32100; EN 1.4541.

Room-temperature properties equal 304 (205/515 MPa minimum), corrosion resistance is a shade lower in aqueous service (Ti carbonitrides), and polishing is poorer. 321H (S32109), with 0.04–0.10 % carbon and a minimum grain size, is the creep-rated version used for ASME pressure parts above 525 °C and rated to 816 °C.

The niobium-stabilized 347 is the sister grade: Nb, unlike Ti, survives the welding arc, so 347 filler (ER347) is used for both. GOST 08Kh18N10T — the most-produced Russian stainless — and EN 1.4541 are identical.

Chemical composition (mass %): C ≤ 0.08 (321H (S32109): 0.04–0.10); Mn ≤ 2; P ≤ 0.045; S ≤ 0.03; Si ≤ 0.75; Cr 17 – 19; Ni 9 – 12; N ≤ 0.1; Ti 5 × (C+N) – 0.7 (321H: 4 × (C+N) min)
ASTM A240/A240M-22 Table 1 (S32100). EN 1.4541 (X6CrNiTi18-10): C ≤ 0.08, Cr 17–19, Ni 9–12, Ti 5×C–0.70 — identical. Niobium-stabilized 347 (S34700 / 1.4550) is the sister grade with better weld-metal stability.

Mechanical properties:
- Plate, sheet, strip — annealed (A240): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 40 %; hardness ≤ 217 HB / ≤ 95 HRB
- Bar — annealed (A276): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 40 %; hardness —
- TP321 pipe (A312): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 35 %; hardness —
- TP321H boiler tube (A213): yield ≥ 205 MPa; tensile ≥ 515 MPa; elongation 35 %; hardness ≤ 192 HB
- Typical Rp0.2 at 500 °C: yield ≈ 130 MPa; tensile ≈ 400 MPa; elongation — %; hardness —
- Typical Rp0.2 at 700 °C: yield ≈ 110 MPa; tensile ≈ 300 MPa; elongation — %; hardness —
Minimums per ASTM A240/A276/A312/A213. Typical annealed sheet: yield 250–290 MPa, tensile 590–640 MPa. ASME II-D allowable stresses for 321H extend to 816 °C (1500 °F); 100 000 h creep-rupture strength ≈ 60 MPa at 650 °C for 321H.
Impact: 80 J at -196 °C (typical)

Equivalents:
- 321S31 (BS (superseded British)) — identical: BS 1449 321S31.
- 1.4541 (EN (European)) — identical: X6CrNiTi18-10: same limits; dual-certified 321/1.4541.
- 06Cr18Ni11Ti (GB/T (China)) — identical: GB/T 20878 06Cr18Ni11Ti (formerly 0Cr18Ni10Ti).
- 08Kh18N10T / 12Kh18N10T (GOST (Russia/CIS)) — identical: GOST 5632 08Kh18N10T (C ≤ 0.08) — the standard Russian austenitic; 12Kh18N10T (C ≤ 0.12) ≈ 321H.
- SUS321 (JIS (Japan)) — identical: JIS G4304 SUS321: C ≤ 0.08, Cr 17–19, Ni 9–13, Ti ≥ 5×C.
- 347 (AISI / SAE) — near: S34700 / 1.4550: Nb-stabilized twin; Nb transfers through the arc so weld metal is also stabilized; slightly better creep. Interchangeable in most specs.
- 304H (AISI / SAE) — near: Unstabilized high-carbon 304 for creep service; sensitizes but is cheaper — used where intergranular corrosion is not a concern.
- 1.4878 (EN (European)) — near: X8CrNiTi18-10 heat-resisting variant (EN 10095) for furnace parts.
- 304L (AISI / SAE) — functional: Low-carbon route to weld stability; not suitable above ~425 °C for strength.
- 310 (AISI / SAE) — functional: Stabilized 18-8 for service to ~870 °C; 310 takes over above that.

Superseded names:
- 1.4541 / X6CrNiTi18-10 — EN 10088: Older DIN name X10CrNiTi18 9; 1.4878 (X8CrNiTi18-10) is the heat-resisting version per EN 10095.
- S32100 / S32109 — UNS: 321 / 321H.
- 321S31 / 321S51 — BS 1449 / BS 970
- AMS 5510 / 5645 — SAE Aerospace: Sheet and bar specifications for aircraft exhaust and manifolds.

Product forms: sheet, strip, plate (ASTM A240); bar and forgings (A276, A479, A182 F321); seamless and welded pipe and tube (A312 TP321, A213 TP321H for boilers, A269); fittings (A403 WP321), flanges; wire, aircraft sheet (AMS 5510)
Tolerances: sheet/plate: ASTM A480; bar: ASTM A484; tube: A213/A1016 (boiler), A312/A999 (pipe)

### 321 stainless steel yield strength
Minimum 205 MPa (30 ksi) annealed; typical 250–290 MPa. At 500 °C ≈ 130 MPa, at 700 °C ≈ 110 MPa (typical).

### 321 tensile strength
Minimum 515 MPa (75 ksi); typical 590–640 MPa annealed; ≈ 400 MPa at 500 °C.

### 321 hardness
Annealed max 217 HB / 95 HRB; typical 150–190 HB. Not hardenable by heat treatment.

### High-temperature and creep properties
Continuous oxidation limit ≈ 870 °C (925 °C intermittent). ASME allowable stresses: 321 to 425 °C for full strength, 321H creep-rated to 816 °C. 100 000 h rupture strength (321H, typical): ≈ 110 MPa at 600 °C, 60 MPa at 650 °C, 30 MPa at 700 °C. Resists intergranular attack after 500–800 °C exposure (ASTM A262 practice E passes).

### Corrosion resistance
PREN ≈ 18 — same class as 304 in most media; slightly lower pitting resistance in chlorides because Ti(C,N) particles act as initiation sites. Good in nitric acid, organic acids, and in the polythionic-acid environments of refinery heaters where 304 fails.

### Physical properties
Density 8.0 g/cm³, E = 193 GPa, expansion 16.6 × 10⁻⁶/K (0–100 °C), 18.6 (0–500 °C), conductivity 16.1 W/m·K, non-magnetic annealed.

### Heat treatment
Solution anneal 955–1065 °C (1750–1950 °F), water or air quench. Stabilizing anneal 845–900 °C 1–4 h for maximum intergranular resistance in service at 425–870 °C. Stress relief at 700–900 °C is permissible (unlike 304) because the steel is stabilized.

### Weldability
Excellent weldability by all arc processes; filler ER347 / E347 (Nb-stabilized) is standard because titanium does not transfer across the arc; ER308L is acceptable when the weld sees no high-temperature service. No preheat, interpass ≤ 150 °C. Post-weld heat treatment is not needed for corrosion resistance; a stabilizing anneal may be specified for critical high-temperature equipment.

### Machining, forming, heat treatment
Machinability ≈ 40 % of B1112 (Ti carbonitrides increase tool wear slightly versus 304). Forming and deep drawing are very good; spinning of exhaust cones and bellows is routine. Polishing to bright finishes is poorer (streaks) — use 304 for decorative work.

Applications: Aircraft and automotive exhaust manifolds, collectors, flexible bellows; Expansion joints and bellows in piping and turbines; Furnace parts, heat-treatment fixtures, thermocouple sheaths, radiant tubes; Refinery heater tubes, hydrotreater and reformer piping (321H, polythionic-acid resistance); Boiler superheater tubes, pressure vessels 425–815 °C (321H); Welded pressure equipment that cannot be post-weld annealed; Chemical process equipment with thermal cycling; jet-engine parts (AMS 5510)

Q: What is the difference between 321 and 304 stainless?
A: 321 adds titanium (≥ 5 × C) which prevents chromium-carbide precipitation at 425–870 °C, so it keeps its corrosion resistance and toughness after welding or high-temperature service where 304 sensitizes. Room-temperature strength and cost are similar (321 slightly dearer). For ambient service 304/304L is the normal choice; for 425–870 °C, 321 or 347.

Q: 321 or 347 — which is better?
A: Both are stabilized 18-8 grades. 347 (niobium) has slightly higher creep strength and its stabilizing element survives welding, so 347 filler is used even for 321. 321 is cheaper and more widely stocked in Europe (1.4541); 347 is common in US refinery specs. They are interchangeable in most applications.

Q: What is 321H?
A: The high-carbon version (0.04–0.10 % C, Ti ≥ 4 × (C+N), grain size ASTM 7 or coarser) with guaranteed creep strength for ASME pressure parts above 525 °C, rated to 816 °C (1500 °F).

Q: What is the maximum temperature for 321?
A: About 870 °C (1600 °F) continuous in air for oxidation; for pressure design ASME allows 321H to 816 °C. Above ~900 °C use 310 or 253MA-type heat-resisting grades.

Q: What is 321 equivalent to in EN and GOST?
A: EN 1.4541 (X6CrNiTi18-10) and GOST 08Kh18N10T are identical; GOST 12Kh18N10T corresponds to 321H.

Q: Is 321 magnetic?
A: No in the annealed state; slight magnetism appears after heavy cold work, as with all austenitics.

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## 410 [S41000] — Martensitic chromium stainless steel, hardenable
URL: https://steelstandart.com/grade/410/
System: AISI / SAE | Family: Stainless steel | Standard: ASTM A276 | Verified against: ASTM A276/A276M-23
Aliases: AISI 410, SS410, Type 410, 410 stainless steel, 410 stainless, S41000, 1.4006, X12Cr13, SUS410, 410 SS, 12Cr13, 12Kh13, 410S21

Type 410 is the basic martensitic stainless steel: 12 % chromium with about 0.1 % carbon, which is just enough to transform to martensite on quenching and reach 38–45 HRC. It is the cheapest stainless that can be heat-treated to high strength, so it is the material of pump shafts, valve trim and seats, steam-turbine blades, fasteners, cutlery blanks, mining screens and press-plate — anywhere hardness or 800–1200 MPa strength matters more than corrosion resistance. UNS S41000; EN 1.4006 (X12Cr13).

Its corrosion resistance is the lowest of the common stainless grades (PREN ≈ 12), adequate for fresh water, steam, mild chemicals, petroleum and food oils but not for chlorides or acids; and it must be used in the hardened-and-tempered condition, because annealed 410 corrodes faster and tempering at 400–550 °C embrittles it. Properly heat-treated 410 is magnetic and tough enough for shafts down to about −20 °C.

The family runs 410S (low carbon, non-hardening, for welded plate) → 410 → 416 (free-machining) → 420 (higher carbon, 50+ HRC) → 440 (very high carbon, 58 HRC). JIS SUS410, GB 12Cr13 and GOST 12Kh13 are the same grade.

Chemical composition (mass %): C ≤ 0.15 (410S (S41008): ≤ 0.08 (non-hardening); 420: ≥ 0.15); Mn ≤ 1; P ≤ 0.04; S ≤ 0.03; Si ≤ 1; Cr 11.5 – 13.5; Ni ≤ 0.75
ASTM A276/A276M-23 (S41000). EN 1.4006 (X12Cr13): C 0.08–0.15, Cr 11.5–13.5, Ni ≤ 0.75 — EN specifies a minimum carbon so the grade always hardens. Typical mill: C 0.10–0.13, Cr 12.0–12.5.

Mechanical properties:
- Bar — annealed (A276 condition A): yield ≥ 275 MPa; tensile ≥ 485 MPa; elongation 20 %; hardness ≤ 223 HB
- Plate/sheet — annealed (A240): yield ≥ 205 MPa; tensile ≥ 450 MPa; elongation 20 %; hardness ≤ 217 HB / ≤ 96 HRB
- Bar — hardened & tempered (A276 condition T): yield ≥ 585 MPa; tensile ≥ 760 MPa; elongation 15 %; hardness ≈ 240–280 HB (≤ 26 HRC)
- Bar — hardened & tempered (A276 condition H): yield ≥ 1000 MPa; tensile ≥ 1210 MPa; elongation 12 %; hardness ≈ 38–42 HRC
- EN 1.4006 +QT650 (for comparison): yield ≥ 450 MPa; tensile 650–850 MPa; elongation 15 %; hardness ≈ 200–250 HB
- EN 1.4006 +QT800: yield ≥ 600 MPa; tensile 800–1000 MPa; elongation 12 %; hardness ≈ 250–300 HB
- As-quenched (typical): yield — MPa; tensile — MPa; elongation — %; hardness 38–45 HRC
ASTM A276 Table 2 conditions A, T (tempered ≥ 565 °C) and H (tempered ≥ 205 °C); EN 10088-3 +QT classes. Impact ≥ 27 J at +20 °C in condition T typical; poor below −10 °C.
Impact: 27 J at 20 °C (typical, tempered ≥ 565 °C)

Equivalents:
- 410S21 (BS (superseded British)) — identical: BS 970 410S21: C 0.09–0.15, Cr 11.5–13.5.
- 1.4006 (EN (European)) — identical: X12Cr13: C 0.08–0.15, Cr 11.5–13.5 — same steel with a carbon minimum; dual-certified.
- 12Cr13 (GB/T (China)) — identical: GB/T 20878 12Cr13 (formerly 1Cr13).
- 12Kh13 (GOST (Russia/CIS)) — identical: GOST 5632 12Kh13: C 0.09–0.15, Cr 12–14.
- SUS410 (JIS (Japan)) — identical: JIS G4303 SUS410: C ≤ 0.15, Cr 11.5–13.5.
- 420 (AISI / SAE) — near: S42000 / 1.4021: C ≥ 0.15 (typically 0.20–0.40) → 48–55 HRC; the cutlery and mould grade.
- 416 (AISI / SAE) — near: S41600 / 1.4005: free-machining 410 with 0.15 % S min.
- 410S (AISI / SAE) — near: S41008 / 1.4000: C ≤ 0.08, does not harden on welding — for annealed plate and clad.
- 430 (AISI / SAE) — functional: Ferritic 17 % Cr: better corrosion resistance, not hardenable.
- 17-4 PH (AISI / SAE) — functional: Conventional martensitic 12 % Cr: cheaper, lower strength (≤ 1200 MPa), poorer corrosion resistance, needs quench hardening.

Superseded names:
- 1.4006 / X12Cr13 — EN 10088: Older DIN name X10Cr13.
- S41000 — UNS: 410S (S41008) low-carbon non-hardening; 416 (S41600) free-machining; 420 (S42000) higher carbon.
- 410S21 — BS 970
- CA-15 — ACI / ASTM A217: Cast equivalent (valve bodies).
- F6a — ASTM A182: Forging grade 410 (classes 1–4 by strength).

Product forms: bar, rod and forgings (ASTM A276, A479, A182 F6a); sheet, strip and plate (A240 — limited); seamless tube (A268 TP410); wire (A580), fasteners (F593 Group 5 / A193 B6); castings CA-15 (A217, A743)
Tolerances: bar: ASTM A484; sheet/plate: ASTM A480; forgings: ASTM A182

### 410 stainless steel yield strength
Annealed bar ≥ 275 MPa (40 ksi), plate ≥ 205 MPa. Hardened and tempered: condition T ≥ 585 MPa (85 ksi), condition H ≥ 1000 MPa (145 ksi); typical +QT at 600 °C ≈ 700–800 MPa.

### 410 tensile strength
Annealed ≥ 485 MPa (70 ksi) bar / ≥ 450 MPa plate; tempered ≥ 760 MPa (T) to ≥ 1210 MPa (H); as-quenched ≈ 1300–1500 MPa.

### 410 hardness
Annealed max 223 HB; as-quenched 38–45 HRC (depending on carbon); tempered 650–700 °C ≈ 20–25 HRC; tempered 200–300 °C ≈ 38–42 HRC. NACE MR0175 sour service: ≤ 22 HRC, double tempered.

### Corrosion resistance
PREN ≈ 12. Resists atmospheric exposure (indoor, rural), fresh water, steam, mild organic acids, petroleum products and food oils when hardened and polished. Pits in chlorides; poor in sulphuric, hydrochloric and most reducing acids.

### Heat treatment
Anneal 815–900 °C, slow cool (≤ 25 K/h to 600 °C) → ≤ 223 HB. Harden 925–1010 °C (1700–1850 °F), oil or air quench. Temper: 205–370 °C for max hardness/strength (38–42 HRC) or 565–650 °C for toughness and corrosion resistance (20–28 HRC). Avoid 400–550 °C (temper embrittlement and loss of corrosion resistance). Ms ≈ 350 °C; sections to ~200 mm harden in air.

### Physical properties
Density 7.7 g/cm³, E = 200 GPa, expansion 9.9 × 10⁻⁶/K (0–100 °C), conductivity 24.9 W/m·K, resistivity 0.57 µΩ·m, ferromagnetic. Scaling limit ≈ 700 °C; creep use to ~480 °C (turbine blades).

### Weldability
Weldable with precautions: air-hardening HAZ reaches 40+ HRC and cracks without preheat. Preheat 200–300 °C, interpass ≤ 300 °C, low-hydrogen process, then post-weld anneal or temper at 650–760 °C. Filler ER410 (matching, then heat-treat) or ER309L/E309L (austenitic, no PWHT but soft weld). 410S is preferred for welded plate; 410NiMo (S41500 / 1.4313) for welded pump and turbine parts.

### Machining, forming, heat treatment
Machinability ≈ 55 % of B1112 annealed (best of the stainless families); machine in the annealed or ≤ 30 HRC tempered condition, then harden; 416 at ≈ 85 % for high-volume turning. Cold forming and bending are fair in the annealed condition (bend radius ≥ 1 t); deep drawing limited. Grinds and polishes well; hard-chrome and nitriding (≈ 1000 HV, for pump sleeves) are common surface treatments.

Applications: Pump shafts, sleeves and impellers (fresh water, oil); Valve trim, stems, seats and discs (API 600 trim no. 1, 'F6'); Steam- and gas-turbine blades and buckets (to ~480 °C); Fasteners, studs and bolts (A193 B6), screws for mild exposure; Cutlery and kitchen-knife blanks (as 410/420), scissors; Mining, coal and mineral screens, sizing plates; Press plates, chutes, wear liners; bakery ovens and hardware; Oilfield: wellhead components, downhole tools (NACE-limited hardness)

Q: What is the difference between 410 and 420 stainless?
A: Carbon. 410 has ≤ 0.15 % C and hardens to 38–45 HRC; 420 has ≥ 0.15 % (typically 0.2–0.4 %) and reaches 48–55 HRC. 410 is tougher and slightly more corrosion-resistant; 420 is harder — the cutlery, surgical-instrument and plastic-mould grade.

Q: Is 410 stainless steel magnetic?
A: Yes, in every condition — martensitic and ferritic stainless steels are ferromagnetic.

Q: Can 410 be hardened?
A: Yes: heat to 925–1010 °C, quench in oil or air, temper at 205–370 °C (max hardness ≈ 40 HRC) or 565–650 °C (toughness, ≈ 25 HRC). Never temper between 400 and 550 °C.

Q: Does 410 stainless rust?
A: More readily than 304: it resists indoor air, fresh water and steam but stains and pits with chlorides, coastal air or acids. Keep it hardened, tempered and polished; annealed or wrongly tempered 410 corrodes fastest.

Q: What is 410 equivalent to in EN?
A: EN 1.4006 (X12Cr13). The EN grade adds a carbon minimum of 0.08 % so it always hardens; ASTM 410 has no minimum, and very-low-carbon heats behave like 410S.

Q: Can 410 be welded?
A: With 200–300 °C preheat and post-weld tempering, yes; without them the hard HAZ cracks. For welded fabrications choose 410S (non-hardening) or 410NiMo.

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## 4130 [G41300] — Chromium-molybdenum low-alloy steel, weldable (chromoly)
URL: https://steelstandart.com/grade/4130/
System: AISI / SAE | Family: Alloy steel | Standard: ASTM A29 | Verified against: ASTM A29/A29M-20 (SAE J404 chemistry)
Aliases: AISI 4130, SAE 4130, 4130 steel, 4130 chromoly, chromoly 4130, 4130 tube, G41300, 25CrMo4, 1.7218, SCM430, 4130 alloy steel

AISI 4130 is the weldable chromoly: the same 1 % Cr / 0.2 % Mo alloying as 4140 but with carbon held to 0.28–0.33 %, so that a welded joint's heat-affected zone does not harden past the point of cracking. That single change made 4130 the aircraft-tube steel of the 1930s (MIL-T-6736) and it is still the material of race-car roll cages, aircraft fuselage frames and engine mounts, bicycle and motorcycle frames, go-kart chassis, sprint-car components and pressure-containing wellhead forgings. UNS G41300.

In the normalized condition — the usual state of 4130 tube — it offers about 435 MPa yield and 670 MPa tensile with 25 % elongation, roughly double mild steel at the same wall thickness, and it keeps good toughness. Quenched and tempered it reaches 860–1000 MPa (aerospace 125–145 ksi level) and, with care, 1240 MPa; deeper hardenability than plain carbon but less than 4140, so through-hardened sections are limited to about 25–35 mm.

EN 25CrMo4 (1.7218) is the usual European substitute (slightly lower carbon); JIS SCM430, GB 30CrMo and GOST 30KhMA are identical. Choose 4130 for welded, impact-loaded structures; 4140 for machined, heat-treated parts needing more strength.

Chemical composition (mass %): C 0.28 – 0.33; Mn 0.4 – 0.6; P ≤ 0.035; S ≤ 0.04; Si 0.15 – 0.35; Cr 0.8 – 1.1; Mo 0.15 – 0.25
SAE J404 / ASTM A29 (G41300). Aerospace 4130 (AMS 6345 etc.) uses the same window with tighter P/S and vacuum degassing. Compare EN 25CrMo4 (1.7218): C 0.22–0.29, Cr 0.90–1.20, Mo 0.15–0.30 — slightly lower carbon; 30CrMo4 was the old DIN match.

Mechanical properties:
- Annealed (865 °C, furnace cool) — typical: yield ≈ 360 MPa; tensile ≈ 560 MPa; elongation 28 %; hardness ≈ 156 HB
- Normalized (870 °C, air) — typical, the usual tube condition ('N'): yield ≈ 435 MPa; tensile ≈ 670 MPa; elongation 25 %; hardness ≈ 197 HB
- Condition N tube per A519 (minimum): yield ≥ 415 MPa; tensile ≥ 620 MPa; elongation 15 %; hardness —
- Q&T, tempered 540 °C (1000 °F), 25 mm — typical: yield ≈ 760 MPa; tensile ≈ 860 MPa; elongation 18 %; hardness ≈ 255 HB
- Q&T, tempered 425 °C (800 °F) — typical: yield ≈ 895 MPa; tensile ≈ 1000 MPa; elongation 16 %; hardness ≈ 300 HB
- Q&T, tempered 315 °C (600 °F) — typical: yield ≈ 1035 MPa; tensile ≈ 1140 MPa; elongation 13 %; hardness ≈ 340 HB
- Q&T, tempered 205 °C (400 °F) — typical: yield ≈ 1240 MPa; tensile ≈ 1380 MPa; elongation 10 %; hardness ≈ 400 HB
- As-quenched (oil, 860 °C): yield — MPa; tensile — MPa; elongation — %; hardness 48–52 HRC
Typical values for 25 mm rounds (ASM); only A519 condition N carries minimums. Aerospace heat-treat levels per AMS 2759: 125–145 ksi (860–1000 MPa), 150–170 ksi, 180–200 ksi tensile.
Impact: 60 J at 20 °C (typical, normalized)

Equivalents:
- 30CrMo4 (EN (European)) — identical: Former DIN 17200 / SEW grade (C 0.26–0.34) — an exact match but no longer in EN 10083-3; still produced by some mills.
- 30CrMo (GB/T (China)) — identical: GB/T 3077 30CrMo: C 0.26–0.34, Cr 0.80–1.10, Mo 0.15–0.25.
- 30KhMA (GOST (Russia/CIS)) — identical: GOST 4543 30KhMA: C 0.26–0.33, Cr 0.80–1.10, Mo 0.15–0.25 — used for Russian aircraft tube.
- SCM430 (JIS (Japan)) — identical: JIS G4053 SCM430: C 0.28–0.33, Cr 0.90–1.20, Mo 0.15–0.30.
- 4140 (AISI / SAE) — near: 0.40 % C: higher strength and hardenability, much poorer weldability.
- 4135 (AISI / SAE) — near: Intermediate 0.35 % C grade (API 6A wellhead forgings).
- 708A30 (EN18) (BS (superseded British)) — near: BS 970 708A30: C 0.28–0.33, Cr 0.85–1.15, Mo 0.15–0.25.
- 25CrMo4 (EN (European)) — near: 1.7218: C 0.22–0.29, Cr 0.90–1.20, Mo 0.15–0.30 — carbon just below 4130's 0.28–0.33; the standard European substitute for tube and bar.
- 1026 / E4130 (AISI / SAE) — functional: Plain-carbon DOM tube (1026) is the budget substitute for non-critical tube structures.

Superseded names:
- G41300 — UNS: 4130H = H41300.
- 25CrMo4 / 1.7218 — EN 10083-3: Nearest European grade (C slightly lower); 30CrMo4 (DIN 17200) was closer.
- 708A30 / EN18 — BS 970
- SCM430 — JIS G4053
- MIL-T-6736 / AMS 6360 — US military / SAE Aerospace: Aircraft tubing specifications.

Product forms: seamless tube (ASTM A519, AMS 6360/6371 — the signature form: roll cages, aircraft frames, bicycle tube); bar (A29, A322, A108), plate and sheet (A829, AMS 6345/6350); forgings (A29, AMS 6370), wire; pressure tube (A423, A213 T11-type Cr-Mo is different), wellhead forgings (API 6A 75K)
Tolerances: tube: ASTM A519 / AMS 2253; bar: ASTM A29 / A108; sheet: AMS 6345 / 6350

### 4130 steel yield strength
Typical: annealed ≈ 360 MPa (52 ksi); normalized ≈ 435 MPa (63 ksi) — A519 condition N minimum 415 MPa; Q&T at 540 °C ≈ 760 MPa; at 425 °C ≈ 895 MPa; at 315 °C ≈ 1035 MPa; at 205 °C ≈ 1240 MPa (180 ksi).

### 4130 tensile strength
Typical: annealed ≈ 560 MPa (81 ksi); normalized ≈ 670 MPa (97 ksi) — A519 N minimum 620 MPa; Q&T 860–1000 MPa (aerospace 125–145 ksi), up to ≈ 1380 MPa (200 ksi) at low temper.

### 4130 hardness
Annealed ≈ 156 HB; normalized ≈ 197 HB; Q&T 255–400 HB depending on temper; as-quenched 48–52 HRC. Nitrided surface ≈ 55 HRC.

### Heat treatment
Anneal 840–870 °C, furnace cool. Normalize 870–900 °C (1600–1650 °F), air cool — the standard tube condition. Harden 855–885 °C, oil quench (water for thin tube with care); temper 205–650 °C. Stress relieve welded assemblies 565–650 °C (600 °C / 1100 °F typical for roll cages). Ac1 ≈ 760 °C, Ac3 ≈ 810 °C, Ms ≈ 380 °C. Ideal critical diameter ≈ 35–50 mm.

### Weldability
Good for an alloy steel (CE ≈ 0.55–0.65). Thin-wall tube (< 3 mm) is TIG-welded without preheat using ER70S-2/ER80S-D2; thicker sections need 150–250 °C preheat. Post-weld normalizing or stress relief is recommended for critical structures.

### Physical properties
Density 7.85 g/cm³, E = 205 GPa, expansion 12.2 × 10⁻⁶/K, conductivity 42.7 W/m·K.

### Weldability
The most weldable of the chromoly family. TIG (GTAW) with ER70S-2 or ER80S-D2 filler for tube < 3 mm wall: no preheat, controlled heat input, no rapid quench (let cool in still air). For > 3–5 mm or heavily restrained joints, preheat 150–250 °C and use low-hydrogen consumables (E8018-B2 for matching Cr-Mo). Post-weld: normalize (870–900 °C) for aircraft-quality structures or stress-relieve at 565–650 °C. Do not weld in the Q&T condition and expect full strength — the HAZ softens; re-heat-treat after welding when strength must be uniform.

### Machining, forming, heat treatment
Machinability ≈ 70 % of B1112 annealed/normalized — better than 4140 (index ≈ 65 %). Cold forming: good in the annealed state (tube bending with mandrel at ≥ 2.5 D radius in normalized condition); hot forming 1200–950 °C then normalize. Surface treatments: nitriding (≈ 55 HRC case), induction hardening (limited by 0.30 % C to ≈ 48 HRC), chrome plating with hydrogen bake, cadmium/zinc plating for aerospace.

Applications: Aircraft fuselage trusses, engine mounts, landing-gear components (AMS 6360/6371 tube); Racing roll cages, chassis and suspension tubes (SFI/FIA-specified 4130 N tube); Bicycle, motorcycle and go-kart frames; sprint-car and midget chassis; Wellhead and Christmas-tree forgings (API 6A 60K/75K, as 4130/4135); Pressure vessels and gas cylinders (with Q&T), hydraulic tubing; Gears, shafts and fasteners at moderate strength; aircraft bolts (AN/NAS); Firearm receivers, sporting goods, tool handles

Q: What is the difference between 4130 and 4140?
A: Carbon: 4130 has 0.30 %, 4140 has 0.40 %. 4130 welds with little or no preheat and is used for tube structures; 4140 reaches higher hardness and strength (to 52+ HRC) but needs 250–350 °C preheat and post-weld tempering. Same Cr and Mo.

Q: Is 4130 chromoly stronger than mild steel?
A: Normalized 4130 has about 435 MPa yield versus ~250 MPa for A36/1018, so a 4130 tube can be roughly 40 % thinner (lighter) at the same strength — the reason it is used in roll cages and aircraft. Stiffness (E ≈ 205 GPa) is the same for all steels.

Q: Do 4130 welds need heat treatment?
A: For thin tube (< 3 mm) TIG-welded with ER70S-2, no — allow slow cooling and the joint retains ~80–90 % of tube strength. For aircraft-critical or thick sections, normalize or stress-relieve (565–650 °C) after welding. Never quench a fresh weld.

Q: What is 4130 equivalent to in EN and JIS?
A: EN 25CrMo4 (1.7218) is the near match (C 0.22–0.29); the old DIN 30CrMo4 was exact. JIS SCM430, GB 30CrMo and GOST 30KhMA are identical.

Q: Can 4130 be hardened?
A: Yes — quench from 855–885 °C in oil and temper: 48–52 HRC as-quenched, 25–40 HRC typical in service (860–1240 MPa tensile). Hardenability limits through-hardening to about 25–35 mm sections.

Q: What does 'condition N' mean for 4130 tube?
A: Normalized: heated to 870–900 °C and air-cooled, giving ≥ 415 MPa yield / ≥ 620 MPa tensile per ASTM A519. It is the standard supply condition for chassis and aircraft tube; 'condition A' is annealed (softer, for bending).

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## 4140 [G41400] — Chromium-molybdenum low-alloy steel (chromoly)
URL: https://steelstandart.com/grade/4140/
System: AISI / SAE | Family: Quenched & tempered steel | Standard: ASTM A29 | Verified against: ASTM A29/A29M-20 (SAE J404 chemistry)
Aliases: AISI 4140, SAE 4140, 4140 steel, 4140 alloy steel, 4140 HT, 4140 PH, 4140 annealed, 4140 Q&T, G41400, 4142, 4140 chromoly, chromoly 4140, SCM440 AISI, 42CrMo AISI

AISI 4140 is the definitive chromoly steel: 0.40 % carbon, 1 % chromium and 0.2 % molybdenum, UNS G41400. Chromium and molybdenum push hardenability deep enough that a 50 mm bar through-hardens in oil, and the steel tempers over a wide range to any strength from 900 to 1800 MPa — which is why it is the standard for shafts, axles, gears, bolts, tooling, drill collars and every 'machine steel' job that needs more than plain carbon steel can give. It is also the most-stocked alloy steel in North America, usually as pre-hardened bar (4140 HT / PH) at 28–32 HRC, ready to machine and use without further heat treatment.

As an AISI grade 4140 is defined by chemistry, not properties; the tables give typical values for annealed, normalized, pre-hard and quenched-and-tempered conditions at various tempers, and the ASTM A434 or customer specification supplies minimums when required. Weldability is poor (CE ≈ 0.8) — preheat and post-weld tempering are mandatory — and hydrogen embrittlement is a real risk above about 38 HRC, so plating and pickling of hardened parts must be followed by baking.

EN 42CrMo4 (1.7225), JIS SCM440, GB 42CrMo and BS 708M40 (EN19) are the same steel; 4142, 4145 and 4150 are the higher-carbon steps, 4130 the weldable low-carbon cousin, 4340 the nickel-bearing upgrade.

Chemical composition (mass %): C 0.38 – 0.43; Mn 0.75 – 1; P ≤ 0.035; S ≤ 0.04; Si 0.15 – 0.35; Cr 0.8 – 1.1; Mo 0.15 – 0.25
SAE J404 / ASTM A29 (G41400). 4142 (G41420): C 0.40–0.45; 4140H (H-band, hardenability guaranteed): slightly wider Mn/Cr. Compare EN 42CrMo4: C 0.38–0.45, Cr 0.90–1.20, Mo 0.15–0.30, Mn 0.60–0.90.

Mechanical properties:
- Annealed (815 °C, furnace cool) — typical: yield ≈ 415 MPa; tensile ≈ 655 MPa; elongation 25 %; hardness ≈ 197 HB
- Normalized (870 °C, air) — typical: yield ≈ 655 MPa; tensile ≈ 1020 MPa; elongation 18 %; hardness ≈ 302 HB
- Pre-hardened 'PH / HT' bar (Q&T 28–32 HRC) — typical: yield ≈ 690–760 MPa; tensile ≈ 930–1000 MPa; elongation 16 %; hardness 269–321 HB (28–34 HRC)
- Q&T, tempered 540 °C (1000 °F), 25 mm — typical: yield ≈ 895 MPa; tensile ≈ 1035 MPa; elongation 15 %; hardness ≈ 311 HB
- Q&T, tempered 425 °C (800 °F), 25 mm — typical: yield ≈ 1100 MPa; tensile ≈ 1240 MPa; elongation 13 %; hardness ≈ 375 HB (40 HRC)
- Q&T, tempered 315 °C (600 °F), 25 mm — typical: yield ≈ 1340 MPa; tensile ≈ 1480 MPa; elongation 11 %; hardness ≈ 445 HB (47 HRC)
- Q&T, tempered 205 °C (400 °F), 25 mm — typical: yield ≈ 1640 MPa; tensile ≈ 1770 MPa; elongation 8 %; hardness ≈ 510 HB (52 HRC)
- As-quenched (oil, 845 °C): yield — MPa; tensile — MPa; elongation — %; hardness 54–59 HRC
AISI/SAE grades are specified by chemistry (and hardenability for H-bands); mechanical values are typical for a 25 mm (1 in) round, not guarantees. Order to ASTM A434 (Class BC/BD) or a customer spec when minimums are needed. Charpy at 540 °C temper ≈ 40–50 J.
Impact: 45 J at 20 °C (typical, Q&T to ≈ 300 HB)

Equivalents:
- 708M40 (EN19) (BS (superseded British)) — identical: BS 970 708M40: C 0.36–0.44, Cr 0.90–1.20, Mo 0.15–0.25.
- 42CrMo4 (EN (European)) — identical: 1.7225: C 0.38–0.45, Cr 0.90–1.20, Mo 0.15–0.30 — windows overlap almost completely; dual-certified 4140/42CrMo4 bar is standard.
- 42CrMo (GB/T (China)) — identical: GB/T 3077 42CrMo: C 0.38–0.45, Cr 0.90–1.20, Mo 0.15–0.25.
- SCM440 (JIS (Japan)) — identical: JIS G4053 SCM440: C 0.38–0.43, Cr 0.90–1.20, Mo 0.15–0.30.
- 4142 (AISI / SAE) — near: C 0.40–0.45 — the upper half of the 42CrMo4 range; slightly higher hardness.
- 4130 (AISI / SAE) — near: 0.30 % C version: lower strength (≈ 1000 MPa max practical), far better weldability; used for tube and welded structures.
- 40KhM / 38KhM (GOST (Russia/CIS)) — near: GOST 4543 38KhM (C 0.35–0.42) / 40KhMFA (V-bearing); 40KhM is the common Russian equivalent in practice.
- 4340 (AISI / SAE) — functional: Adds 1.8 % Ni: deeper hardenability (sections > 100 mm), higher toughness at 1500+ MPa.
- 1045 (AISI / SAE) — functional: Unalloyed medium-carbon: cheaper, through-hardens only ≤ 20 mm.
- 5160 (AISI / SAE) — functional: The general-purpose quenched and tempered engineering steel. Deeper hardening thanks to molybdenum but only 0.40 % carbon, so it tops out well below spring hardness and is used for shafts rather than springs.
- 1.2738 (EN (European)) — functional: The general-purpose quenched and tempered engineering steel at a similar hardness. Sold as bar and plate without mould-block sizes, cleanliness grading or guaranteed through-hardness, so it is used for frames and fixtures rather than cavities.

Superseded names:
- G41400 — UNS: 4140H = H41400 (hardenability band).
- 42CrMo4 / 1.7225 — EN 10083-3: European twin; 42CrMoS4 (1.7227) free-machining.
- 708M40 / 708A42 / EN19 — BS 970 (withdrawn): EN19 is the old British name still used in the UK and India.
- SCM440 — JIS G4053: Japanese twin (SCM4 in older editions).
- 4145H / 4145H Mod — API Spec 7-1: Higher-carbon variant for drill collars and tool joints.

Product forms: hot-rolled and cold-finished bar (ASTM A29 / A322 / A108); pre-hardened bar 'PH' or 'HT' at 28–32 HRC (the most common stock form); forgings (A29, ASTM A788), seamless tube (A519); plate (A829 / A830), wire; downhole and drilling tools per API 7-1 (4145H modified)
Tolerances: hot-rolled bar: ASTM A29 / A6; cold-finished bar: ASTM A108 (h9–h11 typical); tube: ASTM A519; aerospace: AMS 6349 / 6382 / 6529

### 4140 steel yield strength
Typical: annealed ≈ 415 MPa (60 ksi); normalized ≈ 655 MPa; pre-hard 28–32 HRC ≈ 690–760 MPa (100–110 ksi); Q&T tempered at 540 °C ≈ 895 MPa (130 ksi); at 425 °C ≈ 1100 MPa; at 315 °C ≈ 1340 MPa; at 205 °C ≈ 1640 MPa (238 ksi).

### 4140 tensile strength
Typical: annealed ≈ 655 MPa (95 ksi); normalized ≈ 1020 MPa; pre-hard ≈ 930–1000 MPa; Q&T 540 °C ≈ 1035 MPa (150 ksi); 425 °C ≈ 1240 MPa; 315 °C ≈ 1480 MPa; 205 °C ≈ 1770 MPa (257 ksi).

### 4140 hardness
Annealed ≈ 197 HB; normalized ≈ 302 HB; pre-hardened 28–32 HRC (269–321 HB); as-quenched 54–59 HRC; tempered 205 °C ≈ 52 HRC, 315 °C ≈ 47 HRC, 425 °C ≈ 40 HRC, 540 °C ≈ 33 HRC, 650 °C ≈ 25 HRC. Induction-hardened surface 50–55 HRC; nitrided surface 55–60 HRC (≈ 600–700 HV).

### Heat treatment
Anneal 815–870 °C, furnace cool 15 K/h to 480 °C. Normalize 870–900 °C, air. Harden 845–870 °C (1550–1600 °F), oil quench (water for simple shapes ≤ 25 mm). Temper 205–650 °C to the required hardness, 2 h minimum; avoid 230–370 °C. Stress relieve 550–650 °C. Ac1 ≈ 750 °C, Ac3 ≈ 790 °C, Ms ≈ 310 °C. Ideal critical diameter (4140H) ≈ 75–100 mm; Jominy J10 ≈ 47–56 HRC.

### Machinability
≈ 65 % of B1112 annealed (197 HB); ≈ 55–60 % pre-hard at 28–32 HRC (excellent chip control, preferred for CNC). 4140 with 0.02–0.04 % S ('4140 resulfurized' / 42CrMoS4) improves to ≈ 70 %.

### Physical properties
Density 7.85 g/cm³ (0.284 lb/in³), E = 205 GPa (29.7 × 10⁶ psi), expansion 12.3 × 10⁻⁶/K (20–100 °C), conductivity 42.6 W/m·K, specific heat 473 J/kg·K.

### Weldability
Poor weldability (carbon equivalent ≈ 0.75–0.85). Weld only in the annealed or normalized condition where possible: preheat 250–350 °C (higher for thick or restrained joints), maintain interpass ≥ preheat, use low-hydrogen consumables (E8018-B2 / ER80S-B2 for matching Cr-Mo, or E7018 / ER70S-6 when the joint is not strength-critical), slow-cool under insulation, then temper immediately at 550–650 °C. Welding pre-hardened or Q&T bar softens the HAZ and risks cold cracking; for hardened assemblies design mechanical joints.

### Machining, forming, heat treatment
Turning, milling, drilling and threading are all good; pre-hard 28–32 HRC gives the best surface finish and chip control with coated carbide. Rough in the annealed state and finish after hardening only if distortion allows (grinding stock 0.2–0.4 mm). Cold forming is limited to the annealed state; hot forging 1200–950 °C then normalize or anneal. Surface treatments: induction/flame hardening (50–55 HRC), gas or ion nitriding (excellent — 0.3–0.6 mm case at 600+ HV), QPQ, hard chrome plating (bake 190 °C ≥ 4 h after plating to relieve hydrogen), phosphate and black oxide.

Applications: Shafts, axles, spindles, arbors and couplings; Gears, sprockets, pinions (through-hardened or nitrided); High-strength bolts and studs: SAE Grade 8, ASTM A193 B7 (4140/4142 Q&T), A320 L7, ISO 10.9/12.9; Hydraulic cylinder rods, pistons and glands (chrome-plated); Drill collars, tool joints, drill-string subs (4145H Mod), downhole tools; Injection-mould bases, holder blocks and machine frames (pre-hard); Crankshafts, connecting rods, steering components, axle housings; Rifle barrels and firearm receivers, hand tools, wrenches and sockets (forged)

Q: Is 4140 the same as 42CrMo4?
A: Yes for practical purposes. 4140 (C 0.38–0.43, Cr 0.80–1.10, Mo 0.15–0.25) and EN 42CrMo4 (C 0.38–0.45, Cr 0.90–1.20, Mo 0.15–0.30) overlap almost entirely and are dual-certified by mills; JIS SCM440 and GB 42CrMo are also identical.

Q: What is 4140 HT or 4140 PH?
A: Heat-treated / pre-hardened bar: quenched and tempered at the mill to 28–32 HRC (≈ 900–1000 MPa tensile). It machines well and is used without further heat treatment for shafts, mould bases and fixtures — the most common way 4140 is sold.

Q: How hard can 4140 get?
A: 54–59 HRC as-quenched; in service usually 28–32 HRC (pre-hard) up to about 50 HRC (tempered 205–260 °C) for wear parts. Induction hardening gives 50–55 HRC on the surface; nitriding gives 55–60 HRC (600–700 HV) with a soft core.

Q: What is the difference between 4140 and 4130?
A: Carbon: 0.40 % vs 0.30 %. 4130 is weldable with modest preheat and is used for tubing, aircraft and roll-cage structures at up to ~1000 MPa; 4140 reaches higher strength and hardness but must be welded with 250–350 °C preheat and post-weld tempering.

Q: Which is stronger, 1045 or 4140?
A: Both have ~0.45 % carbon, but 4140's Cr and Mo let it through-harden in sections up to 50–75 mm and temper to a tougher structure. In thin sections both reach similar hardness; in anything thicker than about 20 mm, or at the same tempered hardness, 4140 is stronger and tougher. 1045 is cheaper and slightly more machinable.

Q: Can 4140 be welded?
A: Only with preheat (250–350 °C), low-hydrogen consumables and post-weld tempering, and preferably in the annealed condition. Welding pre-hard or Q&T 4140 without these steps causes hydrogen cracking in the hard heat-affected zone.

Q: Is 4140 good for knives?
A: It is used for large choppers and tools where toughness matters more than edge retention, hardened to 52–56 HRC. Its 0.4 % carbon limits edge hardness; dedicated knife steels (1095, 5160, 52100, O1) hold an edge better.

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## 42CrMo4 (1.7225) — Chromium-molybdenum steel for quenching and tempering
URL: https://steelstandart.com/grade/42crmo4/
System: EN (European) | Family: Quenched & tempered steel | Standard: EN 10083-3 | Verified against: EN 10083-3:2006
Aliases: 42CrMoS4, 1.7227, 42 CrMo 4, 1.7225, 42CrMo4+QT, 42CrMo4V, SCM440, 42CrMo, 38KhM, 40KhM, 708M40, SNB7

42CrMo4 is Europe's most-used alloy steel for quenched-and-tempered parts: 0.42 % C, 1 % Cr, 0.2 % Mo, Werkstoff number 1.7225, specified in EN 10083-3. The chromium–molybdenum combination gives deep hardenability — a 40 mm bar through-hardens in oil — and resistance to temper embrittlement, so the same bar can be tempered anywhere between 550 and 650 °C to hit a strength band from 900 to 1300 MPa.

It is the steel of crankshafts, gearbox shafts, high-strength bolts (10.9 and 12.9), hydraulic components and drilling tools. Machinability in the soft-annealed condition is fair; most parts are rough-machined at 240–300 HB in the pre-treated (+QT) condition and finished after nitriding or induction hardening.

42CrMo4 and AISI 4140 are the same steel for practical purposes, as are JIS SCM440, GB 42CrMo and BS 708M40; the cross-reference table below grades each match.

Chemical composition (mass %): C 0.38 – 0.45; Si ≤ 0.4; Mn 0.6 – 0.9; P ≤ 0.025; S ≤ 0.035 (42CrMoS4 (1.7227): S 0.020–0.040 for machinability); Cr 0.9 – 1.2; Mo 0.15 – 0.3
EN 10083-3:2006 Table 2. No Ni specified; V-modified 42CrMoV4 exists in some mill programmes (not in EN 10083-3).

Mechanical properties:
- +QT, ≤ 16 mm: yield 900 MPa; tensile 1100–1300 MPa; elongation 10 %; hardness ≈ 330–380 HB
- +QT, 16–40 mm: yield 750 MPa; tensile 1000–1200 MPa; elongation 11 %; hardness ≈ 300–350 HB
- +QT, 40–100 mm: yield 650 MPa; tensile 900–1100 MPa; elongation 12 %; hardness ≈ 270–320 HB
- +QT, 100–160 mm: yield 550 MPa; tensile 800–950 MPa; elongation 13 %; hardness ≈ 240–290 HB
- +QT, 160–250 mm: yield 500 MPa; tensile 750–900 MPa; elongation 14 %; hardness ≈ 225–270 HB
- +A soft annealed: yield — MPa; tensile ≤ 800 (typ. 650) MPa; elongation — %; hardness ≤ 241 HB
- +N normalized (typical): yield 500 MPa; tensile 800–900 MPa; elongation 14 %; hardness ≈ 240–270 HB
EN 10083-3 Table 8 (+QT). Impact: ≥ 35 J (≤ 16 mm) to ≥ 40 J (≥ 40 mm) longitudinal at +20 °C in the Q&T condition. Normalized values are typical, not standardized.
Impact: 35 J at 20 °C (+QT, ≤ 16 mm, longitudinal; ≥ 40 J for 40–250 mm)

Equivalents:
- 4140 (AISI / SAE) — identical: AISI 4140 (UNS G41400): C 0.38–0.43, Cr 0.80–1.10, Mo 0.15–0.25, Mn 0.75–1.00. Windows overlap almost completely; mills dual-certify 42CrMo4/4140.
- 708M40 (BS (superseded British)) — identical: BS 970 708M40: C 0.36–0.44, Cr 0.90–1.20, Mo 0.15–0.25.
- 42CrMo (GB/T (China)) — identical: GB/T 3077 42CrMo: C 0.38–0.45, Cr 0.90–1.20, Mo 0.15–0.25.
- SCM440 (JIS (Japan)) — identical: JIS G4053 SCM440: C 0.38–0.43, Cr 0.90–1.20, Mo 0.15–0.30 — matches 42CrMo4 exactly on Cr and Mo.
- 4140 (AISI / SAE) — near: C 0.40–0.45 — covers the upper half of the 42CrMo4 carbon range.
- 42CrMoS4 (EN (European)) — near: Same grade with controlled S (0.020–0.040 %) for free machining; slightly lower transverse toughness.
- 40KhM / 38KhM (GOST (Russia/CIS)) — near: GOST 4543 38KhM (C 0.35–0.42, Cr 0.90–1.30, Mo 0.20–0.30); 40KhM is the nearer Russian practice grade.
- 080M40 (BS (superseded British)) — functional: The alloy step up, equivalent to 709M40 (EN19). Substitute where hardenability in sections above about 60 mm or genuine toughness is required — 080M40 cannot deliver either.
- 34CrNiMo6 (EN (European)) — functional: Ni-bearing alternative with deeper hardenability for sections above ~100 mm.
- C45 (EN (European)) — functional: Unalloyed, cheaper, but through-hardens only in thin sections.
- 1.2311 (EN (European)) — functional: 1.7225: the general-purpose quenched and tempered engineering steel. Similar hardness at delivery and cheaper, but supplied in bar rather than mould-block sizes and without the cleanliness and flatness guarantees a mould base needs.
- 51CrV4 (EN (European)) — functional: 1.7225: the general engineering quenched and tempered steel. Overlaps in strength up to about 1100 MPa but has 0.40 % carbon, so it cannot reach spring hardness, and it is not supplied against a decarburisation limit.

Superseded names:
- 42CrMo4 (1.7225) — DIN 17200 (withdrawn): Name and number unchanged since DIN 17200; only the standard moved to EN 10083-3.
- 708M40 / 708A42 — BS 970
- 42CD4 — NF A 35-552
- 42CrMo4 — UNI 7845

Product forms: round bar (hot-rolled, peeled, ground), square and flat bar; forgings and forged blanks; seamless tube (EN 10297, EN 10305); plate (limited, via EN 10083-3 or proprietary)
Tolerances: hot-rolled round: EN 10060; peeled/ground bar: EN 10278 (h9–h11); forgings: EN 10250-3

### 42CrMo4 yield strength
In the Q&T condition Rp0.2 is ≥ 900 MPa (130 ksi) ≤ 16 mm, 750 MPa 16–40 mm, 650 MPa 40–100 mm, 550 MPa 100–160 mm and 500 MPa 160–250 mm.

### 42CrMo4 tensile strength
1100–1300 MPa (≤ 16 mm), 1000–1200 MPa (16–40 mm), 900–1100 MPa (40–100 mm), 800–950 MPa (100–160 mm), 750–900 MPa (160–250 mm).

### 42CrMo4 hardness
Soft-annealed max 241 HB; Q&T typically 270–350 HB depending on section; as-quenched 54–58 HRC; induction-hardened surface 52–56 HRC; gas-nitrided surface 600–700 HV at 0.3–0.5 mm depth.

### Heat treatment
Soft anneal 680–720 °C; normalize 850–880 °C; harden 820–860 °C oil (water only for simple shapes); temper 540–680 °C; stress relieve 550–650 °C. Ac1 ≈ 745 °C, Ac3 ≈ 790 °C, Ms ≈ 310 °C. Ideal critical diameter ≈ 60–80 mm.

### Physical properties
Density 7.83 g/cm³, E = 210 GPa, thermal conductivity ≈ 42 W/m·K, expansion 12.1 × 10⁻⁶/K (20–100 °C).

### Weldability
Poor weldability: CEV ≈ 0.80 %. Welding is only done on annealed or normalized material with preheat 250–350 °C, low-hydrogen consumables (EN ISO 18276 / Cr-Mo types), interpass control and immediate post-weld tempering at 550–650 °C. Q&T parts should not be welded; design for mechanical joints.

### Machining, forming, heat treatment
Machinability index ≈ 50–55 % in the annealed state; 42CrMoS4 improves it to ≈ 60–65 %. Machine at 250–300 HB (pre-treated) with carbide; grinding after hardening. Cold forming limited; hot forging 1100–850 °C then anneal. Surface treatments: induction hardening, gas or plasma nitriding (excellent response), QPQ salt-bath nitrocarburizing.

Applications: Crankshafts, camshafts, gearbox and pump shafts; High-strength fasteners: property classes 10.9 and 12.9 (EN ISO 898-1); Hydraulic cylinder rods and pistons (induction-hardened, chrome-plated); Gears and pinions (nitrided or induction-hardened teeth); Drill collars, tool joints and downhole equipment (API 7-1 grades); Injection-mould frames and machine columns; Automotive: steering knuckles, axle shafts, connecting rods

Q: Is 42CrMo4 the same as 4140?
A: Yes for practical purposes. AISI 4140 spans C 0.38–0.43, Cr 0.80–1.10, Mo 0.15–0.25; 42CrMo4 spans C 0.38–0.45, Cr 0.90–1.20, Mo 0.15–0.30. Most European bar is dual-certified 42CrMo4 / 4140 / SCM440.

Q: What hardness can 42CrMo4 reach?
A: As-quenched 54–58 HRC; tempered to a working strength of 1000–1200 MPa it sits at about 300–350 HB (32–38 HRC). Nitriding adds a 600–700 HV case; induction hardening gives 52–56 HRC on the surface.

Q: What is 42CrMo4+QT?
A: +QT is the quenched-and-tempered delivery condition — the bar is already heat-treated to the EN 10083-3 strength table for its diameter and can be machined and used without further treatment. +A is soft-annealed for machining before the customer heat-treats.

Q: Can 42CrMo4 be welded?
A: Only in the annealed/normalized state with 250–350 °C preheat and post-weld tempering. Welding Q&T bar destroys the properties in the heat-affected zone and risks cold cracking.

Q: What is the difference between 42CrMo4 and 34CrNiMo6?
A: 34CrNiMo6 (1.6582) adds 1.5 % Ni, which pushes hardenability to sections of 150–250 mm and improves toughness at the same strength. Use it for large shafts and forgings; 42CrMo4 is the economical choice below ~100 mm.

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## 430 [S43000] — Ferritic chromium stainless steel
URL: https://steelstandart.com/grade/430/
System: AISI / SAE | Family: Stainless steel | Standard: ASTM A240 | Verified against: ASTM A240/A240M-22
Aliases: AISI 430, SS430, Type 430, 430 stainless steel, 430 stainless, S43000, 1.4016, X6Cr17, SUS430, 430 SS, 10Cr17, 12Kh17, 430S17

Type 430 is the workhorse ferritic stainless steel: 16–18 % chromium, no nickel, body-centred cubic structure, therefore magnetic and — because it carries no nickel — 30–40 % cheaper than 304. UNS S43000, EN 1.4016. It offers good resistance to mild atmospheres, fresh water, food acids and nitric acid, a bright polished or brushed surface, and easier machining than the austenitics; in return it gives up formability, weld toughness, low-temperature toughness and chloride resistance.

The classic uses follow from that trade-off: appliance panels, dishwasher tubs, range hoods, sink surrounds, automotive trim, decorative tube and interior architecture — parts that are stamped or lightly drawn, seldom welded and never exposed to salt. Where welding is needed, the stabilized cousins 439 and 441 (EN 1.4510, 1.4509) avoid grain-boundary sensitization and grain growth in the HAZ.

Minimum properties are 205 MPa yield and 450 MPa tensile; typical 2B sheet is stronger (≈ 320/500 MPa) and has a lower work-hardening rate than 304, so press loads and spring-back are smaller. EN 1.4016, JIS SUS430, GB 10Cr17 and GOST 12Kh17 are the same grade.

Chemical composition (mass %): C ≤ 0.12; Mn ≤ 1; P ≤ 0.04; S ≤ 0.03; Si ≤ 1; Cr 16 – 18; Ni ≤ 0.75 (residual only)
ASTM A240/A240M-22 Table 1 (S43000). EN 1.4016 (X6Cr17): C ≤ 0.08, Cr 16–18 — tighter on carbon. Typical mill analysis C 0.04–0.06, Cr 16.2–16.8.

Mechanical properties:
- Sheet, strip, plate — annealed (A240): yield ≥ 205 MPa; tensile ≥ 450 MPa; elongation 22 %; hardness ≤ 183 HB / ≤ 89 HRB
- Bar — annealed (A276): yield ≥ 205 MPa; tensile ≥ 450 MPa; elongation 20 %; hardness —
- Bar — cold finished ≤ 12.7 mm: yield ≥ 380 MPa; tensile ≥ 585 MPa; elongation 12 %; hardness —
- EN 1.4016 cold-rolled sheet, +A (for comparison): yield ≥ 260 MPa; tensile 450–600 MPa; elongation 20 %; hardness ≤ 200 HB
ASTM A240 Table 2; typical annealed 2B sheet: yield 300–340 MPa, tensile 480–520 MPa, elongation 25–30 %. r-value ≈ 1.0–1.4 (good drawability for a ferritic).
Impact: 20 J at 0 °C (typical, thin sheet; transition around 0 to +20 °C for > 3 mm)

Equivalents:
- 430S17 (BS (superseded British)) — identical: BS 1449 430S17: C ≤ 0.08, Cr 16–18.
- 1.4016 (EN (European)) — identical: X6Cr17: C ≤ 0.08, Cr 16–18. Dual-certified 430/1.4016 sheet is standard in Europe.
- 10Cr17 (GB/T (China)) — identical: GB/T 20878 10Cr17 (formerly 1Cr17).
- 12Kh17 (GOST (Russia/CIS)) — identical: GOST 5632 12Kh17: C ≤ 0.12, Cr 16–18.
- SUS430 (JIS (Japan)) — identical: JIS G4305 SUS430: C ≤ 0.12, Cr 16–18.
- 439 / 1.4510 (AISI / SAE) — near: Ti-stabilized 17 % Cr (S43035 / X3CrTi17): weldable without sensitization, same corrosion class — the upgrade for welded parts.
- 441 / 1.4509 (AISI / SAE) — near: Nb+Ti dual-stabilized 18 % Cr for exhaust systems and heat exchangers.
- 409 / 1.4512 (AISI / SAE) — functional: 11 % Cr ferritic for exhausts; cheaper, lower corrosion resistance.
- 304 (AISI / SAE) — functional: Austenitic 18-8: better corrosion resistance, formability and weldability; 430 replaces it on cost in dry indoor service.
- 410 (AISI / SAE) — functional: Ferritic 17 % Cr: better corrosion resistance, not hardenable.

Superseded names:
- 1.4016 / X6Cr17 — EN 10088: European twin (older DIN name X8Cr17).
- S43000 — UNS: 430F (S43020) = free-machining; 430Ti / 439 (S43035) = Ti-stabilized weldable version.
- 430S17 / 430S15 — BS 1449 / BS 970
- CB-30 — ACI / ASTM A743: Cast equivalent.

Product forms: sheet, strip and plate (ASTM A240) — mostly cold-rolled sheet ≤ 3 mm; bar and wire (A276, A493); welded tube (A268 TP430); castings as CB-30
Tolerances: sheet/plate: ASTM A480 (finishes 2B, BA, No. 4); bar: ASTM A484

### 430 stainless steel yield strength
Minimum 205 MPa (30 ksi) annealed; typical 300–340 MPa; cold-finished bar ≥ 380 MPa.

### 430 tensile strength
Minimum 450 MPa (65 ksi); typical 480–520 MPa annealed.

### 430 hardness
Annealed max 183 HB / 89 HRB (≈ 190 HV); typical 150–170 HB. Slight hardening possible by quenching (martensite from the 0.12 % C), but 430 is not a hardenable grade — use 410/420 for that.

### Corrosion resistance
PREN ≈ 16–18. Resists indoor and rural atmospheres, fresh water, dilute nitric acid, food acids, alkalis; stains in urban/industrial air, pits in chlorides, poor in reducing acids. Roughly equivalent to 304 in mild environments but markedly worse in chloride-containing ones.

### Heat resistance
Oxidation resistance to 815 °C (1500 °F) continuous, 870 °C intermittent — better than 304 for cyclic heating because its expansion coefficient is lower. 475 °C embrittlement on long exposure at 400–540 °C; sigma phase at 550–800 °C.

### Physical properties
Density 7.7 g/cm³, E = 200 GPa, expansion 10.4 × 10⁻⁶/K (0–100 °C — close to carbon steel), conductivity 26 W/m·K (higher than austenitics), resistivity 0.60 µΩ·m, ferromagnetic.

### Heat treatment
Anneal 760–815 °C (1400–1500 °F), air cool or slow cool; do not exceed 900 °C (grain growth and partial austenite → martensite on cooling). Stress relieve 200–300 °C.

### Weldability
Weldable with care: the HAZ coarsens and may sensitize, lowering toughness and corrosion resistance. Use ER308L/E309L filler for ductility, or matching ER430 when colour match matters; keep heat input low, preheat 150–200 °C for > 3 mm, post-weld anneal 760–815 °C for critical parts. For routinely welded products specify 439 or 441 instead.

### Machining, forming, heat treatment
Machinability ≈ 55 % of B1112 — better than 304 (no work hardening); 430F (S43020, 0.15 % S min) is the free-machining version at ≈ 90 %. Forming: good for bending, roll forming and moderate drawing; ridging/roping may appear on deep-drawn surfaces (use ridging-resistant 430 grades). Polishes to a high lustre; standard finishes 2B, BA, No. 4.

Applications: Appliance panels: refrigerator doors, dishwasher tubs, range hoods, microwave cavities; Kitchen equipment and sink surrounds (dry or lightly wet); Automotive trim, mouldings, wheel covers; Decorative tube, interior architectural cladding, lift panels; Cutlery (blades as 420, handles as 430), hollowware; Heat-exchanger and furnace parts to 800 °C (non-welded); Coins and tokens (with Ni or Cu variants)

Q: What is the difference between 430 and 304 stainless steel?
A: 430 is ferritic (16–18 % Cr, no Ni): magnetic, cheaper, less formable, lower corrosion resistance and poorer weldability. 304 is austenitic (18 % Cr, 8 % Ni): non-magnetic, more corrosion-resistant, deep-drawable and readily welded. Use 430 for dry, decorative, stamped parts; 304 for wet, welded or outdoor ones.

Q: Is 430 stainless steel magnetic?
A: Yes — it is ferritic, like carbon steel. This is the quickest way to tell 430 from 304 in the field.

Q: Does 430 stainless rust?
A: It stays bright in dry indoor and rural environments but stains and pits with salt, road de-icers, urban pollution and chloride cleaners. It is not suitable for marine or pool use.

Q: Can 430 be hardened?
A: Not usefully. Its low carbon (≤ 0.12 %) produces only a little martensite on quenching. Hardenable stainless steels are the martensitic grades 410, 420 and 440.

Q: What is 430 equivalent to in EN?
A: EN 1.4016 (X6Cr17). The EN grade caps carbon at 0.08 % versus 0.12 % for ASTM 430; European mills dual-certify.

Q: Is 430 food-safe?
A: Yes for dry and mildly wet food contact (bakeware, appliance interiors, cutlery handles). For process equipment with acidic or salty foods, 304 or 316 are specified.

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## 4340 [G43400] — Nickel-chromium-molybdenum low-alloy steel, deep hardening
URL: https://steelstandart.com/grade/4340/
System: AISI / SAE | Family: Quenched & tempered steel | Standard: ASTM A29 | Verified against: ASTM A29/A29M-20 (SAE J404 chemistry)
Aliases: AISI 4340, SAE 4340, 4340 steel, 4340 alloy steel, E4340, 300M, G43400, 34CrNiMo6, 1.6582, SNCM439, EN24, 817M40, 4340 Q&T

AISI 4340 is the high-strength, high-toughness alloy steel: 0.40 % carbon with 1.8 % nickel, 0.8 % chromium and 0.25 % molybdenum, UNS G43400. Nickel does what chromium and molybdenum alone cannot — it keeps the tempered martensite tough at very high strength and pushes hardenability so far that sections of 100 mm and more through-harden in oil. The result is a steel that can be tempered to any level from 950 to 1900 MPa and still resist impact and fatigue, which is why 4340 is specified for aircraft landing gear (as E4340 or 300M), crankshafts, heavy-duty gears and shafts, power-transmission components, oilfield drilling equipment and armour.

In practice most 4340 is used quenched and tempered to 30–40 HRC (1000–1300 MPa), often bought pre-hardened; the low-temper 1800+ MPa condition is reserved for aerospace parts made from vacuum-melted E4340 with rigorous hydrogen control, since the steel becomes notch- and hydrogen-sensitive above about 1400 MPa. Weldability is poor.

JIS SNCM439, GOST 40KhN2MA, GB 40CrNiMoA and BS 817M40 (EN24) are identical; EN 34CrNiMo6 (1.6582) is the standard European substitute with slightly different Ni/Cr balance.

Chemical composition (mass %): C 0.38 – 0.43; Mn 0.6 – 0.8; P ≤ 0.035 (E4340 (electric-furnace, AMS 6414): P ≤ 0.015, S ≤ 0.015); S ≤ 0.04; Si 0.15 – 0.35; Ni 1.65 – 2; Cr 0.7 – 0.9; Mo 0.2 – 0.3
SAE J404 / ASTM A29 (G43400). E4340 = electric-furnace/vacuum-degassed aerospace quality. 300M (AMS 6257) adds Si 1.45–1.80 and V for 1900–2100 MPa. Compare EN 34CrNiMo6 (1.6582): C 0.30–0.38, Ni 1.30–1.70, Cr 1.30–1.70, Mo 0.15–0.30 — lower C and Ni, higher Cr.

Mechanical properties:
- Annealed (810 °C, furnace cool) — typical: yield ≈ 470 MPa; tensile ≈ 745 MPa; elongation 22 %; hardness ≈ 217 HB
- Normalized (870 °C, air) — typical: yield ≈ 860 MPa; tensile ≈ 1280 MPa; elongation 12 %; hardness ≈ 363 HB
- Pre-hardened bar (Q&T 28–34 HRC) — typical: yield ≈ 800–900 MPa; tensile ≈ 950–1050 MPa; elongation 15 %; hardness 277–321 HB
- Q&T, tempered 650 °C (1200 °F), 25 mm — typical: yield ≈ 855 MPa; tensile ≈ 965 MPa; elongation 19 %; hardness ≈ 280 HB
- Q&T, tempered 540 °C (1000 °F) — typical: yield ≈ 1075 MPa; tensile ≈ 1170 MPa; elongation 14 %; hardness ≈ 350 HB
- Q&T, tempered 425 °C (800 °F) — typical: yield ≈ 1360 MPa; tensile ≈ 1470 MPa; elongation 12 %; hardness ≈ 430 HB (45 HRC)
- Q&T, tempered 315 °C (600 °F) — typical: yield ≈ 1590 MPa; tensile ≈ 1720 MPa; elongation 10 %; hardness ≈ 490 HB (50 HRC)
- Q&T, tempered 205 °C (400 °F) — typical: yield ≈ 1680 MPa; tensile ≈ 1880 MPa; elongation 9 %; hardness ≈ 520 HB (53 HRC)
- As-quenched (oil, 845 °C): yield — MPa; tensile — MPa; elongation — %; hardness 55–59 HRC
Typical values for 25 mm rounds (ASM). Aerospace heat-treat levels (AMS 2759): 125–145 ksi, 150–170 ksi, 180–200 ksi, 260–280 ksi (300M). Fracture toughness KIc ≈ 50–60 MPa√m at 1800 MPa, ≈ 100 MPa√m at 1100 MPa.
Impact: 50 J at 20 °C (typical, Q&T 1100 MPa; ≈ 20 J at 1800 MPa)

Equivalents:
- 817M40 (EN24) (BS (superseded British)) — identical: BS 970 817M40: C 0.36–0.44, Ni 1.30–1.70, Cr 1.00–1.40, Mo 0.20–0.35.
- 40CrNiMoA (GB/T (China)) — identical: GB/T 3077 40CrNiMoA: C 0.37–0.44, Ni 1.25–1.65, Cr 0.60–0.90, Mo 0.15–0.25 (Ni slightly lower).
- 40KhN2MA (GOST (Russia/CIS)) — identical: GOST 4543 40KhN2MA: C 0.37–0.44, Ni 1.25–1.65, Cr 0.60–0.90, Mo 0.15–0.25.
- SNCM439 (JIS (Japan)) — identical: JIS G4053 SNCM439: C 0.36–0.43, Ni 1.60–2.00, Cr 0.60–1.00, Mo 0.15–0.30.
- 300M (AISI / SAE) — near: Si-V modified 4340 for 1900–2100 MPa (landing gear, high-strength bolts).
- 4330V / 4330 Mod (AISI / SAE) — near: Lower-carbon (0.30 %) V-modified version with better weldability and toughness for oilfield and aerospace.
- 34CrNiMo6 (EN (European)) — near: 1.6582: C 0.30–0.38, Ni 1.30–1.70, Cr 1.30–1.70, Mo 0.15–0.30 — lower carbon/nickel, higher chromium; similar hardenability and strength; the standard European substitute.
- 36CrNiMo4 (EN (European)) — near: 1.6511: C 0.32–0.40, Ni 0.90–1.20, Cr 0.90–1.20, Mo 0.15–0.30 — closer on Cr, lower Ni.
- 4140 (AISI / SAE) — functional: Ni-free: same carbon, lower hardenability and toughness; adequate below ~75 mm and 1200 MPa.

Superseded names:
- G43400 / E4340 — UNS / AMS 6414: E = electric-furnace (aircraft quality); 4340H = H43400 hardenability band.
- 34CrNiMo6 / 1.6582 — EN 10083-3: Nearest European grade; 36CrNiMo4 (1.6511) and 40NiCrMo7 (Italy) also quoted.
- 817M40 / EN24 — BS 970: EN24 (BS 970 1955) is still the everyday UK/India name; 817M40 is the 1970+ designation.
- SNCM439 — JIS G4053: Formerly SNCM8.
- 300M — AMS 6257 / 6419: Si-V modified 4340 for 1900–2100 MPa (landing gear).

Product forms: bar and forgings (ASTM A29, A322, A108; AMS 6415/6414 (E4340 vacuum-melted)); pre-hardened bar at 28–34 HRC; seamless tube (A519), plate (A829), wire; aerospace: AMS 6414 (E4340), AMS 6257 (300M modified)
Tolerances: bar: ASTM A29 / A108; forgings: ASTM A788 / AMS 2374; aerospace bar: AMS 6414 / 6415

### 4340 steel yield strength
Typical: annealed ≈ 470 MPa (68 ksi); normalized ≈ 860 MPa; Q&T tempered at 650 °C ≈ 855 MPa; 540 °C ≈ 1075 MPa (156 ksi); 425 °C ≈ 1360 MPa; 315 °C ≈ 1590 MPa; 205 °C ≈ 1680 MPa (244 ksi). 300M at 260–280 ksi level: ≈ 1650–1720 MPa yield / 1930–2000 MPa tensile.

### 4340 tensile strength
Typical: annealed ≈ 745 MPa (108 ksi); normalized ≈ 1280 MPa; Q&T 965 MPa (650 °C temper) to 1880 MPa (205 °C temper, 273 ksi). Aerospace levels 125–145 / 150–170 / 180–200 ksi.

### 4340 hardness
Annealed ≈ 217 HB; normalized ≈ 363 HB; pre-hard 28–34 HRC; Q&T 280 HB (650 °C) → 350 HB (540 °C) → 45 HRC (425 °C) → 50 HRC (315 °C) → 53 HRC (205 °C); as-quenched 55–59 HRC. Nitrided surface 55–60 HRC.

### Heat treatment
Anneal 810–845 °C, furnace cool ≤ 15 K/h to 500 °C (or isothermal 650 °C). Normalize 870–900 °C, air. Harden 830–860 °C (1525–1575 °F), oil quench (air-hardens in thin sections); temper 205–650 °C, 2 h, double temper for aerospace; avoid 230–370 °C (tempered-martensite embrittlement) and slow cooling through 450–550 °C. Stress relieve 550–650 °C. Ac1 ≈ 725 °C, Ac3 ≈ 775 °C, Ms ≈ 290 °C. Ideal critical diameter ≈ 150 mm+ (through-hardens to 100 mm in oil).

### Hydrogen embrittlement
Above ~1240 MPa (180 ksi, ≈ 40 HRC) 4340 is highly susceptible: bake 190 °C for 4–24 h within 4 h of plating, pickling or cadmium/zinc coating; specify low-hydrogen consumables and limit exposure to acids. Aerospace parts are 100 % baked and often shot-peened.

### Physical properties
Density 7.85 g/cm³, E = 205 GPa, expansion 12.3 × 10⁻⁶/K, conductivity 44.5 W/m·K, specific heat 475 J/kg·K.

### Weldability
Poor weldability (CE ≈ 0.85–0.95). Weld only annealed material: preheat 300–370 °C, interpass ≥ preheat, low-hydrogen consumables (E11018-M / ER100S-1 or matching Ni-Cr-Mo), slow cool, temper immediately at 550–650 °C. Never weld Q&T parts intended to stay at strength. Repair welding of hardened 4340 requires full re-heat-treatment. Consider 4330V for weldable applications.

### Machining, forming, heat treatment
Machinability ≈ 50 % of B1112 annealed (217 HB); pre-hard 28–34 HRC machines well with coated carbide (≈ 45 %). Rough in annealed condition, finish after Q&T where distortion allows; grinding with care (burn). Cold forming only annealed and mild; hot forging 1200–950 °C then anneal or normalize. Surface treatments: nitriding (excellent, 0.3–0.6 mm at 600+ HV), induction hardening (55–58 HRC), shot peening, chrome/cadmium plating with mandatory hydrogen bake.

Applications: Aircraft landing-gear components, actuator pistons, flap tracks (E4340 / 300M); Crankshafts, connecting rods and camshafts for high-performance and heavy-duty engines; Heavy gears, pinions, shafts and spindles in power transmission, mining and steel mills; Oilfield: drill collars, kelly bars, subs, wellhead and BOP components (within NACE limits); High-strength bolts and studs (ASTM A320 L43, SAE Grade 8+, aerospace NAS); Armour, gun barrels, ordnance components; Injection-mould and die-casting holder blocks (pre-hard), machine-tool spindles; Motorsport: axles, hubs, gears, con-rods

Q: What is the difference between 4340 and 4140?
A: 4340 adds 1.8 % nickel. At equal hardness it is tougher and it through-hardens in sections 2–3× larger (100+ mm vs ~50 mm). 4140 is cheaper and adequate for most parts under 75 mm at ≤ 1200 MPa; 4340 is chosen for larger sections, higher strength (to 1900 MPa) and fatigue/impact-critical parts.

Q: How hard can 4340 get?
A: 55–59 HRC as-quenched; in service typically 30–45 HRC (1000–1400 MPa) and up to 50–53 HRC at low temper for aerospace parts made from E4340/300M. Nitriding gives 55–60 HRC on the surface.

Q: What is E4340?
A: Electric-furnace (usually vacuum-arc or ESR remelted) aircraft-quality 4340 with P and S ≤ 0.015 %, tighter inclusion control and full traceability (AMS 6414/6415). It is required for landing gear and other flight-critical parts.

Q: What is 300M?
A: A 4340 modified with 1.6 % silicon and 0.07 % vanadium (AMS 6257) that tempers to 1930–2070 MPa (280–300 ksi) with usable toughness — the standard landing-gear and high-strength bolt steel.

Q: What is 4340 equivalent to in EN?
A: EN 34CrNiMo6 (1.6582) is the standard substitute (lower C and Ni, higher Cr; similar strength and hardenability); 36CrNiMo4 (1.6511) is a lower-Ni alternative. BS EN24/817M40, JIS SNCM439 and GOST 40KhN2MA are exact matches.

Q: Can 4340 be welded?
A: Only with difficulty: annealed condition, 300–370 °C preheat, low-hydrogen filler, immediate post-weld tempering, then full re-heat-treatment if strength is required. For welded high-strength structures use 4330V or 4130 instead.

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## 5160 (1.7176) [G51600] — Chromium spring steel, quenched and tempered
URL: https://steelstandart.com/grade/5160/
System: AISI / SAE | Family: Spring steel | Standard: ASTM A29 | Verified against: ASTM A29/A29M-23, SAE J404
Aliases: AISI 5160, SAE 5160, 5160 spring steel, 5160H, G51600, 55Cr3, 1.7176, SUP9, SUP9A, 55CrMnA, 50KhG, 527A60, 9254 leaf

AISI 5160 is the leaf-spring steel of North America and, in its European form 55Cr3, of much of the rest of the world. The recipe is deliberately plain: 0.60 % carbon for hardness, 0.80 % chromium for hardenability, 0.90 % manganese to help both — and nothing else. There is no vanadium, no molybdenum and no excess silicon, which keeps the price near that of a plain carbon steel while giving genuine through-hardness in a 25 mm leaf.

The number that matters when working with it is the as-quenched hardness: 60–63 HRC. At that carbon content 5160 comes out of the oil far harder than any spring needs, so the temper, not the quench, defines the part. A leaf tempered at 425 °C reads 50–53 HRC and 1700–1900 MPa and will take a set or crack under impact; the same leaf tempered at 480–500 °C reads 45–49 HRC and lasts. Nearly every failure attributed to the steel is an under-temper or a decarburised surface.

Outside the spring industry 5160 has a second life as a forging and blade steel. Knife and sword makers choose it precisely because it is not a wear-resistant steel: the low alloy content gives an exceptionally tough blade at 55–58 HRC, it forges easily, it takes a differential or clay-tempered heat treatment well, and a worn edge can be re-hardened by anyone with a forge. Those same properties — tough, cheap, forgiving, not very wear resistant — are why it is also used for agricultural tines, plough points and hand tools.

JIS SUP9A is the same steel; EN 55Cr3 is the same steel with tighter phosphorus, sulphur and decarburisation requirements, which matters for a fatigue-loaded spring and not at all for a knife. 5160H is ordinary 5160 bought against a guaranteed hardenability band rather than against chemistry alone.

Chemical composition (mass %): C 0.56 – 0.64; Si 0.15 – 0.35; Mn 0.75 – 1; P ≤ 0.035; S ≤ 0.04; Cr 0.7 – 0.9
SAE J404 / ASTM A29 grade 5160 (UNS G51600). 5160H is the same analysis ordered to a hardenability band with a slightly widened carbon range (0.55–0.65 %). The European counterpart 55Cr3 (1.7176) in EN 10089 sets C 0.52–0.59, Si 0.25–0.50, Cr 0.60–0.90 and caps phosphorus and sulphur at 0.025 % — a cleaner steel for the same job.

Mechanical properties:
- Annealed (delivery for forming): yield — MPa; tensile ≈ 720–850 MPa; elongation ≈ 17 %; hardness ≤ 255 HB
- Hot rolled, as supplied: yield ≈ 600 MPa; tensile ≈ 1000 MPa; elongation ≈ 12 %; hardness 280–320 HB
- 830–860 °C oil + 425 °C temper: yield 1500–1650 MPa; tensile 1700–1900 MPa; elongation 5 %; hardness 50–53 HRC
- 830–860 °C oil + 480 °C temper: yield 1300–1450 MPa; tensile 1500–1700 MPa; elongation 7 %; hardness 45–49 HRC
- 830–860 °C oil + 540 °C temper: yield 1100–1250 MPa; tensile 1250–1400 MPa; elongation 9 %; hardness 38–42 HRC
- Hardened 840 °C oil, as-quenched: yield — MPa; tensile — MPa; elongation — %; hardness 60–63 HRC
ASTM A29 is a bar specification: it fixes the analysis, the dimensions and the surface quality, and leaves the mechanical properties to be agreed. There is therefore no standard tensile table for 5160 and the figures above are the normal correlation for a 20 mm section. Note the as-quenched row — at 0.60 % carbon the steel reaches 60+ HRC, well above spring hardness, which is why the temper is what sets the property and why an under-tempered leaf cracks rather than bends.

Equivalents:
- SUP9 (JIS (Japan)) — identical: JIS G4801 SUP9: C 0.52–0.60, Si 0.15–0.35, Mn 0.65–0.95, Cr 0.65–0.95. SUP9A raises carbon to 0.56–0.64 and chromium to 0.70–1.00, which is the direct 5160 match.
- 55Cr3 (EN (European)) — near: EN 10089 55Cr3 (1.7176): C 0.52–0.59, Si 0.25–0.50, Mn 0.70–1.00, Cr 0.60–0.90. The same chromium spring steel with slightly less carbon and, more importantly, phosphorus and sulphur capped at 0.025 % against 0.035/0.040 — plus a decarburisation limit that SAE 5160 does not carry.
- 51CrV4 (EN (European)) — near: 1.8159: less carbon, more chromium, and 0.15 % vanadium. The vanadium pins the grain, so 51CrV4 survives hot forming and overheating far better and is tougher at the same hardness; it is the European default where 5160 is the North American one.
- 55CrMnA (GB/T (China)) — near: GB/T 1222 55CrMnA: C 0.52–0.60, Mn 0.65–0.95, Cr 0.65–0.95; 60CrMnA with 0.56–0.64 % C is the closer match to 5160.
- 50KhG (GOST (Russia/CIS)) — near: GOST 14959 50KhGA: C 0.46–0.54, Mn 0.70–1.00, Cr 0.90–1.20 — lower carbon, more chromium. 60S2KhA is the Russian grade closer in strength.
- 9260 (AISI / SAE) — functional: The silicon spring steel: same carbon, 2 % silicon and no chromium. Higher elastic limit and better resistance to sag, but much shallower hardening — the choice for coil springs where 5160 goes into leaves.
- 1095 (AISI / SAE) — functional: Plain high-carbon steel: harder edge, no hardenability. A 1095 leaf is hard at the surface and soft in the middle, which is why carbon spring steels are confined to thin strip and 5160 takes the thick sections.
- 4140 (AISI / SAE) — functional: The general-purpose quenched and tempered engineering steel. Deeper hardening thanks to molybdenum but only 0.40 % carbon, so it tops out well below spring hardness and is used for shafts rather than springs.
- 60Si7 (IS (India)) — functional: The chromium leaf-spring steel: deeper hardening and less decarburisation-sensitive, with a lower elastic limit at the same hardness.

Superseded names:
- 527A60 — BS 970 (withdrawn): The British chromium spring steel of the same class; 527H60 is the hardenability-guaranteed version.
- EN48 — BS 970:1955: The pre-1970 British designation of the 0.60 % C chromium spring steel.
- 55Cr3 — DIN 17221 (withdrawn): The German grade, carried into EN 10089 unchanged with number 1.7176.
- 9254 — SAE J404: Not the same steel — a silicon-chromium grade sometimes substituted in modern coil springs. It is listed here only because stockists occasionally offer it against a 5160 enquiry.

Product forms: hot-rolled flat bar for leaf springs; round and square bar for coil springs and torsion bars; annealed flat stock for knife and tool making; 5160H hardenability-guaranteed bar
Tolerances: hot-rolled spring flats: ASTM A29/A29M and the mill's spring-flat section list; hot-rolled bar: ASTM A29/A29M, or EN 10092-1 where supplied as 55Cr3; hardenability band: 5160H to ASTM A304 (J-distance limits agreed on order)

### 5160 hardness and temper
As-quenched 60–63 HRC, which is above any service condition. The usable bands come from the temper: 50–53 HRC at 425 °C, 45–49 HRC at 480 °C, 38–42 HRC at 540 °C. Automotive leaf springs are finished at 44–48 HRC, agricultural tines and tillage parts at 46–50 HRC, forged blades at 55–58 HRC from a lower temper. Annealed delivery for forming is ≤ 255 HB; as-rolled bar runs 280–320 HB.

### Heat treatment
Normalise 860–880 °C. Austenitise 830–860 °C (hold 10–20 min at section temperature), quench in oil; water quenching is possible on thin leaves but cracks thick ones. Temper 400–550 °C for 1–2 h and air cool. Stay out of the 250–400 °C band, which crosses the tempered-martensite embrittlement trough. Soft anneal 650–700 °C. Hot forge 1150–850 °C and always normalise afterwards — do not quench directly from forging heat, because the grain is coarse. Ac1 ≈ 740 °C, Ac3 ≈ 780 °C, Ms ≈ 255 °C.

### Hardenability
Chromium and manganese give full hardness through about 25–30 mm in oil — thinner than 51CrV4 but enough for the overwhelming majority of leaf sections. Jominy values run roughly 63 HRC at J1.5, 55 HRC at J6 and 40 HRC at J15. 5160H is the same steel ordered to a hardenability band under ASTM A304 and is what a spring maker buys when the quench is fixed and the hardness must repeat heat to heat. Above 40 mm, move to 51CrV4 or a molybdenum grade.

### Why it is tough rather than wear resistant
The alloy content is low and there are no hard alloy carbides — the structure after tempering is a plain tempered martensite with a little chromium carbide. That gives a high fracture toughness and a high fatigue limit at 45–50 HRC, and a low abrasion resistance. For a spring, a plough point or a blade that must survive impact, this is the right trade; for a tool that must hold an edge against abrasive material, a tool steel is the correct choice and 5160 will simply wear.

### Surface condition and fatigue
5160 is normally bought hot rolled, which means mill scale and some decarburisation. Both cut the fatigue limit: the decarburised skin has lost its carbon and therefore its strength, at exactly the fibre carrying the highest stress. Practice is to shot peen after forming and grinding — typically 500–900 MPa compressive in the top 0.2 mm and double the fatigue life — and to specify 55Cr3 to EN 10089 instead where the decarburisation limit needs to be contractual rather than assumed.

### Physical properties
Density 7.85 g/cm³, E = 205 GPa, shear modulus G = 80 GPa. Thermal conductivity ≈ 46 W/m·K, expansion 12.3 × 10⁻⁶/K (20–200 °C). Service temperature up to about 200 °C before relaxation becomes measurable; coil springs running warm move to a silicon-chromium grade.

### Weldability
Weldable only before heat treatment, and that is how spring eyes, brackets and clips are attached. On already-hardened material the carbon equivalent of roughly 0.85 means 300–400 °C preheat, hydrogen-controlled filler, high interpass temperature, slow cooling and an immediate 500 °C temper — and the heat-affected zone will still be softer and coarser than the parent spring. Welding a finished leaf spring is not an accepted repair. Forge welding, by contrast, works well on this steel and is used in blade making.

### Machining, forming, heat treatment
Annealed at ≤ 255 HB machinability is about 60–65 % relative to 1 % C free-cutting steel, routine with carbide. As-rolled at 300 HB it is noticeably tougher and drilling is slow — anneal first if much metal is to come off. After tempering to 48 HRC, grinding only. Hot forging is easy and forgiving between 1150 and 850 °C, which is why the grade is popular with blacksmiths and blade makers; always normalise after forging to recover the grain. Cold shearing and punching are done annealed. Grind and peen after all forming, never before.

Applications: Automotive and truck leaf springs, parabolic springs, spring clips; Heavy coil springs and torsion bars; Agricultural tines, plough points, cultivator shanks, harrow discs; Forged hand tools, pry bars, picks and chisels; Knife, machete and sword blades (forged, 55–58 HRC); Grader and scraper blades, wear strips where impact dominates; Clutch and retaining springs, snap rings

Q: What is the European equivalent of 5160?
A: 55Cr3, material number 1.7176, in EN 10089. It carries slightly less carbon (0.52–0.59 % against 0.56–0.64 %) and the same chromium, but it is a cleaner steel: phosphorus and sulphur capped at 0.025 % against 0.035 and 0.040, plus a contractual limit on surface decarburisation. For a fatigue-loaded spring those delivery requirements matter more than the small carbon difference; for a forged blade they are irrelevant.

Q: What hardness does 5160 reach?
A: 60–63 HRC as-quenched from oil — higher than any spring needs — so the hardness in service is set by the temper: 50–53 HRC at 425 °C, 45–49 HRC at 480 °C, 38–42 HRC at 540 °C. Leaf springs are normally finished at 44–48 HRC and forged blades at 55–58 HRC.

Q: What is 5160H?
A: The same steel ordered to a guaranteed hardenability band instead of to chemistry alone, under ASTM A304. The carbon range is widened slightly to 0.55–0.65 % and the mill instead guarantees the Jominy curve between agreed limits. A spring maker with a fixed quench buys 5160H so that hardness repeats from heat to heat.

Q: 5160 or 51CrV4 — which is better for a spring?
A: 51CrV4 is the better steel and costs more. Its vanadium pins the grain, so it tolerates hot forming and an overheated furnace, it is tougher at the same hardness, and it hardens through 40 mm against 25–30 mm for 5160. 5160 is chosen where the section is moderate and cost matters, which covers most leaf springs ever made.

Q: Is 5160 a good knife steel?
A: For a large chopping blade, yes — it is one of the classic forging steels. The low alloy content gives exceptional toughness at 55–58 HRC, it forges and normalises easily, it takes a differential or clay temper, and it can be re-hardened with simple equipment. It is not stainless and it has low abrasion resistance, so the edge needs more frequent sharpening than a high-alloy blade steel. For a small slicing knife, a higher-carbon steel holds its edge longer.

Q: How thick a section will 5160 harden through?
A: About 25–30 mm in oil. Beyond that the core drops below spring hardness and the choices are 51CrV4 (through to roughly 40 mm) or a molybdenum-bearing grade such as 52CrMoV4 for heavier bars.

Q: Why do 5160 springs break?
A: Three causes account for almost all of it. An insufficient temper leaves the leaf above 53 HRC, where it cracks instead of flexing. A decarburised or scaled surface removes the strength from the fibre carrying the highest stress. And a weld or a drilled hole in the sprung length creates a notch in a component with no tolerance for one. Shot peening addresses the second; the other two are avoided by process, not by material.

Q: Can 5160 be used for coil springs?
A: Yes, and it is, particularly in heavier hot-coiled sizes. For cold-coiled and high-duty coil springs the silicon grades — 9260, 54SiCr6, 61SiCr7 — are usually preferred, because silicon raises the elastic limit and resists sag, which matters more in a coil than in a leaf. 5160 keeps the leaf-spring market because it hardens deeper than the silicon grades.

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## 51CrV4 (1.8159) [G61500] — Chromium-vanadium spring steel, quenched and tempered
URL: https://steelstandart.com/grade/51crv4/
System: EN (European) | Family: Spring steel | Standard: EN 10089 | Verified against: EN 10089:2002
Aliases: 1.8159, 51 CrV 4, 51CrV4 spring steel, 6150, AISI 6150, SAE 6150, 50CrV4, SUP10, 50CrVA, 50KhFA, 735A50, Z50CV4, 51CrV4 material

51CrV4 (1.8159) is the workhorse of EN 10089 and the most widely specified spring steel in Europe. Half a per cent of carbon with 1 % chromium takes it to 44–48 HRC and 1450–1650 MPa tensile after an oil quench and a 450 °C temper; the chromium lets it harden right through a 40 mm leaf or a 25 mm torsion bar, where a plain carbon spring steel would be hard only at the surface.

The vanadium is the part that is usually overlooked. At 0.10–0.25 % it forms fine carbides that pin the grain boundaries, so the steel tolerates being heated for hot forming or coiling without coarsening, and it comes out of an overheated furnace cycle far better than 5160 or a silicon grade would. That is why 51CrV4 is also the steel of choice for hand tools — chisels, wrenches, pry bars, mower blades — where the part is hot-formed, hardened and then used in shock.

The third thing worth understanding is that EN 10089 does not give you a tensile table for your spring. It fixes the analysis, the delivery hardness, the cleanliness and — unusually — a limit on surface decarburisation, because a spring fails from its surface and a decarburised skin has no fatigue strength. Everything else is set by the spring maker: austenitising, quench, temper, and above all shot peening, which routinely doubles the fatigue life of the same bar. A certificate showing 1550 MPa tells you nothing about how long the spring will last.

SAE 6150, JIS SUP10, GB 50CrVA, GOST 50KhFA and BS 735A50 (EN47) are the same steel. The older German name 50CrV4 is still in daily use and refers to the identical grade.

Chemical composition (mass %): C 0.47 – 0.55; Si ≤ 0.4; Mn 0.7 – 1.1; P ≤ 0.025; S ≤ 0.025; Cr 0.9 – 1.2; V 0.1 – 0.25
EN 10089:2002 Table 1 (51CrV4, 1.8159). The phosphorus and sulphur limits of 0.025 % are tighter than in an ordinary engineering steel, and deliberately so: a spring fails from a surface or subsurface defect, and sulphide inclusions are defects. SAE 6150 allows C 0.48–0.53 with P 0.035 and S 0.040 — the analysis is the same, the cleanliness requirement is not.

Mechanical properties:
- +A annealed (delivery for forming): yield — MPa; tensile ≤ 850 MPa; elongation — %; hardness ≤ 248 HB
- +QT, 850 °C oil + 450 °C temper: yield 1250–1400 MPa; tensile 1450–1650 MPa; elongation 6 %; hardness 44–48 HRC
- +QT, 850 °C oil + 500 °C temper: yield 1100–1250 MPa; tensile 1300–1450 MPa; elongation 7 %; hardness 40–44 HRC
- +QT, 850 °C oil + 550 °C temper: yield 950–1100 MPa; tensile 1150–1300 MPa; elongation 9 %; hardness 36–40 HRC
- Hardened 850 °C oil, as-quenched: yield — MPa; tensile — MPa; elongation — %; hardness 55–58 HRC
- Fatigue limit, shot-peened spring at 1500 MPa (typical): yield ≈ 550 (±, bending) MPa; tensile — MPa; elongation — %; hardness —
EN 10089 specifies the chemistry, the annealed or +QT delivery hardness and the decarburisation limit; it does **not** standardise a tensile table for the finished spring, because the properties are set by the spring maker's own heat treatment after forming. The figures above are the usual results for a 20 mm section. The last row is the number that actually decides a spring's life, and it depends far more on the surface — peening, decarburisation, scale pits — than on the tensile strength.

Equivalents:
- 6150 (AISI / SAE) — identical: SAE 6150 (UNS G61500): C 0.48–0.53, Mn 0.70–0.90, Cr 0.80–1.10, V ≥ 0.15. The same chromium-vanadium steel. The difference is in the delivery requirements rather than the analysis — SAE allows P 0.035 and S 0.040 against 0.025 for EN 10089, and does not impose a decarburisation limit.
- 735A50 (BS (superseded British)) — identical: BS 970 735A50, the former EN47: C 0.45–0.55, Mn 0.70–1.00, Cr 0.80–1.20, V 0.15 min. Still quoted on British drawings for torsion bars and hand tools.
- 50CrVA (GB/T (China)) — identical: GB/T 1222 50CrVA: C 0.47–0.54, Mn 0.50–0.80, Cr 0.80–1.10, V 0.10–0.20. The Chinese spring steel standard mirrors EN 10089 closely, including the decarburisation requirement.
- 50KhFA (GOST (Russia/CIS)) — identical: GOST 14959 50KhFA: C 0.46–0.54, Mn 0.50–0.80, Cr 0.80–1.10, V 0.10–0.20.
- SUP10 (JIS (Japan)) — identical: JIS G4801 SUP10: C 0.47–0.55, Si 0.15–0.35, Mn 0.65–0.95, Cr 0.80–1.10, V 0.15–0.25 — effectively the EN analysis with a silicon minimum.
- 5160 (AISI / SAE) — near: The chromium leaf-spring steel without vanadium: C 0.56–0.64, Cr 0.70–0.90. Higher carbon gives similar hardness more cheaply; the missing vanadium means a coarser grain and less tolerance of overheating during forming.
- 52CrMoV4 (EN (European)) — near: 1.7701: the same steel with 0.50 % molybdenum added. Hardens through heavier bars and resists relaxation better at temperature; used for very heavy leaf and parabolic springs.
- 9260 (AISI / SAE) — functional: 1.8159: chromium-vanadium, deeper hardening and far more tolerant of hot forming because the vanadium pins the grain. Chosen where section size or process robustness governs rather than elastic limit.
- 60SiCr7 (EN (European)) — functional: 1.7108: the silicon-chromium coil-spring steel. Higher elastic limit and better sag resistance at the same hardness, but shallower hardening and more prone to decarburisation — the usual choice for valve and suspension coil springs where 51CrV4 goes into leaf springs and torsion bars.
- 42CrMo4 (EN (European)) — functional: 1.7225: the general engineering quenched and tempered steel. Overlaps in strength up to about 1100 MPa but has 0.40 % carbon, so it cannot reach spring hardness, and it is not supplied against a decarburisation limit.
- 60Si7 (IS (India)) — functional: 1.8159: chromium-vanadium instead of silicon. Hardens through roughly twice the section and tolerates hot forming far better, at a higher price. Within IS 3431 itself the equivalent step is to 50Cr4V2.

Superseded names:
- 50CrV4 — DIN 17221 (withdrawn): Same number 1.8159. EN 10089 renamed it 51CrV4 when the carbon window was re-centred; the two names are used interchangeably in the trade and on mill certificates.
- 735A50 — BS 970 Part 2 / BS 970:1955 EN47: The British spring and tool grade, also written EN47 in the pre-1970 scheme.
- Z50CV4 — NF A 35-571: The French designation.
- 50CrV4 — UNI 3545: The Italian standard used the German short name directly.

Product forms: hot-rolled flat bar for leaf springs (annealed or +QT); round bar for torsion bars and coil springs; cold-rolled strip (EN 10132-4); square and profiled spring bar; peeled and ground bar for machined parts
Tolerances: hot-rolled flat spring bar: EN 10092-1 (dimensions and tolerances for spring steel flats); hot-rolled round and square: EN 10092-2 / EN 10060; cold-rolled spring strip: EN 10132-4; surface decarburisation: limited by EN 10089 Table 6 as a proportion of thickness — part of the delivery condition, not an extra

### 51CrV4 tensile strength and hardness
Delivered annealed at ≤ 248 HB for forming, or quenched and tempered. The working condition is set by the temper: 1450–1650 MPa at 44–48 HRC from a 450 °C temper, 1300–1450 MPa at 40–44 HRC from 500 °C, 1150–1300 MPa at 36–40 HRC from 550 °C. Leaf springs are normally finished at 1450–1600 MPa; hand tools at 44–50 HRC; torsion bars towards the upper end.

### Heat treatment
Soft anneal 650–700 °C. Normalise 850–880 °C. Austenitise 840–870 °C (hold 10–20 min at temperature), quench in oil; water is used on heavy leaves with care. Temper 420–550 °C for 1–2 h, then air cool. Avoid tempering between 250 and 400 °C: that range crosses the tempered-martensite embrittlement trough and costs toughness without buying strength. Hot form between 1050 and 850 °C and normalise afterwards. Ac1 ≈ 750 °C, Ac3 ≈ 800 °C, Ms ≈ 270 °C.

### Hardenability and section size
The chromium gives genuine through-hardness: full martensite to about 40 mm in oil, which covers virtually every leaf spring and most torsion bars. The Jominy curve runs roughly 58 HRC at J1.5, 55 HRC at J9 and 45 HRC at J25. Where a bar above 50 mm must be uniform, the molybdenum version 52CrMoV4 is the grade to move to; adding hardness by raising carbon instead costs toughness.

### Decarburisation — why EN 10089 limits it
A spring is a surface-stressed component: the maximum stress is at the outer fibre, which is exactly where a decarburised layer has lost its carbon and therefore its strength. EN 10089 limits the total decarburisation depth as a proportion of thickness and makes it part of the delivery condition. The practical consequences: protect the surface during hot forming and hardening, use a controlled atmosphere or salt where possible, and if the surface has been exposed, grind or peen it. A ground bar and a hot-rolled bar from the same heat can differ by a factor of two in fatigue life.

### Shot peening and fatigue
The single most effective thing done to a 51CrV4 spring. Peening puts a compressive residual stress of 500–900 MPa into the top 0.2 mm, which has to be overcome before a fatigue crack can open; measured fatigue life typically doubles or better. Stress peening (peening under load) adds more. For comparison, raising the tensile strength from 1450 to 1600 MPa gains far less and costs ductility. Pitting, scale, shot-blast damage and decarburisation all work in the opposite direction.

### Physical properties
Density 7.85 g/cm³, E = 206 GPa, shear modulus G = 79.5 GPa — the two numbers a spring designer needs, since leaf deflection goes with E and coil deflection with G. Thermal conductivity ≈ 45 W/m·K, expansion 12.2 × 10⁻⁶/K (20–200 °C). Maximum service temperature about 200–250 °C before relaxation becomes significant; above that, a silicon-chromium or molybdenum grade is required.

### Weldability
Weldable only with care and never in the sprung part. The carbon equivalent is roughly 0.85–0.95, so preheat 300–400 °C, hydrogen-controlled or matching filler, high interpass temperature, slow cooling and an immediate post-weld temper at 500–550 °C are all required — and the heat-affected zone will still have lost the structure the spring depends on. Standard practice is to attach brackets and eyes mechanically or by welding before heat treatment, never after. A welded repair on a finished leaf spring is not a repair; it is a planned fracture.

### Machining, forming, heat treatment
Machined in the annealed condition at ≤ 248 HB, where machinability is about 60–65 % relative to 1 % C free-cutting steel — straightforward with carbide tooling. After quenching and tempering to 45 HRC, only grinding is practical. Hot forming of leaves and coils is done between 1050 and 850 °C and is followed by a full austenitise and quench, not by a direct quench from the forming heat, because the grain is coarse at forming temperature. Cold coiling is done on annealed or +QT wire and followed only by a stress-relief at 400–450 °C. Shot peen after all forming and grinding, never before.

Applications: Leaf springs, parabolic springs and spring leaves for trucks and trailers; Torsion bars and anti-roll bars; Hot and cold coiled compression springs in heavy sections; Hand tools — chisels, wrenches, pry bars, pliers, shears; Agricultural tines, mower and cutter blades, tillage parts; Clutch and brake springs, retaining rings; Machine knives and scraper blades where shock matters more than wear

Q: Is 50CrV4 the same as 51CrV4?
A: Yes. Both names describe material number 1.8159. 50CrV4 is the older DIN 17221 designation; EN 10089 re-centred the carbon window at 0.47–0.55 % and renamed it 51CrV4. Mills and stockists use the two interchangeably and a certificate may carry either, so match the analysis rather than the name.

Q: What is the AISI equivalent of 51CrV4?
A: SAE 6150 (UNS G61500), with C 0.48–0.53, Cr 0.80–1.10 and vanadium above 0.15 %. The analysis is effectively the same. What differs is the delivery requirement: EN 10089 caps phosphorus and sulphur at 0.025 % and limits surface decarburisation, while SAE 6150 as such does neither. For a fatigue-loaded spring that difference matters more than the chemistry.

Q: What tensile strength does 51CrV4 reach?
A: 1450–1650 MPa at 44–48 HRC after an oil quench and a 450 °C temper, falling to about 1150–1300 MPa if tempered at 550 °C. Leaf springs are usually finished at 1450–1600 MPa. The annealed delivery condition is 850 MPa maximum, for forming.

Q: What does the vanadium in 51CrV4 do?
A: It forms fine carbides that pin the grain boundaries, so the steel resists grain coarsening when it is heated for forging, hot coiling or hardening. In practice that means a more forgiving heat treatment and better toughness at the same hardness than a plain chromium grade such as 5160. It also contributes a little secondary hardening, which is why 51CrV4 holds its properties better than a carbon spring steel near 250 °C.

Q: How thick a section will 51CrV4 harden through?
A: About 40 mm in oil, which covers almost all leaf springs and torsion bars. Beyond 50 mm the core falls away and the grade to use is 52CrMoV4 (1.7701), which adds 0.50 % molybdenum for exactly this reason.

Q: Why must 51CrV4 springs be shot peened?
A: Because a spring is loaded hardest at its surface, and fatigue cracks start there. Peening leaves 500–900 MPa of compressive stress in the top 0.2 mm, which must be overcome before a crack can open; it routinely doubles fatigue life or better. It also partly offsets surface damage from scale and handling. Peening is applied after all forming and grinding.

Q: Can 51CrV4 be welded?
A: Not in the sprung section. The carbon equivalent is around 0.9, so welding needs 300–400 °C preheat, hydrogen control and an immediate temper, and even then the heat-affected zone no longer has the quenched and tempered structure the spring relies on. Brackets and eyes are attached before heat treatment or fixed mechanically. A weld on a finished leaf spring is where it will break.

Q: Is 51CrV4 a good steel for tools and knives?
A: For impact tools, yes — it is one of the standard steels for chisels, wrenches, pry bars and mower blades, because the vanadium-refined grain gives good toughness at 45–50 HRC. For a cutting edge it is a compromise: at 0.5 % carbon it cannot hold the hardness of 1095 or a 1 % carbon tool steel, so the edge dulls sooner while the blade is far less likely to snap.

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## 52100 [G52986] — High-carbon chromium bearing steel
URL: https://steelstandart.com/grade/52100/
System: AISI / SAE | Family: Bearing steel | Standard: ASTM A295 | Verified against: ASTM A295/A295M-21
Aliases: AISI 52100, SAE 52100, 52100 steel, 52100 bearing steel, E52100, 52100 knife steel, G52986, 100Cr6, 1.3505, SUJ2, GCr15, ShKh15, 535A99, EN31, chrome steel

AISI 52100 is the world's bearing steel: 1.0 % carbon and 1.5 % chromium, UNS G52986, melted to extreme cleanliness (oxygen ≤ 15 ppm, near-zero large inclusions) because every rolling-element bearing ball, roller and race is made from it or from its identical twins EN 100Cr6, JIS SUJ2, GB GCr15 and GOST ShKh15. After hardening from 840 °C in oil and tempering at 150–180 °C it reaches 60–64 HRC with a fine dispersion of chromium carbides that gives outstanding rolling-contact fatigue life and wear resistance, plus dimensional stability from the low retained-austenite content that the chromium addition and a cold treatment ensure.

Outside bearings, 52100 is a favourite of knifemakers and blacksmiths (very fine grain, keen edge, forgiving of forging), and it is used for rollers, cams, bushings, gauges, punches, needle valves and any small part that must be hard, precise and wear-resistant. Its hardenability is moderate — sections above about 20–30 mm need the Mn-Si variant 100CrMnSi6-4 (SUJ3) — and, with no ductility to speak of at 62 HRC, it must be machined in the spheroidized state and ground after hardening. Corrosion resistance is nil; stainless bearings use 440C.

Chemical composition (mass %): C 0.93 – 1.05; Mn 0.25 – 0.45; P ≤ 0.025; S ≤ 0.015; Si 0.15 – 0.35; Cr 1.35 – 1.6; Ni ≤ 0.25; Mo ≤ 0.1; Cu ≤ 0.3; Al ≤ 0.05; O ≤ 0.002 (15 ppm oxygen max — inclusion control is the essence of bearing quality)
ASTM A295/A295M-21 (52100). 'E52100' = electric-furnace (all modern material). Compare EN 100Cr6 (1.3505): C 0.93–1.05, Cr 1.35–1.60, Mn 0.25–0.45, Si 0.15–0.35 — identical; JIS SUJ2 and GB GCr15 likewise.

Mechanical properties:
- Spheroidize annealed (delivery) — typical: yield ≈ 450 MPa; tensile ≈ 680 MPa; elongation 22 %; hardness ≤ 207 HB (typ. 180–200)
- Normalized (900 °C) — typical: yield — MPa; tensile ≈ 1000 MPa; elongation — %; hardness ≈ 290 HB
- Hardened 840 °C oil + tempered 150 °C — bearing condition: yield ≈ 1700 (compressive yield ≈ 2000+) MPa; tensile ≈ 2200 (bend) MPa; elongation < 1 %; hardness 60–64 HRC
- Hardened + tempered 200 °C: yield — MPa; tensile — MPa; elongation — %; hardness 58–61 HRC
- Hardened + tempered 260 °C (knives, heavy-duty): yield — MPa; tensile — MPa; elongation — %; hardness 56–59 HRC
- Hardened + tempered 400 °C (springs, tools): yield — MPa; tensile — MPa; elongation — %; hardness ≈ 50 HRC
- As-quenched (oil, 840 °C): yield — MPa; tensile — MPa; elongation — %; hardness 64–67 HRC
Bearing steel is specified by chemistry, cleanliness (ASTM E45 / A295 inclusion ratings), decarburization limits and annealed hardness; hardened tensile values are typical and rarely used in design (contact fatigue governs). Rolling-contact fatigue life is the functional property.
Impact: 8 J at 20 °C (typical, 60 HRC, unnotched ≈ 15–25 J)

Equivalents:
- 535A99 (EN31) (BS (superseded British)) — identical: BS 970 535A99: C 0.95–1.10, Cr 1.20–1.60.
- 100Cr6 (EN (European)) — identical: 1.3505 (EN ISO 683-17): C 0.93–1.05, Cr 1.35–1.60, Mn 0.25–0.45, Si 0.15–0.35 — identical; dual-certified.
- GCr15 (GB/T (China)) — identical: GB/T 18254 GCr15: C 0.95–1.05, Cr 1.40–1.65, Mn 0.25–0.45, Si 0.15–0.35.
- ShKh15 (GOST (Russia/CIS)) — identical: GOST 801 ShKh15: C 0.95–1.05, Cr 1.30–1.65, Mn 0.20–0.40, Si 0.17–0.37.
- SUJ2 (JIS (Japan)) — identical: JIS G4805 SUJ2: C 0.95–1.10, Cr 1.30–1.60, Mn ≤ 0.50, Si 0.15–0.35.
- 100CrMnSi6-4 (EN (European)) — near: 1.3520 (SUJ3 / GCr15SiMn / ShKh15SG): Mn 1.0–1.2, Si 0.5–0.7 — higher hardenability for rings > 30 mm wall.
- 100CrMo7-3 (EN (European)) — near: 1.3536 (SUJ5-type): Mo-bearing for large bearings and high-temperature use.
- 1095 (AISI / SAE) — functional: Plain 0.95 % C: similar hardness, much lower hardenability, no chromium carbides — cheaper knife/spring alternative.
- O1 / 1.2510 (AISI / SAE) — functional: Oil-hardening tool steel: similar heat treatment window, more W/V carbides for wear; preferred for dies.
- 440C (AISI / SAE) — functional: Stainless bearing steel (S44004) for corrosive environments at similar hardness.
- AR450 (Proprietary (trade names)) — functional: Bearing steel at 60–64 HRC, around 700 HBW. Listed to mark where the plate route ends: above about 550 HBW the practical answers are carbide overlay, cast chrome iron, a tool steel insert or a ceramic liner, not a harder plate.

Superseded names:
- E52100 — AISI: E = electric-furnace melted; all current 52100 is E52100.
- G52986 — UNS
- 100Cr6 / 1.3505 — EN ISO 683-17 / DIN 17230: European twin; 100CrMnSi6-4 (1.3520) for larger sections.
- 535A99 / EN31 — BS 970: EN31 remains the common Indian/UK name.
- SUJ2 — JIS G4805: Japanese twin; SUJ3 = higher Mn/Si.
- GCr15 — GB/T 18254: Chinese twin.
- ShKh15 — GOST 801: Russian twin.

Product forms: bar and rod (ASTM A295, A29) — spheroidize-annealed; tube for bearing rings (A295 / A534); wire for balls and rollers (A295); forgings, ring blanks; ground flat stock for knifemakers; powder / ESR variants for aerospace bearings (AMS 6440/6444)
Tolerances: bar: ASTM A295 / A29; cold-finished: ASTM A108; aerospace: AMS 6440 (bar), AMS 6444 (premium)

### 52100 hardness
As-quenched 64–67 HRC; bearing condition (tempered 150–180 °C) 60–64 HRC; knives 58–61 HRC (200 °C temper); tools 56–59 HRC; annealed (spheroidized) ≤ 207 HB, typically 180–200 HB. Bainite-hardened (austempered 230–250 °C) 58–60 HRC with better toughness.

### 52100 strength (hardened)
Tensile ≈ 2200 MPa in bending, compressive yield > 2000 MPa, contact stress capability ≈ 4 GPa; elongation < 1 %. Annealed: ≈ 450 MPa yield / 680 MPa tensile, 22 % elongation.

### Heat treatment
Spheroidize anneal 780–800 °C, slow cool 10–20 K/h to 650 °C (delivery condition). Harden 830–860 °C (1525–1575 °F), 20–30 min, oil quench (thin sections may be salt-quenched or air-cooled in fast-quench variants); sub-zero −70 to −80 °C for dimensional stability (bearings); temper 150–180 °C for bearings, 200–260 °C for knives/tools, 2 h. Stress relieve after grinding 120–150 °C. Ac1 ≈ 745 °C, Ms ≈ 220 °C. Retained austenite 5–15 % after quench, < 5 % after cold treatment.

### Hardenability and section size
Ideal critical diameter ≈ 25–35 mm in oil; rings with wall > 20–30 mm use 100CrMnSi6-4 / SUJ3 / GCr15SiMn, and large bearings (> 100 mm wall) use 100CrMo7-3/7-4 or carburizing steels.

### Cleanliness and fatigue
Bearing quality requires ASTM A295 / ISO 683-17 inclusion limits (E45 method A: A ≤ 2.5, B ≤ 1.5, C ≤ 0.5, D ≤ 1.0 thin) and oxygen ≤ 15 ppm (≤ 8 ppm premium); L10 rolling-contact life scales strongly with cleanliness — the reason vacuum-degassed or ESR 52100 is specified for aerospace.

### Physical properties
Density 7.81 g/cm³, E = 210 GPa, expansion 11.9 × 10⁻⁶/K (20–100 °C), conductivity ≈ 46 W/m·K; ferromagnetic; not corrosion-resistant despite 1.5 % Cr (all chromium is in carbides).

### Weldability
Not weldable in the practical sense (CE > 1.2): hardens and cracks on cooling. Repair welding only with 300–400 °C preheat, immediate annealing and full re-hardening; forge-welding for damascus is common in knifemaking (1100–1200 °C, flux, then normalize several times and spheroidize).

### Machining, forming, heat treatment
Machinability ≈ 40 % of B1112 in the spheroidized condition (hard Cr carbides): carbide tooling, moderate speed, generous coolant. All machining, drilling and rough grinding in the annealed state; after hardening only grinding (CBN/soft wheels, avoid burn), honing, lapping and superfinishing. Hot forging 1050–850 °C followed by normalizing 870–900 °C and spheroidizing. Surface treatments: black oxide, thin dense chrome (bearings), no plating without hydrogen bake.

Applications: Ball and roller bearing rings, balls, rollers and needle rollers (the dominant use); Linear bearing rails, ball screws and guide shafts; Cams, cam followers, rollers, tappets, bushings and sleeves; Knife blades, forged blades and damascus (with 15N20); Gauges, plug gauges, measuring pins, precision spindles; Punches, dies, thread-rolling dies and small wear parts; Valve balls and seats, needle valves, injection-pump components

Q: Is 52100 the same as 100Cr6?
A: Yes. 52100 (ASTM A295), EN 100Cr6 (1.3505), JIS SUJ2, GB GCr15, GOST ShKh15 and BS 535A99/EN31 share the 1.0 % C / 1.5 % Cr analysis and are dual-certified worldwide; only the cleanliness and inspection clauses differ by standard.

Q: How hard is 52100?
A: 60–64 HRC as used in bearings (tempered 150–180 °C), 64–67 HRC as-quenched. Knifemakers usually run it at 58–61 HRC for a balance of edge retention and toughness.

Q: Is 52100 a good knife steel?
A: Yes — it forges well, has very fine grain, takes a razor edge and holds it well, and is tougher than 1095 at equal hardness thanks to its Cr carbides and hardenability. It is not stainless: blades need oil or a patina.

Q: How do you heat-treat 52100?
A: Austenitize 830–860 °C (soak 20–30 min), oil quench, optional cold treatment at −70 °C, temper 150–180 °C (bearings) or 200–260 °C (knives) for 2 h, twice. Spheroidize at 780–800 °C with slow cooling before machining or if the steel has been forged.

Q: Why is 52100 not stainless with 1.5 % chromium?
A: Practically all the chromium is bound in (Fe,Cr)₃C carbides, leaving almost none in the matrix to form a passive film; stainless behaviour needs ≥ 10.5 % dissolved Cr. 440C (17 % Cr) is the stainless bearing steel.

Q: What is the difference between 52100 and SUJ3 / 100CrMnSi6-4?
A: SUJ3 (1.3520, GCr15SiMn) adds ~1.1 % Mn and 0.6 % Si to raise hardenability for bearing rings with wall thickness above 20–30 mm; otherwise the same steel and heat treatment.

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## 60Si7 — Silicon spring steel (Indian standard), quenched and tempered
URL: https://steelstandart.com/grade/60si7/
System: IS (India) | Family: Spring steel | Standard: IS 3431 | Verified against: IS 3431:1982 (grade list and scope)
Aliases: 60 Si 7, 60Si7 spring steel, 60Si7 material, IS 3431 60Si7, 60Si7 leaf spring, 60Si7 chemical composition, 60Si7 equivalent, 60Si7 hardness

60Si7 is the steel most leaf springs made in India are rolled from. Its specification is IS 3431, the Bureau of Indian Standards document for hot-rolled bars and flats used to make volute, helical and laminated springs for automotive suspension; the other four grades in the same standard are 55Si7, 65Si7, 50Cr4V2 and 60Cr4V2. The analysis — 0.55–0.65 % carbon with 1.5–2.0 % silicon and no chromium — makes it the same silicon spring steel the rest of the world knows as SAE 9260, JIS SUP7, EN 56Si7 or GB 60Si2MnA.

The designation is readable once the convention is known, and it is the same convention EN uses. The leading number is carbon in hundredths of a per cent; the number after an element symbol is that element's content multiplied by four. So 60Si7 is 0.60 % carbon with 7 ÷ 4 = 1.75 % silicon, 65Si7 is the same steel at 0.65 % carbon, and 50Cr4V2 reads as 0.50 % C with 1.0 % Cr and 0.5 % V — the Indian counterpart of 51CrV4.

The question that causes the most trouble in enquiries is a boundary between documents rather than a metallurgical one. IS 3431 specifies the steel; IS 7906 specifies the spring. A mill certificate to IS 3431 reports the analysis, the hardenability and the bar's freedom from defects, and says nothing about the hardness, camber, load rating or fatigue life of the finished leaf — those belong to the spring standard and to the spring maker's heat treatment. "What is the hardness of 60Si7" is a question IS 3431 does not answer.

Two features of the standard are worth knowing because they are unusual. It requires a minimum 16:1 reduction ratio from ingot to finished product, which is a soundness requirement aimed at closing centreline porosity in a component that must not contain internal defects. And it lists hardenability among the mandatory tests, which matters precisely because a silicon steel with no chromium does not harden deep.

Chemical composition (mass %): C 0.55 – 0.65; Si 1.5 – 2; Mn 0.6 – 0.9
IS 3431:1982, grade 60Si7. The standard also sets ceilings on phosphorus and sulphur; they are looser than the 0.025 % of EN 10089, so the heat analysis on the certificate is what should be read rather than assumed. The other four grades in the same standard are 55Si7 and 65Si7 (the same steel at lower and higher carbon) and the chromium-vanadium grades 50Cr4V2 and 60Cr4V2.

Mechanical properties:
- Annealed (delivery for forming): yield — MPa; tensile ≈ 780–900 MPa; elongation ≈ 15 %; hardness ≤ 269 HB
- Hot rolled, as supplied: yield ≈ 650 MPa; tensile ≈ 1050 MPa; elongation ≈ 11 %; hardness 280–340 HB
- 830–870 °C oil + 420 °C temper: yield 1550–1700 MPa; tensile 1750–1900 MPa; elongation 5 %; hardness 50–54 HRC
- 830–870 °C oil + 460 °C temper: yield 1400–1550 MPa; tensile 1600–1750 MPa; elongation 6 %; hardness 46–50 HRC
- 830–870 °C oil + 500 °C temper: yield 1250–1400 MPa; tensile 1420–1570 MPa; elongation 7 %; hardness 42–46 HRC
- Hardened 850 °C oil, as-quenched: yield — MPa; tensile — MPa; elongation — %; hardness 60–63 HRC
IS 3431 covers the bar and flat: composition, hardenability, mechanical properties, freedom from defects, straightness and tolerances. What it does not fix is the hardness of your spring, because that is produced by the spring maker after forming and is accepted against **IS 7906** and the vehicle maker's drawing. The rows above are the usual results for a 12–20 mm leaf.

Equivalents:
- 9260 (AISI / SAE) — identical: SAE 9260 (UNS G92600): C 0.56–0.64, Si 1.80–2.20, Mn 0.75–1.00. The same steel for all practical purposes. 9260 sits at the top of the silicon range where 60Si7 spans the whole of it, so a 60Si7 heat at 1.55 % Si is a shade leaner than any 9260 heat.
- 60Si2MnA (GB/T (China)) — identical: GB/T 1222 60Si2MnA: C 0.56–0.64, Si 1.60–2.00, Mn 0.60–0.90 — the grade most often offered against a 60Si7 enquiry, and a genuine match.
- 60S2A (GOST (Russia/CIS)) — identical: GOST 14959 60S2A: C 0.57–0.65, Si 1.60–2.00, Mn 0.60–0.90.
- SUP7 (JIS (Japan)) — identical: JIS G4801 SUP7: C 0.56–0.64, Si 1.80–2.20, Mn 0.70–1.00. SUP6 corresponds more closely to the leaner end of the 60Si7 window.
- 56Si7 (EN (European)) — near: EN 10089 56Si7 (1.5026): C 0.52–0.60, Si 1.60–2.00, Mn 0.60–0.90. Almost the same analysis, bought against phosphorus and sulphur limits of 0.025 % and a contractual surface decarburisation limit — for an importer the difference to examine is the delivery condition, not the chemistry.
- 65Si7 (IS (India)) — near: The next grade up in IS 3431, with carbon at 0.60–0.70 % and the same silicon. Harder and stronger at the same temper, marginally less tough; Indian spring makers select between the two by leaf thickness.
- 5160 (AISI / SAE) — functional: The chromium leaf-spring steel: deeper hardening and less decarburisation-sensitive, with a lower elastic limit at the same hardness.
- 51CrV4 (EN (European)) — functional: 1.8159: chromium-vanadium instead of silicon. Hardens through roughly twice the section and tolerates hot forming far better, at a higher price. Within IS 3431 itself the equivalent step is to 50Cr4V2.

Superseded names:
- 60Si7 — IS 3431:1965: The designation has not changed across editions; the 1982 third revision reworked the grade list and the test requirements around it.
- 55Si2Mn90 — older Indian practice: The silicon-manganese spring grade, closer to SAE 9255, still written on some older drawings.
- SUP7 — JIS G4801: Not an Indian designation, but the cross-reference most often printed beside 60Si7 on export drawings.

Product forms: hot-rolled spring flats for laminated leaf springs; round and square bar for coiled and volute springs; tapered and parabolic rolled leaf sections; annealed flat bar for forming before heat treatment
Tolerances: hot-rolled bars and flats: dimensions, tolerances and straightness are specified inside IS 3431 itself; general delivery conditions: IS 8910; finished spring: IS 7906 — the spring, not the steel, is what that standard governs

### How to read the designation 60Si7
60 = 0.60 % carbon, written in hundredths of a per cent. Si7 = silicon at 7 ÷ 4 = 1.75 %, four being the standard divisor for silicon, manganese, chromium and nickel in this scheme. The same rule reads 65Si7 as 0.65 % C with 1.75 % Si, and 50Cr4V2 as 0.50 % C with 1.0 % Cr and 0.5 % V. It is the convention behind the European names 56Si7 and 51CrV4 as well, which is why the Indian and EN grade names look so similar — and why a 60Si7 drawing can be read by a European mill without a conversion table.

### 60Si7 hardness in a finished spring
Typical acceptance for a laminated leaf spring is 46–50 HRC, from an oil quench at 830–870 °C and a temper near 440–470 °C. As-quenched the steel reaches 60–63 HRC, so the temper is what sets the part. Above roughly 52 HRC the leaf cracks under impact instead of flexing; below about 43 HRC it takes a permanent set and the spring loses camber in service.

### IS 3431 against IS 7906 and IS 3195
Three documents that get confused in enquiries. IS 3431 is the automotive spring *steel*: bars and flats, five grades, composition, hardenability, defects, tolerances. IS 7906 is the *spring*: helical compression springs and automobile leaf-spring assemblies, with the dimensions, load, camber and testing that a vehicle maker accepts against. IS 3195 is the parallel steel standard for railway rolling-stock volute and helical springs — a different application and a different grade list, and not the standard for an automotive leaf. If the question is about material, look at IS 3431; if it is about what the spring must do, look at IS 7906.

### Why silicon and not chromium
Silicon raises the elastic limit disproportionately — it strengthens the ferrite in solid solution and slows tempering — so a 60Si7 spring resists taking a set and relaxes less in service than a chromium steel at the same hardness. What it does not improve is hardenability. With no chromium, full hardness reaches only about 15–20 mm in oil, which is why IS 3431 makes hardenability a mandatory test and why the core of a heavy leaf will read lower than the surface. Where that becomes the limit, the step within the same standard is to 50Cr4V2 or 60Cr4V2.

### Decarburisation and the 16:1 reduction ratio
A leaf spring carries its highest stress at the surface, and 2 % silicon accelerates surface carbon loss during rolling, forming and austenitising. A decarburised skin has lost its strength exactly where it is needed — the result is a spring that passes a hardness check and fails on fatigue. IS 3431 attacks internal soundness by requiring a minimum 16:1 reduction from ingot to product and by requiring the bar to be free of pipe, heavy scale, laminations, seams and cracked edges; the surface carbon question is handled by the spring plant through controlled furnace atmospheres, short cycle times and shot peening after forming and grinding.

### Physical properties
Density 7.80 g/cm³, E = 200 GPa, shear modulus G = 78 GPa — leaf deflection scales with E and coil deflection with G, so both matter depending on the spring type. Thermal conductivity ≈ 38 W/m·K, expansion 11.9 × 10⁻⁶/K (20–200 °C). Usable to roughly 250 °C before relaxation becomes measurable, better than a plain carbon spring steel, which is another consequence of the silicon.

### Weldability
Not weldable in the sprung length. Silicon at around 1.75 % makes the heat-affected zone more crack-sensitive than a plain spring steel, on top of a carbon equivalent near 0.9. Spring eyes, centre bolts, clips and brackets are formed or attached before heat treatment, or fixed mechanically. Where a weld cannot be avoided it needs 300–400 °C preheat, hydrogen-controlled consumables, a high interpass temperature and an immediate temper at 480–520 °C — and the welded zone will still lack the quenched and tempered structure the leaf depends on.

### Machining, forming, heat treatment
Machined annealed at ≤ 269 HB, where machinability is around 55–60 % relative to 1 % C free-cutting steel; silicon stiffens the ferrite so the cut is harder than the hardness number suggests. Centre-bolt holes are punched or drilled before hardening, never after. Hot forming of leaves, eyes and tapered sections runs at 1150–850 °C and is followed by a full austenitise and quench, not by quenching from the forming heat, because the grain is coarse at that temperature; furnace time is kept short to limit decarburisation. After tempering to 48 HRC, grinding only — and grind wet, since a burnt surface is a locally tempered, weakened surface. Shot peen last.

Applications: Laminated and parabolic leaf springs for trucks, buses, trailers and tractors; Spring flats, tapered leaves and helper leaves; Volute and hot-coiled helical springs for suspension; Agricultural spring tines, cultivator shanks and seed-drill springs; Spring clips, washers and retaining springs; Flat and spiral springs in general engineering; Forged hand tools where flex matters more than edge retention

Q: What is the equivalent of 60Si7?
A: SAE 9260 and JIS SUP7 are the closest matches, with GB 60Si2MnA and GOST 60S2A equally close; EN 10089 56Si7 (1.5026) is the European counterpart. All are 0.55–0.65 % carbon silicon spring steels with no chromium. The difference between them is not chemistry but delivery condition — EN 10089 caps phosphorus and sulphur at 0.025 % and limits surface decarburisation, where IS 3431 sets looser ceilings and leaves the surface carbon question to the spring plant.

Q: What does the 7 in 60Si7 mean?
A: Silicon content multiplied by four: 7 ÷ 4 = 1.75 % nominal, with IS 3431 allowing 1.5–2.0 %. The leading 60 is carbon in hundredths of a per cent, so 60Si7 is 0.60 % C with 1.75 % Si. The same convention gives 65Si7 at 0.65 % carbon and 50Cr4V2 at 0.50 % C with 1.0 % Cr and 0.5 % V.

Q: What is the hardness of 60Si7?
A: It depends entirely on the heat treatment, and IS 3431 does not specify one for the finished part — it is a steel standard. A laminated leaf spring is normally accepted at 46–50 HRC, from an oil quench at 830–870 °C and a temper near 450 °C. As-quenched the steel reaches 60–63 HRC, far too hard for service.

Q: Which standard covers 60Si7?
A: IS 3431 — steel for the manufacture of volute, helical and laminated springs for automotive suspension — which lists 55Si7, 60Si7, 65Si7, 50Cr4V2 and 60Cr4V2. IS 3195 is the parallel standard for railway rolling-stock springs and is a different grade list; IS 7906 covers the finished springs. General delivery conditions come from IS 8910.

Q: What is the difference between 60Si7 and 65Si7?
A: Carbon only: 0.55–0.65 % against 0.60–0.70 %, with the same silicon. 65Si7 is harder and stronger at the same tempering temperature and marginally less tough, so it tends to go into thinner leaves and higher-stressed springs. Spring makers treat them as near-interchangeable and choose by leaf thickness.

Q: How thick a leaf will 60Si7 harden through?
A: About 15–20 mm in oil. There is no chromium to slow the transformation, so hardness falls away in thicker sections and the middle of a heavy leaf reads lower than the surface — which is why IS 3431 includes hardenability among its mandatory tests. For thicker springs the choices are 50Cr4V2 or 60Cr4V2 within the same standard, or 51CrV4 and 5160 from the EN and SAE systems.

Q: Why do 60Si7 springs lose camber in service?
A: Because they have taken a permanent set, which is a yield problem rather than a fracture problem. The usual causes are an over-temper that left the leaf below about 43 HRC, a core that never hardened because the section was too thick for a chromium-free grade, or a decarburised surface that yields at a lower stress than the certificate implies. Checking hardness at mid-thickness rather than only at the surface normally identifies which one it is.

Q: Why does IS 3431 require a 16:1 reduction ratio?
A: To close internal defects. A cast ingot or billet carries centreline porosity and segregation, and a spring is a component in which an internal defect becomes a fatigue origin. Requiring the cross-section to be reduced at least sixteenfold from ingot to finished bar forces enough hot work to weld that porosity shut. It is a soundness requirement, not a strength requirement, and it sits alongside the standard's demand that the bar be free of pipe, laminations, seams and cracked edges.

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## 8620 [G86200] — Nickel-chromium-molybdenum case-hardening steel
URL: https://steelstandart.com/grade/8620/
System: AISI / SAE | Family: Case-hardening steel | Standard: ASTM A29 | Verified against: ASTM A29/A29M-20 (SAE J404 chemistry)
Aliases: AISI 8620, SAE 8620, 8620 steel, 8620 alloy steel, 8620 case hardening steel, G86200, 8620H, 21NiCrMo2, 1.6523, SNCM220, 805M20, EN362, 20CrNiMo, 20KhGNM

AISI 8620 is the American standard case-hardening alloy steel: 0.20 % carbon with 0.55 % nickel, 0.5 % chromium and 0.2 % molybdenum, UNS G86200. The triple alloying is 'lean' — no single element above 0.7 % — but together they give enough hardenability for a 25 mm gear to develop a 58–62 HRC carburized case over a tough 30–35 HRC core, plus the nickel toughness that lets gear teeth take shock without spalling. It is the default steel for automotive and truck transmission gears, differential ring and pinion gears, camshafts, piston pins, splined shafts, kingpins, chain sprockets and, in the through-hardened condition, for medium-strength bolts and pins.

8620 is normally bought as 8620H (hardenability-guaranteed band) for gears, machined in the annealed or normalized state, then carburized at 900–930 °C, quenched in oil and tempered at 150–200 °C. Core properties depend strongly on section size — the table gives typical values at 25 mm.

EN 20NiCrMo2-2 (1.6523, ex 21NiCrMo2), JIS SNCM220, GB 20CrNiMo and BS 805M20/EN362 are the same steel; European gear practice more often uses 16MnCr5 or 18CrNiMo7-6, which are functional substitutes.

Chemical composition (mass %): C 0.18 – 0.23; Mn 0.7 – 0.9; P ≤ 0.035; S ≤ 0.04; Si 0.15 – 0.35; Ni 0.4 – 0.7; Cr 0.4 – 0.6; Mo 0.15 – 0.25
SAE J404 / ASTM A29 (G86200). 8620H (H86200) hardenability band: J1.5 = 41–48 HRC, J9 ≈ 24–36 HRC. Compare EN 21NiCrMo2 (1.6523): C 0.17–0.23, Ni 0.40–0.70, Cr 0.35–0.70, Mo 0.15–0.25 — the same steel; 20NiCrMo2-2 (1.6523) in EN 10084 is the current name.

Mechanical properties:
- Annealed (860 °C, furnace cool) — typical: yield ≈ 385 MPa; tensile ≈ 540 MPa; elongation 31 %; hardness ≈ 149 HB
- Normalized (915 °C, air) — typical: yield ≈ 360 MPa; tensile ≈ 635 MPa; elongation 26 %; hardness ≈ 183 HB
- Cold drawn — typical: yield ≈ 550 MPa; tensile ≈ 690 MPa; elongation 15 %; hardness ≈ 200 HB
- Carburized 925 °C, direct oil quench, temper 150 °C — core, 25 mm — typical: yield ≈ 690–800 MPa; tensile ≈ 900–1050 MPa; elongation 15 %; hardness ≈ 280–320 HB (core)
- Carburized, single reheat quench (845 °C), temper 150 °C — core — typical: yield ≈ 640 MPa; tensile ≈ 850 MPa; elongation 17 %; hardness ≈ 260 HB (core)
- Carburized — surface (0.8–1.0 % C case): yield — MPa; tensile — MPa; elongation — %; hardness 58–62 HRC (case), depth 0.5–2.0 mm
- Through-hardened (oil, 845 °C), tempered 200 °C — typical, ≤ 15 mm: yield ≈ 900 MPa; tensile ≈ 1100 MPa; elongation 12 %; hardness ≈ 40 HRC
Typical values (ASM); AISI grades carry no property minimums. Core hardness after carburizing depends on section: ≈ 40 HRC at 12 mm, 30–35 HRC at 25 mm, 25 HRC at 50 mm. Charpy (core) ≈ 50–80 J.
Impact: 60 J at 20 °C (typical, carburized core)

Equivalents:
- 805M20 (EN362) (BS (superseded British)) — identical: BS 970 805M20: C 0.17–0.23, Ni 0.35–0.75, Cr 0.35–0.65, Mo 0.15–0.25.
- 20NiCrMo2-2 (EN (European)) — identical: 1.6523 (EN 10084; formerly 21NiCrMo2): C 0.17–0.23, Ni 0.40–0.70, Cr 0.35–0.70, Mo 0.15–0.25.
- 20CrNiMo (GB/T (China)) — identical: GB/T 3077 20CrNiMo: C 0.17–0.23, Ni 0.35–0.75, Cr 0.40–0.70, Mo 0.20–0.30.
- SNCM220 (JIS (Japan)) — identical: JIS G4053 SNCM220: C 0.17–0.23, Ni 0.40–0.70, Cr 0.40–0.65, Mo 0.15–0.30.
- 8615 / 8617 / 8622 (AISI / SAE) — near: Carbon steps of the 86xx family (0.15, 0.17, 0.22 % C) for lighter or heavier cores.
- 20KhGNM / 20KhN2M (GOST (Russia/CIS)) — near: GOST 4543 20KhGNM (C 0.18–0.23, Ni 0.40–0.70, Cr 0.40–0.70, Mo 0.15–0.25) is the closest Russian match.
- 4320 / 18CrNiMo7-6 (AISI / SAE) — functional: Higher-Ni grades (1.8 / 1.5 % Ni) for larger, more heavily loaded gears.
- 1018 / C15 (AISI / SAE) — functional: Unalloyed case-hardening steels for small, lightly loaded parts.
- 16MnCr5 (EN (European)) — functional: European Mn-Cr case-hardening steel with similar hardenability, no Ni — the usual EU substitute in gear practice.

Superseded names:
- G86200 / H86200 — UNS: 8620H = hardenability-guaranteed version, standard for gears.
- 21NiCrMo2 / 20NiCrMo2-2 / 1.6523 — EN 10084 / DIN 17210: European twin.
- 805M20 / 805A20 / EN362 — BS 970: EN362 still used in the UK/India.
- SNCM220 — JIS G4053: Formerly SNCM21.
- 20CrNiMo — GB/T 3077: Chinese twin.

Product forms: hot-rolled and cold-finished bar (ASTM A29, A322, A108); forgings and forged gear blanks (A29 / A788); seamless tube (A519), plate (limited); wire and cold-heading stock, pre-machined gear blanks
Tolerances: bar: ASTM A29 / A108; forgings: ASTM A788; aerospace: AMS 6274 / 6276

### 8620 core strength after carburizing
Direct oil quench from 925 °C + 150 °C temper, 25 mm section: ≈ 690–800 MPa yield / 900–1050 MPa tensile (100–150 ksi), core ≈ 280–320 HB (30–35 HRC). Single reheat quench: ≈ 640 / 850 MPa. Larger sections give lower core hardness (≈ 25 HRC at 50 mm).

### 8620 surface hardness
Carburized case 58–62 HRC (≈ 700–750 HV) at 0.8–1.0 % surface carbon; effective case depth (550 HV) typically 0.5–2.0 mm. Carbonitrided: 60–64 HRC at shallower depth.

### 8620 annealed / normalized properties
Annealed ≈ 385 MPa yield / 540 MPa tensile, ≈ 149 HB; normalized ≈ 360 / 635 MPa, 183 HB; cold-drawn ≈ 550 / 690 MPa, 200 HB.

### Heat treatment
Anneal 855–885 °C, furnace cool. Normalize 900–925 °C (1650–1700 °F), air. Carburize 900–930 °C (1650–1700 °F); direct quench in oil from 845–870 °C, or reheat-quench from 845 °C for core refinement; temper 150–200 °C (300–400 °F) 1–2 h. Through-harden (if used un-carburized) 845–870 °C oil → ≈ 40 HRC in thin sections. Ac1 ≈ 730 °C, Ac3 ≈ 830 °C, Ms ≈ 395 °C (core). Jominy 8620H: J1.5 = 41–48, J9 = 24–36 HRC.

### Machinability
≈ 65 % of B1112 annealed/normalized — good; machine before carburizing, leaving 0.1–0.3 mm grinding stock on gear flanks. Cold drawn 8620 machines slightly better.

### Physical properties
Density 7.85 g/cm³, E = 205 GPa, expansion 11.3 × 10⁻⁶/K, conductivity 46.6 W/m·K.

### Weldability
Fair weldability in the annealed/normalized state (CE ≈ 0.45–0.50): preheat 100–200 °C for sections > 12 mm, low-hydrogen consumables (E7018 / ER70S-6 or ER80S-D2), post-weld stress relief 550–650 °C. Never weld carburized surfaces; mask or machine off the case first.

### Machining, forming, heat treatment
Turning, hobbing, shaping, broaching and drilling in the annealed or normalized condition are all good; consistent hardness (149–183 HB) gives predictable tool life. Cold heading and cold extrusion are possible after spheroidizing. Hot forging 1200–950 °C then normalize. After carburizing only grinding, honing and lapping; distortion is moderate and predictable with 8620H.

Applications: Transmission and differential gears, ring and pinion sets (automotive, truck, off-highway); Camshafts, rocker arms, piston pins, kingpins, universal-joint crosses; Splined shafts, spline couplings, chain sprockets and roller-chain pins; Bearing races and rollers for large sizes (as 8620 or 4320 carburized); Hydraulic pump gears, planetary carriers, drive pinions; Medium-strength fasteners, pins and bushings (through-hardened or carburized); Firearm components (bolt carriers, receivers), tooling blanks

Q: What is 8620 steel used for?
A: Mainly carburized gears, shafts, pins and cams that need a hard, wear-resistant surface (58–62 HRC) over a tough core — transmission and differential gears, camshafts, sprockets, splines. Un-carburized it serves as a medium-strength machining and fastener steel.

Q: What is the difference between 8620 and 4140?
A: 8620 is a case-hardening steel (0.20 % C): soft, tough core with a carburized hard skin. 4140 is a through-hardening steel (0.40 % C): uniform 28–50 HRC throughout. Use 8620 for gears and wear surfaces needing shock resistance, 4140 for shafts, bolts and parts needing strength through the section.

Q: How hard can 8620 get?
A: Carburized surface 58–62 HRC (up to 64 HRC carbonitrided); core 30–40 HRC depending on section. Through-hardened without carburizing it reaches only about 40–45 HRC in thin sections.

Q: What is 8620H?
A: 8620 with a guaranteed Jominy hardenability band (H86200: J1.5 = 41–48 HRC, J9 = 24–36 HRC). Gear manufacturers specify 8620H so the core hardness after carburizing is predictable from heat to heat.

Q: What is 8620 equivalent to in EN?
A: EN 20NiCrMo2-2 (1.6523, formerly 21NiCrMo2) is identical. European gear shops often substitute 16MnCr5 or 20MnCr5 (Mn-Cr, no Ni) or step up to 18CrNiMo7-6 for heavier gears.

Q: Can 8620 be welded?
A: Yes in the annealed or normalized condition with 100–200 °C preheat for thicker sections and low-hydrogen filler; stress-relieve afterwards. Do not weld after carburizing.

---

## 9260 [G92600] — Silicon-manganese spring steel, quenched and tempered
URL: https://steelstandart.com/grade/9260/
System: AISI / SAE | Family: Spring steel | Standard: ASTM A29 | Verified against: ASTM A29/A29M-23, SAE J404
Aliases: AISI 9260, SAE 9260, 9260 spring steel, 9260H, G92600, 56Si7, 61SiCr7, SUP7, 60Si2Mn, 60Si2MnA, 60S2, 250A58, 9255, 9262

AISI 9260 is the silicon spring steel — 0.60 % carbon, 2 % silicon, and no chromium, molybdenum or vanadium at all. Everything that distinguishes it comes from that silicon, and the mechanism is worth stating plainly: silicon dissolves in the ferrite and raises the yield strength much more than it raises the tensile strength. At a 450 °C temper the yield-to-tensile ratio is about 0.89 against roughly 0.86 for 5160 at the same hardness, which means a larger share of the steel's strength is available before anything takes a permanent set.

For a spring that is the whole point. A coil or leaf that sags has failed just as surely as one that breaks, and sag is a yield phenomenon. Silicon also slows the diffusion that drives tempering, so the steel holds its strength further up the temper curve and relaxes less at warm running temperatures. This is why the silicon family — 9260, 9254, 54SiCr6, 61SiCr7 — dominates modern automotive coil springs, and why 9260 at 52–55 HRC is a favourite of sword makers who need a long blade to flex and return straight.

The price is paid in two places. Hardenability is poor: with no chromium there is nothing to hold the transformation back, so full hardness reaches only 15–20 mm in oil, about half the depth of 5160. And silicon promotes decarburisation — it accelerates carbon loss from the surface during hot forming and hardening, in a component whose highest stress is at that surface. ASTM A29 sets no decarburisation limit, so on a fatigue-critical spring the European grade 56Si7 to EN 10089, which does, is the safer purchase.

JIS SUP7, GB 60Si2MnA, GOST 60S2A and IS 60Si7 are the same steel. The sister grades differ only in carbon and, in 9262, in a chromium addition that buys back some of the missing depth.

Chemical composition (mass %): C 0.56 – 0.64; Si 1.8 – 2.2; Mn 0.75 – 1; P ≤ 0.035; S ≤ 0.04
SAE J404 / ASTM A29 grade 9260 (UNS G92600). The sister grades differ only in carbon: 9254 at 0.51–0.59 % and 9255 at 0.51–0.59 % with the same silicon, 9262 at 0.55–0.65 % with 0.25–0.40 % chromium added. There is **no chromium, molybdenum or vanadium** in 9260 — the silicon does all the work, and that single fact explains both its strengths and its limits.

Mechanical properties:
- Annealed (delivery for forming): yield — MPa; tensile ≈ 780–900 MPa; elongation ≈ 15 %; hardness ≤ 269 HB
- Hot rolled, as supplied: yield ≈ 650 MPa; tensile ≈ 1050 MPa; elongation ≈ 11 %; hardness 290–340 HB
- 830–860 °C oil + 400 °C temper: yield 1650–1800 MPa; tensile 1850–2000 MPa; elongation 4 %; hardness 52–55 HRC
- 830–860 °C oil + 450 °C temper: yield 1500–1650 MPa; tensile 1700–1850 MPa; elongation 6 %; hardness 48–52 HRC
- 830–860 °C oil + 500 °C temper: yield 1300–1450 MPa; tensile 1450–1600 MPa; elongation 7 %; hardness 43–47 HRC
- Hardened 850 °C oil, as-quenched: yield — MPa; tensile — MPa; elongation — %; hardness 61–64 HRC
ASTM A29 fixes the analysis and the bar quality, not the mechanical properties, so there is no standard tensile table for 9260 and the rows above are typical for a 20 mm section. The figure worth comparing against other spring steels is the **ratio of yield to tensile**: at 450 °C temper it is about 0.89, against roughly 0.86 for 5160 at the same hardness. That elastic margin — not strength — is what silicon buys.

Equivalents:
- 60Si2MnA (GB/T (China)) — identical: GB/T 1222 60Si2MnA: C 0.56–0.64, Si 1.60–2.00, Mn 0.60–0.90. One of the most widely produced spring steels in China; the A suffix marks the higher-cleanliness version.
- 60S2A (GOST (Russia/CIS)) — identical: GOST 14959 60S2A: C 0.57–0.65, Si 1.60–2.00, Mn 0.60–0.90. 60S2KhA adds chromium for deeper hardening.
- 60Si7 (IS (India)) — identical: IS 3431 60Si7: C 0.55–0.65, Si 1.50–2.00, Mn 0.60–0.90. The Indian silicon spring steel and the dominant leaf-spring grade on the subcontinent; functionally the same steel as 9260.
- SUP7 (JIS (Japan)) — identical: JIS G4801 SUP7: C 0.56–0.64, Si 1.80–2.20, Mn 0.70–1.00. The same steel, same windows. SUP6 is the lower-silicon version.
- 5160 (AISI / SAE) — near: The chromium leaf-spring steel at the same carbon level. 5160 hardens roughly twice as deep; 9260 has the higher elastic limit and resists sag better. The split in practice is 5160 for thick leaves, 9260 and its relatives for coils and thinner sections.
- 56Si7 (EN (European)) — near: EN 10089 56Si7 (1.5026): C 0.52–0.60, Si 1.60–2.00, Mn 0.60–0.90. Slightly less carbon and silicon than 9260, and — the real difference — phosphorus and sulphur capped at 0.025 % with a contractual decarburisation limit. 61SiCr7 (1.7108) is the higher-strength European silicon grade with chromium added.
- 1095 (AISI / SAE) — functional: Plain 0.95 % carbon steel. Harder at the surface and much cheaper, but it has essentially no hardenability and no silicon, so it takes a permanent set where 9260 springs back.
- 51CrV4 (EN (European)) — functional: 1.8159: chromium-vanadium, deeper hardening and far more tolerant of hot forming because the vanadium pins the grain. Chosen where section size or process robustness governs rather than elastic limit.

Superseded names:
- 250A58 / 250A53 — BS 970 (withdrawn): The British silicon-manganese spring steels of the same class.
- EN45 / EN45A — BS 970:1955: The pre-1970 British designation; EN45A is the higher-carbon version and the closer match to 9260.
- 56Si7 — DIN 17221 (withdrawn): Carried into EN 10089 unchanged (1.5026); the European 2 % silicon grade.
- 9255 / 9254 — SAE J404: Lower-carbon members of the same silicon family; 9254 is the one used in modern automotive coil springs.

Product forms: hot-rolled flat bar for leaf springs; round bar for hot-coiled compression springs; annealed flat stock for blade and tool making; 9260H hardenability-guaranteed bar
Tolerances: hot-rolled bar and spring flats: ASTM A29/A29M; hardenability band: 9260H to ASTM A304; surface quality: ASTM A29 requires freedom from injurious imperfections but sets no decarburisation depth — specify it separately or buy to EN 10089 instead

### 9260 hardness and elastic limit
As-quenched 61–64 HRC; usable hardness comes from the temper: 52–55 HRC at 400 °C, 48–52 HRC at 450 °C, 43–47 HRC at 500 °C. Tensile strength reaches 1850–2000 MPa at the 400 °C temper, among the highest of any plain spring steel. The number that matters more is the yield: 1650–1800 MPa in the same condition, close to 90 % of the tensile. Annealed delivery for forming is ≤ 269 HB.

### What the 2 % silicon actually does
Three things. It strengthens the ferrite in solid solution, raising the yield disproportionately — the elastic limit, not the breaking strength, is what a spring is designed against. It retards tempering by slowing carbon diffusion, so hardness falls more slowly with tempering temperature and relaxation at service temperature is lower. And it raises the austenitising temperature slightly and widens the useful temper window. The cost is decarburisation sensitivity and graphitisation risk on long anneals.

### Hardenability — the limiting property
With no chromium, manganese alone carries the hardenability: full hardness through about 15–20 mm in oil, roughly half the depth of 5160 and less than half that of 51CrV4. Jominy falls off quickly — around 63 HRC at J1.5 but below 45 HRC by J9. Consequences: thick leaves will be soft in the middle, and either the section is kept thin, or a chromium-bearing silicon grade (9262, 61SiCr7, 60S2KhA) is used. 9260H ordered to ASTM A304 is how a spring maker makes the result repeatable despite the steep curve.

### Decarburisation and graphitisation
Silicon accelerates carbon loss from the surface at forming and austenitising temperatures. Because a spring carries its highest stress at the outer fibre, a decarburised skin cuts the fatigue limit directly — and ASTM A29 imposes no depth limit, unlike EN 10089. Practice: protect the surface with a controlled atmosphere, salt bath or coating; minimise time at temperature; grind or shot peen the surface afterwards. A separate risk on prolonged soft annealing is graphitisation, the precipitation of free graphite, which is why the anneal is kept short and below 700 °C.

### Heat treatment
Soft anneal 680–700 °C, kept short. Normalise 870–890 °C. Austenitise 840–870 °C — slightly above a plain carbon steel because silicon raises the transformation temperatures — hold 10–20 min, quench in oil. Temper 380–520 °C for 1–2 h and air cool; avoid the 250–380 °C embrittlement trough. Hot form 1150–850 °C and normalise afterwards. Ac1 ≈ 765 °C, Ac3 ≈ 810 °C, Ms ≈ 250 °C.

### Physical properties
Density 7.80 g/cm³ — a little lower than plain steel because of the silicon. E = 200 GPa, shear modulus G = 78 GPa, both marginally below a carbon steel and the reason a silicon spring of the same geometry is slightly softer in rate. Thermal conductivity ≈ 38 W/m·K, expansion 11.9 × 10⁻⁶/K (20–200 °C). Useful service temperature to roughly 250 °C, better than the carbon grades.

### Weldability
Not weldable in the sprung section. The 2 % silicon makes the weld metal and the heat-affected zone more crack-sensitive than in a plain spring steel, on top of a carbon equivalent near 0.9. Where attachment is unavoidable, weld before heat treatment, with 300–400 °C preheat, hydrogen-controlled consumables and an immediate 500 °C temper. Forge welding is practical and is used in blade making. A weld across a finished spring is a fracture waiting for its first cycle.

### Machining, forming, heat treatment
Annealed at ≤ 269 HB machinability is roughly 55–60 % relative to 1 % C free-cutting steel — slightly harder cutting than 5160 at the same hardness because silicon stiffens the ferrite and the chip is abrasive. Carbide tooling, moderate speeds, sharp edges. As-rolled at 300–340 HB, drilling is slow and annealing first is usually worth the time. After tempering to 50 HRC, grinding only — and grind wet, because this steel is easy to burn and a burnt surface is a tempered, weakened surface. Hot forging is straightforward between 1150 and 850 °C; normalise afterwards and keep the furnace time short to limit decarburisation.

Applications: Hot-coiled compression springs for rail, mining and heavy vehicles; Automotive coil springs (more often the lower-carbon 9254); Leaf springs in thinner sections, spring clips and spring washers; Flat and spiral springs, clutch springs; Sword and large knife blades needing flex and return (52–55 HRC); Spring-loaded machine parts, detents and latch springs; Agricultural spring tines and seed-drill springs

Q: What is the European equivalent of 9260?
A: 56Si7, material number 1.5026, in EN 10089 — C 0.52–0.60, Si 1.60–2.00, Mn 0.60–0.90. It is marginally leaner in carbon and silicon but, more importantly, it is bought against tighter phosphorus and sulphur limits and a contractual decarburisation limit, which 9260 to ASTM A29 does not have. Where chromium is wanted as well, the European grade is 61SiCr7.

Q: What hardness does 9260 reach?
A: 61–64 HRC as-quenched, and in service 52–55 HRC from a 400 °C temper, 48–52 HRC from 450 °C or 43–47 HRC from 500 °C. Tensile strength at the 400 °C temper is 1850–2000 MPa, with yield around 90 % of that — the high elastic ratio is the point of the grade.

Q: 9260 or 5160 — which should I use?
A: Section size usually decides it. 5160 hardens through 25–30 mm against 15–20 mm for 9260, so thick leaves go to 5160. Where the section is thin enough for either, 9260 has the higher elastic limit and resists sag and relaxation better, which is why coil springs favour the silicon grades. 9260 is also the more decarburisation-sensitive of the two.

Q: Why is 9260 popular for swords?
A: Because a long blade has to bend a long way and come back straight, which is an elastic-limit problem rather than a hardness problem — exactly what 2 % silicon improves. At 52–55 HRC a 9260 blade takes a large deflection without setting, and it is tough because there are no hard alloy carbides. The trade-off is modest edge retention and no corrosion resistance.

Q: How thick a section will 9260 harden through?
A: About 15–20 mm in oil. With no chromium there is little to slow the transformation, so the Jominy curve falls away quickly — below 45 HRC by J9. For thicker parts use 9262 (which adds chromium), 61SiCr7, 5160 or 51CrV4.

Q: Is 9260 prone to decarburisation?
A: Yes, noticeably more so than the chromium grades, because silicon accelerates surface carbon loss at forming and austenitising temperatures. On a spring that matters a great deal, since the highest stress sits at the surface the decarburisation has weakened. Protect the surface during heat treatment, keep furnace times short, and shot peen or grind afterwards. ASTM A29 sets no depth limit — specify one, or buy 56Si7 to EN 10089 where the limit is part of the standard.

Q: What is the difference between 9260, 9254 and 9262?
A: Carbon and chromium. 9254 and 9255 carry 0.51–0.59 % carbon with the same 2 % silicon and are the usual automotive coil-spring steels. 9260 raises carbon to 0.56–0.64 % for more hardness. 9262 keeps the higher carbon and adds 0.25–0.40 % chromium, which buys back part of the hardenability that 9260 lacks.

Q: Can 9260 be annealed soft for machining?
A: Yes, at 680–700 °C, down to 269 HB or below. Keep the cycle short and the temperature under about 700 °C: at 2 % silicon a prolonged high anneal risks graphitisation, the precipitation of free graphite, which permanently damages the steel. Machine annealed, then harden and temper.

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## A106 Grade B [K03006] — Seamless carbon steel pipe for high-temperature service
URL: https://steelstandart.com/grade/a106-b/
System: ASTM / ASME | Family: Pipe & tube steel | Standard: ASTM A106 | Verified against: ASTM A106/A106M-19a
Aliases: ASTM A106, A106 Gr B, A106-B, SA-106 Gr B, SA106B, ASME SA-106 Grade B, A106 GR B, K03006, A106 grade A, A106 grade C, A106 pipe, seamless carbon steel pipe, A53 Gr B

ASTM A106 Grade B (ASME SA-106 Gr B) is the seamless carbon steel pipe of refineries, power plants, chemical plants and process piping everywhere ASME B31.1/B31.3 apply: 240 MPa (35 ksi) minimum yield, 415 MPa (60 ksi) tensile, killed steel with a silicon minimum, intended for high-temperature service (ASME allowables run to 538 °C, practical use to about 425 °C). UNS K03006. Grade A is the softer version for bending and cold-forming, Grade C the stronger one (275/485 MPa) for higher pressure.

The specification is often confused with A53 Grade B, which has identical strength: the differences are that A106 is seamless only, must be fully killed (Si ≥ 0.10 %), has tighter chemistry with residual limits, and requires hydrostatic and NDE testing suited to pressure work. In practice most seamless pipe from NPS 1/2 to 24 is triple-stencilled A106 B / A53 B / API 5L B because it meets all three. Wall schedules follow ASME B36.10M (Sch 40, 80, 160, XXS…), and the pipe is supplied hot-finished (or cold-drawn in small sizes) with bevelled ends for butt welding.

For temperatures below −29 °C, A333 Grade 6 (same strength, Charpy-tested at −45 °C) replaces it; above 425 °C the Cr-Mo grades A335 P11/P22. European P235GH/P265GH (EN 10216-2), JIS STPG370/STPT410, GB 20/20G and GOST 20 are the near matches.

Chemical composition (mass %): C ≤ 0.3 (Grade A: 0.25; Grade B: 0.30; Grade C: 0.35); Mn 0.29 – 1.06 (Grade A: 0.27–0.93; Grade B: 0.29–1.06; Grade C: 0.29–1.06); P ≤ 0.035; S ≤ 0.035; Si ≥ 0.1; Cr ≤ 0.4 (Cr + Cu + Mo + Ni + V ≤ 1.00 (Grade B/C)); Cu ≤ 0.4; Mo ≤ 0.15; Ni ≤ 0.4; V ≤ 0.08
ASTM A106/A106M-19a Table 1. Killed steel (Si ≥ 0.10 %) — the essential difference from A53 (which may be semi-killed). For each 0.01 % C below 0.30, Mn may rise 0.06 % to a maximum of 1.35 % (Grade B/C).

Mechanical properties:
- Grade A: yield 205 MPa; tensile ≥ 330 MPa; elongation 35 (L) / 25 (T), ≥ 8 mm wall %; hardness —
- Grade B (standard): yield 240 MPa; tensile ≥ 415 MPa; elongation 30 (L) / 16.5 (T), ≥ 8 mm wall %; hardness ≈ 130–170 HB (typ.)
- Grade C: yield 275 MPa; tensile ≥ 485 MPa; elongation 30 (L) / 16.5 (T) %; hardness —
- Grade B — typical mill certificate: yield ≈ 280–340 MPa; tensile ≈ 450–520 MPa; elongation ≈ 35–45 (L) %; hardness ≈ 140–160 HB
- Grade B — ASME II-D allowable stress at 20–400 °C: yield S = 118 MPa (17.1 ksi) MPa; tensile — MPa; elongation — %; hardness —
- Grade B — allowable stress at 425 °C (800 °F): yield S ≈ 91 MPa (13.2 ksi) MPa; tensile — MPa; elongation — %; hardness —
ASTM A106/A106M-19a Table 2; elongation in 50 mm longitudinal (L) and transverse (T), reduced for thinner walls by the A106 formula. Bend and flattening tests are required; hydrostatic test to ASME B31.3 / A106 §17. No Charpy unless S5 ordered (ASME B31.3 requires impact tests below −29 °C).
Impact: 18 J at -29 °C (typical, seamless Grade B ≤ 12 mm wall; not required by default)

Equivalents:
- A53 Gr. B (Type S) (ASTM / ASME) — near: Same 240/415 MPa; A53 may be semi-killed and is intended for general (not high-temperature) service; most seamless pipe is dual-certified A106-B/A53-B.
- API 5L Gr. B (ASTM / ASME) — near: Line pipe: yield 241 MPa (35 ksi), tensile 414 MPa (60 ksi); PSL1/PSL2 with different testing; often triple-certified.
- A333 Grade 6 (ASTM / ASME) — near: Same strength as A106-B with guaranteed 18 J (avg 13.5 J) Charpy at −45 °C for low-temperature service; normalized.
- P235GH / P265GH (EN (European)) — near: EN 10216-2 seamless pressure tube: P235GH (yield 235, Rm 360–500) is the usual substitute; P265GH (265 / 410–570) matches A106-B tensile. Both guarantee yield to 400–450 °C.
- P235TR2 / P265TR2 (EN (European)) — near: EN 10216-1 non-alloy tubes for pressure (room temperature) — the A53-type equivalents.
- 20 / 20G (GB/T (China)) — near: GB/T 8163 grade 20 (fluid) and GB/T 5310 20G (boiler): C 0.17–0.24, yield ≥ 245, Rm ≥ 410 MPa.
- 20 / 10 (GOST (Russia/CIS)) — near: GOST 8731/8732 Steel 20 seamless tube: yield ≥ 245, Rm ≥ 412 MPa.
- STPG370 / STPG410 (JIS (Japan)) — near: JIS G3454 STPG370 (Rm ≥ 370, yield ≥ 215) and STPG410 (Rm ≥ 410, yield ≥ 245) — pressure piping to 350 °C; STPT410 (G3456) for high temperature ≈ A106-B.
- A335 P11 / P22 (ASTM / ASME) — functional: Cr-Mo seamless pipe for service above ~425 °C where carbon steel graphitizes.
- IS 1239 / IS 3589 (IS (India)) — functional: Indian ERW pipe specs; IS 1239 Heavy (yield 195–320) is the water/gas pipe; for seamless pressure pipe India uses A106/SA-106 directly.

Superseded names:
- K03006 (Gr B), K02501 (Gr A), K03501 (Gr C) — UNS
- SA-106 — ASME BPVC Section II Part A: ASME adoption; pipe is dual-marked A106/SA-106 and usually also A53 B and API 5L B (triple stencil).
- A53 Grade B — ASTM A53 (Type S): General-service seamless/welded pipe with the same strength; A106 adds killed steel, Si min and high-temperature intent.
- API 5L Grade B — API 5L: Line pipe with the same 241/414 MPa; triple-certified pipe is common.
- St 35.8 / St 45.8 — DIN 17175 (withdrawn): German boiler tube grades now P235GH/P265GH (EN 10216-2).

Product forms: seamless pipe NPS 1/8 to 48 (DN 6–1200), wall schedules per ASME B36.10M (Sch 10–XXS); hot-finished (standard) or cold-drawn (small sizes, closer tolerance); ends: plain, bevelled (30° ±5°), threaded; NOT welded — A106 is seamless only (welded equivalents: A53 Type E/F, A672)
Tolerances: dimensions: ASME B36.10M (OD ±1 % or ±0.4 mm small sizes; wall −12.5 %); hydrostatic test and NDE (eddy current/UT) per A106 §17–18; supplementary: S1–S9 (product analysis, transverse tension, flattening, metal structure, Charpy, etc.)

### A106 Grade B yield strength
Minimum 240 MPa (35 ksi); typical 280–340 MPa. Grade A: 205 MPa (30 ksi); Grade C: 275 MPa (40 ksi).

### A106 Grade B tensile strength
Minimum 415 MPa (60 ksi), no maximum; typical 450–520 MPa. Grade A: ≥ 330 MPa; Grade C: ≥ 485 MPa.

### ASME allowable stress (SA-106 B)
118 MPa (17.1 ksi) from −29 °C to 400 °C; 116 MPa at 425 °C (B31.3 values differ slightly by edition); 85 MPa at 455 °C; creep-governed above ~425 °C; listed to 538 °C (1000 °F). B31.3 exempts from impact testing down to −29 °C for most walls.

### Elongation, hardness, bend
Elongation ≥ 30 % longitudinal / 16.5 % transverse (Grade B, wall ≥ 8 mm; reduced for thinner walls). Hardness not specified; typical 130–170 HB (NACE ≤ 22 HRC easily met). Bend test 180° around 12 × wall (Grade B) without cracking; flattening test per §14.

### Dimensions and pressure rating
OD per ASME B36.10M (NPS 1/8–48); wall tolerance −12.5 %. Working pressure per B31.3: P = 2·S·E·t/(D − 2·Y·t) with S = 118 MPa, E = 1.0 (seamless) — e.g. NPS 4 Sch 40 (114.3 × 6.02 mm, t_min 5.27) ≈ 8.7 MPa (1260 psi) at 400 °C before corrosion allowance.

### Physical properties
Density 7.85 g/cm³, E = 200 GPa (29 × 10⁶ psi) at 20 °C, 186 GPa at 400 °C; expansion 11.7 × 10⁻⁶/K (20–100 °C), 13.9 (20–400 °C); conductivity ≈ 50 W/m·K.

### Heat treatment
Supplied hot-finished (as-rolled) or, for cold-drawn pipe, normalized or stress-relieved (A106 §6: cold-drawn pipe must be heat-treated at ≥ 650 °C). Normalize 870–930 °C if specified. PWHT 595–650 °C required by B31.1/B31.3 above 19 mm wall (P-No. 1) or for specific services.

### Weldability
Excellent weldability (CE ≈ 0.35–0.45): GTAW root (ER70S-2/-6) with SMAW/FCAW fill (E7018 / E71T-1), or full SMAW with E6010 root in pipelines; procedures per ASME IX / B31.3. Preheat 10 °C minimum, 80–95 °C for wall > 25 mm or C > 0.30; PWHT 595–650 °C above 19 mm wall (P-No. 1 Group 1) per B31.3 Table 331.1.1. Bevel 37.5° per B16.25; back-purge not required for carbon steel. Weld to stainless with ER309L; to Cr-Mo with the lower-alloy filler.

### Machining, forming, heat treatment
Threading (NPT per B1.20.1) and grooving (Victaulic) are routine on Sch 40/80; machinability ≈ 65–70 % of B1112. Cold bending: minimum radius 5 D (Grade A) to 6 D (Grade B) without heat; hot bending 900–1050 °C followed by normalizing when required; induction bending common. Flaring and swaging in the annealed state. Cut by saw, abrasive, plasma or oxy-fuel; grind heat-affected edges before welding.

Applications: Refinery and petrochemical process piping (ASME B31.3) to ~425 °C; Power-plant steam and feedwater piping (ASME B31.1), boiler external piping; Steam headers, condensate and hot-oil systems, heat-transfer fluid loops; Pressure-vessel nozzles, manways and long-weld-neck fittings machined from pipe; Hydraulic and pneumatic lines at high pressure (Sch 160 / XXS); Fire-water and utility piping in plants (often A53-B); Structural columns and mechanical tubing where seamless pipe is specified

Q: What is the difference between A106 Grade B and A53 Grade B?
A: Same strength (240 / 415 MPa). A106 is seamless only, fully killed with Si ≥ 0.10 %, has tighter chemistry and residual limits, and is intended for high-temperature pressure service; A53 may be seamless (Type S) or welded (Types E/F), may be semi-killed, and is for general service. Most seamless pipe is dual-certified A106-B/A53-B, so buying A106-B covers both.

Q: What is the maximum temperature for A106 Grade B?
A: ASME lists allowable stresses to 538 °C (1000 °F), but long-term use is limited to about 425 °C (800 °F) because carbon steel graphitizes and loses creep strength above that; Cr-Mo pipe (A335 P11/P22) takes over.

Q: Can A106 Grade B be used at low temperature?
A: ASME B31.3 exempts it from impact testing to −29 °C (−20 °F) for most wall thicknesses. Below that, use A333 Grade 6 (same strength, Charpy-tested at −45 °C) or order A106 with supplementary S5 impact testing.

Q: What is the European equivalent of A106 Grade B?
A: EN 10216-2 P235GH (yield 235, Rm 360–500 MPa) is the usual substitute; P265GH (265 / 410–570 MPa) matches the tensile more closely. Both are seamless pressure tubes with guaranteed elevated-temperature yield. Cross-use in ASME systems requires the pipe to be also certified to SA-106 or accepted by the owner.

Q: What are A106 Grades A, B and C?
A: Grade A: 205 MPa yield / 330 MPa tensile, C ≤ 0.25 % — for bending and cold forming. Grade B: 240 / 415 MPa, C ≤ 0.30 % — the standard. Grade C: 275 / 485 MPa, C ≤ 0.35 % — for higher pressure, less weldable.

Q: Does A106 pipe need PWHT after welding?
A: Per ASME B31.3, P-No. 1 carbon steel needs PWHT at 595–650 °C when the wall exceeds 19 mm (3/4 in), or regardless of thickness for certain services (caustic, amine, wet H₂S, lethal). Below that, no PWHT.

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## A333 Grade 6 [K03006] — Carbon steel pipe for low-temperature service, impact tested at −45 °C
URL: https://steelstandart.com/grade/a333-6/
System: ASTM / ASME | Family: Pipe & tube steel | Standard: ASTM A333 | Verified against: ASTM A333/A333M
Aliases: A333, ASTM A333, ASTM A333 Grade 6, A333 Gr 6, A333 Gr. 6, A333 Grade 6 pipe, ASTM A333/A333M, SA333 Gr 6, ASME SA-333 Grade 6, A333 Grade 1, A333 Grade 3, A333 Grade 6 equivalent, low temperature carbon steel pipe

ASTM A333 Grade 6 is the low-temperature carbon steel pipe, and the way to understand it is to see what it is not offering. Its strength minima — 240 MPa (35 ksi) yield and 415 MPa (60 ksi) tensile — are exactly those of A106 Grade B and A53 Grade B. Its analysis is close to A106's. No one buys A333 Grade 6 for strength.

What the specification adds is a single requirement neither A106 nor A53 contains anywhere: a mandatory Charpy V-notch test at −45 °C (−50 °F), 18 J average of three specimens with 14 J minimum for any one. Carbon steel loses its ductility abruptly somewhere below room temperature, and where that transition happens depends on composition, deoxidation, grain size and heat treatment — none of which an unimpacted specification controls tightly enough to predict. A333 forces it to be measured.

That is why the composition reads the way it does. Silicon has a minimum of 0.10 %, so the steel must be fully killed and fine grained. Manganese has a minimum as well as a maximum, because manganese is the economical way to push the transition temperature down in a plain carbon steel. Phosphorus and sulphur are capped at 0.025 %, half the A53 allowance, because both embrittle. And the pipe is normally normalised, which refines the grain. These are not quality refinements; they are the mechanism by which 18 J at −45 °C becomes achievable.

The specification then ranks its grades by test temperature rather than by strength, which is unusual and is the key to reading it. Grade 1 and Grade 6 are plain carbon steels tested at −45 °C. Grade 7 (2.5 % Ni) goes to −75 °C, Grade 9 (2 % Ni + Cu) to −100 °C, Grade 3 (3.5 % Ni) to −101 °C, and Grade 8 (9 % Ni) to −195 °C for LNG. Nickel is what buys the extra cold, and the price rises steeply with it — which is why Grade 6 is specified wherever −45 °C is enough.

Chemical composition (mass %): C ≤ 0.3; Si ≥ 0.1; Mn 0.29 – 1.06; P ≤ 0.025; S ≤ 0.025
ASTM A333/A333M, Grade 6 (UNS K03006). Note what the limits tell you. **Silicon has a minimum of 0.10 %**, so the steel is fully killed — fine grained and deoxidised, which is what makes toughness at −45 °C achievable at all. Phosphorus and sulphur are capped at 0.025 %, tighter than the 0.05/0.045 of A53, because both embrittle at low temperature. Manganese carries a **minimum** as well as a maximum, since manganese is what lowers the transition temperature in a plain carbon steel.

Mechanical properties:
- Grade 6 — specified minimum: yield 240 MPa; tensile 415 MPa; elongation 30 (longitudinal) %; hardness —
- Grade 1 — specified minimum: yield 205 MPa; tensile 380 MPa; elongation 35 (longitudinal) %; hardness —
- Grade 3 (3.5 % Ni) — specified minimum: yield 240 MPa; tensile 450 MPa; elongation 30 (longitudinal) %; hardness —
- Grade 8 (9 % Ni) — specified minimum: yield 515 MPa; tensile 690 MPa; elongation 22 (longitudinal) %; hardness —
- Grade 6, typical mill result: yield 290–380 MPa; tensile 450–530 MPa; elongation 32–40 %; hardness 130–165 HB
- Hardness ceiling (sour or NACE service, by agreement): yield — MPa; tensile — MPa; elongation — %; hardness ≤ 200 HB where specified
A333 states the minima in ksi: Grade 6 is **35 ksi yield / 60 ksi tensile**, identical to A106 Grade B and A53 Grade B. The room-temperature strength is therefore not what you are buying. What you are buying is the row that neither of those specifications contains — the **mandatory Charpy test**, which is listed separately below because it is the entire purpose of the specification.
Impact: 18 J average of three specimens, 14 J minimum for any one J at −45 °C (−50 °F) °C (Transverse Charpy V-notch, full-size specimens where the wall permits; sub-size specimens are tested with reduced energy requirements in proportion to the specimen thickness, per the standard's table. Specimens are taken from each heat and each heat-treatment lot.)

Equivalents:
- STPL380 (JIS (Japan)) — identical: JIS G3460 STPL380: 215 MPa minimum yield, 380 MPa minimum tensile, carbon steel pipe for low-temperature service impact tested at −45 °C. The Japanese counterpart to Grade 6, marginally lower in strength. STPL450 and STPL690 correspond to the nickel grades.
- A106 Grade B (ASTM / ASME) — near: Identical minima — 240 MPa yield, 415 MPa tensile — and a very similar analysis including the 0.10 % silicon minimum. The difference is the one that matters here: **A106 requires no impact test**, so it carries no documented toughness at any temperature. A333 Grade 6 is, in effect, A106 Grade B with a mandatory Charpy test at −45 °C and tighter phosphorus and sulphur.
- P275NL1 (EN (European)) — near: EN 10216-4 P275NL1: 275 MPa minimum yield, normalised seamless tube for low-temperature service, impact tested at −40 °C; P275NL2 is tested at −50 °C. Slightly stronger than Grade 6 with a comparable toughness requirement — the direct European counterpart for carbon-steel cryogenic-adjacent piping.
- 316L (AISI / SAE) — functional: Austenitic stainless steel has no ductile-to-brittle transition, so it needs no impact test at cryogenic temperature and is often the alternative to a nickel steel below about −100 °C. It costs several times more and has a much higher thermal expansion.
- A53 Grade B (ASTM / ASME) — functional: ASTM A53 Grade B: the same strength again, but with no silicon minimum, looser phosphorus and sulphur and no impact test. It is the general-service pipe at this strength level and has no place in low-temperature work.
- A516 Grade 70 (ASTM / ASME) — functional: The low-temperature plate counterpart. A516 Grade 70 plate and A333 Grade 6 pipe are the pair normally used together in a cold vessel and its piping — the plate at 260 MPa yield and 485–620 MPa tensile, impact tested when ordered to supplementary requirement S5 or to the vessel code's curves.
- A333 Grade 3 (ASTM / ASME) — functional: 3.5 % nickel, 450 MPa tensile, impact tested at −101 °C. The grade to move to when −45 °C is not cold enough; Grade 7 (2.5 % Ni, −75 °C) and Grade 9 (2 % Ni + Cu, −100 °C) sit between.
- A333 Grade 8 (ASTM / ASME) — functional: 9 % nickel, 515 MPa yield, impact tested at **−195 °C** — the LNG grade. A different class of steel entirely, quenched and tempered, far more expensive, and welded with nickel-base consumables.

Superseded names:
- ASME SA-333 Grade 6 — ASME BPVC Section II Part A: Not a different material — the ASME adoption of the same specification, for use inside the Boiler and Pressure Vessel Code. Pipe is commonly dual-marked A333/SA-333.
- A333 Grade 2 / Grade 5 — ASTM A333, earlier editions: Withdrawn grades; Grades 1, 3, 4, 6, 7, 8, 9, 10 and 11 remain.
- StE 255 / TTSt 35N — DIN 17173 (withdrawn): The German low-temperature pipe grades, replaced by EN 10216-4.

Product forms: seamless pipe; electric-resistance-welded pipe; double submerged-arc welded pipe in larger sizes; normalised, or as agreed heat treated to meet the impact requirement
Tolerances: diameter and wall: ASTM A333/A333M, wall schedules to ASME B36.10M; every length hydrostatically tested, or non-destructively inspected by agreement; impact test specimens taken from each heat and heat-treatment lot — the lot definition is part of the specification

### A333 Grade 6 strength
240 MPa (35 ksi) minimum yield, 415 MPa (60 ksi) minimum tensile, 30 % minimum elongation longitudinal. Typical mill results are 290–380 MPa yield and 450–530 MPa tensile. The figures are identical to A106 Grade B, which is the point: the grade exists for its toughness, not its strength, and substituting it for A106 gains nothing in a hot or ambient line.

### The −45 °C impact requirement
18 J average of three transverse Charpy V-notch specimens at −45 °C, with 14 J minimum for any single specimen. Where the wall is too thin for full-size specimens, sub-size specimens are used and the required energy is reduced in proportion, per the standard's table — a 7.5 mm specimen is held to three quarters of the energy, and so on. Specimens are drawn from each heat and each heat-treatment lot, so the toughness is verified on the material supplied rather than inferred from the grade.

### Why carbon steel needs this and stainless does not
Ferritic and pearlitic steels have a ductile-to-brittle transition: below a certain temperature a crack propagates by cleavage with almost no energy absorbed, so a pipe that is perfectly ductile at +20 °C can shatter at −30 °C. The transition temperature is not a property of the grade name — it moves with grain size, deoxidation, phosphorus, and the normalising cycle. Austenitic stainless steels and aluminium have a face-centred cubic structure and no transition at all, which is why 316L needs no impact test at cryogenic temperature and why it is the alternative below about −100 °C where a nickel steel becomes expensive.

### Grade ladder by test temperature
This is how the specification is actually navigated. Grade 1 — carbon steel, 380 MPa tensile, −45 °C. Grade 6 — carbon steel, 415 MPa tensile, −45 °C; the default. Grade 7 — 2.5 % Ni, −75 °C. Grade 9 — 2 % Ni + Cu, −100 °C. Grade 3 — 3.5 % Ni, 450 MPa tensile, −101 °C. Grade 8 — 9 % Ni, 690 MPa tensile, −195 °C, quenched and tempered, for LNG. Grades 4, 10 and 11 are alloy grades for particular duties. Choose by the minimum design metal temperature, then check the strength.

### Heat treatment and grain size
Grade 6 is normally supplied normalised — austenitised around 900 °C and air cooled — because the resulting fine, uniform ferrite-pearlite grain is what delivers the impact energy. Welded pipe is heat treated after welding so that the weld and the heat-affected zone meet the same requirement as the body. The standard permits other treatments provided the impact test is met, which puts the burden on the result rather than the route. Post-weld heat treatment on site at 595–650 °C is common on heavy wall and is required by the piping code in some thicknesses.

### Where it is used and what it replaces
Any carbon-steel line whose minimum design metal temperature falls below the exemption curve of the piping code: LPG and ethylene handling, ammonia refrigeration, cryogenic plant utility lines, cold-climate gas processing, offshore blowdown and depressurisation systems. The practical rule in ASME B31.3 terms is that where a material's MDMT cannot be exempted by curve or by thickness, an impact-tested material is required — and A333 Grade 6 is the cheapest pipe that supplies that documentation at this strength level.

### Weldability
Readily weldable with the same consumables and procedures as A106 Grade B — E7018 or ER70S-2/ER70S-6 — but with one addition that governs everything: the weld and heat-affected zone must also meet the impact requirement, so the welding procedure has to be qualified with Charpy testing at −45 °C and not merely for soundness. Low-hydrogen processes, controlled heat input and controlled interpass temperature matter because excessive heat input coarsens the heat-affected-zone grain and destroys the toughness the pipe was bought for. Preheat 100–150 °C for heavy wall or restrained joints; post-weld heat treatment at 595–650 °C where the code requires it for thickness. For Grade 8 (9 % Ni), nickel-base consumables are used instead and the rules are entirely different.

### Machining, forming, heat treatment
Machines and threads like any 0.30 % carbon pipe steel, roughly 70 % relative to 1 % C free-cutting steel. End preparation, bevelling and cutting are as for A106. The cautions are about heat and cold work rather than cutting: avoid heavy local cold working, flattening or hard hammering on the pipe, since cold work raises the transition temperature and can push the material above its rated test temperature; and avoid uncontrolled flame heating for bending or straightening, which coarsens the grain. Hot bending at 850–950 °C followed by re-normalising and re-testing is the correct route where a tight bend is needed.

Applications: LPG, ethylene and propylene piping; Ammonia and industrial refrigeration systems; Cryogenic plant utility and process lines above −45 °C; Cold-climate gas gathering and processing piping; Offshore blowdown, flare and depressurisation lines; Low-temperature heat exchanger and vessel nozzles; Any carbon-steel line whose minimum design metal temperature falls below the code exemption curve

Q: What is the difference between A333 Grade 6 and A106 Grade B?
A: The strengths are identical — 240 MPa yield, 415 MPa tensile — and the analyses are close, both requiring at least 0.10 % silicon. A333 Grade 6 adds a mandatory Charpy V-notch test at −45 °C (18 J average of three, 14 J minimum) and caps phosphorus and sulphur at 0.025 % instead of 0.035 and 0.035. A106 requires no impact test at all, so it carries no documented toughness at low temperature. A333 Grade 6 is essentially A106 Grade B with the toughness proven.

Q: What temperature is A333 Grade 6 rated to?
A: It is impact tested at −45 °C (−50 °F), and that test temperature is what the piping code uses to establish the minimum design metal temperature. It is not a hard physical limit — the code may permit lower temperatures with additional testing, or require higher ones in heavy wall — but −45 °C is the figure the specification certifies.

Q: What are the grades of A333?
A: Grades 1 and 6 are plain carbon steels impact tested at −45 °C, Grade 6 being stronger at 415 MPa tensile. Grade 7 is 2.5 % nickel tested at −75 °C, Grade 9 is 2 % nickel with copper at −100 °C, Grade 3 is 3.5 % nickel at −101 °C, and Grade 8 is 9 % nickel at −195 °C for LNG service. Grades 4, 10 and 11 are alloy grades for specific duties. The grades are ranked by test temperature rather than by strength.

Q: Is SA-333 Grade 6 the same as A333 Grade 6?
A: Yes. SA-333 is the ASME adoption of the ASTM specification, published in Boiler and Pressure Vessel Code Section II Part A for use with the ASME codes. The requirements are the same and pipe is routinely dual-marked A333/SA-333. Which marking is needed depends on whether the design code is ASME or not.

Q: Why does low-temperature pipe need a silicon minimum?
A: Because the silicon is there to kill the steel — to deoxidise it fully so that it solidifies without blowholes and with a fine, uniform grain. Grain size is one of the strongest influences on the ductile-to-brittle transition temperature, so a rimmed or semi-killed steel cannot reliably pass an 18 J test at −45 °C. A53, which has no silicon requirement, gives no assurance on this point.

Q: What is the European equivalent of A333 Grade 6?
A: EN 10216-4 P275NL1, impact tested at −40 °C, or P275NL2 at −50 °C, for seamless tube; the welded counterparts are in EN 10217-6. Both are a little stronger than Grade 6 at 275 MPa minimum yield. JIS G3460 STPL380 is the Japanese equivalent, tested at the same −45 °C with slightly lower strength.

Q: Can A333 Grade 6 be substituted for A106 Grade B?
A: Technically it meets or exceeds every A106 Grade B requirement except that A106 has its own elevated-temperature allowable stresses, so an upward substitution needs the design code's agreement rather than being automatic. More to the point it is pointless: A333 Grade 6 costs more and the extra you are paying for is low-temperature toughness, which a hot or ambient line does not use.

Q: Does the welding procedure need impact testing too?
A: Yes, and this is the step most often missed. The weld metal and the heat-affected zone must meet the same impact requirement as the pipe body, so the procedure has to be qualified with Charpy specimens at −45 °C — not merely for soundness and strength. Excessive heat input coarsens the heat-affected-zone grain and will fail that test even when the pipe itself is perfectly good.

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## A36 [K02600] — Carbon structural steel
URL: https://steelstandart.com/grade/a36/
System: ASTM / ASME | Family: Structural steel | Standard: ASTM A36 | Verified against: ASTM A36/A36M-19
Aliases: ASTM A36, A36 steel, ASTM A36 steel, A36 plate, A36 mild steel, SA-36, ASME SA36, K02600, A36 structural steel, A36 carbon steel, grade 36

ASTM A36 is the default structural carbon steel of North America: 250 MPa (36 ksi) minimum yield and 400–550 MPa (58–80 ksi) tensile for plate, shapes and bar, UNS K02600. Introduced in 1960 to replace A7, it defines what American engineers mean by 'mild steel' — cheap, ductile (20 % elongation in 200 mm), easily welded, bent and machined, and available from every service center as plate, angle, channel, flat and round. Chemistry is deliberately loose (carbon up to 0.25–0.29 % depending on thickness, no carbon-equivalent limit) because the specification guarantees mechanical properties rather than composition.

Since the late 1990s W-shapes (wide-flange beams) are almost exclusively rolled to A992 (345 MPa), and A572 Grade 50 has taken over much of the plate market where weight matters, so A36 today lives in plate up to 25 mm, angles, channels, bars, base plates, stiffeners and general fabrication. Bridge work uses A709 Grade 36, which adds Charpy zones; pressure vessels use A516, not A36.

The European counterpart is S235JR (weaker) or S275JR (stronger); JIS SS400, GB Q235B, GOST St3sp and IS 2062 E250 are the near or identical matches listed below. Note that A36 is not a bar grade like 1018: it specifies strength, 1018 specifies chemistry.

Chemical composition (mass %): C ≤ 0.25 (plate ≤ 20 mm: 0.25; 20–40 mm: 0.25; 40–65 mm: 0.26; 65–100 mm: 0.27; > 100 mm: 0.29. Shapes: 0.26; bar: 0.26–0.29 by size); Mn ≤ 1.2 (plate > 20 mm: 0.80–1.20; ≤ 20 mm and shapes: not specified (typ. 0.60–0.90); bar: 0.60–0.90 above 20 mm); P ≤ 0.03; S ≤ 0.03; Si ≤ 0.4 (plate > 40 mm: 0.15–0.40; ≤ 40 mm: 0.40 max; shapes: 0.40 max); Cu ≥ 0.2 (when copper steel is specified (atmospheric corrosion resistance))
ASTM A36/A36M-19 Table 2; limits vary with product and thickness (values shown are the most common). A36 is a 'loose' specification: no CE limit, no grain-size or impact requirement unless supplementary requirements are ordered.

Mechanical properties:
- Plate, shapes, bar ≤ 200 mm (8 in): yield 250 MPa; tensile 400–550 MPa; elongation 20 (L0 = 200 mm) / 23 (L0 = 50 mm) %; hardness ≈ 119–159 HB (typ.)
- Plate > 200 mm (8 in): yield 220 MPa; tensile 400–550 MPa; elongation 20 / 23 %; hardness —
- Shapes > 634 kg/m (426 lb/ft) — heavy: yield 250 MPa; tensile ≥ 400 (no max) MPa; elongation 19 / 22 %; hardness —
- Typical mill certificate (plate 6–25 mm): yield ≈ 280–340 MPa; tensile ≈ 450–500 MPa; elongation ≈ 28–34 %; hardness ≈ 130–150 HB
ASTM A36/A36M-19 Table 3; yield is a minimum (no maximum), tensile a range; elongation in 200 mm (8 in) or 50 mm (2 in). Yield-to-tensile ratio typically 0.65–0.75. Charpy not required — order supplementary S5 (Charpy) or use A709 for impact-critical work.
Impact: 27 J at 20 °C (typical only; not a standard requirement)

Equivalents:
- IS 2062 E250 A (IS (India)) — identical: IS 2062 E250 (Fe 410): yield 250 MPa, Rm 410 MPa min, C ≤ 0.23 — the Indian A36.
- A283 Gr. C / D (ASTM / ASME) — near: Lower-strength plate (205 / 230 MPa yield) for tanks and non-critical structures; Grade D is near A36.
- A1011 CS / SS Gr 36 (ASTM / ASME) — near: Hot-rolled sheet/strip < 6 mm; SS Grade 36 has the same 250 MPa yield in sheet form.
- 43A / S275 (BS (superseded British)) — near: BS 4360 43A (withdrawn; 275 MPa yield) was the historical UK match; today S275JR.
- St37-2 (DIN (superseded German)) — near: Yield 250 MPa, Rm 400–550 MPa — slightly stronger; the usual US substitute on St37 drawings.
- S235JR (EN (European)) — near: Yield 235 MPa (≤ 16 mm), Rm 360–510 MPa, 27 J at +20 °C guaranteed; slightly weaker than A36 but with impact toughness. S275JR (275 MPa) exceeds A36 on yield.
- S235J0 (EN (European)) — near: A36 has a higher yield (250 MPa) and no Charpy requirement at all, so it does not substitute where the 0 °C toughness is the reason for the specification.
- Q235 (GB/T (China)) — near: GB/T 700 Q235B: yield 235 MPa, Rm 370–500 MPa, 27 J at +20 °C. Q255/Q275 are stronger.
- Q235 (GB/T (China)) — near: A36 yield is 250 MPa with no impact requirement; close on strength, different on quality class.
- St3sp (GOST (Russia/CIS)) — near: GOST 380 St3sp: yield 245 MPa (≤ 20 mm), Rm 370–480 MPa.
- E250 (IS (India)) — near: A36 is 250 MPa yield and 400–550 MPa tensile: the same yield, a slightly lower tensile floor and a ceiling that E250 does not have.
- SS400 (JIS (Japan)) — near: JIS G3101 SS400: yield 245 MPa (≤ 16 mm), Rm 400–510 MPa — the closest Asian match; no chemistry beyond P/S limits.
- 1018 / 1020 (AISI / SAE) — functional: Bar grades with defined chemistry and no guaranteed yield — what buyers receive for 'A36 round bar' is often 1018/1020 hot-rolled.
- 1018 (AISI / SAE) — functional: Structural plate/shape with guaranteed 250 MPa yield — the alternative for welded structures; 1018 is a bar product with no guaranteed properties.
- A572 Grade 50 (ASTM / ASME) — functional: HSLA 345 MPa yield — the upgrade for weight-critical shapes; A992 for W-shapes.
- A516 Grade 70 (ASTM / ASME) — functional: Structural plate without pressure-vessel quality (grain size, testing, chemistry control) — not accepted for ASME pressure parts except by special provisions.
- A53 Grade B (ASTM / ASME) — functional: The structural plate and shape specification at 250 MPa yield. Relevant because A53 Grade B pipe is widely used as a structural member — but structural pipe is properly specified to ASTM A500 or A501, not to A53, and the allowable stresses differ.
- A572 Grade 50 (ASTM / ASME) — functional: 250 MPa carbon steel — the grade A572-50 replaces when weight matters.
- S275JR (EN (European)) — functional: A36 yield 250 MPa is below 275 MPa; A36 is not a drop-in replacement where the design used fy = 275.

Superseded names:
- A7 — ASTM A7 (withdrawn 1967): The predecessor structural steel (33 ksi / 230 MPa yield); A36 replaced it in 1960.
- K02600 — UNS
- SA-36 — ASME BPVC Section II: ASME adoption for non-pressure and limited pressure use (e.g. structural attachments, some vessels to 340 °C).
- Grade 36 — AASHTO M270 / ASTM A709: A709 Grade 36 is the bridge version (with Charpy zones).
- CSA G40.21 300W — Canada: Canadian equivalent (300 MPa yield, slightly stronger).

Product forms: plate (all thicknesses; yield drops to 220 MPa above 200 mm); shapes: W, S, M, C, L, HP sections (A36 largely replaced by A992 for W-shapes since ~2000); bar: flats, rounds, squares (hot-rolled merchant bar); sheet piling is A328; hollow sections are A500, not A36
Tolerances: plate: ASTM A6/A6M (thickness, flatness, camber); shapes and bar: ASTM A6/A6M; surface: A6 (mill scale as-rolled unless pickled/blasted)

### A36 yield strength
Minimum 250 MPa (36 ksi) for plate ≤ 200 mm, shapes and bar; 220 MPa (32 ksi) for plate over 200 mm. Typical mill values 280–340 MPa (40–49 ksi); no maximum is specified.

### A36 tensile strength
400–550 MPa (58–80 ksi); typical 450–500 MPa. Heavy shapes (> 634 kg/m) have no upper limit.

### A36 elongation
≥ 20 % in 200 mm (8 in) or ≥ 23 % in 50 mm (2 in); typical 28–34 % in 50 mm.

### A36 hardness
Not specified; typical 119–159 HB (≈ 67–85 HRB) as rolled. Cannot be usefully hardened (C ≤ 0.25 %); flame-cut edges may reach 250–300 HV locally.

### A36 density and modulus
Density 7.85 g/cm³ (0.284 lb/in³), E = 200 GPa (29 × 10⁶ psi), G = 77 GPa, Poisson 0.26–0.30, thermal expansion 11.7 × 10⁻⁶/K (6.5 × 10⁻⁶/°F), conductivity ≈ 50 W/m·K. AISC design values: Fy = 36 ksi, Fu = 58 ksi.

### A36 weldability
Excellent — CE typically 0.30–0.40; prewelded with E70XX/ER70S-6 without preheat up to about 40 mm (AWS D1.1 Table 3.3: no preheat ≤ 19 mm, 10 °C to 38 mm, 65 °C to 64 mm, 110 °C above).

### Weldability
One of the most weldable structural steels: SMAW E7018/E6010, GMAW ER70S-6, FCAW E71T-1, SAW F7A2-EM12K, all matching AWS D1.1 prequalified procedures. Preheat per AWS D1.1 Table 3.3 by thickness (none ≤ 19 mm). No PWHT for structural work; ASME SA-36 vessels may require stress relief per code thickness. Heavy plate (> 50 mm) with carbon near 0.27–0.29 % benefits from 65–110 °C preheat and low-hydrogen electrodes.

### Machining, forming, heat treatment
Machinability ≈ 72 % of B1112 (hot-rolled) — gummy like other low-carbon steels; use positive rake and chip breakers. Flame, plasma, laser and waterjet cutting are routine; shearing to 25 mm; punching to ~19 mm. Cold bending: inside radius ≥ 1.5 t transverse per AISC guidance (1 t for thin plate); hot forming 900–1100 °C. Galvanizes well (check Si + 2.5 P for Sandelin effect on bright coatings); paints readily after blast cleaning (SSPC-SP6/SP10).

Applications: Building and industrial steelwork: angles, channels, base plates, stiffeners, gussets, connection plates; General fabrication: frames, skids, tanks (non-pressure), hoppers, chutes, guards; Machinery bases, weldments, jigs and fixtures; Bridge components as A709 Grade 36 (with Charpy); Bar stock for brackets, anchor bolts (A307 uses A36-type steel), tie rods; Cold-formed light-gauge components (as A1011 SS36 in sheet); Ship structure secondary members (ABS Grade A is the marine equivalent)

Q: What is the yield strength of A36 steel?
A: 250 MPa (36 ksi) minimum for plate up to 200 mm thick, shapes and bar; 220 MPa (32 ksi) for plate over 200 mm. Typical mill certificates show 280–340 MPa.

Q: What is the difference between A36 and A572 Grade 50?
A: Yield: 250 vs 345 MPa (36 vs 50 ksi). A572-50 is an HSLA steel micro-alloyed with Nb/V; it saves about 25–30 % weight in strength-governed members at a small cost premium. A36 is more ductile and slightly easier to form. W-shapes today are A992 (a 50 ksi grade), so A36 is mostly plate, angle, channel and bar.

Q: Is A36 the same as 1018?
A: No. A36 is an ASTM structural spec guaranteeing 250 MPa yield with loose chemistry; 1018 is an AISI chemistry grade (0.15–0.20 % C) with no guaranteed properties, usually sold cold-drawn at ≈ 370 MPa yield. Hot-rolled 1018 and A36 behave similarly, but they are ordered and certified differently.

Q: What is the European equivalent of A36?
A: S235JR (EN 10025-2) is the usual cross-reference — slightly weaker (235 MPa yield) but with guaranteed 27 J impact at +20 °C. Where the design needs A36's 250 MPa, S275JR is the safe substitute.

Q: Can A36 be heat treated or hardened?
A: No practical hardening — carbon is too low (≤ 0.25–0.29 %). It can be normalized (900–930 °C) to refine grain after heavy hot work, and stress-relieved at 600–650 °C, but it is used as-rolled.

Q: Is A36 magnetic?
A: Yes — like all plain carbon steels it is ferromagnetic.

Q: What is the hardness of A36?
A: About 119–159 HB (67–85 HRB) as rolled; ASTM A36 does not specify hardness.

---

## A516 Grade 70 [K02700] — Carbon steel plate for pressure vessels, moderate and lower temperature
URL: https://steelstandart.com/grade/a516-70/
System: ASTM / ASME | Family: Pressure vessel steel | Standard: ASTM A516 | Verified against: ASTM A516/A516M-17
Aliases: ASTM A516, A516 Gr 70, A516-70, SA-516 Gr 70, SA516-70, ASME SA-516 Grade 70, A516 GR70, K02700, A516 grade 60, A516 grade 65, A516 grade 55, pressure vessel plate, boiler plate

ASTM A516 Grade 70 (ASME SA-516-70) is the plate that most of the world's carbon-steel pressure vessels are made from: a killed, fine-grain carbon-manganese steel with 260 MPa (38 ksi) minimum yield and 485–620 MPa (70–90 ksi) tensile, UNS K02700. A516 covers Grades 55, 60, 65 and 70 (numbers = minimum tensile in ksi); Grade 70 is the default because its ASME allowable stress of 138 MPa (20 ksi) gives the thinnest wall for the money.

The title says 'moderate and lower temperature service': fine-grain aluminium-killed practice and normalizing (mandatory above 40 mm, optional but usual below) give the toughness that lets normalized Grade 70 certify Charpy values at −45 °C and below — hence its use in LPG bullets and spheres, air receivers, refinery drums, heat-exchanger shells and channels, storage vessels and cold-climate equipment. A515 is the coarse-grain sister for higher temperature; A537 the normalized upgrade for 345 MPa; A285 the low-pressure economy grade.

Sour and hydrogen service is handled by ordering HIC-resistant A516-70 (S ≤ 0.002 %, Ca-treated, NACE TM0284 tested) — a large share of refinery orders. European P295GH/P265GH, Chinese Q345R/Q245R and JIS SB450/SPV315 are the near matches; none is identical, so cross-supplied plate needs code appraisal.

Chemical composition (mass %): C ≤ 0.27 (Grade 70: ≤ 12.5 mm 0.27; 12.5–50 mm 0.28; 50–100 mm 0.30; 100–200 mm 0.31. Grade 60: 0.21–0.25; Grade 65: 0.24–0.29; Grade 55: 0.18–0.26); Mn 0.85 – 1.2 (Grade 70 plate > 12.5 mm: 0.85–1.20 (heat), 0.79–1.30 (product); ≤ 12.5 mm: 0.60–0.90); P ≤ 0.025; S ≤ 0.025 (HIC-resistant orders: S ≤ 0.002–0.005, Ca treated); Si 0.15 – 0.4
ASTM A516/A516M-17 Table 1 (heat analysis). Residuals per A20 (Cu ≤ 0.40, Ni ≤ 0.40, Cr ≤ 0.30, Mo ≤ 0.12, V ≤ 0.03, Nb ≤ 0.02 when not specified). Killed, fine-grain practice (Al) is mandatory — grain size 5 or finer.

Mechanical properties:
- Grade 70 — all thicknesses (as-rolled ≤ 40 mm; normalized > 40 mm): yield 260 MPa; tensile 485–620 MPa; elongation 17 (L0 200 mm) / 21 (50 mm) %; hardness ≈ 140–180 HB (typ.)
- Grade 65: yield 240 MPa; tensile 450–585 MPa; elongation 19 / 23 %; hardness —
- Grade 60: yield 220 MPa; tensile 415–550 MPa; elongation 21 / 25 %; hardness —
- Grade 55: yield 205 MPa; tensile 380–515 MPa; elongation 23 / 27 %; hardness —
- Grade 70 — typical mill certificate, normalized 25 mm: yield ≈ 300–340 MPa; tensile ≈ 520–560 MPa; elongation ≈ 28–32 (50 mm) %; hardness ≈ 150–165 HB
- Grade 70 — ASME II-D allowable stress at 20–340 °C: yield S = 138 MPa (20 ksi) MPa; tensile — MPa; elongation — %; hardness —
- Grade 70 — allowable stress at 425 °C (800 °F): yield S ≈ 100 MPa (14.5 ksi) MPa; tensile — MPa; elongation — %; hardness —
ASTM A516/A516M-17 Table 2; elongation in 200 mm or 50 mm. Yield is a minimum, tensile a range. Charpy is not mandatory in A516 but is required by ASME VIII (UCS-66) below the exemption curve — order S5 with test temperature; normalized Grade 70 typically gives 27 J at −45 °C or lower.
Impact: 27 J at -45 °C (typical, normalized ≤ 50 mm; not a default requirement)

Equivalents:
- A516 Gr. 60 (ASTM / ASME) — near: Same spec, lower strength (220 MPa / 415–550 MPa); chosen for better toughness and formability.
- A537 Cl. 1 (ASTM / ASME) — near: Normalized C-Mn-Si plate, yield 345 MPa — the upgrade when A516-70 is not strong enough.
- P295GH (EN (European)) — near: EN 10028-2 P295GH (1.0481, ex 17Mn4): yield 295 MPa, Rm 460–580 MPa, guaranteed yield to 400 °C — strength closest to A516-70; chemistry C ≤ 0.08–0.20 lower.
- P265GH (EN (European)) — near: Yield 265 MPa, Rm 410–530 MPa — the EN grade most often substituted for A516-60/65; slightly weaker than Grade 70.
- P355GH / P355NH (EN (European)) — near: 355 MPa grades exceed A516-70 yield; used when a European mill supplies a Grade 70 design.
- Q345R (GB/T (China)) — near: GB/T 713 Q345R: yield 345 MPa, Rm 510–640 MPa, 31 J at 0 °C — the Chinese pressure plate normally offered for A516-70 (stronger); Q245R ≈ A516-60.
- 16GS / 17GS / 20K (GOST (Russia/CIS)) — near: GOST 5520 boiler plates: 16GS (yield 265–295, Rm 460–490), 17GS (345 / 490), 20K (245 / 410).
- IS 2002 Gr. 2 / Gr. 3 (IS (India)) — near: IS 2002 grade 2 (yield 240, Rm 410–530) and 3 (yield 290, Rm 490–610).
- SB450 / SPV315 (JIS (Japan)) — near: JIS G3103 SB450 boiler plate (yield 245, Rm 450–590) and G3115 SPV315 (yield 315, Rm 490–610) bracket A516-70.
- A36 (ASTM / ASME) — functional: Structural plate without pressure-vessel quality (grain size, testing, chemistry control) — not accepted for ASME pressure parts except by special provisions.

Superseded names:
- K02700 (Gr 70), K02403 (Gr 60), K02800 (Gr 65), K01800 (Gr 55) — UNS
- SA-516 — ASME BPVC Section II Part A: ASME adoption — identical to A516 with ASME editorial changes; the form used on vessel drawings.
- A515 — ASTM A515: Sister spec for intermediate/higher temperature (coarse-grain Si-killed); A516 replaced it for most work.
- A285 Gr. C — ASTM A285: Lower-strength, lower-quality vessel plate for low-pressure tanks.
- BS 1501-224 Gr 490 — BS 1501 (withdrawn): British counterpart.

Product forms: plate (only) — as-rolled ≤ 40 mm, normalized > 40 mm (or when specified); heads, shells and nozzles cut from plate; clad plate base (A263/A264/A265); HIC-resistant and NACE-tested variants (supplementary S-requirements, low S/P, Ca treatment)
Tolerances: plate: ASTM A20/A20M (thickness, flatness, UT per A435/A578 when ordered); surface: A20; edges per A20

### A516 Grade 70 yield strength
Minimum 260 MPa (38 ksi) for all thicknesses; typical normalized plate 300–340 MPa. Grade 65: 240 MPa; Grade 60: 220 MPa; Grade 55: 205 MPa.

### A516 Grade 70 tensile strength
485–620 MPa (70–90 ksi); typical 520–560 MPa. Grade 65: 450–585; Grade 60: 415–550; Grade 55: 380–515 MPa.

### ASME allowable stress
SA-516-70: 138 MPa (20.0 ksi) from −29 to 340 °C, 131 MPa at 370 °C, 118 MPa at 400 °C, ≈ 100 MPa at 425 °C; maximum code temperature 538 °C (1000 °F) with reduced allowables (creep range above ~400 °C). Not for prolonged use above 425 °C (graphitization).

### Elongation and hardness
≥ 17 % in 200 mm / ≥ 21 % in 50 mm (typical 28–32 %). Hardness not specified; typical 140–180 HB. NACE MR0175 (≤ 22 HRC / 237 HB) is met by base metal; weld HAZ must be controlled by PWHT.

### Impact toughness
Not mandatory, but ASME VIII UCS-66 exempts normalized A516 (curve D) to lower MDMTs than as-rolled (curve B); normalized Grade 70 typically gives ≥ 27 J at −45 °C for ≤ 50 mm. Order supplementary S5 with the required temperature and energy (e.g. 20 J at −46 °C for LPG).

### Heat treatment
Normalize 870–930 °C (1600–1700 °F), air cool — mandatory > 40 mm, and above 25 mm when Charpy is required. Stress relief / PWHT 595–650 °C (1100–1200 °F), 1 h per 25 mm — required by ASME VIII above 38 mm (32 mm without preheat) and for lethal, sour and caustic service regardless of thickness.

### Physical properties
Density 7.85 g/cm³, E = 200 GPa, expansion 11.7 × 10⁻⁶/K (6.5 × 10⁻⁶/°F), conductivity ≈ 50 W/m·K.

### Weldability
Very good weldability (CE ≈ 0.40–0.45 for Grade 70; supplementary S-requirements can cap it). ASME IX-qualified procedures with E7018 / ER70S-6 / F7A2-EM12K; preheat 10 °C ≤ 25 mm, 80 °C to 38 mm, 95–120 °C above (ASME VIII UCS-56 / typical fabricator practice). PWHT 595–650 °C required by code above 38 mm and for wet H₂S, amine, caustic and lethal service. Low-hydrogen practice mandatory for HIC-resistant material; limit HAZ hardness to 248 HV for sour service.

### Machining, forming, heat treatment
Machinability ≈ 65–70 % of B1112 — drilling and boring of nozzles, flanges and tubesheets are routine. Cold forming of heads and shells: strain ≤ 5 % without post-forming heat treatment (ASME UCS-79), otherwise normalize; hot forming 870–1100 °C followed by normalizing when required. Flame cutting standard; grind cut edges and check for laminations (A435/A578 UT for critical plate).

Applications: Pressure vessels, separators, reactors and drums (ASME VIII Div. 1 and 2); LPG and ammonia storage spheres, bullets and road tankers (normalized, Charpy-tested); Heat-exchanger shells, channels, tubesheets and covers (TEMA); Boiler drums and headers at moderate temperature, air receivers; Refinery and gas-plant equipment in sour service (HIC-resistant A516-70); Storage tanks (API 650 Group III/IV) and low-temperature tanks; Clad-plate base for stainless or nickel-alloy lined vessels

Q: What is the difference between A516 Grade 60 and Grade 70?
A: Strength: Grade 60 has 220 MPa yield / 415–550 MPa tensile (60 ksi), Grade 70 has 260 MPa / 485–620 MPa (70 ksi). Grade 70 gives a thinner wall (ASME allowable 138 vs 118 MPa); Grade 60 has slightly more carbon headroom for toughness and is preferred by some for very low temperature or heavy forming. Most vessels use Grade 70.

Q: What is the difference between A516 and SA-516?
A: None in substance. SA-516 is the ASME Boiler and Pressure Vessel Code adoption of ASTM A516 (Section II Part A); vessel drawings cite SA-516 because ASME requires ASME-adopted specifications. Mills certify plate to both.

Q: Is A516 Grade 70 normalized?
A: Mandatory for plate over 40 mm (1.5 in); optional but almost universal below that when Charpy testing is specified, because normalizing moves the plate to ASME UCS-66 curve D and allows lower design temperatures. Order 'normalized' explicitly for LPG and cold service.

Q: What is the European equivalent of A516 Grade 70?
A: No exact match. P295GH (EN 10028-2, 295 MPa yield) is closest in strength; P265GH is often supplied for Grade 60/65 designs; P355GH or P355NH exceed it. For PED equipment the substitution needs a particular material appraisal; for ASME vessels the plate must be SA-516 or an accepted equivalent.

Q: What is the maximum temperature for A516 Grade 70?
A: ASME lists allowables to 538 °C (1000 °F), but carbon steel is generally limited to about 425 °C (800 °F) for long-term service because of graphitization and creep; above that use A204 (C-½Mo) or A387 (Cr-Mo) grades.

Q: What is HIC-resistant A516-70?
A: A516 Grade 70 melted with very low sulphur (≤ 0.002 %), calcium treatment for inclusion shape control, low P and often low Mn, and tested to NACE TM0284 for hydrogen-induced cracking. It is specified for wet H₂S (sour) service in refineries and gas plants per NACE MR0175/ISO 15156 and MR0103.

---

## A53 Grade B [K03005] — Pipe steel for general and structural service, welded or seamless
URL: https://steelstandart.com/grade/a53-b/
System: ASTM / ASME | Family: Pipe & tube steel | Standard: ASTM A53 | Verified against: ASTM A53/A53M
Aliases: A53, ASTM A53, ASTM A53 Grade B, A53 Gr B, A53B, A53 Grade A, A53 Type E, A53 Type S, A53 Type F, ASTM A53/A53M, A53 Grade B pipe, A53 Grade B equivalent

ASTM A53 Grade B is the most widely produced pipe steel in the world — the black or galvanized pipe used for water, gas, air, steam at low pressure, fire sprinklers, handrails, scaffolding and ten thousand general-purpose jobs. Its strength level is modest and fixed: 240 MPa (35 ksi) minimum yield and 415 MPa (60 ksi) minimum tensile, with Grade A one step below at 205/330.

What makes A53 unusual among the specifications on this site is that it defines three manufacturing types rather than one steel. Type S is seamless. Type E is electric-resistance welded. Type F is continuous furnace butt welded, restricted to Grade A and to NPS 4 and smaller, and not permitted where the pipe will be close-coiled or flanged. All three can be supplied black or hot-dip galvanized, plain end or threaded. A certificate that says only "A53 Grade B" is incomplete until the type is stated.

The question asked about A53 more often than any other is how it differs from A106, since both Grade B specify 240/415. The answer is not in the strength but in what the specification requires: A106 demands a silicon minimum of 0.10 % — meaning fully killed, deoxidised steel — sets carbon and manganese as ranges rather than bare ceilings, is seamless only, and publishes allowable stresses for elevated-temperature service. A53 requires no silicon at all and sets only ceilings. So A106 Grade B can be used wherever A53 Grade B is called for; the reverse is not true, and that asymmetry is why so much pipe is dual-stencilled to both.

Two further boundaries are worth keeping straight. A53 contains no impact-test requirement, so for low-temperature service the specification to use is A333. And although A53 pipe is constantly used as a structural member, structural hollow sections are properly specified to ASTM A500 or A501, which carry the section properties and tolerances a structural designer needs.

Chemical composition (mass %): C ≤ 0.3; Mn ≤ 1.2; P ≤ 0.05; S ≤ 0.045; Cu ≤ 0.4; Ni ≤ 0.4; Cr ≤ 0.4; Mo ≤ 0.15; V ≤ 0.08
ASTM A53/A53M, Grade B seamless. The welded grade allows slightly less carbon and manganese, and Grade A is leaner still at 0.25 % C maximum. Every limit in this table is a **ceiling with no minimum** — including carbon — and there is no silicon requirement at all, which is the single most important difference from A106 and the reason A53 is not a high-temperature pipe.

Mechanical properties:
- Grade B — specified minimum: yield 240 MPa; tensile 415 MPa; elongation see note %; hardness —
- Grade A — specified minimum: yield 205 MPa; tensile 330 MPa; elongation see note %; hardness —
- Grade B, typical mill result: yield 290–380 MPa; tensile 450–520 MPa; elongation 28–35 %; hardness 130–160 HB
- Type F (butt welded), Grade A only: yield 205 MPa; tensile 330 MPa; elongation see note %; hardness —
- Flattening and bend test: yield — MPa; tensile — MPa; elongation — %; hardness required by type and size
- Hydrostatic test pressure: yield — MPa; tensile — MPa; elongation — %; hardness to 60 % of SMYS, per the standard's formula
A53 states the yield and tensile minima in ksi: Grade B is **35 ksi yield / 60 ksi tensile** and Grade A is 30 / 48, which convert to the metric figures above. Elongation is not a single number — the standard computes the minimum from a formula involving wall thickness and specified tensile strength, so a thin-wall pipe is held to a lower figure than a heavy wall. There is no impact-test requirement in A53 at all; where toughness matters the pipe to specify is A333.

Equivalents:
- A106 Grade B (ASTM / ASME) — near: Identical strength minima — 240 MPa yield, 415 MPa tensile — but a different specification with a different purpose. A106 is seamless only, requires a **silicon minimum of 0.10 %** so the steel is killed, sets carbon and manganese ranges rather than ceilings, and publishes allowable stresses for high-temperature service. A53 Grade B does none of that. The two are not interchangeable upward: A106 can replace A53, A53 cannot replace A106.
- P235TR1 (EN (European)) — near: EN 10217-1 P235TR1: 235 MPa minimum yield, 360–500 MPa tensile — the European welded pipe for general service. Slightly lower strength, and TR1 carries no impact requirement while TR2 does; A53 carries none either, which makes TR1 the closer match.
- STPG370 (JIS (Japan)) — near: JIS G3454 STPG370: 215 MPa minimum yield, 370 MPa minimum tensile, carbon steel pipe for pressure service, welded or seamless. The closest Japanese counterpart to A53 Grade B, a little lower in strength.
- L360 / X52 (API (line pipe)) — functional: API 5L X52: the line-pipe grade at 360 MPa minimum yield. A53 Grade B is a general-service pipe tested to 60 % of SMYS; X52 is a transmission-pipeline grade with PSL2 chemistry, toughness and weldability requirements A53 does not contain.
- A36 (ASTM / ASME) — functional: The structural plate and shape specification at 250 MPa yield. Relevant because A53 Grade B pipe is widely used as a structural member — but structural pipe is properly specified to ASTM A500 or A501, not to A53, and the allowable stresses differ.
- S195T (EN (European)) — functional: EN 10255 S195T: the threadable general-purpose tube used across Europe for water, gas and low-pressure service, at 195 MPa minimum yield. It occupies the same place in the market as galvanized threaded A53, with lighter and heavier series instead of schedules.
- Q235 (GB/T (China)) — functional: Chinese pipe to GB/T 3091 (galvanized welded pipe for water) and GB/T 8162/8163 is normally rolled from Q235B. Similar carbon and strength level; the pipe specification, grade system and test regime are all different, so a dual stencil to A53 should be confirmed rather than assumed.

Superseded names:
- A53 Grade A / Grade B — ASTM A53, earlier editions: The grade designations have been stable for decades; what has changed is the type list — Type F is now restricted to Grade A and to NPS 4 and smaller.
- API 5L Grade B — API 5L: Not the same specification, but the same strength level. Pipe is frequently dual-certified to A53 Grade B and API 5L Grade B, which is why one length can carry both stencils.
- ASTM A120 — withdrawn: The former specification for black and galvanized welded and seamless pipe for ordinary use; its scope was absorbed into A53.

Product forms: seamless pipe (Type S), NPS 1/8 to 26; electric-resistance-welded pipe (Type E), NPS 1/8 to 26; continuous furnace butt-welded pipe (Type F), Grade A only, NPS 1/8 to 4; black or hot-dip galvanized; plain end, threaded, or threaded and coupled
Tolerances: wall thickness and outside diameter: ASTM A53/A53M, with wall schedules to ASME B36.10M (Sch 40, Sch 80, STD, XS, XXS); galvanized coating: ASTM A53 requires hot-dip zinc to the standard's own mass requirement; every length is hydrostatically tested or, by agreement, inspected non-destructively instead

### A53 Grade B strength
240 MPa (35 ksi) minimum yield and 415 MPa (60 ksi) minimum tensile. Grade A is 205 MPa (30 ksi) and 330 MPa (48 ksi). Typical mill results for Grade B run 290–380 MPa yield and 450–520 MPa tensile, so there is normally a comfortable margin — but design must use the specified minimum, not the certificate. Elongation is calculated from a formula in the standard rather than fixed, so a thin wall is held to a lower minimum than a heavy wall.

### The three types: S, E and F
Type S — seamless, hot finished or cold finished, the premium route and the one usually specified for pressure work. Type E — electric-resistance welded, a longitudinally welded pipe made from strip; weld-line properties are verified by flattening and hydrostatic tests, and the type is available in both grades. Type F — continuous furnace butt welded, the cheapest route, Grade A only, NPS 4 and under, and expressly not for close coiling or flanging. The grade tells you the strength; the type tells you how it was made and where it may be used.

### A53 Grade B against A106 Grade B
Same minima, different specifications. A106 requires Si ≥ 0.10 % (killed steel), gives carbon and manganese as ranges, is seamless only, and tabulates allowable stresses to 400 °C and above for ASME B31 piping. A53 has no silicon requirement, only ceilings, allows welded construction and publishes no elevated-temperature allowables. In practice: specify A106 Grade B for process piping, steam and anything hot; A53 Grade B for utility, structural and ambient service. Pipe meeting both is routinely dual-stencilled, and that dual certificate — not the A53 mark alone — is what permits high-temperature use.

### Black and galvanized
The title of the specification is "black and hot-dipped, zinc-coated, welded and seamless" — galvanizing is inside the standard, not an extra. Hot-dip zinc to the standard's own coating mass is the usual finish for water, sprinkler and handrail work; black (uncoated, mill-scale) is used for gas, steam, air and anything to be painted or welded. Galvanized pipe must not be welded without removing the zinc from the joint area: the fume is hazardous and the weld is porous.

### Testing: hydrostatic, flattening and bend
Every length is hydrostatically tested — the test pressure is computed from the standard's formula, limited to a fibre stress of 60 % of the specified minimum yield — or, by agreement, inspected non-destructively instead. Flattening tests verify the weld and the pipe body on welded grades; bend tests apply to smaller sizes intended for coiling or bending. There is no impact test and no chemistry re-check beyond the heat analysis unless the order asks for a product analysis.

### Sizes, schedules and the NPS system
A53 is sized in NPS with wall schedules to ASME B36.10M, not in outside diameter and wall. NPS 1/8 to 26 for Types S and E, NPS 1/8 to 4 for Type F. Schedule 40 and Schedule 80 cover most work, with STD, XS and XXS as the older equivalents — STD and Sch 40 are identical to NPS 10, and XS and Sch 80 to NPS 8, after which they diverge. For sizes NPS 14 and above the outside diameter equals the nominal size; below that it does not, which is the usual source of ordering mistakes.

### Weldability
Readily weldable by every arc process with no preheat in normal wall thicknesses; carbon equivalent is typically 0.35–0.45 at the 0.30 % carbon ceiling. Because carbon has no minimum and silicon is not controlled, the actual weldability varies from heat to heat more than it does with A106 — for a critical joint, check the certificate rather than the specification. E6010/E7018 or ER70S-2/ER70S-6 consumables; preheat 100 °C for heavy wall or restrained joints. Type F butt-welded pipe should not be welded across the seam. Galvanized pipe: remove the zinc coating from the weld zone first — zinc fume is a serious hazard and the weld is porous and cracks otherwise.

### Machining, forming, heat treatment
Machinable without difficulty, roughly 70 % relative to 1 % C free-cutting steel; threading to ASME B1.20.1 (NPT) is the normal operation and A53 is specifically produced for it, with threaded-and-coupled ends available as a delivery condition. Cutting by saw, abrasive wheel, plasma or oxy-fuel is routine. Cold bending is practical within the standard's bend-test sizes; for close coiling and flanging, Types S and E must be specified because Type F is excluded. Grooving for mechanical couplings is standard practice on sprinkler work and must be done to the coupling maker's wall-thickness limits.

Applications: Fire sprinkler and standpipe systems (NFPA 13 and equivalents); Water, gas, air and steam service at low pressure; Plumbing and mechanical services, threaded pipework; Handrails, barriers, scaffolding and general fabrication; Structural columns and bracing where A500 is not required; Casing and conduit, sleeve pipe; Piles, posts and fencing (galvanized)

Q: What is the difference between A53 and A106?
A: Grade B of both specifies 240 MPa yield and 415 MPa tensile, so the strengths are identical. The difference is in the requirements around them: A106 is seamless only, demands a silicon minimum of 0.10 % so the steel is fully killed, sets carbon and manganese as ranges rather than ceilings, and publishes allowable stresses for high-temperature service. A53 allows welded construction, requires no silicon and sets only ceilings. A106 Grade B can be used wherever A53 Grade B is specified; A53 cannot substitute for A106 in hot service.

Q: What is A53 Grade B yield strength?
A: 240 MPa, which is 35 ksi, as the specified minimum; tensile is 415 MPa (60 ksi) minimum. Grade A is 205 MPa (30 ksi) yield and 330 MPa (48 ksi) tensile. Mill results for Grade B typically come out at 290–380 MPa yield, but design must use the specified minimum.

Q: What do Type S, Type E and Type F mean?
A: The manufacturing route. Type S is seamless. Type E is electric-resistance welded from strip. Type F is continuous furnace butt welded and is restricted to Grade A, to NPS 4 and smaller, and may not be used where the pipe will be close-coiled or flanged. All three can be black or galvanized. A specification should state both the grade and the type.

Q: Is A53 Grade B suitable for high-temperature service?
A: Not on its own. A53 publishes no elevated-temperature allowable stresses and does not require killed steel, so ASME B31 process piping calls for A106 instead. Much mill pipe is dual-certified to A53 Grade B and A106 Grade B, and in that case the A106 certificate is what permits the hot service — not the A53 stencil.

Q: Can A53 Grade B be used for structural work?
A: It is, constantly, for handrails, posts, bracing and light columns. For engineered structural hollow sections the correct specifications are ASTM A500 or A501, which carry the dimensional tolerances and section properties a structural designer needs and are produced for that purpose. Using A53 as a structural member is a judgement the designer makes, with the specified minimum yield of 240 MPa as the basis.

Q: What is the European equivalent of A53 Grade B?
A: EN 10217-1 P235TR1 is the nearest welded pipe equivalent at 235 MPa minimum yield and 360–500 MPa tensile, with no impact requirement — which matches A53, since A53 has none either. For threaded general-purpose tube the practical counterpart is EN 10255 S195T. None of these is a drop-in substitution, because the test regimes and dimensional systems differ.

Q: Does A53 require impact testing?
A: No, and that is a real limitation. There is no Charpy requirement anywhere in the specification, so A53 pipe carries no documented toughness at low temperature. For service below about 0 °C the specification to use is ASTM A333, whose grades are impact tested at their rated temperatures — Grade 6 at −45 °C, for example.

Q: Can galvanized A53 pipe be welded?
A: Only after the zinc is removed from the weld area. Zinc fume from welding is a serious health hazard, and zinc entering the weld pool causes porosity and cracking. Grind or chemically strip the coating back from the joint, weld, then restore the coating with a zinc-rich paint or cold-galvanizing compound. Where joints are to be welded, black pipe should be specified and the assembly galvanized afterwards.

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## A572 Grade 50 [K02303] — High-strength low-alloy (HSLA) columbium-vanadium structural steel
URL: https://steelstandart.com/grade/a572-50/
System: ASTM / ASME | Family: Structural steel | Standard: ASTM A572 | Verified against: ASTM A572/A572M-21
Aliases: ASTM A572, A572 Gr 50, A572-50, ASTM A572 Grade 50, A572 GR50, grade 50 steel, 50 ksi steel, A572 steel, K02303, A572 grade 42, A572 grade 60, A572 grade 65

ASTM A572 is the American high-strength low-alloy (HSLA) structural steel: carbon-manganese steel micro-alloyed with niobium (columbium) and/or vanadium so that fine grain and precipitation strengthening lift the yield from A36's 250 MPa to 290, 345, 380, 415 or 450 MPa (Grades 42, 50, 55, 60, 65) without hurting weldability. Grade 50 — 345 MPa (50 ksi) yield, 450 MPa (65 ksi) tensile — is by far the most used and is what engineers mean by '50 ksi steel' or 'Grade 50'. UNS K02303.

Because the alloying is measured in hundredths of a percent, A572-50 costs only a few percent more than A36 while saving 25–30 % weight in strength-governed members; it is the standard for plate girders, columns, crane rails and runways, transmission towers, heavy equipment, truck frames and trailer chassis. W-shapes are rolled to the closely related A992 (which adds a yield cap for seismic design) and are dual-certified A992/A572-50; bridges use A709 Grade 50, which adds Charpy zones. A572 itself has no impact requirement unless supplementary S5 is ordered.

European S355J2 (non-alloy) and S355M/N (fine-grain HSLA) are the practical substitutes; JIS SM490, GB Q355B, GOST 09G2S and IS 2062 E350 are the Asian near matches.

Chemical composition (mass %): C ≤ 0.23 (Grade 50 plate/shapes; Grade 42: 0.21; Grades 60/65: 0.26); Mn ≤ 1.35 (Grade 50: 1.35 (1.65 for Grades 60/65); shapes may go to 1.60 with C ≤ 0.21); P ≤ 0.03; S ≤ 0.03; Si ≤ 0.4 (plate > 40 mm: 0.15–0.40); Nb 0.005 – 0.05 (Type 1 (Nb); Type 2 (V 0.01–0.15); Type 3 (Nb + V); Type 5 (N ≤ 0.015 with V)); V 0.01 – 0.15 (Type 2 / Type 3); Cu ≥ 0.2 (when copper steel is specified)
ASTM A572/A572M-21 Tables 1 and 2. Micro-alloy 'Type' (1–5) is at the producer's option unless specified. Grade 50 shapes over 634 kg/m and plate over 40 mm: Mn ≤ 1.35, Si 0.15–0.40. Supplementary S90/S91 for CE limits, S5 for Charpy.

Mechanical properties:
- Grade 42 (290 MPa) — plate ≤ 150 mm, all shapes: yield 290 MPa; tensile ≥ 415 MPa; elongation 20 (L0 200 mm) / 24 (50 mm) %; hardness —
- Grade 50 (345 MPa) — plate ≤ 100 mm, all shapes: yield 345 MPa; tensile ≥ 450 MPa; elongation 18 / 21 %; hardness ≈ 135–185 HB (typ.)
- Grade 55 (380 MPa) — plate ≤ 50 mm, shapes: yield 380 MPa; tensile ≥ 485 MPa; elongation 17 / 20 %; hardness —
- Grade 60 (415 MPa) — plate ≤ 32 mm, shapes ≤ 634 kg/m: yield 415 MPa; tensile ≥ 520 MPa; elongation 16 / 18 %; hardness —
- Grade 65 (450 MPa) — plate ≤ 32 mm, shapes ≤ 634 kg/m: yield 450 MPa; tensile ≥ 550 MPa; elongation 15 / 17 %; hardness —
- Grade 50 — typical mill certificate (plate 10–25 mm): yield ≈ 370–420 MPa; tensile ≈ 500–550 MPa; elongation ≈ 25–30 (50 mm) %; hardness ≈ 150–170 HB
ASTM A572/A572M-21 Table 3; yield minimum only (no maximum; A992 adds a 450 MPa cap and Fy/Fu ≤ 0.85 for seismic design). Elongation in 200 mm or 50 mm. No Charpy unless S5 ordered; bridge plate uses A709-50 with Charpy zones.
Impact: 27 J at 20 °C (typical only; not required by A572)

Equivalents:
- A992 (ASTM / ASME) — identical: Same 345 MPa yield for W-shapes with added yield cap and Fy/Fu limit; shapes are dual-certified.
- A709 Gr. 50 (ASTM / ASME) — identical: A572-50 chemistry and strength plus Charpy zone requirements for bridges.
- A588 / A709-50W (ASTM / ASME) — near: Weathering HSLA with 345 MPa yield and Cu-Cr-Ni for unpainted service.
- S355JR / S355J2 (EN (European)) — near: Yield 355 MPa (≤ 16 mm), Rm 470–630 MPa, guaranteed Charpy (+20 / −20 °C); non-alloy rather than HSLA chemistry. S355J2 is the standard European substitute for A572-50 plate.
- S355M / S355N (EN (European)) — near: EN 10025-4 / -3 thermomechanical or normalized fine-grain HSLA — the closest metallurgical match (Nb/V micro-alloyed, 355 MPa).
- Q355B / Q345B (GB/T (China)) — near: GB/T 1591 Q355B: yield 355 MPa, Rm 470–630 MPa, 34 J at +20 °C (formerly Q345B: 345 MPa).
- 09G2S / S345 (GOST (Russia/CIS)) — near: GOST 19281 09G2S (C345): yield 325–345 MPa; GOST 27772 S345 structural class.
- IS 2062 E350 (IS (India)) — near: Yield 350 MPa, Rm 490 MPa min (quality A/BR/B0/C by impact).
- SM490A / SM490YB (JIS (Japan)) — near: JIS G3106 SM490A: yield 325 MPa (≤ 16 mm), Rm 490–610 MPa; SM490YB: yield 365 MPa, 27 J at 0 °C.
- A36 (ASTM / ASME) — functional: 250 MPa carbon steel — the grade A572-50 replaces when weight matters.
- S355MC (EN (European)) — functional: Same yield class (345 MPa) as plate/sections, but not thermomechanically rolled and without the guaranteed bend radii.

Superseded names:
- K02303 (Gr 50), K02703 (Gr 42), K02003 (Gr 60/65) — UNS
- A441 — ASTM A441 (withdrawn 1989): Predecessor Mn-V HSLA (50 ksi) replaced by A572.
- A709 Grade 50 — ASTM A709 / AASHTO M270: Bridge version with Charpy zones; 50W is the weathering variant (A588 chemistry).
- A992 — ASTM A992: W-shape grade (50–65 ksi yield, Fy/Fu ≤ 0.85); most W-shapes are dual-certified A992/A572-50.
- CSA G40.21 350W — Canada: Canadian 350 MPa structural equivalent.

Product forms: plate up to 100 mm (Grade 50), 150 mm (Grade 42); shapes: W, S, M, C, L, HP (W-shapes usually dual-certified A992/A572-50); bar and merchant sections; sheet piling (as A572-50 or A690), bridge plate (as A709-50)
Tolerances: plate, shapes, bar: ASTM A6/A6M; surface: A6 (mill scale); blast-cleaned to SSPC on request

### A572 Grade 50 yield strength
Minimum 345 MPa (50 ksi) for plate up to 100 mm and all shapes; typical 370–420 MPa. Other grades: 42 → 290 MPa, 55 → 380 MPa, 60 → 415 MPa, 65 → 450 MPa.

### A572 Grade 50 tensile strength
Minimum 450 MPa (65 ksi), no maximum (A992 caps W-shapes at 450–620 MPa); typical 500–550 MPa. Grade 42: ≥ 415; 55: ≥ 485; 60: ≥ 520; 65: ≥ 550 MPa.

### A572 elongation and hardness
Grade 50: ≥ 18 % in 200 mm / ≥ 21 % in 50 mm (typical 25–30 %). Hardness not specified; typical 135–185 HB.

### Thickness limits
Grade 42: plate to 150 mm; Grade 50: plate to 100 mm; Grade 55: 50 mm; Grades 60/65: 32 mm and shapes ≤ 634 kg/m. Yield does not step down with thickness inside these limits (unlike EN 10025).

### Weldability
Good: CE typically 0.35–0.45 (S90/S91 supplementary requirements cap CE for critical work). AWS D1.1 prequalified with E70XX/ER70S-6 (matching) — preheat per Table 3.3 category B: none ≤ 19 mm, 10 °C to 38 mm, 65 °C to 64 mm, 110 °C above; low-hydrogen consumables mandatory.

### Physical properties
Density 7.85 g/cm³, E = 200 GPa (29 × 10⁶ psi), expansion 11.7 × 10⁻⁶/K, conductivity ≈ 47 W/m·K. AISC design: Fy = 50 ksi, Fu = 65 ksi.

### Weldability
Readily weldable by SMAW (E7018), GMAW (ER70S-6), FCAW (E71T-1) and SAW (F7A2) under AWS D1.1 prequalified procedures; matching-strength 70 ksi consumables suffice for Grade 50 (80 ksi for Grades 60/65). Preheat by thickness per AWS D1.1 Table 3.3 (category B); low-hydrogen practice required. No PWHT for structural work. For seismic connections use A992 shapes with demand-critical weld consumables (Charpy-rated).

### Machining, forming, heat treatment
Machinability ≈ 65–70 % of B1112 (slightly harder than A36). Flame, plasma, laser and waterjet cutting routine; shearing to ~20 mm; punching to 16 mm. Cold bending: inside radius ≥ 1.5–2 t transverse (AISC/producer guidance), 2.5 t for Grades 60/65; hot forming 900–1100 °C followed by air cooling (do not quench). Galvanizes and paints as A36.

Applications: Plate girders, columns and trusses in buildings and industrial structures; W-shapes (as A992/A572-50), HP piles, channels and angles for heavy framing; Crane runway girders, crane booms and lifting-equipment structures; Transmission and telecom towers, wind-tower internals, substation structures; Truck frames, trailer chassis, dump bodies, heavy-equipment weldments; Bridge girders (as A709-50 / 50W), sign structures, culverts; Pressure-free tanks, bins and hoppers where thinner walls save weight

Q: What is the difference between A572 Grade 50 and A36?
A: Yield 345 vs 250 MPa (50 vs 36 ksi) and tensile ≥ 450 vs 400–550 MPa. A572-50 is micro-alloyed HSLA steel; it lets members be 25–30 % lighter for a few percent more per tonne. A36 is more ductile and remains common for plate, bar, angle and channel; A572-50 (or A992) dominates beams, columns and girders.

Q: What is the difference between A572 Grade 50 and A992?
A: A992 is written specifically for rolled W-shapes: same 345 MPa (50 ksi) minimum yield but with a 450 MPa (65 ksi) yield cap, Fy/Fu ≤ 0.85 and a carbon-equivalent limit for predictable seismic behaviour. Most W-shapes are dual-certified A992/A572-50; plate cannot be A992.

Q: What is the European equivalent of A572 Grade 50?
A: S355J2 (EN 10025-2) for general plate and sections — 355 MPa yield with guaranteed −20 °C impact — or S355M/S355N (EN 10025-4/-3) for a true fine-grain HSLA match. Both are graded 'near' because chemistry and thickness rules differ.

Q: Does A572 have an impact (Charpy) requirement?
A: Not by default. Order supplementary requirement S5 with the temperature and energy needed, or specify A709 Grade 50 (bridges) which includes Charpy zones 1–3.

Q: What are the A572 grades?
A: Grade 42 (290 MPa / 42 ksi), Grade 50 (345 MPa / 50 ksi), Grade 55 (380 MPa / 55 ksi), Grade 60 (415 MPa / 60 ksi) and Grade 65 (450 MPa / 65 ksi). Grade 50 is the standard; 60/65 are limited to 32 mm plate and lighter shapes.

Q: Is A572 Grade 50 weldable without preheat?
A: Yes up to 19 mm under AWS D1.1 (category B) with low-hydrogen consumables; 10 °C preheat to 38 mm, 65 °C to 64 mm, 110 °C above 64 mm.

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## AR400 — Abrasion-resistant quenched and tempered plate, nominal 400 HBW
URL: https://steelstandart.com/grade/ar400/
System: Proprietary (trade names) | Family: Quenched & tempered steel | Standard:  | Verified against: 
Aliases: AR 400, AR400 steel, AR400 plate, AR400 wear plate, 400 HBW wear plate, Hardox 400, XAR 400, Quard 400, Dillidur 400, Raex 400, Abrazo 400, Durostat 400, Everhard 400, abrasion resistant steel 400, AR400 equivalent

AR400 is abrasion-resistant quenched and tempered plate at a nominal hardness of 400 HBW — the default wear plate, and by volume the most used material in the class. It is roughly three to four times as resistant to sliding abrasion as the S355 structural plate around it, at perhaps twice to three times the price per tonne, which is why a 10 mm AR400 liner is bolted into a 12 mm S355 chute rather than the chute being made thicker.

The first thing to establish is that AR400 is not a grade. No EN or ASTM specification defines it; there is no composition table, no mechanical table and no test regime with independent backing. "AR400" is a trade description meaning *abrasion-resistant plate, about 400 Brinell*, and every mill's version is its own product: SSAB's Hardox 400, ThyssenKrupp's XAR 400, Dillinger's Dillidur 400, NLMK's Quard 400, and a dozen others. Two plates can both be correctly labelled AR400 and differ in analysis, guaranteed impact energy, minimum bend radius and thickness tolerance. The one standard that does apply is EN 10029 or ASTM A6, for thickness and flatness.

The second thing is what the hardness is for. Abrasive wear resistance tracks hardness only within a given microstructure, and that is precisely why wear plate is quenched and tempered martensite rather than simply high-carbon steel: the hardness has to come from a tough, uniform structure that will not spall when a rock hits it. The analysis is designed around hardenability in thickness — the chromium, nickel, molybdenum and boron are there so that a 40 mm plate transforms right through, not to add hardness of their own.

The third is why 400 and not 500. Every step up the hardness ladder costs formability and weldability. AR400 can still be press-brake bent to about 3 × thickness across the rolling direction, welded with ordinary low-hydrogen consumables at modest preheat, and plasma or laser cut without special precautions. AR500 can do none of those things comfortably. The right plate is usually the softest one that outlives the maintenance interval, because the fabrication penalty is paid once per part and the wear saving is paid once per plate change.

Chemical composition (mass %): C ≤ 0.23; Si ≤ 0.7; Mn ≤ 1.6; P ≤ 0.025; S ≤ 0.01; Cr ≤ 1; Ni ≤ 1; Mo ≤ 0.5; B ≤ 0.005
**These are indicative ceilings across the AR400-class products, not a specification.** No standard defines AR400 and no two producers' analyses are identical; the figures above bracket what the common brands declare. The composition exists to deliver hardenability in thickness, not hardness as such — the ~0.2 % carbon sets the achievable hardness, while the chromium, nickel, molybdenum and especially **boron** at a few thousandths of a per cent are there so a 40 mm plate transforms to martensite through its whole thickness in a water quench. Read the mill's own declared analysis from the certificate.

Mechanical properties:
- AR400 class — hardness band as delivered: yield — MPa; tensile — MPa; elongation — %; hardness 370–430 HBW (typical, brand dependent)
- Typical tensile properties at 400 HBW: yield 1000–1100 MPa; tensile 1250–1400 MPa; elongation 10 %; hardness ≈ 400 HBW
- AR450 class — for comparison: yield 1100–1250 MPa; tensile 1400–1550 MPa; elongation 9 %; hardness 425–475 HBW
- AR500 class — for comparison: yield 1250–1400 MPa; tensile 1600–1750 MPa; elongation 8 %; hardness 470–530 HBW
- S355J2 structural plate — for comparison: yield 355 MPa; tensile 470–630 MPa; elongation 22 %; hardness ≈ 150 HBW
- Charpy impact (where guaranteed): yield — MPa; tensile — MPa; elongation — %; hardness 27–45 J at −40 °C, longitudinal — brand dependent, often quoted as typical rather than guaranteed
Wear plate is **sold on hardness, not on strength**, and the tensile figures are a consequence rather than a requirement — most datasheets quote them as typical and some do not quote them at all. Two cautions follow. First, the hardness that matters is **through-thickness**, because a surface reading on a quenched plate flatters it. Second, several brands publish impact energy as a *typical* value; a typical value is not a requirement and cannot be inspected against, so if the part sees impact at low temperature the guarantee must appear on the certificate.
Impact: 27–45 J longitudinal (brand dependent) J at −40 °C °C (Not required by any standard, because no standard applies. Some producers guarantee a minimum at −40 °C on specified thicknesses, others publish typical values only, and the dedicated high-toughness variants (Hardox HiTuf, XAR HT and similar) are sold on exactly this property.)

Equivalents:
- Hardox 400 (Proprietary (trade names)) — identical: SSAB's product in this class and the usual reference point. Specifying it by name means specifying one supplier; specifying the properties — through-thickness hardness band, guaranteed impact energy and temperature, bend radius at thickness, tolerance class — lets several mills quote the same requirement.
- AR450 (Proprietary (trade names)) — near: The next hardness class, 425–475 HBW. Roughly 20–30 % longer life in pure abrasion for a higher plate price and a noticeably harder fabrication: larger bend radii, more preheat, slower cutting. The step is worth making where plate changes are the dominant cost and the part is simple.
- AR500 (Proprietary (trade names)) — near: 470–530 HBW. The practical limit for a plate that still has to be bent and welded; above it formability and weldability fall away quickly and the plate becomes a liner rather than a structure.
- AR450 (Proprietary (trade names)) — near: The 450-class product, and in most ranges the volume seller rather than the 400 — which is worth knowing when comparing prices, because the better-stocked thickness is often the cheaper one per kilogram.
- A514 (ASTM / ASME) — functional: ASTM A514 (historically T-1): quenched and tempered alloy structural plate at 690 MPa minimum yield, about 235–290 HBW. Frequently confused with wear plate on American drawings; it is a structural specification with no hardness requirement.
- S355J2 (EN (European)) — functional: EN 10025-2 S355J2 at roughly 150 HBW. Listed as the benchmark: in sliding abrasion AR400 lasts about **three to four times** as long, which is the whole economic case for wear plate. S355J2 is what the surrounding structure is made of.
- S690QL (EN (European)) — functional: EN 10025-6 S690QL: quenched and tempered **structural** plate at 690 MPa minimum yield, around 250 HBW. The closest thing to a standardised grade in this territory, and the key distinction — EN 10025-6 specifies plate by strength, not hardness, and stops far short of 400 HBW. It is the grade for a load-carrying member, not a wearing surface.
- 1.2379 (EN (European)) — functional: X153CrMoV12 (D2) at 58–62 HRC, roughly 700 HBW. Far more abrasion resistant and entirely unsuitable for this job: it cannot be bent, barely welded, and is sold in tool sizes. Listed to mark the boundary — above about 600 HBW the answer is a tool steel, a carbide overlay or a ceramic liner, not a thicker wear plate.

Superseded names:
- Hardox 400 — SSAB trademark: The reference product of this class and the name most often written on drawings. Hardox is a registered trademark of SSAB; naming it here describes the product, nothing more.
- XAR 400 — ThyssenKrupp trademark: Dillidur 400 (Dillinger), Durostat 400 (voestalpine), Brinar 400 are the other German-origin names in the class.
- Quard 400 / Raex 400 — NLMK / SSAB trademarks: Abrazo 400 (Ancofer), Creusabro 4800 (ArcelorMittal, a different metallurgical approach), Everhard 400 (JFE).
- T-1 / Jalloy — older US trade names: Historic quenched and tempered plate brands; T-1 corresponds to ASTM A514 structural plate rather than to a wear grade, and the two are often confused on old drawings.

Product forms: hot-rolled quenched and tempered plate, typically 3 to 80 mm; profile-cut parts, laser and plasma cut blanks; press-brake formed liners, chutes and buckets; wear strip, bar and cut-to-size blanks
Tolerances: thickness and flatness: EN 10029 (class A, B or C as ordered) or ASTM A6 — the only part of a wear-plate order backed by an independent standard; flatness is normally ordered to a tighter class than EN 10029 normal, because quenched plate is harder to flatten and a wavy liner does not fit; hardness: the producer's own datasheet band, measured through thickness

### AR400 hardness
Nominally 400 HBW, delivered in a band that varies with the producer — commonly 370–430 HBW, with some brands quoting 370–430 and others 380–430. Brinell is the reference scale for wear plate because the 10 mm ball averages over a large area and is insensitive to the local variation a Rockwell indent would pick up; 400 HBW corresponds to roughly 43 HRC. Insist on a through-thickness figure: hardness is measured below the surface, typically at a stated depth, because a surface reading on quenched plate reads high and tells you nothing about what the part will look like after the first few millimetres have worn away.

### Hardness against wear life — and the limits of the relationship
In pure sliding abrasion against a harder abrasive, life rises roughly in proportion to hardness, so AR400 lasts about three to four times as long as S355 and AR450 adds perhaps 20–30 % over AR400. The relationship breaks down in three situations. Where the abrasive is softer than the plate — most sand against 400 HBW — extra hardness buys little, because the abrasive is being crushed rather than cutting. Where the wear is impact-dominated, as in a crusher liner or a rock box, toughness governs and a harder plate chips. And where the mechanism is gouging by large lumps, work-hardening austenitic manganese steel can outlast martensitic plate entirely. Matching the plate to the mechanism matters more than the hardness number.

### Bending and forming
AR400 is the hardest wear plate that bends comfortably. Typical minimum inner bend radius is about 3 × thickness with the bend line transverse to the rolling direction, and 4–5 × thickness for a bend parallel to it — the difference is real and is the commonest cause of cracked liners. Allow a generous die opening, use a large punch radius, and check the cut edge before bending: a plasma- or laser-cut edge carries a hardened, notched zone that initiates cracks, and grinding it smooth is standard practice on a part that will be formed. Cold forming at below about 10 °C increases the cracking risk; warming the plate to room temperature is worth the delay. Roll forming to large radii is routine.

### Welding
Readily weldable with low-hydrogen consumables, and this is another reason the 400 class is the default. Carbon equivalent is typically 0.40–0.50, so preheat of 75–100 °C is usual above about 20 mm and often unnecessary below it; check the producer's own table, which is thickness and combined-thickness based. Use a softer consumable than the plate — an ordinary 355–500 MPa class filler — because a hard weld in a tough plate cracks, and the weld is not the wearing surface. Keep heat input moderate: the heat-affected zone is tempered by welding and loses hardness over a few millimetres, which is unavoidable and is why a liner is bolted or plug welded rather than seam welded along its wearing face. No post-weld heat treatment: tempering the plate would remove the hardness it was bought for.

### Cutting and machining
Plasma, laser and oxy-fuel cutting are all standard and are how most wear parts are made; abrasive waterjet is used where no heat-affected zone is acceptable. Expect a locally hardened cut edge of 1–3 mm, which should be ground off where the part will be bent or fatigue loaded. Machining is possible but slow — about 30–35 % relative to 1 % C free-cutting steel — with coated carbide, rigid set-ups and low speeds; drilling at 400 HBW needs cobalt or carbide drills and firm feed, and holes are better punched in the soft grade and plug-welded, or cut by waterjet, than drilled. Shearing is practical only in thin gauges and within the shear maker's hardness limit.

### How to specify it instead of naming a brand
A requirement written as "Hardox 400 or equivalent" has no referent, because there is no document to be equivalent to. Specify the properties and several mills can quote the same thing: through-thickness hardness range (for example 370–430 HBW at a stated depth), guaranteed impact energy and temperature if the part sees impact, maximum carbon equivalent if it will be field welded, minimum inner bend radius at the ordered thickness if it will be formed, and thickness and flatness class to EN 10029 or ASTM A6. Those five lines are inspectable on arrival; a brand name is not.

### Weldability
Weldable with all arc processes using low-hydrogen consumables and a filler softer than the plate — a hard weld in a tough plate cracks, and the weld seam is not where the wear happens. Carbon equivalent typically 0.40–0.50; preheat 75–100 °C above roughly 20 mm thickness, often none below, with the producer's combined-thickness table taking precedence. Keep interpass temperature and heat input moderate, and accept that the heat-affected zone will be softened by a few millimetres: that is inherent to welding a quenched plate and is why liners are plug welded or bolted rather than seam welded across a wearing face. Never post-weld heat treat — a stress-relief cycle tempers the plate and destroys the hardness. Weld-on wear buttons and overlays are the normal way to protect a weld line that must sit in the wear path.

### Machining, forming, heat treatment
Machinable but slow and demanding: roughly 30–35 % relative to 1 % C free-cutting steel at 400 HBW. Coated carbide, rigid work holding, low cutting speeds and firm feeds; interrupted cuts on a cut edge are the usual tool-killer because of the hardened edge zone. Drilling needs cobalt HSS at best and carbide for production, with constant feed — dwelling work-hardens the hole bottom. Tapping is avoided; where a threaded fixing is needed, weld a boss on instead. For holes and profiles, thermal or waterjet cutting is the normal route, not machining. Grinding is straightforward with conventional wheels and is used to dress cut edges before forming.

Applications: Dump truck and tipper bodies, bucket and loader liners; Chutes, hoppers, bins and transfer points; Conveyor skirts, scrapers and deflector plates; Screen decks, grizzly bars and feeder pans; Excavator bucket wear strips, cutting edges and side protectors; Mixer and pug-mill liners, concrete plant wear parts; Recycling and shredder housings, baler wear plates

Q: Is AR400 a standard grade of steel?
A: No. There is no EN or ASTM specification for AR400 — it is a trade description meaning abrasion-resistant plate at about 400 Brinell. Each producer sells its own product under its own name (Hardox 400, XAR 400, Dillidur 400, Quard 400 and others) against its own datasheet. The only independently backed requirements in a wear-plate order are the dimensional ones, to EN 10029 or ASTM A6.

Q: What is the hardness of AR400?
A: Nominally 400 HBW, delivered in a band that depends on the producer, commonly 370–430 HBW — about 43 HRC. Brinell is used because the 10 mm ball averages over a large area. Ask for the figure measured through thickness at a stated depth rather than at the surface, since a surface reading on quenched plate reads high.

Q: Is AR400 the same as Hardox 400?
A: Hardox 400 is one product in the AR400 class — SSAB's, and the reference for the class — but AR400 is a description rather than a definition, so the two are not interchangeable terms. A plate correctly sold as AR400 may differ from Hardox 400 in analysis, guaranteed impact energy, minimum bend radius and tolerance class. If the drawing says Hardox, it is naming a supplier.

Q: Can AR400 be bent?
A: Yes — it is the hardest wear plate that bends comfortably, which is much of why it is the default. Typical minimum inner radius is about 3 × thickness with the bend transverse to the rolling direction, and 4–5 × thickness parallel to it. Grind the thermal-cut edges smooth before bending, use a large punch radius, and avoid forming cold plate below about 10 °C.

Q: Can AR400 be welded?
A: Yes, with low-hydrogen consumables and a filler softer than the plate, typically with 75–100 °C preheat above about 20 mm. Two rules matter: do not use a hard filler, because a hard weld in a tough plate cracks; and never post-weld heat treat, because a stress-relief cycle tempers the plate and removes the hardness. Expect a softened heat-affected zone a few millimetres wide — that is inherent and is why liners are plug welded or bolted rather than seam welded along a wearing face.

Q: AR400 or AR450 — which should I use?
A: The softest plate that outlives the maintenance interval. AR450 gives perhaps 20–30 % more life in pure sliding abrasion, but costs more per tonne and is harder to fabricate: larger bend radii, more preheat, slower cutting. Since the fabrication penalty is paid once per part and the wear saving once per plate change, AR450 pays on simple shapes that are replaced often and loses on complex formed parts.

Q: Is AR400 a structural steel?
A: No, and it should not be used as one. It has no specified minimum yield strength, no standard behind it and no design values in any structural code, so there is nothing a structural engineer can calculate with. The quenched and tempered structural plates are EN 10025-6 S690QL and ASTM A514, which are specified by strength and have no hardness requirement. Wear plate is a sacrificial lining fastened to a structure made of something else.

Q: Does a harder plate always last longer?
A: Only in pure sliding abrasion against a harder abrasive. Where the abrasive is softer than the plate — most sand against 400 HBW — extra hardness buys very little. Where the wear is impact-dominated, a harder plate chips and a tougher one lasts longer. And in heavy gouging by large lumps, work-hardening austenitic manganese steel can outlast martensitic wear plate altogether. Identify the wear mechanism before buying hardness.

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## AR450 — Abrasion-resistant quenched and tempered plate, nominal 450 HBW
URL: https://steelstandart.com/grade/ar450/
System: Proprietary (trade names) | Family: Quenched & tempered steel | Standard:  | Verified against: 
Aliases: AR 450, AR450 steel, AR450 plate, AR450 wear plate, 450 HBW wear plate, Hardox 450, XAR 450, Quard 450, Dillidur 450, Raex 450, Abrazo 450, Durostat 450, Everhard 450, abrasion resistant steel 450, AR450 equivalent

AR450 is the plate the wear-plate industry actually sells. Nominally 450 HBW, delivered in a band of about 425–475, it is the most widely stocked hardness in every major range — which matters commercially as well as technically, because the best-stocked thickness is often the cheapest per kilogram even when a softer plate would do.

The question with AR450 is never what it is but whether the step up from AR400 pays. The arithmetic is more interesting than it looks. In pure sliding abrasion AR450 returns roughly 20–30 % more life, for perhaps 5–15 % more per tonne. On a flat bolt-in liner that is replaced three times a year, that is an obvious gain: the plate cost is a small part of the total and the saved downtime and labour are the real prize.

On a formed and welded part the arithmetic inverts. Every fabrication parameter is worse at 450 HBW — the minimum bend radius goes from about 3 × thickness to 3.5–4 ×, the preheat threshold drops from roughly 20 mm to 15 mm, cutting is slower, drilling is harder, and the guaranteed impact energy is lower just when the part needs it. That penalty is paid once per part manufactured, while the wear saving is collected once per plate change. A complex formed chute made twice a year will usually be cheaper in AR400; a flat skirt plate changed monthly will usually be cheaper in AR450.

The second thing that changes at this hardness is the dominant failure mode. At 400 HBW most wear parts wear out. At 450 a larger share crack or chip instead — from a bend radius that was too tight, a hardened thermal-cut edge that was never ground, a hard weld filler, or impact the plate was not tough enough for. This is why every major producer offers a high-toughness variant at the same hardness (Hardox 450 HiTuf and its counterparts), and why specifying a guaranteed Charpy figure rather than a typical one is worth doing at this level and optional at 400.

As with the rest of the class, no standard defines AR450 — see the AR400 page for what the designation does and does not mean, and the proprietary-grades page for how to write a specification that several mills can quote.

Chemical composition (mass %): C ≤ 0.26; Si ≤ 0.7; Mn ≤ 1.6; P ≤ 0.025; S ≤ 0.01; Cr ≤ 1.4; Ni ≤ 1.5; Mo ≤ 0.6; B ≤ 0.005
**Indicative ceilings across the AR450-class products, not a specification** — no standard defines the grade and each producer declares its own analysis. Compared with the 400 class the carbon ceiling rises slightly and the chromium, nickel and molybdenum allowances rise more, because the quench has to produce a higher hardness through the same thickness. The practical effect on a fabricator is the **carbon equivalent**, which runs higher and pushes the preheat threshold down.

Mechanical properties:
- AR450 class — hardness band as delivered: yield — MPa; tensile — MPa; elongation — %; hardness 425–475 HBW (typical, brand dependent)
- Typical tensile properties at 450 HBW: yield 1100–1250 MPa; tensile 1400–1550 MPa; elongation 9 %; hardness ≈ 450 HBW
- Charpy impact, standard product (where guaranteed): yield — MPa; tensile — MPa; elongation — %; hardness 27–40 J at −40 °C, longitudinal
- Charpy impact, high-toughness variant: yield — MPa; tensile — MPa; elongation — %; hardness 45–65 J at −40 °C, longitudinal (brand dependent)
- Minimum inner bend radius, transverse: yield — MPa; tensile — MPa; elongation — %; hardness ≈ 3.5–4 × thickness
- Preheat threshold, single plate: yield — MPa; tensile — MPa; elongation — %; hardness ≈ 100 °C above 15–20 mm (producer's table governs)
Hardness is the sold property; the tensile numbers follow from it and are usually published as typical. The rows that decide whether this plate can be used for a given part are the last three — **impact energy, bend radius and preheat threshold** — and all three are worse than at 400 HBW. A quotation that lists only the hardness band has not told you what you need to know.
Impact: 27–40 J longitudinal standard product; 45–65 J for high-toughness variants J at −40 °C °C (No standard applies, so whether a figure is guaranteed or merely typical is a commercial matter. The high-toughness variants of this hardness class exist precisely because the standard product's toughness is marginal for impact-loaded parts such as rock boxes and crusher chutes.)

Equivalents:
- Hardox 450 (Proprietary (trade names)) — identical: SSAB's product in this class. Specifying it by name specifies one supplier; specifying through-thickness hardness band, guaranteed impact energy and temperature, bend radius at thickness and tolerance class lets several mills quote the same requirement.
- AR400 (Proprietary (trade names)) — near: 370–430 HBW: easier to bend (about 3 × thickness), lower preheat, better toughness margin, cheaper per tonne. The default where the part is complex or impact-loaded. The background on what AR designations mean and how hardness relates to wear is set out on that page.
- AR500 (Proprietary (trade names)) — near: 470–530 HBW: another 15–20 % of abrasion life, with bend radii around 5 × thickness and a narrow welding window. The step from 450 to 500 costs considerably more in fabrication than the step from 400 to 450.
- 52100 (AISI / SAE) — functional: Bearing steel at 60–64 HRC, around 700 HBW. Listed to mark where the plate route ends: above about 550 HBW the practical answers are carbide overlay, cast chrome iron, a tool steel insert or a ceramic liner, not a harder plate.
- S690QL (EN (European)) — functional: EN 10025-6 S690QL: quenched and tempered structural plate, 690 MPa minimum yield, about 250 HBW, with real design values in the structural codes. The grade for the member that carries the load; AR450 is the lining bolted to it.
- S355J2 (EN (European)) — functional: EN 10025-2 S355J2 at roughly 150 HBW — the reference point for wear calculations. AR450 lasts roughly four to five times as long in sliding abrasion.
- Creusabro 4800 (Proprietary (trade names)) — functional: ArcelorMittal's alternative route: delivered around 370 HBW but **work-hardening to about 440–470 HBW in service** through a titanium-carbide and transformation-induced plasticity mechanism. It is easier to form and cut at delivery hardness and reaches AR450 performance after bedding in — a genuinely different trade-off, not a cheaper 450.
- Mn13 (Proprietary (trade names)) — functional: Austenitic manganese steel (Hadfield steel, around 12–14 % Mn), as-cast at 200 HBW and work-hardening past 500 HBW at the surface under heavy impact. It outlasts martensitic wear plate in **gouging** service — crusher jaws, cones, rail frogs — and is far worse in pure sliding abrasion.

Superseded names:
- Hardox 450 — SSAB trademark: The most widely stocked single wear plate in the world and the usual reference for the class. Hardox is a registered trademark of SSAB; the name is used here to identify the product.
- XAR 450 / Dillidur 450 — ThyssenKrupp / Dillinger trademarks: Durostat 450 (voestalpine), Brinar 400/500 bracket this hardness in the voestalpine and Buderus ranges.
- Quard 450 / Raex 450 — NLMK / SSAB trademarks: Abrazo 450 (Ancofer), Everhard 450 (JFE). Creusabro 4800 (ArcelorMittal) is sold against this class but works by work-hardening in service rather than by delivered hardness.
- Hardox 450 HiTuf / XAR HT — producer variants: Higher-toughness versions at the same hardness, for impact-loaded parts in thick section.

Product forms: hot-rolled quenched and tempered plate, typically 3 to 80 mm (widest stock range of the class); profile-cut parts and laser or plasma cut blanks; press-brake formed liners and chutes; wear strip, round bar and tube in some ranges; high-toughness variants for impact duty (HiTuf, HT and similar designations)
Tolerances: thickness and flatness: EN 10029 or ASTM A6, normally ordered to a tighter flatness class than normal; hardness: the producer's own band, measured through thickness; for cut parts, the contour tolerance is the cutter's, not the mill's — specify it separately

### AR450 hardness and wear life
425–475 HBW as delivered, nominally 450, about 47 HRC. Against S355 structural plate at 150 HBW it returns roughly four to five times the life in sliding abrasion; against AR400 the gain is 20–30 %. Those multipliers hold only where the abrasive is harder than the plate and the mechanism is sliding. Measure through thickness, not at the surface.

### When the step from AR400 pays
Run the comparison on cost per tonne of material moved, not on plate price. The step pays when the part is simple (flat or single-bend), frequently replaced (so the wear saving is collected often), and bolted rather than welded (so no welding penalty). It does not pay when the part is complex (multiple tight bends, welded assembly), long-lived (the wear saving arrives once a decade), or impact-loaded (where the lower toughness is a liability rather than a cost). The fabrication penalty is per part made; the wear gain is per plate changed.

### Forming at 450 HBW
Minimum inner bend radius rises to about 3.5–4 × thickness transverse to the rolling direction and 5–6 × parallel to it. Three precautions become mandatory rather than advisable: grind the thermal-cut edges in the bend zone, because the hardened and notched cut edge is where the crack starts; form at room temperature or above, never on cold plate from an outside rack; and orient the bend across the rolling direction wherever the layout allows. A cracked bend at this hardness is almost always one of those three, not a material fault.

### Welding window
Carbon equivalent runs higher than at 400 HBW, so the preheat threshold drops to roughly 15 mm for a single plate and lower for combined thicknesses — the producer's own table governs and should be followed rather than interpolated. Low-hydrogen consumables, filler softer than the plate, moderate heat input, no post-weld heat treatment. The softened heat-affected zone is wider in proportion than at 400 HBW, so designs that place a weld seam in the wear path fail faster here; plug welding, bolting and weld-on wear buttons are the normal answers.

### The high-toughness variants
Every major range offers a version at the same hardness with substantially higher impact energy — typically 45–65 J at −40 °C against 27–40 J for the standard product — achieved through cleaner steel, tighter segregation control and a modified quench. They cost more and are stocked in fewer thicknesses. They are the right answer for thick-section impact parts: rock boxes, crusher feed chutes, grizzly bars, truck body floors taking large lump drop. For sliding abrasion with no impact they add nothing.

### Alternatives at the same performance level
Two genuinely different routes reach AR450 performance. Work-hardening plate (Creusabro 4800 and similar) is delivered at about 370 HBW — so it forms, cuts and drills like a softer plate — and hardens to 440–470 HBW in service. It is attractive for complex formed parts and less so where the wear is light enough that it never fully hardens. Austenitic manganese steel at 12–14 % Mn is delivered soft and work-hardens past 500 HBW at the surface, but only under heavy impact; it is the material of crusher jaws and rail frogs and is poor in pure sliding abrasion. Choose by mechanism, not by hardness number.

### Weldability
As for the 400 class but with less margin. Low-hydrogen consumables, a filler softer than the plate, moderate heat input and interpass temperature, and no post-weld heat treatment under any circumstances. The difference is the preheat threshold: roughly 100 °C above 15–20 mm single-plate thickness, and lower again where combined thickness is high or the joint is restrained — use the producer's table rather than a rule of thumb, because the carbon equivalents differ between brands at this hardness. Hydrogen control matters more here: dry the electrodes, clean the joint, and do not weld damp plate. Expect a proportionally wider softened heat-affected zone, and design the joint out of the wear path.

### Machining, forming, heat treatment
Slower and harder than AR400 throughout: roughly 25–30 % machinability relative to 1 % C free-cutting steel. Carbide tooling only for anything beyond a single hole, rigid set-ups, low speeds, firm uninterrupted feed. Drilling at 475 HBW is at the limit of cobalt HSS and should be done with carbide; punching is out of the question and plasma or waterjet cutting is the normal route for holes. Thermal cutting leaves a 2–4 mm hardened edge that must be ground where the part is formed or fatigue loaded. Grinding is routine. Where a threaded fixing is needed, weld a boss rather than tap the plate.

Applications: Tipper and dump body floors and sides (the volume application of the class); Bolt-in liners for chutes, hoppers, bins and transfer points; Conveyor skirts, scrapers, deflectors and impact plates; Excavator and loader bucket liners, side cutters and wear strips; Screen decks, feeder pans and grizzly bars (high-toughness variant); Recycling and shredder wear parts, baler liners; Cement, quarry and mining plant wear components

Q: What is the hardness of AR450?
A: Nominally 450 HBW, delivered in a band of about 425–475 HBW depending on the producer — roughly 47 HRC. Ask for the figure measured through thickness at a stated depth, because a surface reading on a quenched plate reads high and does not represent the material that will be exposed once the part has worn.

Q: Is AR450 worth the extra cost over AR400?
A: On a simple, frequently replaced, bolted part — usually yes: 20–30 % more life for 5–15 % more per tonne, with the saved downtime on top. On a complex formed and welded part — usually no, because the fabrication penalty is paid once per part made while the wear saving is collected once per plate change, and at 450 HBW the bend radius, preheat threshold and toughness are all worse. Compare cost per tonne of material moved, not plate price.

Q: Is AR450 the same as Hardox 450?
A: Hardox 450 is a product in the AR450 class — SSAB's, and the most widely stocked wear plate in the world — but AR450 is a trade description, not a definition, so the terms are not interchangeable. Another mill's AR450 may differ in analysis, guaranteed impact energy, bend radius and tolerance class. Naming Hardox on a drawing names a supplier.

Q: What bend radius does AR450 need?
A: About 3.5–4 × thickness for an inner radius with the bend transverse to the rolling direction, and 5–6 × thickness parallel to it. Grind the thermal-cut edges in the bend zone first, form at room temperature or above, and orient the bend across the rolling direction. Most cracked bends in this hardness class come from one of those three being skipped rather than from the plate.

Q: Does AR450 need preheat for welding?
A: Usually above about 15–20 mm single-plate thickness, at roughly 100 °C, and at lower thickness where combined thickness is large or the joint restrained. The threshold is lower than for AR400 because the carbon equivalent is higher, and it differs between brands at the same hardness — follow the producer's own combined-thickness table rather than a general rule. Use low-hydrogen consumables and a filler softer than the plate, and never post-weld heat treat.

Q: What is a high-toughness AR450 and when do I need it?
A: A version at the same hardness with roughly 45–65 J at −40 °C instead of 27–40 J, achieved through cleaner steel and a modified quench — sold as Hardox 450 HiTuf and equivalent names. Specify it for thick-section impact duty: rock boxes, crusher feed chutes, grizzly bars, truck floors taking large lump drop. For sliding abrasion without impact it costs more and gains nothing.

Q: Why do AR450 parts crack rather than wear out?
A: Because at this hardness the toughness margin is narrower, so the fabrication defects that AR400 tolerates become failures. The four usual causes are a bend radius below the minimum, an unground thermal-cut edge in a stressed or formed zone, a weld filler harder than the plate, and impact loading beyond what the standard product's toughness supports. All four are process problems with known fixes.

Q: What is the alternative to AR450 for a complex formed part?
A: A work-hardening plate such as Creusabro 4800 is delivered around 370 HBW — so it forms, cuts and drills like a much softer steel — and hardens to 440–470 HBW in service. That is a real alternative where the part geometry is the obstacle. Where the duty is heavy gouging impact rather than sliding, austenitic manganese steel is the other route: soft on delivery, over 500 HBW at the surface after bedding in, and poor in pure abrasion.

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## AR500 — Abrasion-resistant quenched and tempered plate, nominal 500 HBW
URL: https://steelstandart.com/grade/ar500/
System: Proprietary (trade names) | Family: Quenched & tempered steel | Standard:  | Verified against: 
Aliases: AR 500, AR500 steel, AR500 plate, AR500 wear plate, 500 HBW wear plate, Hardox 500, XAR 500, Quard 500, Dillidur 500, Raex 500, Abrazo 500, Durostat 500, Everhard 500, AR500 target, AR500 equivalent, AR550, AR600

AR500 is the last hardness in the wear-plate range that can still be fabricated, and understanding it means understanding where the limits fall. At a nominal 500 HBW — delivered around 470–530, roughly 50 HRC — it gives about five to six times the sliding-abrasion life of S355 structural plate and some 15–20 % more than AR450.

Everything else about it is worse. The minimum inner bend radius rises to roughly 5 × thickness, against 3 × for AR400. Preheat becomes mandatory from about 10 mm rather than 20. Guaranteed impact energy, where it is guaranteed at all, falls to 20–30 J at −40 °C, and the high-toughness variants that exist at 450 HBW thin out sharply above it, because the metallurgy that buys toughness and the metallurgy that buys 500 HBW work against each other. The available thickness range narrows too, because a mill can only quench so deep so hard. In practice AR500 is specified for flat, bolted, sliding-wear liners and avoided for anything that must be formed into a shape or welded into a structure.

That leads to the selection rule that matters most at this hardness: the harder plate does not always last longer in service. Where there is impact, AR500 chips and AR450 does not, and a plate that chips loses material far faster than one that abrades. Where the abrasive is softer than the plate, the extra hardness does almost nothing because the abrasive is being crushed rather than cutting. AR500 earns its place in heavy sliding abrasion by hard rock, and loses it almost everywhere else.

Finally, a point that causes real confusion and occasionally real harm. AR500 is not armour plate. The name is widely used for steel shooting targets, and "Armox 500T" sounds like the same thing, but a protection plate is a different product: specified to ballistic acceptance criteria, with controlled through-thickness hardness, high guaranteed toughness, cleanliness to a protection standard, and testing against MIL-DTL-46100 or MIL-DTL-12560 class requirements. AR500 meets none of those and must never be substituted into an armour specification. For targets it is the conventional material, but that is a commercial usage of the same plate, not a protection rating — and the plate's own distance, calibre and angle limits come from the target maker, not from the steel.

Chemical composition (mass %): C ≤ 0.3; Si ≤ 0.7; Mn ≤ 1.6; P ≤ 0.025; S ≤ 0.01; Cr ≤ 1.5; Ni ≤ 2.5; Mo ≤ 0.8; B ≤ 0.005
**Indicative ceilings across the AR500-class products, not a specification** — no standard defines the grade. The carbon ceiling reaches about 0.30 % and the nickel and molybdenum allowances roughly double against the 400 class, because 500 HBW through a 40 mm plate demands a much deeper hardening response. The consequence for the user is a **carbon equivalent that is no longer comfortable**: preheat becomes the rule rather than the exception, and the welding window narrows to the point where many parts are designed to avoid welding altogether.

Mechanical properties:
- AR500 class — hardness band as delivered: yield — MPa; tensile — MPa; elongation — %; hardness 470–530 HBW (typical, brand dependent)
- Typical tensile properties at 500 HBW: yield 1250–1400 MPa; tensile 1600–1750 MPa; elongation 8 %; hardness ≈ 500 HBW
- AR550 / AR600 classes — for comparison: yield 1400–1700 MPa; tensile 1800–2100 MPa; elongation 6–7 %; hardness 525–625 HBW
- Charpy impact (where guaranteed): yield — MPa; tensile — MPa; elongation — %; hardness 20–30 J at −40 °C, longitudinal — often typical rather than guaranteed
- Minimum inner bend radius, transverse: yield — MPa; tensile — MPa; elongation — %; hardness ≈ 5 × thickness (6–8 × parallel to rolling)
- Preheat threshold, single plate: yield — MPa; tensile — MPa; elongation — %; hardness ≈ 125–150 °C from about 10 mm (producer's table governs)
The hardness and strength rows improve on the softer classes; **every other row gets worse**, and that is the real content of this page. Bend radius roughly doubles against AR400, the preheat threshold halves, the guaranteed impact energy falls to 20–30 J where it is guaranteed at all, and the available thickness range narrows. AR500 is specified for what it survives, not for what it can be made into.
Impact: 20–30 J longitudinal where guaranteed J at −40 °C °C (Several producers publish typical values only at this hardness, and some publish none. High-toughness variants exist at 450 HBW but thin out sharply above it, because the metallurgy that buys toughness and the metallurgy that buys 500 HBW pull in opposite directions.)

Equivalents:
- AR450 (Proprietary (trade names)) — near: 425–475 HBW: 15–20 % less abrasion life, and a far easier plate to work with — bend radius around 3.5–4 × thickness against 5 ×, preheat from 15–20 mm against 10 mm, and a genuine high-toughness variant available. For most formed or welded parts it is the better choice, and the selection economics are set out on that page.
- AR400 (Proprietary (trade names)) — near: 370–430 HBW, the fabrication-friendly end of the class and the page that explains what AR designations mean, how hardness relates to wear, and how to specify wear plate without naming a brand.
- 1.2379 (EN (European)) — functional: X153CrMoV12 (D2) at 58–62 HRC, about 700 HBW, with roughly 15 % carbide volume. The tool-steel route for small, high-wear inserts; not available or usable as a plate product.
- S355J2 (EN (European)) — functional: EN 10025-2 S355J2 at roughly 150 HBW — the reference point. AR500 lasts about five to six times as long in sliding abrasion, and that multiplier is the whole reason to accept its fabrication penalties.
- Armox 500T (Proprietary (trade names)) — functional: **Protection plate, not wear plate, despite the similar number.** Armox and its counterparts (Mars, Ramor, Secure) are specified to ballistic acceptance criteria with controlled through-thickness hardness, high guaranteed toughness and cleanliness to a protection standard, and are tested to MIL-DTL-46100 / MIL-DTL-12560 class requirements. An AR500 plate meets none of those requirements and must never be substituted for an armour specification.
- Creusabro 8000 (Proprietary (trade names)) — functional: ArcelorMittal's work-hardening route against this class: delivered around 430 HBW and hardening to about 550–600 HBW in service. It forms, cuts and drills far more easily than a delivered-500 plate, which makes it the practical alternative where part geometry rules AR500 out.
- Mn13 (Proprietary (trade names)) — functional: Austenitic manganese steel, delivered near 200 HBW and work-hardening past 500 HBW at the surface under heavy impact. Where the mechanism is **gouging** rather than sliding — crusher jaws and cones, rail frogs, hammer mill parts — it outlasts any martensitic plate, and it is poor in pure abrasion.
- chromium carbide overlay (Proprietary (trade names)) — functional: A mild-steel backing plate with a welded chromium-carbide deposit at 600–750 HV. This is the normal answer above AR500 for sliding abrasion: the backing stays weldable and formable while the working face is far harder than any through-hardened plate. It cannot take impact and the overlay cracks by design.

Superseded names:
- Hardox 500 — SSAB trademark: The reference product of the class; Hardox 550 and 600 sit above it in limited thicknesses, and Hardox Extreme at around 650–700 HBW is a liner material only. Hardox is a registered trademark of SSAB.
- XAR 500 / Dillidur 500 — ThyssenKrupp / Dillinger trademarks: Durostat 500 (voestalpine), Brinar 500 (Buderus).
- Quard 500 / Raex 500 — NLMK / SSAB trademarks: Abrazo 500 (Ancofer), Everhard 500 (JFE). Creusabro 8000 (ArcelorMittal) is the work-hardening product sold against this class.
- AR500 target plate — shooting-range trade usage: A separate commercial usage of the same name for steel shooting targets. It is the same class of plate, but the selection criteria are entirely different and it is **not** armour plate — see below.

Product forms: hot-rolled quenched and tempered plate, typically 4 to 50 mm (thinner range than the softer classes); profile-cut parts, usually waterjet or plasma cut and used flat; wear strip and bar; harder variants at 550 and 600 HBW in some ranges, in limited thicknesses
Tolerances: thickness and flatness: EN 10029 or ASTM A6; flatness is harder to hold at this hardness and should be ordered to a stated class; hardness: the producer's own band, measured through thickness; thickness availability is the real constraint — the harder the class, the narrower the range a mill can quench uniformly

### AR500 hardness and what it returns
470–530 HBW as delivered, nominally 500, about 50 HRC. Roughly five to six times the sliding-abrasion life of S355 structural plate and 15–20 % more than AR450. The multiplier applies only where the abrasive is harder than the plate and the mechanism is sliding; in impact-dominated or soft-abrasive service it collapses. Measure through thickness.

### Where the fabrication limits bite
Four numbers change the design. Bend radius ≈ 5 × thickness transverse and 6–8 × parallel, so most AR500 parts are used flat or with a single generous bend. Preheat from about 10 mm at 125–150 °C, with combined thickness pulling that lower. No post-weld heat treatment, ever — a stress-relief cycle tempers the plate below its purchase hardness. No punching, no tapping, no practical drilling in production; holes are waterjet or plasma cut, and threaded fixings are welded-on bosses. A part that needs several tight bends and a welded assembly should not be in AR500.

### Why harder is sometimes shorter-lived
Three mechanisms reverse the hardness ranking. Impact: at 20–30 J the plate chips, and a chip removes more material in one event than hours of abrasion; AR450 with a guaranteed 40 J will outlast it on a crusher chute. Soft abrasive: against a particle softer than the surface, the particle deforms instead of cutting, and the difference between 450 and 500 HBW is negligible — most sand and most coal fall here. Gouging by large lumps: the surface is being ploughed rather than scratched, and work-hardening austenitic manganese steel, delivered at 200 HBW, outperforms every martensitic plate. Identify the mechanism before buying hardness.

### AR500 is not armour plate
A protection plate is a different product sold against different criteria: ballistic acceptance testing, a controlled and narrow through-thickness hardness profile, high guaranteed toughness (because a brittle plate shatters rather than resisting), and cleanliness and segregation control to a protection standard — Armox, Mars, Ramor and Secure, qualified against MIL-DTL-46100 or MIL-DTL-12560 class requirements. AR500 carries no ballistic testing, no toughness guarantee in many ranges, and no standard at all. It must not be substituted into an armour specification. Its use for shooting targets is a separate commercial practice, and the calibre, distance and angle limits for a target come from the target maker's rating, not from the plate's hardness.

### What to use above AR500
The through-hardened plate route effectively ends here. AR550 and AR600 exist in limited thicknesses and are liner materials — essentially unformable and barely weldable. Above that the practical answers change kind: chromium carbide overlay (a weldable mild-steel backing with a 600–750 HV deposit) for sliding abrasion; cast high-chrome iron for slurry pumps and mill liners; austenitic manganese steel for gouging impact; ceramic tile or rubber-ceramic composite for fine high-velocity abrasive; and tool steel inserts at 700 HBW for small, concentrated wear points. Each of these solves a problem a harder plate cannot.

### Cutting and hole-making
Waterjet is preferred where no heat-affected zone is acceptable, and that is more often at this hardness because the thermal-cut edge zone — 3–5 mm of re-hardened, notched material — is a crack initiator in a plate with little toughness to spare. Plasma and laser cutting work and are the volume route; grind the edge wherever the part will be formed, fatigue loaded or welded near the cut. Oxy-fuel cutting on thick plate needs controlled preheat to avoid edge cracking. Drilling is impractical in production; use cut holes. Flame straightening is not an option — localised heating tempers the plate.

### Weldability
Weldable, but with the narrowest window of the class and often designed around rather than used. Low-hydrogen consumables, filler clearly softer than the plate, preheat 125–150 °C from about 10 mm single-plate thickness and lower where combined thickness or restraint is high — the producer's table governs, and at this hardness the brands differ enough that interpolating is unwise. Hydrogen control is critical: dry consumables, clean dry joints, no welding on damp or cold plate. Keep heat input moderate and accept a proportionally wide softened heat-affected zone. No post-weld heat treatment under any circumstances. In practice AR500 parts are bolted, plug welded or fitted as loose liners, and the structure behind them is made of a weldable grade.

### Machining, forming, heat treatment
Effectively a grinding-and-cutting material rather than a machining one: machinability around 20–25 % relative to 1 % C free-cutting steel. Production drilling, tapping, punching and shearing are all impractical at 500 HBW. Single holes can be made with carbide drills in a rigid set-up at low speed and firm continuous feed, but cut holes are the normal route. Milling and turning of cut edges is possible with carbide or CBN at very low speed. Grinding works normally and is the standard way to dress thermal-cut edges, which should be done on any part that will be formed, welded near the cut, or cyclically loaded. Flame straightening and local heating are prohibited — they temper the plate.

Applications: Flat bolt-in liners for severe sliding abrasion — ore chutes, transfer points, rock boxes; Dump and haul truck body liners in hard-rock mining; Crusher and screen wear plates where impact is low; Conveyor skirt and scraper blades in abrasive duty; Cutting edges, side cutters and bucket lips (often with overlay or weld-on protection); Wear strips, slide plates and chute deflectors; Steel shooting targets (commercial usage — see the note above; not armour)

Q: Is AR500 armour plate?
A: No. Armour, or protection plate, is a different product: specified to ballistic acceptance criteria with a controlled through-thickness hardness profile, high guaranteed toughness and cleanliness to a protection standard, and qualified against MIL-DTL-46100 or MIL-DTL-12560 class requirements. Products such as Armox, Mars, Ramor and Secure are in that category. AR500 has no standard at all, no ballistic testing and often no guaranteed toughness, and it must never be substituted into an armour specification.

Q: What is the hardness of AR500?
A: Nominally 500 HBW, delivered in a band of roughly 470–530 HBW depending on the producer — about 50 HRC. Ask for a through-thickness measurement at a stated depth rather than a surface reading, because quenched plate reads high at the surface.

Q: Can AR500 be bent?
A: Only to generous radii. The minimum inner radius is about 5 × thickness with the bend transverse to the rolling direction, and 6–8 × thickness parallel to it — roughly double what AR400 needs. Thermal-cut edges in the bend zone must be ground, the plate must be at room temperature or above, and the bend must run across the rolling direction. Most AR500 parts are designed flat or with a single large-radius bend for this reason.

Q: Can AR500 be welded?
A: Yes, with the narrowest window of the class: low-hydrogen consumables, a filler clearly softer than the plate, and preheat of 125–150 °C from about 10 mm single-plate thickness and lower with combined thickness or restraint. Hydrogen control is critical and the producer's own table should be followed rather than interpolated. Never post-weld heat treat. In practice AR500 is usually bolted or plug welded as a liner rather than welded into a structure.

Q: Does AR500 always last longer than AR450?
A: No. In heavy sliding abrasion by hard rock it gives 15–20 % more life. But where there is impact it chips, and a chip removes more material in one event than hours of abrasion, so AR450 with a guaranteed 40 J will outlast it. Where the abrasive is softer than the plate — much sand and coal — the extra hardness does almost nothing. And in heavy gouging, work-hardening manganese steel beats both. Identify the wear mechanism before buying hardness.

Q: What should I use if AR500 is not hard enough?
A: Change kind rather than climbing further. Chromium carbide overlay gives a 600–750 HV working face on a weldable mild-steel backing and is the usual answer for severe sliding abrasion. Cast high-chrome iron suits slurry pumps and mill liners, austenitic manganese steel suits gouging impact, ceramic or rubber-ceramic composite suits fine high-velocity abrasive, and tool-steel inserts at 700 HBW suit small concentrated wear points. AR550 and AR600 exist but are liner materials — essentially unformable and barely weldable.

Q: Can holes be drilled in AR500?
A: Single holes can be made with carbide drills in a rigid set-up at low speed and firm continuous feed, but production drilling is impractical and punching and tapping are out of the question. Holes are normally waterjet, plasma or laser cut, and threaded fixings are made by welding a boss onto the plate rather than tapping it.

Q: Is AR500 the same as Hardox 500?
A: Hardox 500 is SSAB's product in this class and the usual reference, but AR500 is a trade description rather than a definition — another mill's AR500 may differ in analysis, guaranteed impact energy, bend radius, available thickness and tolerance class. To get comparable quotations, specify the through-thickness hardness band, the guaranteed impact energy and temperature, the bend radius at the ordered thickness and the tolerance class, rather than a brand name.

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## C10 (1.0301) — Unalloyed low-carbon case-hardening steel
URL: https://steelstandart.com/grade/c10/
System: EN (European) | Family: Case-hardening steel | Standard: EN 10084 | Verified against: EN 10084:2008
Aliases: C10E, 1.1121, C10R, 1.1207, Ck10, C 10, 1.0301, C8, C12, Ck 10, C10 steel

C10 is the lowest-carbon case-hardening steel in EN 10084: 0.07–0.13 % carbon, 0.3–0.6 % manganese, Werkstoff number 1.0301 (base) or 1.1121 for C10E, the old Ck10. Its very soft core (≈ 110–140 HB normalized) and outstanding cold formability make it above all a cold-heading and deep-drawing steel — screws, rivets, clevis pins, small bushes and drawn cups — that can afterwards be carburized to a 55–60 HRC skin where wear resistance is needed.

Because hardenability is minimal, the case is thin and only small parts are treated; for anything larger or more highly loaded, C15E or 16MnCr5 take over. Un-carburized C10 is also a general low-carbon bar and tube steel comparable to AISI 1010.

A note on names: searches for 'C8 steel' and 'C12 steel' almost always mean the cold-heading wire grades C8C and C12C of EN 10263-2, or simply a 0.08–0.12 % C steel — there is no separate C8 or C12 grade in EN 10084. C10/C10E is the grade to order.

Chemical composition (mass %): C 0.07 – 0.13; Si ≤ 0.4; Mn 0.3 – 0.6; P ≤ 0.045 (C10E (1.1121): P ≤ 0.035, S ≤ 0.035; C10R (1.1207): S 0.020–0.040); S ≤ 0.045; Cr ≤ 0.4 (Cr + Mo + Ni ≤ 0.63 (C10E/C10R)); Mo ≤ 0.1; Ni ≤ 0.4
EN 10084:2008 Table 3. There is no EN grade 'C8' or 'C12': those names belong to older DIN/ISO usage (C8C, C12C cold-heading grades of EN 10263-2 with C 0.06–0.10 / 0.10–0.15) — C10 covers the same territory.

Mechanical properties:
- Core after carburize, harden & temper, 11 mm ref. bar (C10E): yield ≥ 295 MPa; tensile 490–690 MPa; elongation 15 %; hardness —
- Core, 30 mm ref. bar: yield ≥ 255 MPa; tensile 440–590 MPa; elongation 16 %; hardness —
- Surface after carburizing: yield — MPa; tensile — MPa; elongation — %; hardness 55–60 HRC
- +N normalized (typical): yield ≈ 240–300 MPa; tensile ≈ 400–480 MPa; elongation 30 %; hardness ≈ 110–140 HB
- +A annealed (delivery): yield — MPa; tensile — MPa; elongation — %; hardness ≤ 131 HB
- Cold-drawn +C (typical, ≤ 16 mm): yield ≥ 390 MPa; tensile 500–650 MPa; elongation 10 %; hardness ≈ 160–200 HB
Core values per EN 10084 Annex F (informative). Normalized and cold-drawn values are typical, not standardized.

Equivalents:
- 1010 (AISI / SAE) — identical: AISI/SAE 1010 (G10100): C 0.08–0.13, Mn 0.30–0.60 — same window.
- 045M10 (BS (superseded British)) — identical: BS 970 045M10: C 0.07–0.13, Mn 0.30–0.60.
- 10 (GB/T (China)) — identical: GB/T 699 grade 10 (10#): C 0.07–0.13, Mn 0.35–0.65.
- 10 / 10kp (GOST (Russia/CIS)) — identical: GOST 1050 Steel 10: C 0.07–0.14, Mn 0.35–0.65.
- S10C / S09CK (JIS (Japan)) — identical: JIS G4051 S10C: C 0.08–0.13, Mn 0.30–0.60; S09CK is the case-hardening quality.
- 1008 (AISI / SAE) — near: C ≤ 0.10, Mn 0.30–0.50: covers the lower half of C10; the usual US cold-heading/sheet grade.
- SAE 1010 (ASTM / ASME) — near: EN 10084 C10 / 1.0301: 0.07–0.13 % C, 0.30–0.60 % Mn — the same steel in European designation, used as a case-hardening grade. The EN standard adds hardenability and case-depth requirements that SAE 1010 does not carry.
- C8C / C10C (EN (European)) — near: EN 10263-2 cold-heading wire grades (C 0.06–0.10 / 0.08–0.13) — what 'C8' usually refers to.
- C15 (EN (European)) — near: Next carbon step (0.12–0.18 %) with slightly stronger core.

Superseded names:
- Ck10 — DIN 17210 (withdrawn): = C10E (1.1121).
- C10 (1.0301) — DIN 17210: Base quality.
- 045M10 / 040A10 — BS 970
- XC10 — NF A 35-551

Product forms: bar (hot-rolled, bright); wire rod and cold-heading wire (dominant form); strip and sheet (as DC01-type or C10S); seamless tube (EN 10305-1 E155 / C10)
Tolerances: bright bar: EN 10278; wire rod: EN 10108 / EN 10263 (cold-heading)

### C10 hardness
Delivery (+A) ≤ 131 HB; normalized ≈ 110–140 HB; cold-drawn 160–200 HB; carburized surface 55–60 HRC (shallow case 0.2–0.6 mm); core 10–20 HRC.

### C10 yield and tensile strength
Normalized: yield ≈ 240–300 MPa, tensile ≈ 400–480 MPa, elongation ≈ 30 %. Cold-drawn: yield ≥ 390 MPa, tensile 500–650 MPa. Carburized core (11 mm ref.): 490–690 MPa.

### Heat treatment
Carburize 880–980 °C; quench in water from 880–920 °C (small parts) or oil; temper 150–200 °C. Normalize 900–940 °C. Spheroidize (+AC) 680–710 °C for cold heading. Ac1 ≈ 725 °C, Ac3 ≈ 875 °C.

### Physical properties
Density 7.85 g/cm³, E = 210 GPa, conductivity ≈ 52 W/m·K, expansion 12.2 × 10⁻⁶/K.

### Weldability
Excellent weldability (CEV ≈ 0.15 %): all processes, no preheat, ideal for resistance welding of headed parts and tube. Do not weld carburized surfaces.

### Machining, forming, heat treatment
Machinability is poor-to-fair when annealed (gummy, built-up edge) — index ≈ 55–60 %; cold-drawn bar machines better. C10R with controlled sulphur is used for automatic lathes. Cold heading, extrusion, drawing and bending are excellent — the reason it exists. Hot forging 1200–900 °C.

Applications: Cold-headed screws, rivets, nails and small fasteners (property classes 4.6–5.8); Clevis pins, spring pins, small bushes and rollers (carburized); Deep-drawn cups, caps and housings; Bright-drawn shafting for low-stress parts; Welded tube and fittings, bicycle and furniture tube (E155/E195 lineage); Chain side plates and links

Q: What is C8 steel or C12 steel?
A: There is no C8 or C12 in EN 10084. 'C8' usually means C8C (EN 10263-2 cold-heading wire, C 0.06–0.10) or an 0.08 % carbon commercial steel; 'C12' is C12C or an 0.10–0.15 % C steel. For bar and case-hardening parts, C10E covers the C8 range and C15E the C12 range.

Q: Is C10 the same as 1010?
A: Yes. AISI/SAE 1010 has C 0.08–0.13 and Mn 0.30–0.60 — the same window as C10. Case-hardening quality C10E corresponds to 1010 with tighter P/S.

Q: What is C10 used for?
A: Mainly cold-headed fasteners and small pressed or drawn parts, and small carburized parts such as pins, rollers and bushes. It is also a general low-carbon bar and tube steel.

Q: What is the difference between C10 and C15?
A: Carbon: 0.07–0.13 vs 0.12–0.18 %. C15 gives a slightly stronger core after carburizing and is used for somewhat larger or more loaded parts; C10 forms more easily.

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## C15 (1.0401) — Unalloyed case-hardening steel
URL: https://steelstandart.com/grade/c15/
System: EN (European) | Family: Case-hardening steel | Standard: EN 10084 | Verified against: EN 10084:2008
Aliases: C15E, 1.1141, C15R, 1.1140, Ck15, C 15, 1.0401, C15 steel, Ck 15

C15 is the simplest case-hardening steel: 0.12–0.18 % carbon, no alloying, Werkstoff number 1.0401 for the base quality and 1.1141 for C15E (the old Ck15, with lower phosphorus and fine-grain practice) — both in EN 10084. Carburizing puts 0.7–0.9 % carbon into the surface, which quenches to 55–62 HRC over a soft, tough core of about 500–600 MPa. Hardenability is very low, so the hard case is thin and the part must be small: pins, bushes, small gears, rollers, levers and cold-headed fasteners.

C15 also serves outside case hardening as a general low-carbon engineering bar — the European version of AISI 1015/1018 — for machined parts, welded fittings and cold-drawn shafting where a bright, dimensionally accurate bar is needed and strength is not critical. Cold drawing raises its yield to around 450 MPa.

AISI 1015, JIS S15C and GB/GOST 15 are identical in composition; 1018 is the near match most US warehouses supply. For larger case-hardened parts the step up is 16MnCr5.

Chemical composition (mass %): C 0.12 – 0.18; Si ≤ 0.4; Mn 0.3 – 0.6; P ≤ 0.045 (C15E (1.1141): P ≤ 0.035; C15R (1.1140): S 0.020–0.040); S ≤ 0.045; Cr ≤ 0.4 (C15E/C15R: Cr + Mo + Ni ≤ 0.63); Mo ≤ 0.1; Ni ≤ 0.4
EN 10084:2008 Table 3 (C15E/C15R) and EN 10083-2 for C15 as a general-use grade. C10E (1.1121, ex Ck10) is the 0.07–0.13 % C sibling; C16E (1.1148) the 0.12–0.18 % fine-grain variant.

Mechanical properties:
- Core after carburize, harden & temper, 11 mm ref. bar (C15E): yield ≥ 355 MPa; tensile 590–780 MPa; elongation 12 %; hardness —
- Core, 30 mm ref. bar: yield ≥ 295 MPa; tensile 490–640 MPa; elongation 14 %; hardness —
- Surface after carburizing: yield — MPa; tensile — MPa; elongation — %; hardness 55–62 HRC
- +N normalized (typical bar): yield ≥ 260 (typ. 280–320) MPa; tensile ≥ 430 (typ. 450–520) MPa; elongation 27 %; hardness ≈ 130–160 HB
- +A / +AC annealed (delivery): yield — MPa; tensile — MPa; elongation — %; hardness ≤ 143 HB
- Cold-drawn +C (typical, ≤ 16 mm): yield ≥ 450 MPa; tensile 600–750 MPa; elongation 8 %; hardness ≈ 180–220 HB
Core values from EN 10084 Annex F (informative, blank-hardened reference bars). Normalized and cold-drawn values are typical supplier data; EN 10084 specifies only chemistry and delivery hardness.

Equivalents:
- 1015 (AISI / SAE) — identical: AISI/SAE 1015 (G10150): C 0.13–0.18, Mn 0.30–0.60 — same window as C15. 1016/1018 have higher Mn (0.60–0.90) for slightly better hardenability.
- 080M15 (BS (superseded British)) — identical: BS 970 080M15: C 0.13–0.18, Mn 0.70–1.00 (Mn higher).
- 15 (GB/T (China)) — identical: GB/T 699 grade 15 (15#): C 0.12–0.18, Mn 0.35–0.65.
- 15 / 15kp (GOST (Russia/CIS)) — identical: GOST 1050 Steel 15: C 0.12–0.19, Mn 0.35–0.65.
- S15C / S15CK (JIS (Japan)) — identical: JIS G4051 S15C: C 0.13–0.18, Mn 0.30–0.60; S15CK is the case-hardening quality (P/S ≤ 0.025).
- 1018 (AISI / SAE) — near: C 0.15–0.20, Mn 0.60–0.90; the US stock grade most often supplied against a C15 request.
- C10 (EN (European)) — near: 1.1121 (ex Ck10): C 0.07–0.13 — softer core, better cold-heading.
- C10 (EN (European)) — near: Next carbon step (0.12–0.18 %) with slightly stronger core.
- 16MnCr5 (EN (European)) — functional: Alloyed case-hardening steel for larger sections and higher core strength.
- S235JR (EN (European)) — functional: Structural steel of similar carbon; not a case-hardening quality (no hardenability or cleanliness control).

Superseded names:
- Ck15 — DIN 17210 (withdrawn): = C15E (1.1141). The common German workshop name.
- C15 (1.0401) — DIN 17210 / DIN 17200: Base quality, unchanged number.
- Cm15 — DIN 17210: = C15R (controlled S).
- 080M15 / 080A15 — BS 970
- XC15 / XC18 — NF A 35-551

Product forms: round, square and hexagon bar (hot-rolled, bright); wire rod and cold-heading wire; forgings; seamless tube (EN 10305 as E155/C15); strip (EN 10132-2 as C15S)
Tolerances: hot-rolled bar: EN 10060; bright bar: EN 10278; wire: EN 10218

### C15 core and surface hardness
Carburized case 55–62 HRC at 0.3–1.0 mm case depth; core ≈ 15–25 HRC (590–780 MPa in an 11 mm bar, 490–640 MPa at 30 mm). Delivery hardness (+A) ≤ 143 HB.

### C15 yield and tensile strength (uncarburized)
Normalized: yield ≈ 280–320 MPa, tensile 450–520 MPa, elongation ≈ 27 %. Cold-drawn (+C) small bar: yield ≥ 450 MPa, tensile 600–750 MPa, elongation ≈ 8 %.

### Heat treatment
Carburize 880–980 °C (pack, gas or salt); direct quench in water (small parts) or oil from 850–880 °C; core-refine 880–920 °C; temper 150–200 °C. Normalize 880–920 °C. Ac1 ≈ 725 °C, Ac3 ≈ 860 °C.

### Hardenability
Very low (no Jominy band specified). Case hardness falls off below the surface rapidly; not suitable for parts over ~20 mm needing a deep case — use 16MnCr5 or 20MnCr5.

### Physical properties
Density 7.85 g/cm³, E = 210 GPa, conductivity ≈ 50 W/m·K, expansion 11.9 × 10⁻⁶/K.

### Weldability
Excellent weldability in the uncarburized state (CEV ≈ 0.20 %): all arc and resistance processes without preheat. Carburized surfaces should not be welded (cracking); mask or machine off the case first.

### Machining, forming, heat treatment
Machinability ≈ 65–70 % (gummy in the annealed state; better after cold drawing or normalizing). C15R with controlled sulphur is preferred for automatic lathes. Cold heading, cold extrusion and bending are excellent (this is a classic cold-heading grade as C15E/C10E). Hot forging 1150–900 °C.

Applications: Small case-hardened parts: pins, bushes, rollers, cam followers, small gears and sprockets; Cold-headed screws, rivets and studs (often as C10E/C15E); Bright-drawn shafting and machined general-purpose parts (as 1.0401); Levers, links, spacers and washers; Welded fittings and low-stress tube parts; Chain components (roller chain bushes and pins after carburizing)

Q: What is the difference between C15 and C15E?
A: C15E (1.1141, ex Ck15) is the case-hardening quality: P ≤ 0.035 %, fine-grain (Al-treated) practice, guaranteed hardenability response. C15 (1.0401) is the base quality with P/S ≤ 0.045 % for general engineering use.

Q: Is C15 the same as 1018?
A: Close but not identical: 1018 has C 0.15–0.20 and Mn 0.60–0.90, slightly richer than C15 (C 0.12–0.18, Mn 0.30–0.60). AISI 1015 is the exact match. 1018 is what most US suppliers deliver against a C15 order and it works in practice.

Q: How hard can C15 get?
A: Only through carburizing: 55–62 HRC on the surface with a shallow case. Without carburizing it cannot be usefully hardened (as-quenched ≈ 35–40 HRC in very thin sections).

Q: What is C15 equivalent to in JIS and GB?
A: JIS S15C / S15CK and GB/T 699 grade 15 — identical carbon and manganese windows.

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## C45 (1.0503) — Medium-carbon steel for quenching and tempering
URL: https://steelstandart.com/grade/c45/
System: EN (European) | Family: Carbon steel | Standard: EN 10083-2 | Verified against: EN 10083-2:2006
Aliases: C45E, 1.1191, C45R, 1.1201, Ck45, C 45, 1.0503, C45+N, C45+QT, C45E AISI, 080M46 EN

C45 is the medium-carbon steel everybody has in the rack: 0.42–0.50 % carbon, no deliberate alloying, Werkstoff number 1.0503, specified in EN 10083-2 for quenching and tempering. Supplied normalized it gives 305–340 MPa yield and ~600 MPa tensile; quenched in water and tempered it reaches 490 MPa yield and 700–850 MPa tensile in sections up to 16 mm, and it can be induction- or flame-hardened to 55–58 HRC on the surface.

The catch is hardenability: with no Cr or Mo, C45 through-hardens only in thin sections (roughly 15–20 mm in water). Above that the core stays pearlitic and designers move to 42CrMo4. That trade-off — cheap, machinable, surface-hardenable, but shallow — defines where C45 is used: shafts, pins, gears with induction-hardened teeth, keys, bolts and machine parts of moderate size.

C45E (1.1191, the old Ck45) is the same chemistry with lower phosphorus and a guaranteed impact value; C45R (1.1201) adds controlled sulphur for machining. Internationally C45 is identical to AISI 1045, JIS S45C and GB/GOST 45.

Chemical composition (mass %): C 0.42 – 0.5; Si ≤ 0.4; Mn 0.5 – 0.8; P ≤ 0.045 (C45E (1.1191): P ≤ 0.030, S ≤ 0.035; C45R (1.1201): S 0.020–0.040 for machinability); S ≤ 0.045; Cr ≤ 0.4 (Cr + Mo + Ni ≤ 0.63 %); Mo ≤ 0.1; Ni ≤ 0.4
EN 10083-2:2006 Table 3. C45 is the base quality; C45E is the fine-grain, low-P version (former Ck45); C45R has controlled sulphur.

Mechanical properties:
- +N normalized, ≤ 16 mm: yield 340 MPa; tensile ≥ 620 MPa; elongation 14 %; hardness ≤ 207 HB (+A)
- +N normalized, 16–100 mm: yield 305 MPa; tensile ≥ 580 MPa; elongation 16 %; hardness —
- +N normalized, 100–250 mm: yield 275 MPa; tensile ≥ 560 MPa; elongation 16 %; hardness —
- +QT quenched & tempered, ≤ 16 mm: yield 490 MPa; tensile 700–850 MPa; elongation 14 %; hardness ≈ 210–250 HB
- +QT, 16–40 mm: yield 430 MPa; tensile 650–800 MPa; elongation 16 %; hardness —
- +QT, 40–100 mm: yield 370 MPa; tensile 630–780 MPa; elongation 17 %; hardness —
EN 10083-2 Tables 5 and 6. Q&T values apply to the ruling section given; C45 has low hardenability, so through-hardening is only achieved below ~20 mm.
Impact: 25 J at 20 °C (+QT, ≤ 16 mm, longitudinal, C45E only)

Equivalents:
- 1045 (AISI / SAE) — identical: AISI/SAE 1045 (UNS G10450): C 0.43–0.50, Mn 0.60–0.90 — same carbon window; C45 additionally caps Cr/Mo/Ni. Interchangeable in practice.
- 45 (GOST (Russia/CIS)) — identical: GOST 1050 Steel 45: C 0.42–0.50, Mn 0.50–0.80, Si 0.17–0.37.
- S45C (JIS (Japan)) — identical: JIS G4051 S45C: C 0.42–0.48, Mn 0.60–0.90; matches C45 within rounding.
- 080M46 (BS (superseded British)) — near: BS 970 080M46: C 0.42–0.50, Mn 0.60–1.00 — slightly wider Mn.
- 080M40 (BS (superseded British)) — near: C45 (1.0503) is 0.42–0.50 % C against 080M40's 0.36–0.44 %, so it sits slightly above — closer to 080M46. For general shafting the substitution is routine, but C45 will through-harden marginally deeper and machine marginally harder.
- C45E (EN (European)) — near: Same grade with P ≤ 0.030 and guaranteed impact; order C45E when toughness or fine grain matters.
- 42CrMo4 (EN (European)) — functional: Alloyed alternative with far higher hardenability for the same part geometry above 25 mm.

Superseded names:
- Ck45 — DIN 17200 (withdrawn 1987): Ck45 = today's C45E (1.1191). Still the most-used name in German-speaking workshops.
- C45 (1.0503) — DIN 17200: Base quality, number unchanged.
- 080M46 — BS 970 (withdrawn)
- XC45 / XC48 — NF A 35-552
- C45 / C46 — UNI 7845

Product forms: round, square and flat bar (hot-rolled, peeled, cold-drawn); plate and wide flat; forgings; seamless tube (EN 10297); wire rod
Tolerances: hot-rolled round bar: EN 10060; bright bar: EN 10278 (h9–h11); plate: EN 10029

### C45 yield strength
Normalized (+N): ≥ 340 MPa ≤ 16 mm, ≥ 305 MPa 16–100 mm. Quenched and tempered (+QT): ≥ 490 MPa ≤ 16 mm, 430 MPa 16–40 mm, 370 MPa 40–100 mm.

### C45 tensile strength
+N: ≥ 620 MPa (≤ 16 mm) / ≥ 580 MPa (16–100 mm). +QT: 700–850 MPa (≤ 16 mm), 650–800 MPa (16–40 mm), 630–780 MPa (40–100 mm).

### C45 hardness
Soft-annealed (+A) max 207 HB; normalized ≈ 170–210 HB; Q&T ≈ 210–250 HB (core, ≤ 16 mm). Surface hardening by induction or flame reaches 55–58 HRC; through-hardened thin sections quenched in water reach 58–60 HRC before tempering.

### Heat treatment temperatures
Normalize 840–880 °C air; soft anneal 650–700 °C; harden 820–860 °C water (or oil for thin, simple shapes); temper 550–660 °C for Q&T, 150–200 °C after surface hardening. Ac1 ≈ 725 °C, Ac3 ≈ 785 °C, Ms ≈ 340 °C.

### Physical properties
Density 7.85 g/cm³, E = 210 GPa, thermal conductivity ≈ 45 W/m·K, expansion 11.5 × 10⁻⁶/K (20–100 °C).

### Weldability
Weldability is limited: with CEV ≈ 0.55–0.65 % C45 hardens in the heat-affected zone and cracks without precautions. Preheat 200–300 °C, use low-hydrogen basic electrodes, and temper or stress-relieve at 550–650 °C after welding. Where possible weld in the normalized (not Q&T) condition and heat-treat afterwards. Avoid welding surface-hardened areas.

### Machining, forming, heat treatment
Machinability index about 55–60 % (annealed/normalized) relative to 1212; C45R with 0.02–0.04 % S improves chip breaking. Machine before hardening wherever possible; Q&T at 250 HB is still machinable with carbide. Cold forming is limited to gentle bends in the annealed state; hot forming 1100–850 °C followed by normalizing. Induction and flame hardening are the main surface treatments; nitriding is possible but shallow.

Applications: Shafts, axles and spindles up to ~60 mm diameter; Gears and sprockets with induction-hardened teeth; Pins, bolts (property class 8.8 after Q&T), studs and keys; Hydraulic cylinder rods (chrome-plated C45E); Machine components, couplings, rollers, rams; Hand tools, hammers and agricultural wear parts (flame-hardened)

Q: Is C45 the same as 1045?
A: Yes. C45 (EN 10083-2) and AISI/SAE 1045 have the same carbon window (0.42–0.50 %) and near-identical Mn; mills routinely dual-certify. C45E is the cleaner version (P ≤ 0.030 %, guaranteed impact).

Q: What is the difference between C45 and C45E?
A: C45E (1.1191, formerly Ck45) has P ≤ 0.030 % and S ≤ 0.035 %, fine-grain practice and a guaranteed 25 J impact in the Q&T condition. C45 (1.0503) allows P and S up to 0.045 % and has no impact requirement.

Q: How hard can C45 get?
A: Surface: 55–58 HRC after induction or flame hardening. Through-hardened: 58–60 HRC as-quenched in thin sections (≤ 15–20 mm water quench), falling quickly in thicker bars because hardenability is low. Typical Q&T core hardness is 210–250 HB.

Q: Can C45 be welded?
A: Only with preheat (200–300 °C), low-hydrogen consumables and post-weld tempering. For welded assemblies designers usually choose S355J2 for the structure and C45 only for the machined part, joined mechanically.

Q: What is C45 equivalent to in China and Japan?
A: GB/T 699 grade 45 (45#) and JIS G4051 S45C are both identical in composition.

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## DC01 (1.0330) — Cold-rolled low-carbon steel for cold forming
URL: https://steelstandart.com/grade/dc01/
System: EN (European) | Family: Cold-rolled & coated sheet | Standard: EN 10130 | Verified against: EN 10130:2006
Aliases: DC01+ZE, DC 01, St12, St 12, 1.0330, DC01 A, DC01 B, CR1, St2

DC01 is the commercial-quality cold-rolled steel sheet of EN 10130 — the flat, smooth, 0.4–3 mm material that becomes cabinets, panels, brackets, drums and light enclosures. The name decodes as D (flat product for cold forming), C (cold-rolled), 01 (the lowest forming class); the Werkstoff number is 1.0330 and the pre-1991 name St12 is still in daily use.

Chemistry is minimal — carbon ≤ 0.12 %, Mn ≤ 0.60 % — and the standard guarantees only a yield window of 140–280 MPa, a tensile range of 270–410 MPa and 28 % elongation. There is no guaranteed r-value or n-value, so DC01 suits bending, roll forming, mild stretching and shallow pressings; deep drawing moves the buyer to DC03, DC04 or DC06.

Surface quality A or B, finish b/g/m/r and the option of an electro-galvanized skin (DC01+ZE) are all ordered under EN 10130 / EN 10152 designations. JIS SPCC, BS CR1 and IS 513 CR1 are the same class; the American A1008 CS Type B is the nearest by intent but has no mechanical guarantees.

Chemical composition (mass %): C ≤ 0.12; Mn ≤ 0.6; P ≤ 0.045; S ≤ 0.045
EN 10130:2006 Table 2, ladle analysis. Si and Al not limited. Al-killed or rimmed practice at the mill's option; Al-killed is standard in Europe today.

Mechanical properties:
- 0.35 ≤ t < 0.70 mm: yield 140–280 MPa; tensile 270–410 MPa; elongation 28 %; hardness ≈ 60–90 HRB (typ.)
- 0.70 ≤ t ≤ 3.0 mm: yield 140–280 MPa; tensile 270–410 MPa; elongation 28 %; hardness —
- Skin-passed, first 8 days after rolling: yield ≤ 280 (yield-point elongation may return after) MPa; tensile 270–410 MPa; elongation 28 %; hardness —
EN 10130 Table 3: transverse test pieces, L0 = 80 mm. The yield range is wide because DC01 is not guaranteed for deep drawing; a yield-point elongation (stretcher strain) may reappear with time. For guaranteed r and n values order DC04–DC06.

Equivalents:
- CR1 (BS (superseded British)) — identical: BS 1449-1 CR1 (commercial quality).
- DC01 (GB/T (China)) — identical: GB/T 5213 adopted the EN name DC01 (formerly Q195/Q215 cold-rolled, or 08Al under GB 710).
- IS 513 CR1 (IS (India)) — identical: IS 513 grade CR1 (formerly O): commercial quality cold-rolled.
- SPCC (JIS (Japan)) — identical: JIS G3141 SPCC: C ≤ 0.15, Mn ≤ 0.60, P ≤ 0.100, S ≤ 0.035; Rm ≥ 270 MPa, A ≥ 28–37 % by thickness. Same commercial cold-rolled class.
- CS Type B (ASTM / ASME) — near: ASTM A1008 Commercial Steel Type B: C ≤ 0.02–0.15, Mn ≤ 0.60; no guaranteed mechanicals — the US commercial-quality counterpart.
- DC03 (EN (European)) — near: Next grade up (yield 140–240, A ≥ 34 %) for moderate drawing.
- 08kp / 08ps (GOST (Russia/CIS)) — near: GOST 9045 / 16523 08kp (rimmed) and 08ps (semi-killed): C ≤ 0.10, Mn 0.25–0.50 — Russian commercial cold-rolled sheet.
- SAE 1010 (ASTM / ASME) — functional: For cold-rolled sheet the practical European counterpart is DC01 rather than C10, because sheet is specified by forming behaviour, not by bar chemistry.
- DC04 (EN (European)) — functional: Deep-drawing grade (A ≥ 38 %, r90 ≥ 1.6) — order when DC01 splits.
- S235JR (EN (European)) — functional: Hot-rolled structural steel of similar chemistry; not a cold-rolled forming grade and not interchangeable in surface or gauge.
- DX51D (EN (European)) — functional: The uncoated cold-rolled base; DX51D is roughly DC01 substrate plus zinc.
- P235TR1 (EN (European)) — functional: EN 10130 DC01: the cold-rolled forming sheet that welded precision tube is often made from. Listed because enquiries confuse the two — DC01 is a forming grade with no strength guarantee, and a tube rolled from it is a precision tube to EN 10305-3, not a pressure tube.

Superseded names:
- St12 — DIN 1623-1 (withdrawn 1991): Still the everyday German/Turkish name for DC01.
- St2 — DIN 1623 (older)
- Fe P01 — EN 10130:1991: Renamed DC01 in the 1999 edition.
- CR1 — BS 1449-1: British designation; CR4 = DC04.
- C — NF A 36-401: Tôle C.

Product forms: cold-rolled coil and sheet 0.35–3.0 mm; cut lengths and slit strip; electro-galvanized as DC01+ZE (EN 10152); narrow strip (EN 10139 as DC01 C290–C590)
Tolerances: thickness/width/flatness: EN 10131 (normal or special tolerances); surface quality A (minor defects allowed) or B (better face defect-free); surface finish b (bright), g (semi-matt), m (matt), r (rough)

### DC01 yield strength
140–280 MPa (20–41 ksi) transverse. The upper limit only applies for eight days after skin-passing; ageing can raise it and bring back stretcher-strain marks.

### DC01 tensile strength
270–410 MPa (39–59 ksi). Typical certificates show 300–340 MPa.

### DC01 elongation
≥ 28 % (A80, transverse) for t ≥ 0.7 mm; for 0.35–0.70 mm the minimum is reduced by 2 points.

### DC01 hardness
Not specified by EN 10130. Typical 60–90 HRB (≈ 100–150 HV) as delivered; increases substantially after cold forming.

### Physical properties
Density 7.85 g/cm³, E = 210 GPa. Thickness range 0.35–3.0 mm (EN 10130), widths to 2000 mm, coil weights to 30 t.

### Weldability
Excellent weldability by resistance spot and seam welding, MAG, TIG and laser thanks to very low carbon. Spot-weld current ranges are the widest of any sheet steel. Electro-galvanized DC01+ZE needs slightly higher current and electrode dressing. No preheat, no PWHT.

### Machining, forming, heat treatment
Sheared, punched, laser- and plasma-cut without issues; edge burr is small. Bending: 0 t inside radius is routinely achieved in 1–2 mm across the rolling direction. Roll forming excellent. Stretch forming and deep drawing are limited (no guaranteed r/n; earing and stretcher strains possible) — use DC04+ for draws. Painting, powder coating and e-coating: standard, after degreasing/phosphating; the surface finish letter (b/g/m) is chosen for paint adhesion.

Applications: Electrical cabinets, enclosures, switchgear panels; Domestic appliance housings and shelves; Office furniture, lockers, shelving; Automotive non-visible brackets and reinforcements; Steel drums, pails and cans (with DC01 tinplate variants); Lighting fixtures, ventilation ducting, HVAC components; Roll-formed profiles and drywall track (as DC01 or DX51D)

Q: What is the difference between DC01 and S235JR?
A: DC01 is a cold-rolled forming sheet (EN 10130) sold by surface and gauge with a yield window of 140–280 MPa; S235JR is a hot-rolled structural steel (EN 10025-2) with a guaranteed minimum yield of 235 MPa and impact toughness. Chemistry overlaps, but they are ordered, priced and used differently: DC01 for pressed parts and enclosures, S235JR for load-bearing structure.

Q: Is DC01 the same as St12?
A: Yes. St12 (DIN 1623) became Fe P01 (EN 10130:1991) and then DC01 (EN 10130:1999). Same steel, same use.

Q: Can DC01 be deep drawn?
A: Only shallow draws. DC01 has no guaranteed r-value and may show stretcher strains. For drawn parts specify DC03 (moderate), DC04 (deep) or DC05/DC06 (extra deep).

Q: What is DC01+ZE?
A: DC01 with an electrolytic zinc coating per EN 10152, e.g. DC01+ZE25/25 = 2.5 µm zinc on each face. It gives a paint-ready, lightly protected surface for indoor parts; hot-dip galvanized DX51D+Z is used for heavier corrosion protection.

Q: What is the JIS equivalent of DC01?
A: SPCC (JIS G3141) — commercial-quality cold-rolled sheet. SPCD corresponds to DC03 and SPCE to DC04.

---

## DD11 (1.0332) — Hot-rolled low-carbon steel for cold forming
URL: https://steelstandart.com/grade/dd11/
System: EN (European) | Family: Cold-rolled & coated sheet | Standard: EN 10111 | Verified against: EN 10111:2008
Aliases: DD 11, StW22, St W 22, 1.0332, FeP11, HR1, DD11 steel

DD11 is the hot-rolled counterpart of DC01: a low-carbon sheet and coil steel specified in EN 10111 for cold forming, Werkstoff number 1.0332, formerly StW22. Where DC01 covers 0.4–3 mm cold-rolled, DD11 covers roughly 1.5–12 mm hot-rolled — the thickness band of wheel rims, agricultural panels, automotive chassis brackets, pressed pipe fittings, drums and gas cylinders.

EN 10111 guarantees a yield window of 170–360 MPa, tensile ≤ 440 MPa and 23–28 % elongation depending on thickness, with carbon ≤ 0.12 % and Mn ≤ 0.60 %. The wide yield range and absence of r/n values mark DD11 as a bending and general pressing grade; DD12, DD13 and DD14 are the drawing, deep-drawing and extra-deep-drawing steps. Most DD11 is sold pickled and oiled (DD11+P) for a scale-free surface.

Buyers often confuse DD11 with S235JR because the chemistry overlaps: the difference is what is guaranteed. S235JR promises a minimum yield and impact toughness for structures; DD11 promises a yield window and ductility for forming. JIS SPHC, BS HR1 and IS 1079 D are the same class; ASTM A1011 CS Type B is the nearest US grade.

Chemical composition (mass %): C ≤ 0.12; Mn ≤ 0.6; P ≤ 0.045; S ≤ 0.045
EN 10111:2008 Table 2, ladle analysis. DD12–DD14 progressively tighten C (0.10, 0.08, 0.08), Mn (0.45, 0.35, 0.35), P and S. Typical DD11 coil: C 0.04–0.08, Mn 0.20–0.40, Al-killed.

Mechanical properties:
- t < 2 mm (transverse): yield 170–360 MPa; tensile ≤ 440 MPa; elongation 23 %; hardness ≈ 55–85 HRB (typ.)
- 2 ≤ t < 3 mm: yield 170–360 MPa; tensile ≤ 440 MPa; elongation 24 %; hardness —
- 3 ≤ t < 5 mm: yield 170–360 MPa; tensile ≤ 440 MPa; elongation 27 %; hardness —
- 5 ≤ t ≤ 11 mm: yield 170–360 MPa; tensile ≤ 440 MPa; elongation 28 %; hardness —
- DD12 (for comparison): yield 170–340 MPa; tensile ≤ 420 MPa; elongation 25–30 %; hardness —
- DD13: yield 170–330 MPa; tensile ≤ 400 MPa; elongation 28–33 %; hardness —
- DD14: yield 170–310 MPa; tensile ≤ 380 MPa; elongation 31–36 %; hardness —
EN 10111 Table 3; A80 for t < 3 mm, A (L0 = 5.65√S0) for t ≥ 3 mm. Yield upper limit for DD11 applies only within one month of manufacture (ageing). No r/n guarantee for DD11.

Equivalents:
- HR1 (BS (superseded British)) — identical: BS 1449-1 HR1 (commercial hot-rolled).
- St 22 (DIN (superseded German)) — identical: EN 10111 DD11 is the direct replacement: same chemistry envelope, same role as the general hot-rolled forming sheet. Any supplier asked for St 22 today will quote DD11, and the certificate will say DD11.
- IS 1079 D (IS (India)) — identical: IS 1079 grade D (drawing) / O (ordinary); D is the DD11 match.
- SPHC (JIS (Japan)) — identical: JIS G3131 SPHC: C ≤ 0.15, Mn ≤ 0.60, Rm ≥ 270 MPa, A ≥ 27–31 % by thickness. Commercial hot-rolled forming sheet — SPHD ≈ DD12, SPHE ≈ DD13.
- CS Type B (A1011) (ASTM / ASME) — near: ASTM A1011 Commercial Steel Type B hot-rolled: C ≤ 0.02–0.15, Mn ≤ 0.60, no guaranteed mechanicals. DS (Drawing Steel) Type B corresponds to DD12/DD13.
- DD12 (EN (European)) — near: Drawing quality with tighter chemistry and higher elongation.
- Q195 / SPHC (GB/T (China)) — near: GB/T 5213 hot-rolled uses DD11-type names in newer editions; older specs use Q195 (yield ≥ 195 MPa) or 08Al.
- 08kp / 08ps hot-rolled (GOST (Russia/CIS)) — near: GOST 16523 group KhP (cold-forming quality) on 08kp/08ps base.
- St37-2 (DIN (superseded German)) — functional: Hot-rolled forming sheet often bought 'as St37' in Turkey/Middle East — but it has no guaranteed minimum yield.
- DD13 (EN (European)) — functional: Deep-drawing quality (A ≥ 28–33 %) for demanding pressings.
- S235JR (EN (European)) — functional: Structural steel of similar chemistry with guaranteed 235 MPa yield and impact; DD11 has no minimum yield guarantee for structural design.

Superseded names:
- StW22 — DIN 1614-1 (withdrawn): Still the common German/Turkish shop name; StW23 = DD12, StW24 = DD13.
- FeP11 — EN 10111:1991: Renamed DD11 in 1998.
- HR1 / HR2 — BS 1449-1: HR1 is the nearer match.
- 1C — NF A 36-301

Product forms: hot-rolled coil and sheet 1.5–12 mm (typically 1.5–6 mm); pickled and oiled (DD11+P or 'P&O'); slit strip, cut lengths; narrow strip (EN 10111 applies to width ≥ 600 mm; narrow strip to EN 10139)
Tolerances: thickness/width/flatness: EN 10051 (normal or special); surface: as-rolled (mill scale) or pickled; surface quality per EN 10163-2 (class A/B, subclass 1–3) for plate-type products

### DD11 yield strength
170–360 MPa (25–52 ksi) transverse; the upper limit is only guaranteed for one month after rolling. Typical coil: 220–300 MPa.

### DD11 tensile strength
≤ 440 MPa (64 ksi max, no minimum); typical 320–400 MPa.

### DD11 elongation
≥ 23 % below 2 mm rising to ≥ 28 % at 5–11 mm (A80 below 3 mm, A above).

### DD11 hardness
Not specified; typically 55–85 HRB (≈ 100–150 HV) as rolled.

### Physical properties
Density 7.85 g/cm³, E = 210 GPa. Thickness 1.5–12 mm (mill-dependent; EN 10111 covers up to 11 mm for the elongation table), width 600–2000 mm.

### DD11 or S235JR
The question turns on what is guaranteed, not on the analysis. A part that is bent, pressed or stamped wants DD11; a part that carries a load and has to be verified wants S235JR. Where both are needed — a formed structural part — either order S235JR and allow for wider spring-back scatter, or use a hot-rolled forming grade with a guaranteed minimum yield from EN 10149.

### Weldability
Excellent weldability by all arc and resistance processes without preheat (CEV ≈ 0.15–0.25). Pickled DD11+P welds cleaner than scaled material. Use E38/G38 consumables; no PWHT.

### Machining, forming, heat treatment
Bending to 0.5–1 t inside radius transverse to rolling direction is normal; punching, shearing, laser and plasma cutting are routine (pickled surface improves laser consistency). Moderate stretch forming and shallow drawing are fine; for deep draws in hot-rolled gauge use DD13 or DD14. Machinability of the low-carbon matrix is good but gummy (index ≈ 70 %). Hot-dip galvanizing after fabrication: good, but check Si + 2.5 P ≤ 0.09 % (Sandelin range) if a bright coating is required.

Applications: Wheel rims and disc blanks (as DD11–DD13); Automotive chassis brackets, cross-members, seat frames; Pressed pipe fittings, flanges and end caps; Gas cylinders (as DD11/DD12 or P245NB for pressure); Agricultural implements, guards and panels; Steel drums, containers and heavy enclosures; Cold-formed profiles and general sheet-metal fabrication 2–6 mm

Q: What is the difference between DD11 and S235JR?
A: Both are low-carbon hot-rolled steels, but DD11 (EN 10111) is a forming grade with a yield window of 170–360 MPa and no impact guarantee, while S235JR (EN 10025-2) is a structural grade with a guaranteed 235 MPa minimum yield and 27 J at +20 °C. Use S235JR for load-bearing design; DD11 for pressed and bent parts.

Q: Is DD11 the same as StW22?
A: Yes. StW22 (DIN 1614) became FeP11 (EN 10111:1991) and then DD11 (EN 10111:1998). Same steel and use.

Q: What is DD11+P?
A: DD11 supplied pickled (mill scale removed in acid) and lightly oiled — the usual condition for laser cutting, welding and painting without descaling.

Q: What is the JIS equivalent of DD11?
A: SPHC (JIS G3131) is the commercial hot-rolled forming sheet equivalent to DD11; SPHD ≈ DD12 and SPHE ≈ DD13.

Q: Can DD11 be galvanized?
A: Yes, both by continuous hot-dip (then it is designated DX51D/DX52D with a hot-rolled substrate) and by batch galvanizing after fabrication. Ask the mill for Si and P control if a smooth, bright zinc layer matters.

---

## DX51D (1.0226) — Hot-dip coated low-carbon steel for bending and profiling
URL: https://steelstandart.com/grade/dx51d/
System: EN (European) | Family: Cold-rolled & coated sheet | Standard: EN 10346 | Verified against: EN 10346:2015
Aliases: DX51D+Z, DX51D+Z275, DX51D+ZF, DX51D+AZ, DX51D+ZM, DX 51 D, St02Z, St 02 Z, 1.0226, FeP02G, DX51DZ

DX51D is the everyday hot-dip galvanized steel sheet: a low-carbon cold-rolled (or hot-rolled) substrate continuously coated with zinc, specified in EN 10346 for bending and profiling. Werkstoff number 1.0226; the old DIN name St02Z is still what many buyers ask for. The designation means D (flat product for cold forming), X (rolling condition not specified — may be hot- or cold-rolled), 51 (bending quality), D (hot-dip coated), plus the coating code: +Z275 is 275 g/m² of zinc over both faces (about 20 µm per side), the European default; Z100 to Z600 exist, and +ZF (galvannealed), +AZ (55 % Al-Zn), +ZA, +ZM (zinc-magnesium, ~2× the corrosion life of Z at the same mass) are alternatives.

Mechanically, EN 10346 promises only tensile 270–500 MPa and 22 % elongation — no yield minimum. That is deliberate: DX51D is for roll forming, bending and simple pressing (ducting, profiles, trapezoidal roofing, drywall track). For drawing, the ladder runs DX52D → DX53D → DX54D → DX56D; for load-bearing profiles the structural grades S220GD–S550GD guarantee yield.

JIS SGCC, GB DX51D+Z and IS 277 are the same class; ASTM A653 CS Type B G90 is the nearest American equivalent.

Chemical composition (mass %): C ≤ 0.18; Si ≤ 0.5; Mn ≤ 1.2; P ≤ 0.12; S ≤ 0.045; Ti ≤ 0.3
EN 10346:2015 Table 1 (DX51D). The limits are wide because DX51D is defined by formability class, not chemistry; typical coil has C 0.04–0.08, Mn 0.20–0.40.

Mechanical properties:
- DX51D+Z, all thicknesses (transverse): yield — (no minimum; typ. 200–320) MPa; tensile 270–500 MPa; elongation 22 %; hardness ≈ 55–85 HRB (typ.)
- DX52D+Z (for comparison): yield 140–300 MPa; tensile 270–420 MPa; elongation 26 %; hardness —
- DX53D+Z: yield 140–260 MPa; tensile 270–380 MPa; elongation 30 %; hardness —
- DX54D+Z: yield 120–220 MPa; tensile 260–350 MPa; elongation 36 %; hardness —
- DX56D+Z: yield 120–180 MPa; tensile 260–350 MPa; elongation 39 %; hardness —
EN 10346 Table 4; A80, transverse. DX51D has no guaranteed yield or r/n values — it is a bending and profiling grade. Ductility ladder: DX51D (bending) → DX52D (drawing) → DX53D (deep drawing) → DX54D (special deep) → DX56D (extra deep) → DX57D (super deep).

Equivalents:
- DX51D+Z (GB/T (China)) — identical: GB/T 2518 adopted the EN designation DX51D+Z.
- IS 277 Grade O (IS (India)) — identical: IS 277 galvanized sheet, ordinary (O) grade.
- SGCC (JIS (Japan)) — identical: JIS G3302 SGCC: commercial galvanized, Rm ≥ 270 MPa, no yield minimum; coating Z12–Z60 (g/m² one side ×10). Z27 ≈ Z275.
- CS Type B (A653) (ASTM / ASME) — near: ASTM A653 Commercial Steel Type B, coating G90 (≈ Z275): the US commercial galvanized sheet; no guaranteed mechanicals, C ≤ 0.15.
- DX52D (EN (European)) — near: Next formability class with guaranteed yield 140–300 MPa — order when DX51D cracks in drawing.
- 08kp / 08ps galvanized (GOST (Russia/CIS)) — near: GOST 14918 galvanized sheet on 08kp/08ps base, group KhP (cold forming).
- S250GD (EN (European)) — functional: Structural galvanized grade with guaranteed 250 MPa yield (EN 10346 Table 5) for load-bearing profiles.
- DC01 (EN (European)) — functional: The uncoated cold-rolled base; DX51D is roughly DC01 substrate plus zinc.

Superseded names:
- St02Z — DIN 17162 (withdrawn): Still the common Turkish/German shop name; St02Z ≈ DX51D+Z.
- FeP02G / FeP02GZ — EN 10142:1990: Renamed DX51D in EN 10142:2000, moved to EN 10346 in 2009.
- Z1 / Z2 — BS 2989: British commercial galvanized qualities.

Product forms: hot-dip galvanized coil and sheet 0.30–3.0 mm (+Z); galvannealed (+ZF), zinc-aluminium (+ZA), aluminium-zinc (+AZ), zinc-magnesium (+ZM) variants; slit strip, cut lengths, pre-painted (EN 10169) base
Tolerances: thickness/width/flatness: EN 10143; coating mass: triple-spot test, e.g. Z275 = 275 g/m² both faces total (≈ 20 µm per face); surface: A (normal), B (improved), C (best, for painting); finish: N (normal spangle), M (minimized spangle)

### DX51D yield strength
No guaranteed minimum. Typical coil measures 200–320 MPa; if the design needs a yield value, order DX52D (140–300 MPa) or a structural S250GD/S280GD.

### DX51D tensile strength
270–500 MPa (39–73 ksi) transverse.

### DX51D elongation
≥ 22 % (A80, transverse); reduced by 2 points below 0.7 mm.

### Zinc coating and corrosion life
Z275 ≈ 20 µm/face gives roughly 20–40 years in rural C2, 10–20 years in urban C3 and 3–8 years in coastal C4 atmospheres (ISO 9223 categories, EN ISO 14713-1 guidance). Z140 ≈ 10 µm/face; Z600 ≈ 42 µm/face. ZM120 ≈ Z275 in corrosion life at less than half the coating mass.

### Physical properties
Density 7.85 g/cm³ (steel), E = 210 GPa; thickness 0.30–3.0 mm (thicker on request), width to 1800 mm. Coating mass is measured by the triple-spot test in g/m² total for both faces.

### Weldability
Resistance spot welding is standard with 10–20 % higher current, electrode dressing and shorter electrode life than uncoated sheet. MAG/laser welding is possible with zinc fume extraction; ZF (galvannealed) welds more easily than Z. Welded areas lose zinc and need zinc-rich paint. Avoid welding ZM without checking fume data.

### Machining, forming, heat treatment
Roll forming, bending (0.5–1 t radius), punching, shearing, slitting and laser cutting all routine; the zinc coating survives bending without flaking (test per EN 10346 T-bend). Deep drawing is limited (no r-value) — use DX53D+. Cut edges are protected by zinc's sacrificial action up to ~2 mm. Painting: pre-treat (phosphate or chromate-free conversion) or use pre-painted DX51D+Z per EN 10169.

Applications: Roofing and cladding sheets (trapezoidal, corrugated), pre-painted or bare; Drywall studs and track, ceiling profiles, light steel framing (S grades for load-bearing); HVAC ducting, ventilation and air-handling units; Electrical enclosures, cable trays, junction boxes; Appliance panels, washing-machine cabinets (as DX52D–DX54D for drawn parts); Automotive underbody parts (DX53D–DX56D+ZF); Fencing, guardrails (often post-galvanized instead), shelving, silos

Q: What does DX51D+Z275 mean?
A: DX51D = flat cold-forming product, rolling condition not specified, bending quality, hot-dip coated; +Z275 = zinc coating of 275 g/m² total on both faces (≈ 20 µm each side). Additional letters give surface quality (A/B/C), spangle (N/M) and surface treatment (C chromated, O oiled, P phosphated).

Q: What is the yield strength of DX51D?
A: EN 10346 does not guarantee one. Measured values are usually 200–320 MPa. If the design needs a minimum, order DX52D (140–300 MPa yield) or the structural grade S250GD (≥ 250 MPa).

Q: DX51D or DX52D — which for pressing?
A: DX51D is for bending and roll forming; DX52D is the first drawing grade with a guaranteed yield window and 26 % elongation. For deep-drawn parts go to DX53D or DX54D.

Q: Is DX51D the same as St02Z or SGCC?
A: Yes. St02Z was the DIN 17162 name, FeP02G the 1990 EN name, and DX51D the current EN 10346 name. JIS SGCC is the Japanese commercial galvanized equivalent.

Q: How long does Z275 galvanizing last?
A: Depends on the atmosphere: 20–40 years in rural areas, 10–20 in urban/industrial, 3–8 near the coast. Zinc-magnesium (ZM) coatings double that life at equal mass; pre-painting extends it further.

---

## DX52D (1.0350) — Hot-dip coated low-carbon steel for drawing
URL: https://steelstandart.com/grade/dx52d/
System: EN (European) | Family: Cold-rolled & coated sheet | Standard: EN 10346 | Verified against: EN 10346:2015
Aliases: dx52d, dx52d+z, dx52d z275, 1.0350, dx52d equivalent, dx52d vs dx51d

DX52D is the second rung of the EN 10346 forming ladder for hot-dip coated sheet, and it is bought for one reason: DX51D bent and cracked. The designation decodes as D for cold forming, X for a rolling condition left to the producer, 52 for the formability class and D for hot-dip coating. Its Werkstoff number is 1.0350.

Where DX51D is specified only by a tensile ceiling and 22 % elongation, DX52D adds a guaranteed yield band of 140–300 MPa, drops the tensile ceiling to 420 MPa and lifts elongation to 26 %. The yield band is the operationally useful part: it tells a press shop how hard the material can possibly arrive, which is what sets springback compensation and what decides whether a die works on every coil or only on some.

The coating is a separate specification written after the plus sign — +Z for zinc, +ZF for galvannealed, +ZM for zinc-magnesium, +AZ for aluminium-zinc — followed by the coating class, most commonly Z140 or Z275. DX52D+Z275 and DX52D+Z100 are the same steel with different corrosion lives.

Chemical composition (mass %): C ≤ 0.12 (0.06 % below DX51D); Mn ≤ 0.6 (half the DX51D ceiling of 1.20 %); P ≤ 0.1; S ≤ 0.045; Ti ≤ 0.3
Ladle analysis per EN 10346:2015. The composition is a ceiling, not a recipe: mills run well below these limits on modern production, and the difference that matters commercially is the manganese cap, which is what keeps DX52D soft enough to draw.

Mechanical properties:
- DX52D+Z (transverse): yield 140–300 MPa; tensile 270–420 MPa; elongation 26 %; hardness —
- DX51D+Z (the grade below): yield — (no minimum specified) MPa; tensile 270–500 MPa; elongation 22 %; hardness —
- DX53D+Z (the grade above): yield 140–260 MPa; tensile 270–380 MPa; elongation 30 %; hardness —
- DX54D+Z: yield 120–220 MPa; tensile 260–350 MPa; elongation 36 %; hardness —
- DX56D+Z: yield 120–180 MPa; tensile 260–350 MPa; elongation 39 %; hardness —
Values are transverse, A80 elongation, for coating classes up to Z275 and thicknesses from 0.5 mm. EN 10346 limits how long after delivery the mechanical values remain valid, because coated forming grades age — an old coil tests harder than a fresh one, which is a real cause of press problems on stock material.
Impact:  J at  °C (not applicable)

Equivalents:
- DX51D (EN (European)) — near: One formability step below: no guaranteed yield, tensile up to 500 MPa and 22 % elongation. Interchangeable only on simple bends.
- S250GD (EN (European)) — functional: Same standard and coatings but a structural grade with a 250 MPa minimum yield — specified when the sheet carries load rather than being formed.
- SPHC (JIS (Japan)) — functional: Uncoated hot-rolled commercial sheet; comparable base metal but no coating and no yield band. The coated JIS counterpart is SGCD1 in G3302.

Superseded names:
- St 03 Z — DIN 17162 (withdrawn): Legacy German designation for the drawing quality of hot-dip zinc coated sheet.
- FeP02G — EN 10142:1990 (withdrawn): The pre-2000 European designation before EN 10346 merged the coating standards.
- DX52D+Z — EN 10142 / EN 10327 (both withdrawn): Same designation, earlier standards; EN 10346 replaced EN 10142, 10214, 10215, 10326 and 10327 in one document.

Product forms: galvanized coil and sheet (+Z); galvannealed coil (+ZF); zinc-magnesium coated coil (+ZM); aluminium-zinc coated coil (+AZ); slit strip and cut-to-length sheet
Tolerances: dimensional: EN 10143 (continuously coated sheet and strip); coating mass: EN 10346 Table 6 (Z100 to Z600); flatness and edge: EN 10143, normal or special class by agreement; surface quality: EN 10346 classes A and B, appearance MA or MB

### DX52D mechanical properties
Yield 140–300 MPa, tensile 270–420 MPa, elongation A80 ≥ 26 %, measured transverse. The yield is a band and not a minimum, which is deliberate: for a forming steel, material that arrives too hard is the failure mode, so the standard caps it.

### DX52D vs DX51D
DX51D has no yield requirement at all, a tensile ceiling of 500 MPa and 22 % elongation. DX52D narrows all three. On a simple 90° bend the two behave the same; on a deep flange, a tight radius or a drawn corner, DX51D is the one that splits, and that is when the specification is stepped up.

### DX52D coating options
+Z zinc (Z100 to Z600), +ZF galvannealed for painting and welding, +ZM zinc-magnesium for two to three times the corrosion life at the same coating mass, +AZ aluminium-zinc for heat and reflectivity. The coating class and the steel grade are two independent lines on the order; ordering DX52D without naming a coating class leaves the most important number blank.

### DX52D welding and painting
Resistance spot and seam welding are standard on coated sheet, with electrode life shortened by zinc pickup; MAG welding needs extraction because of zinc fume. For painting, the surface treatment matters more than the grade: order it unpassivated and unoiled if it goes to a paint line, because chromate film and protective oil both prevent primer bonding.

### DX52D thickness and availability
Commonly rolled from 0.35 to 3.0 mm, widths to 1500 mm, with Z100–Z275 the stock coating classes and heavier classes made to order. Anything below about 0.4 mm or above Z350 tends to be a mill order with a minimum quantity rather than a stock item.

### Weldability
DX52D welds by every process used on coated sheet, and the complications come from the zinc rather than the steel. Resistance spot welding is the production norm: currents run higher than on uncoated sheet and electrode dressing intervals are shorter because zinc alloys with the copper. For MAG welding, zinc vaporises ahead of the pool and causes porosity unless a gap is left and the travel speed is controlled; extraction is mandatory for fume. Laser welding works well on thin coated sheet with a controlled gap. In every case the coating is destroyed locally and the joint has only the galvanic protection thrown by the surrounding zinc, which is adequate on thin material and not on thick.

### Machining, forming, heat treatment
As a thin coated flat product DX52D is processed by shearing, punching, laser and roll forming rather than by cutting tools. Minimum inside bend radius is typically 0.5–1.0 × thickness depending on coating class and bend direction — heavier zinc classes crack at tighter radii than lighter ones, which is the usual reason a Z600 part fails a bend test that a Z140 part passes. Cut edges need no coating repair up to roughly 2–3 mm thickness, where the surrounding zinc protects the exposed steel galvanically.

Applications: Roll-formed profiles with tight radii: purlins, cable tray, drywall framing; Ventilation and ducting components with drawn flanges and spun ends; Enclosure and cabinet panels with formed edges and corner draws; Appliance housings and structural backing panels; Automotive and agricultural non-visible pressings on coated substrate; Welded tube where the strip is formed and seam welded on the mill

Q: What is DX52D steel?
A: DX52D is the drawing-quality grade of EN 10346, the European standard for continuously hot-dip coated steel strip. It guarantees a yield band of 140–300 MPa, a tensile of 270–420 MPa and 26 % elongation, which places it one formability step above DX51D.

Q: What is the difference between DX51D and DX52D?
A: DX51D has no guaranteed yield, a tensile ceiling of 500 MPa and 22 % elongation; DX52D narrows the yield to 140–300 MPa, the tensile to 270–420 MPa and lifts elongation to 26 %. In practice DX52D forms more deeply and, just as importantly, more consistently from coil to coil.

Q: What does the D in DX52D mean?
A: There are two. The first D means the steel is for cold forming; the final D means it is intended for hot-dip coating. The X between them says the rolling condition — hot or cold rolled — is left to the producer, and 52 is the formability class.

Q: What does DX52D+Z275 mean?
A: DX52D is the steel and +Z275 is the coating: zinc applied on both faces to a total mass of 275 g/m², roughly 20 µm per side. The grade and the coating class are separate specifications, so the same steel is sold as Z100, Z140, Z275 or heavier.

Q: Can DX52D be welded?
A: Yes, by resistance, MAG and laser processes. The zinc rather than the steel sets the practice: spot welding needs higher current and more frequent electrode dressing, and MAG welding needs fume extraction and a controlled gap to avoid porosity from vaporising zinc.

Q: Is DX52D structural steel?
A: No. It is specified by a yield band with a ceiling rather than a minimum, so there is no guaranteed value to design against. For a coated sheet that carries load, the structural grades in the same standard are S220GD to S350GD.

Q: What is the equivalent of DX52D?
A: In the JIS system, SGCD1 to G3302; in ASTM terms, A653 FS (forming steel) is the nearest class. Both are equivalences rather than identities — the property bands and the coating designations differ, so the certificate has to be read against the actual requirement.

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## E250 — Hot rolled structural steel (Indian national standard)
URL: https://steelstandart.com/grade/e250/
System: IS (India) | Family: Structural steel | Standard: IS 2062 | Verified against: IS 2062:2011
Aliases: e250, e 250, is 2062 e250, is2062, is 2062, fe 410, fe410w, fe 410 wa, e250a, e250br, e250b0, e250c, is 2062 grade b, e250 equivalent

E250 is the base grade of IS 2062, the Indian hot-rolled structural steel standard, and the specification written on the great majority of Indian project drawings. It is called up directly by IS 800, the Indian structural design code, so a structure designed in India is in practice designed in IS 2062 steel.

The designation is the yield stress: E for the elastic limit and 250 for its minimum value in MPa up to 20 mm. That convention arrived with the 2006 revision. Before it the same steel was Fe 410W, named after its 410 MPa tensile minimum, and those older names are still in daily use across Indian stockholding — Fe 410W A is E250A.

The letters after the grade are the impact test: A has none, BR is tested at room temperature, B0 at 0 °C and C at −20 °C, all to 27 J. BR and B0 are genuinely different requirements, and reading "B0" as "BR" on a drawing is a mistake with consequences.

Two features set IS 2062 apart from its Asian neighbours. First, the carbon equivalent is part of the grade — 0.42 for E250A down to 0.39 for E250C — where JIS G3101 sets none at all and GB/T 700 leaves it to agreement. Second, the tensile requirement is a floor with no ceiling. An E250 plate meeting 410 MPa minimum may test at 520 MPa and still conform, which matters for any procedure written against a capped European band.

Chemical composition (mass %): C ≤ 0.23 (E250A; 0.22 % for BR and B0, 0.20 % for C); Mn ≤ 1.5; S ≤ 0.045 (0.045 % for A, BR and B0; 0.040 % for C); P ≤ 0.045 (0.045 % for A, BR and B0; 0.040 % for C); Si ≤ 0.4; CEV ≤ 0.42 (carbon equivalent: 0.42 for A, 0.41 for BR and B0, 0.39 for C)
IS 2062:2011 ladle analysis. What distinguishes this standard from its Chinese, Russian and Japanese counterparts is that a **carbon equivalent limit is part of the grade**, not a supplementary requirement — 0.42 for E250A, tightening to 0.39 for E250C. Indian practice treats weldability as a delivered property, and the CEV appears on the mill certificate as a matter of course.

Mechanical properties:
- ≤ 20 mm: yield 250 MPa; tensile ≥ 410 MPa; elongation 23 %; hardness ≈ 120–150 HB (typical)
- > 20 ≤ 40 mm: yield 240 MPa; tensile ≥ 410 MPa; elongation 23 %; hardness —
- > 40 mm: yield 230 MPa; tensile ≥ 410 MPa; elongation 23 %; hardness —
Yield stress steps at 20 mm and 40 mm, not at 16 mm as in EN 10025-2. The tensile requirement is a floor of 410 MPa with no ceiling, which is the single most important difference from the European grades: an E250 plate can be considerably stronger than its nominal class, and a weld procedure written for a capped tensile band does not automatically cover it. Elongation is 23 % on a gauge length of 5.65√S₀.
Impact: 27 J at 0 °C (E250B0; BR at room temperature, C at −20 °C)

Equivalents:
- A36 (ASTM / ASME) — near: A36 is 250 MPa yield and 400–550 MPa tensile: the same yield, a slightly lower tensile floor and a ceiling that E250 does not have.
- S235JR (EN (European)) — near: The usual counterpart on quality structure: E250BR is tested to 27 J at room temperature as S235JR is at +20 °C. E250 is 250 MPa yield against 235 and 410 MPa tensile floor against 360, so it is the stronger of the two at both limits.
- Q235 (GB/T (China)) — near: Q235B is 235 MPa yield and 370–500 MPa tensile; E250 sits one small step above it on both counts, with a carbon equivalent limit that Q235 does not carry.
- St3sp (GOST (Russia/CIS)) — near: St3sp is 245 MPa yield and 370–480 MPa tensile — the same tier, with mechanical values that come from a separate product standard rather than from the grade standard itself.
- SS400 (JIS (Japan)) — near: Same commodity structural tier — SS400 is 245 MPa yield and 400–510 MPa tensile — but SS400 has no carbon equivalent limit and no impact requirement at all.
- S275JR (EN (European)) — functional: Matches on tensile — S275JR is 410–560 MPa — but E250's yield is 250 MPa against 275. Where the design is tensile-governed the substitution works; where it is yield-governed it does not.
- E355 (EN (European)) — functional: Listed only as the Indian structural reference point; India specifies mechanical tube to IS 3601 and IS 4923, not to a precision-tube standard of this kind.

Superseded names:
- Fe 410W A / Fe 410W B / Fe 410W C — IS 2062:1999 (superseded): The pre-2006 designation, named after the tensile minimum in N/mm² rather than the yield. Fe 410W A became E250A. Indian drawings and stock lists still carry the Fe names widely.
- IS 226 — withdrawn: The older Indian structural standard, superseded by IS 2062. Occasionally still quoted on legacy drawings.
- E250 Grade A / B / C per IS 2062:2006 — IS 2062:2006 (superseded): The 2006 revision introduced the E-designation; the 2011 revision split grade B into BR and B0 by test temperature and extended the ladder to E550.

Product forms: hot-rolled plate and sheet; sections: beams and columns (IS 808 / IS 12778 profiles), channel, angle; hot-rolled coil and strip; flats and round bar; structural hollow sections certified separately to IS 4923
Tolerances: plate and sheet: IS 1852 / IS 8910; beams and channels: IS 808, parallel-flange IS 12778; angles: IS 808; hot-rolled coil: IS 1852

### E250 yield strength
250 MPa minimum up to 20 mm, 240 MPa from 20 to 40 mm and 230 MPa above 40 mm. The steps fall at 20 and 40 mm, where EN 10025-2 steps at 16 and 40 — so between 16 and 20 mm E250 is nominally 15 MPa stronger than S235JR and 25 MPa weaker than S275JR.

### E250 tensile strength
410 MPa minimum, with no upper limit. The floor is identical to S275JR's and 50 MPa above S235JR's. The absent ceiling is the practical difference: European structural grades cap tensile so that forming and welding behaviour stay predictable, and IS 2062 does not.

### A, BR, B0 and C
The sub-grade is the Charpy requirement. A: none, C ≤ 0.23 %, CEV ≤ 0.42. BR: 27 J at room temperature, C ≤ 0.22 %, CEV ≤ 0.41. B0: 27 J at 0 °C, same chemistry as BR. C: 27 J at −20 °C, C ≤ 0.20 %, P and S ≤ 0.040 %, CEV ≤ 0.39. BR and B0 differ only in test temperature.

### The carbon equivalent is part of the grade
IS 2062 sets CEV as a delivered property: 0.42 / 0.41 / 0.41 / 0.39 for A / BR / B0 / C, calculated on the usual IIW formula. It appears on the mill certificate without being asked for. This is a real advantage over SS400, which limits nothing but phosphorus and sulphur, and it makes E250 the better-defined of the two when a welding procedure has to be written.

### The IS 2062 ladder
E250, E275, E300, E350, E410, E450 and E550, each named after its yield stress in MPa and each available in the A / BR / B0 / C quality pattern. E250 and E350 carry most of Indian construction; E350 is the grade to compare with S355, at 350 MPa yield and 490 MPa tensile minimum.

### Accepting E250 against S235JR
The substitution is usually comfortable because E250 is stronger at both the yield and tensile floor. Three checks remain. The sub-grade letter: E250A has no impact test at all. The thickness band, since the ladders step at different points between 16 and 20 mm. And the tensile ceiling, which E250 does not have — a fabricator working to a capped procedure should confirm the actual tested value rather than the class.

### Weldability
E250 is readily weldable by all arc processes, and the guaranteed carbon equivalent makes it more predictable than most commodity structural grades: at CEV ≤ 0.42 for grade A and ≤ 0.39 for grade C, preheat is normally unnecessary below about 25 mm at Indian ambient temperatures. Consumables are the ordinary mild-steel classes — E7018 and ER70S-6 equivalents, or the IS 814 electrode designations used locally. Two points deserve attention. Grade A carries no impact test, so it should not be used for welded work where toughness is part of the design; specify BR as a minimum and B0 or C where the structure sees low temperature. And because tensile is uncapped, a plate at the high end of the delivered range is harder than the class implies, which shows up in thick restrained joints.

### Machining, forming, heat treatment
Machinability is good and comparable with other low-carbon structural steels, with manganese up to 1.5 % giving slightly higher cutting forces than St3sp or S235JR. Cold forming, bending and roll forming are acceptable in the usual structural thicknesses; elongation is 23 % across the thickness range. The uncapped tensile band means spring-back varies more between heats than on a European grade, so a press brake set from a previous batch will need checking on the new one. For pressing and deep drawing the Indian specification is IS 513 cold-rolled or IS 1079 hot-rolled forming grades, not IS 2062.

Applications: Building and industrial steelwork across India, designed to IS 800; Bridges, gantries and transmission towers in the higher sub-grades; Welded frames, platforms, stairs and walkways; Plate for tanks, hoppers, silos and chutes without pressure duty; Railway and heavy vehicle structural components; Sections and plate exported against an S235JR or A36 requirement

Q: What is IS 2062 E250 steel?
A: E250 is the base grade of IS 2062, the Indian hot-rolled structural steel standard called up by the IS 800 design code. It guarantees 250 MPa yield up to 20 mm, 410 MPa minimum tensile and 23 % elongation, with a carbon equivalent limit built into the grade.

Q: What is the difference between E250A, E250BR, E250B0 and E250C?
A: The impact test and the chemistry that supports it. A has no Charpy requirement; BR is tested at room temperature, B0 at 0 °C and C at −20 °C, each to 27 J. Carbon and carbon equivalent tighten down the ladder, from 0.23 % and 0.42 for A to 0.20 % and 0.39 for C.

Q: Is E250 the same as Fe 410?
A: Yes — Fe 410W is the pre-2006 name for the same steel, taken from its 410 MPa tensile minimum rather than its yield. Fe 410W A became E250A when IS 2062 was renamed to the E-series. Indian stock lists still use both.

Q: Is IS 2062 E250 equivalent to S235JR?
A: It is the usual counterpart and is stronger at both limits — 250 MPa yield against 235 and a 410 MPa tensile floor against 360. The checks that matter are the sub-grade letter, because E250A has no impact test, and the missing tensile ceiling.

Q: What is the difference between E250 and E350?
A: Strength class. E350 guarantees 350 MPa yield and 490 MPa minimum tensile against E250's 250 and 410, with the same A / BR / B0 / C quality pattern. E250 to E350 is the Indian equivalent of the S235 to S355 step, and E350 is the grade to compare with S355.

Q: Does IS 2062 specify a carbon equivalent?
A: Yes, and that is unusual for a commodity structural standard. CEV is limited to 0.42 for grade A, 0.41 for BR and B0 and 0.39 for C, calculated on the IIW formula, and it is reported on the mill certificate as a matter of course.

Q: Can E250 be used for structural hollow sections?
A: Not directly. Indian structural hollow sections are specified to IS 4923, which has its own grades and its own tolerance table. IS 2062 covers plate, sheet, strip, sections, flats and bars.

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## E355 (1.0580) — Seamless cold drawn precision tube
URL: https://steelstandart.com/grade/e355/
System: EN (European) | Family: Pipe & tube steel | Standard: EN 10305-1 | Verified against: EN 10305-1:2016 (+N values); +SR and +C from supplier tables to EN 10305-1 — confirm against the current standard
Aliases: E355+SR, E355+N, E355+C, E355 SR, E355 N, E355 tube, E355 material, E355 steel, EN 10305-1 E355, St 52 tube, St 52.0, St 52.4, E355 equivalent, E235, E470

E355 is the high-strength member of EN 10305-1, the European standard for seamless cold drawn precision tube, and material number 1.0580 — the same number the old German grade St 52 carried, which is why most enquiries for this tube still arrive written that way.

The thing that distinguishes a precision tube from every other tube on this site is what the standard actually guarantees. EN 10217 and EN 10216 promise wall integrity and leak-tightness: they are pressure specifications. EN 10305-1 promises dimensions and surface — close tolerances on outside diameter, wall thickness and straightness, plus specified inside and outside roughness, which no pressure standard mentions. A precision tube is bought so that a piston can run in it, a bearing can press into it, or a part can be machined from it with minimal stock.

That leads to the point this page exists to make. E355 has no single set of mechanical properties. The delivery condition decides them, and the spread is enormous:

+N (normalised) — 355 MPa minimum yield, 490–630 MPa tensile, 22 % elongation. The same figures as S355 plate, because it is essentially the same steel in the same condition.

+SR (cold drawn, stress relieved) — around 450 MPa yield, 580 MPa minimum tensile, 10 % elongation. The usual condition for hydraulic cylinders: most of the cold-work strength kept, the drawing stresses relieved so the tube does not move when it is machined.

+C (cold drawn, hard) — 640 MPa minimum tensile, 4 % elongation, and no specified yield strength at all. Strong, dimensionally exact, and with almost no ductility left.

So a drawing that says only "E355" has not specified the tube. It must say E355+N, E355+SR or E355+C, and a certificate without the suffix is incomplete. Where no yield value is given, the published practice is to assume at least 80 % of the tensile for the hard condition and 70 % for the soft — a recommendation rather than a guarantee, and a reminder that this is a dimensional standard first.

Chemical composition (mass %): C ≤ 0.22; Si ≤ 0.55; Mn ≤ 1.6; P ≤ 0.025; S ≤ 0.025
EN 10305-1, grade E355 (1.0580). The analysis is essentially that of S355J2 — and indeed 1.0580 is the material number shared with the old St 52 family — which is why E355 tube and S355 plate behave alike once the tube is normalised. The leaner grades in the same standard are E215, E235 and E275; E470 sits above.

Mechanical properties:
- +N normalised: yield ≥ 355 MPa; tensile 490–630 MPa; elongation 22 %; hardness —
- +SR cold drawn, stress relieved: yield ≈ 450 MPa; tensile ≥ 580 MPa; elongation 10 %; hardness —
- +C cold drawn, hard: yield not specified (≈ 80 % of Rm) MPa; tensile ≥ 640 MPa; elongation 4 %; hardness —
- E235+N — for comparison: yield ≥ 235 MPa; tensile 340–480 MPa; elongation 25 %; hardness —
- E235+C — for comparison: yield not specified MPa; tensile ≥ 480 MPa; elongation 4 %; hardness —
- +A and +LC conditions: yield — MPa; tensile — MPa; elongation — %; hardness see the standard's table — intermediate between +N and +SR
**Read the suffix before the grade.** A single E355 tube can be delivered at 490 MPa tensile with 22 % elongation or at 640 MPa with 4 %, depending only on whether it was normalised or left cold-drawn hard, and the yield strength is **not stated at all** for the hard condition. Published practice where no yield is given is to take **≥ 80 % of the tensile strength for the hard condition and ≥ 70 % for the soft**, but that is a recommendation, not a specified value — which matters because EN 10305-1 is a *dimensional* standard first. Supplier tables also differ slightly on the +SR yield (435 or 450 MPa is quoted); take the figure from the current standard or the certificate.

Equivalents:
- a519-1026 (ASTM / ASME) — near: ASTM A519 grade 1026 seamless mechanical tubing: the nearest North American counterpart — mechanical rather than pressure tubing, supplied cold drawn or normalised, with properties stated by condition in the same way. A513 covers the welded mechanical equivalent.
- St52-3 (DIN (superseded German)) — near: The withdrawn DIN name and the one still used in the shop for this tube — St 52.4 for the cold-finished precision tube, St 52.0 for the seamless pressure tube, both material number 1.0580. The caution is the same as on the St 52 page: St 52-3 as a *structural* grade corresponds to S355J2, not to S355JR, and the tube grades are specified differently again.
- S355J2 (EN (European)) — near: EN 10025-2 S355J2: effectively the same analysis and, in the +N condition, the same 355 MPa yield and 490–630 MPa tensile. The difference is what else each standard demands — S355J2 guarantees 27 J at −20 °C and structural tolerances, while E355 guarantees dimensional precision and surface finish and requires no impact test at all.
- E470 (EN (European)) — near: The strongest grade of EN 10305-1, used where a hydraulic cylinder wall must be thinner. Less formable and harder to machine; E355 is the normal choice.
- E235 (EN (European)) — near: The general-purpose precision tube at 235 MPa yield in the +N condition. Easier to bend and form; the usual choice for fuel and brake lines, furniture and light mechanical work where E355 is specified for pressure-bearing cylinders.
- STKM 13C (JIS (Japan)) — near: JIS G3445 STKM 13C: carbon steel tube for machine structural purposes, cold drawn, 510 MPa minimum tensile. The JIS series likewise splits each grade by delivery condition with suffixes A, B and C.
- P235TR1 (EN (European)) — functional: EN 10217-1 P235TR1: the welded pressure tube at 235 MPa yield. A pressure tube is specified for leak-tightness and wall integrity; a precision tube is specified for dimensions and finish. Neither substitutes for the other, and a precision tube should not be used as a pressure-retaining part without checking the design code.
- E250 (IS (India)) — functional: Listed only as the Indian structural reference point; India specifies mechanical tube to IS 3601 and IS 4923, not to a precision-tube standard of this kind.

Superseded names:
- St 52.4 / St 52.0 — DIN 2391-2 / DIN 1629 (withdrawn): The German precision and seamless tube grades E355 descends from, sharing material number 1.0580. Still the common shop name for this tube across Germany, Turkey and Poland, and the reason E355 enquiries so often arrive written as "St 52 tube".
- St 35 / St 45 — DIN 2391 (withdrawn): The lower grades of the same family, now E235 and E275.
- CFS 4 / CDS 4 — BS 6323 Part 4 (withdrawn): The British cold-finished seamless tube grades of comparable strength.
- TU 52b — NF A 49-310: The French precision tube designation.

Product forms: seamless cold drawn tube (EN 10305-1); welded cold drawn tube (EN 10305-2) and as-welded (EN 10305-3); honed and skived-roller-burnished hydraulic cylinder tube (EN 10305-4); delivery conditions +C, +LC, +SR, +A, +N
Tolerances: close dimensional tolerances on outside diameter, wall thickness and straightness are the purpose of the standard and are tabulated by condition — much tighter than EN 10216 or EN 10217; inside and outside surface roughness is specified, which no pressure-tube standard does; hydraulic cylinder tube: EN 10305-4 adds honed-bore tolerance classes and bore roughness

### E355 properties by delivery condition
+N normalised: ReH ≥ 355 MPa, Rm 490–630 MPa, A ≥ 22 %. +SR cold drawn and stress relieved: ReH ≈ 450 MPa, Rm ≥ 580 MPa, A ≥ 10 %. +C cold drawn hard: Rm ≥ 640 MPa, A ≥ 4 %, yield not specified. +A annealed and +LC lightly cold worked sit between +N and +SR and are tabulated in the standard. The condition is part of the grade designation, not an afterthought — note that supplier tables differ slightly on the +SR yield (435 or 450 MPa), so the certificate or the current standard is the authority.

### What the E number means
The minimum yield strength in MPa in the normalised condition — E355+N is 355 MPa yield, the same level as S355. This is read wrongly as often as it is read correctly, usually because the cold-finished conditions have far higher tensile strengths (640 MPa for +C) with no stated yield, so the number appears not to match anything on the certificate. The E prefix follows EN 10027-1 for engineering steels, exactly as S follows it for structural and P for pressure.

### Why +SR is the hydraulic cylinder condition
A cold-drawn tube carries large residual stresses from drawing. Machine a keyway, a port or a flange seat into it and those stresses redistribute — the tube bends, the bore goes oval, and the cylinder leaks. +SR relieves them at around 550–620 °C while keeping most of the cold-work strength: 580 MPa tensile against 490 for +N, with 10 % elongation still available for the end forming. That combination of dimensional stability and strength is why EN 10305-4 cylinder tube is normally E355+SR, and why a cylinder maker will not accept +C.

### Precision tube against pressure tube
Different standards answering different questions, and they are not interchangeable. EN 10305-1 guarantees outside diameter, wall thickness, straightness, inside and outside roughness — and tests nothing for pressure. EN 10216-1 / EN 10217-1 guarantee a leak test, weld integrity and in the TR2 qualities an impact test, with generous dimensional tolerances. A hydraulic cylinder needs the first; a pressure-retaining pipework component needs the second. Using a precision tube as a pressure part — common in practice because it is available and strong — is a decision for the design code, not for the stockist.

### Forming, bending and end work
Strongly condition dependent. +N bends and expands freely: mandrel bending to 2–3 D, flaring, beading and swaging all routine. +SR bends to larger radii, typically 3–4 D, and tolerates moderate expansion. +C should be treated as unformable — 4 % elongation leaves nothing for a bend, and attempting one cracks the tube. The practical rule: choose the condition from the most demanding operation the tube must survive, not from the strength the finished part needs.

### Machining and surface
Machinability around 65–70 % relative to 1 % C free-cutting steel in +N, somewhat better in the cold-drawn conditions where the harder surface gives cleaner chips. The attraction is the stock allowance: a precision tube's bore and outside diameter are close enough to finished size that many parts need only a light cut, and honed EN 10305-4 tube needs none at all on the bore. Cut a +C tube and expect movement; cut a +SR tube and it stays where it was put. Welding a cold-drawn tube locally anneals it and destroys the dimensional precision over several diameters, which is why precision tube assemblies are pressed, bolted or welded at the ends only.

### Weldability
Weldable at this carbon level — the carbon equivalent runs around 0.35–0.45, so arc welding with E7018 or ER70S-6 needs no preheat in normal wall thickness, and the +N condition welds like S355. The caution is not metallurgical but dimensional: welding a cold-drawn tube locally anneals it and relieves its residual stresses unevenly, so the bore distorts for several diameters either side of the joint and the precision the tube was bought for is lost. Precision tube assemblies are therefore welded at the ends, outside the working length, or joined by pressing and threading. For a hydraulic cylinder, welding on the working length of a honed tube is not done.

### Machining, forming, heat treatment
The reason the grade exists: close outside diameter and wall tolerances and specified surface roughness mean a part can be finished with a single light pass, and an EN 10305-4 honed tube needs no bore machining at all. Machinability about 65–70 % relative to 1 % C free-cutting steel in the normalised condition. The decisive point is residual stress — a +C tube moves when metal is removed from one side, while a +SR tube holds its shape, so any tube that will be slotted, ported, keyed or heavily turned should be ordered +SR or +N. Parting, drilling and cross-boring are straightforward. Keep clamping forces moderate on thin wall: a precision tube is easy to distort in a three-jaw chuck.

Applications: Hydraulic and pneumatic cylinder barrels (usually E355+SR, honed to EN 10305-4); Hydraulic lines and high-pressure piping on mobile machinery; Shock absorber and gas spring tubes; Machined components made from tube — bushes, spacers, housings, rollers; Bearing housings and press-fit sleeves; Drive shafts, torque tubes and telescopic sections; Machine frames and precision structures where tolerance matters more than strength

Q: What is the difference between E355+N, E355+SR and E355+C?
A: The delivery condition, and it changes the properties completely. +N (normalised) gives 355 MPa minimum yield, 490–630 MPa tensile and 22 % elongation. +SR (cold drawn and stress relieved) gives about 450 MPa yield, 580 MPa minimum tensile and 10 % elongation. +C (cold drawn hard) gives 640 MPa minimum tensile, only 4 % elongation, and no specified yield at all. A drawing that says just "E355" has not specified the tube.

Q: Does the 355 in E355 mean tensile or yield strength?
A: Yield — the minimum yield strength in MPa in the normalised condition, following EN 10027-1 just as S does for structural and P for pressure grades. It is misread as tensile because the cold-finished conditions have much higher tensile strengths (640 MPa for +C) and often no stated yield, so the number appears not to match the certificate.

Q: Is E355 the same as St 52?
A: It is the successor. The precision tube St 52.4 to DIN 2391-2 and the seamless tube St 52.0 to DIN 1629 both carried material number 1.0580, which E355 kept, and the analysis is essentially unchanged. The name St 52 is still in daily use for this tube. Note that St 52-3 as a *structural* grade is a different specification lineage and corresponds to S355J2.

Q: Which condition should a hydraulic cylinder tube be?
A: E355+SR, honed or skived-and-roller-burnished to EN 10305-4. Cold drawing leaves residual stresses that make the bore distort when ports and mountings are machined; the stress-relief anneal removes them while keeping most of the cold-work strength — 580 MPa tensile with 10 % elongation still available for end forming. A +C tube is strong but will move during machining, and cylinder makers do not accept it.

Q: Can E355 precision tube be used as a pressure pipe?
A: Not without the design code's agreement. EN 10305-1 guarantees dimensions and surface finish and contains no leak test, no weld integrity requirement and no impact test; those belong to EN 10216-1 and EN 10217-1, the seamless and welded pressure tube standards. E355 is widely used for high-pressure hydraulic lines, but that is done inside hydraulic design rules, not as a substitution for a pressure-tube specification in pipework.

Q: What is the yield strength of E355+C?
A: The standard does not state one. Where a yield value is needed and none is specified, the published recommendation is to take at least 80 % of the tensile strength for the hard condition and 70 % for the soft — about 510 MPa for a 640 MPa +C tube. That is a recommendation rather than a guaranteed value, and if the design depends on it, order +SR or +N where the yield is specified.

Q: Can E355 be bent?
A: It depends on the condition. +N bends freely, to 2–3 diameters on a mandrel, and tolerates flaring and swaging. +SR needs larger radii, typically 3–4 diameters. +C should be treated as unformable: 4 % elongation leaves nothing for a bend and the tube cracks. Choose the condition from the most demanding operation the tube has to survive, not from the strength the finished part needs.

Q: What is the ASTM equivalent of E355?
A: ASTM A519 grade 1026 seamless mechanical tubing is the nearest, with A513 covering the welded equivalent. Both are mechanical rather than pressure tubing and, like EN 10305-1, state properties by delivery condition. JIS G3445 STKM 13C is the Japanese counterpart. None is a drop-in substitute, because the dimensional tolerance tables and surface requirements differ.

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## L360 / X52 — Line pipe steel, 360 MPa minimum yield
URL: https://steelstandart.com/grade/l360-x52/
System: API (line pipe) | Family: Pipe & tube steel | Standard: API 5L | Verified against: API 5L / ISO 3183
Aliases: X52, API 5L X52, 5L X52, L360, API 5L L360, X52 pipe, X52 line pipe, X52 PSL1, X52 PSL2, L360N, L360M, L360Q, X52 equivalent, ISO 3183 L360

API 5L X52 is the middle of the line-pipe ladder and the grade most onshore transmission and gathering lines are built from. The designation gives its own definition: X52 means a specified minimum yield strength of 52 ksi, which is 360 MPa, and the same grade is written L360 in the metric designation. Minimum tensile is 460 MPa (66 ksi). API 5L and ISO 3183 are harmonised, so a pipe specified to either is specified to both.

The grade name is less than half the specification. The decisive choice is the product specification level. PSL1 gives minima only — 360 MPa yield and up, with no ceiling, no carbon equivalent limit and no impact testing whatsoever. PSL2 gives a range (360–530 MPa yield, 460–760 MPa tensile), caps the yield-to-tensile ratio at 0.93, limits the carbon equivalent, holds sulphur to 0.015 %, and makes Charpy testing mandatory with drop-weight tear testing on larger sizes. Those are two different products at one strength level, and "X52" without a level is an incomplete order.

The reason PSL2 exists is the way a pipeline fails. A transmission line is girth welded in the field by crews working to a fixed procedure, so the carbon equivalent must be bounded or the weld cracks; and a gas line stores enough energy to drive a fracture for hundreds of metres, so the steel must be tough enough to arrest it. Neither property is visible in a yield figure, which is why the upper bound, the CE cap and the Charpy requirement had to be added as a separate level rather than folded into the grade.

One more thing to understand about X52 in particular: it spans a metallurgical change of era. The grade was originally made as a plain carbon-manganese steel near 0.26 % carbon. Modern X52 is typically a thermomechanically rolled microalloyed steel at 0.08–0.12 % carbon with niobium, vanadium and titanium, reaching the same yield through grain refinement. The new pipe is tougher, far more weldable and lower in carbon equivalent while carrying the identical grade name — so an old certificate and a new one describe genuinely different steels.

Chemical composition (mass %): C ≤ 0.24; Mn ≤ 1.4; P ≤ 0.025; S ≤ 0.015; Si ≤ 0.45
API 5L / ISO 3183, grade L360/X52, **PSL2 seamless** — the ceilings tighten or loosen with the level and the route, and PSL1 permits 0.28 % C with P to 0.030 and S to 0.030. PSL2 additionally caps the **carbon equivalent** (CE<sub>IIW</sub> ≤ 0.43 above 0.12 % C, or CE<sub>Pcm</sub> ≤ 0.25 at or below it) and allows niobium, vanadium and titanium up to a combined 0.15 %. Nothing in the specification prescribes an analysis — the mill reaches 360 MPa by whatever route it chooses, and for modern pipe that route is microalloying rather than carbon.

Mechanical properties:
- PSL1 — specified minimum: yield 360 MPa; tensile 460 MPa; elongation per formula %; hardness —
- PSL2 — specified range: yield 360–530 MPa; tensile 460–760 MPa; elongation per formula %; hardness —
- PSL2 — yield to tensile ratio: yield — MPa; tensile ratio ≤ 0.93 MPa; elongation — %; hardness —
- Typical modern TMCP pipe: yield 400–470 MPa; tensile 510–580 MPa; elongation 30–38 %; hardness 150–185 HB
- PSL2 Charpy (pipe body, average of 3): yield — MPa; tensile — MPa; elongation — %; hardness 27 J minimum at the specified test temperature, typically 0 to −20 °C
- PSL1 Charpy: yield — MPa; tensile — MPa; elongation — %; hardness not required
The two levels differ fundamentally in this table. **PSL1 gives minima only** — a pipe at 520 MPa yield passes — whereas **PSL2 gives a range and caps the yield-to-tensile ratio**, because a pipeline designer needs to know the upper bound as well as the lower one: an over-strong pipe welded to a normal one puts the weld in the weaker material, and a high yield-to-tensile ratio means little plastic reserve before rupture. Elongation is calculated from the standard's formula using the specimen area and the specified tensile strength, not fixed.
Impact: 27 J average of three, pipe body, full-size equivalent J at 0 to −20 °C (order-specified) °C (PSL2 only. Weld and heat-affected zone are tested at the same temperature; drop-weight tear testing is additionally required on larger diameters and wall thicknesses to demonstrate that a running fracture will arrest.)

Equivalents:
- L360 (API (line pipe)) — identical: The metric designation of this same grade: 360 MPa is 52 ksi. Both names appear in API 5L and a certificate may carry either or both.
- L360NB / L360MB (EN (European)) — identical: EN 10208-2 L360NB (normalised) and L360MB (thermomechanically rolled): the same 360 MPa minimum yield with the same L-number logic, and a test regime broadly matching PSL2 including mandatory impact testing. EN 10208-1 class A has the lower requirements and corresponds more nearly to PSL1.
- X56 (API (line pipe)) — near: L390/X56: the next grade up at 390 MPa minimum yield. One step on the same ladder — the chemistry route is the same and the choice is made by the wall thickness the Barlow formula returns at the design pressure.
- X42 (API (line pipe)) — near: L290/X42: 290 MPa minimum yield, the grade below. Common in gathering lines and distribution where pressures are lower and field weldability is prized over thin walls.
- S355J2H (EN (European)) — near: EN 10219 S355J2H: 355 MPa minimum yield with 27 J at −20 °C — almost the same strength and toughness, but it is a **structural** hollow section specification with no pipeline requirements: no yield ceiling, no carbon equivalent cap, no fracture-arrest testing. Suitable for a structural pipe, not for a transmission line.
- A106 Grade B (ASTM / ASME) — functional: ASTM A106 Grade B: 240 MPa yield, seamless process pipe with elevated-temperature allowables. Much lower strength and a different purpose — A106 is for refinery and plant piping, X52 for transporting fluid between them. No ASTM pipe specification reaches 360 MPa.
- A53 Grade B (ASTM / ASME) — functional: ASTM A53 Grade B: 240 MPa yield general-service pipe. Dual certification with API 5L **Grade B** is common, but there is no ASTM counterpart to X52 and no route by which A53 pipe satisfies an X52 requirement.
- Q355 (GB/T (China)) — functional: GB/T 1591 Q355: 355 MPa minimum yield structural steel, and the plate from which much Chinese line pipe is rolled. The yield level matches, but Q355 is a structural specification — Chinese line pipe is properly specified to GB/T 9711, which mirrors API 5L.

Superseded names:
- API 5LX X52 — API 5LX (withdrawn): The former separate specification for high-strength line pipe; merged into API 5L, which previously covered only Grades A and B.
- API 5LS X52 — API 5LS (withdrawn): The former specification for spiral-welded line pipe; also absorbed into API 5L.
- ISO 3183 L360 — ISO 3183: Not superseded — API 5L and ISO 3183 are harmonised, and the same grade is specified by either designation.
- StE 360.7 / GRS 360 — DIN 17172 (withdrawn): The German line-pipe grade at the same yield level, replaced by EN 10208-2 L360NB/MB.

Product forms: seamless pipe (S); high-frequency welded pipe (HFW); longitudinally submerged-arc welded pipe (SAWL); helically submerged-arc welded pipe (SAWH); as-rolled, normalised (N), quenched and tempered (Q) or thermomechanically rolled (M)
Tolerances: diameter, wall thickness, straightness and end preparation: API 5L / ISO 3183, by manufacturing route and size; hydrostatic test on every length; PSL2 adds non-destructive inspection of the weld and the pipe body; sour service to Annex H (suffix S); offshore service to Annex J (suffix O)

### X52 yield and tensile strength
360 MPa (52 ksi) minimum yield, 460 MPa (66 ksi) minimum tensile. Under PSL2 these become a range: yield 360–530 MPa, tensile 460–760 MPa, with the yield-to-tensile ratio capped at 0.93. Typical modern thermomechanically rolled pipe lands at 400–470 MPa yield and 510–580 MPa tensile. Elongation is not a fixed figure — the standard computes the minimum from the specimen area and the specified tensile strength.

### Why the upper limits matter
A minimum-only specification is adequate for a plate that will be designed to its yield. A pipeline is different. An over-strong pipe welded to a normal one moves the weakest point into the weld, which is also the least inspected point, and a high yield-to-tensile ratio means the steel reaches its ultimate strength shortly after yielding, leaving almost no plastic reserve to redistribute stress at a dent, a weld defect or a settlement. Strain-based design makes both bounds explicit requirements rather than good practice, which is why PSL2 writes them into the grade.

### Carbon equivalent and field weldability
PSL2 caps the carbon equivalent: CEIIW ≤ 0.43 where carbon exceeds 0.12 %, or CEPcm ≤ 0.25 at or below it — the second formula being used precisely because the IIW expression misrepresents low-carbon microalloyed steels. The purpose is field welding: a pipeline girth weld is made outdoors, often without preheat, by a crew following a fixed procedure, and hydrogen-induced cracking in the heat-affected zone is the failure it is written against. PSL1 has no CE limit at all, so a PSL1 pipe's weldability is unknown until the certificate is read.

### Toughness and fracture arrest
PSL2 requires 27 J average of three on full-size equivalent specimens from the pipe body, weld and heat-affected zone, at a temperature stated on the order and typically 0 to −20 °C. On larger diameters and walls it additionally requires drop-weight tear testing with a minimum shear area, because Charpy energy alone does not prove that a running ductile fracture will stop. This is the requirement that distinguishes a gas transmission pipe from any structural or process pipe at the same strength: a buried gas line stores enough energy to propagate a fracture for hundreds of metres if the steel cannot arrest it.

### Delivery conditions and manufacturing routes
Two suffix systems appear on the certificate and both matter. Delivery condition: as-rolled, N normalised, Q quenched and tempered, M thermomechanically rolled — written as L360N, L360Q, L360M. Manufacturing route: S seamless, HFW high-frequency welded, SAWL longitudinally submerged-arc welded, SAWH helically (spiral) welded. The route determines where the weld sits, how it was inspected, and the practical diameter range: HFW to about 24 inches, SAWL and SAWH above it. Service suffixes S (sour, Annex H) and O (offshore, Annex J) add further requirements.

### Physical properties and design
Density 7.85 g/cm³, E = 207 GPa, Poisson's ratio 0.30, thermal conductivity ≈ 48 W/m·K, expansion 11.7 × 10⁻⁶/K (20–100 °C). Wall thickness follows from the Barlow formula — t = PD / (2 · SMYS · F · E · T) in the ASME B31.4 and B31.8 forms — in which the specified minimum yield is the only material property. That is why line pipe is named by yield and by nothing else.

### Weldability
Designed to be welded in the field, and under PSL2 that intent is written into the specification through the carbon equivalent cap. Girth welds are made by SMAW with cellulosic electrodes (E6010/E8010 stovepipe technique), by mechanised GMAW, or by flash-butt welding; procedures are qualified to API 1104, not to AWS D1.1. Preheat is often unnecessary at PSL2 carbon equivalents but is specified for heavy wall, low ambient temperature, restrained joints or sour service. PSL1 pipe should not be field welded to a pipeline procedure without first reading the certificate — with no CE limit, the heat-affected-zone hardness is unknown. For sour service (suffix S), weld and heat-affected-zone hardness limits of 250–300 HV apply to resist sulphide stress cracking.

### Machining, forming, heat treatment
Rarely machined as such; the operations that matter are end preparation and cutting. Bevelling to the API 5L standard angle is done by lathe or by machine-guided flame or plasma cutting. Cold field bending is standard on X52 within the bend radius limits of the pipeline code, typically 30 to 40 diameters, and the pipe's bend-test performance and uniform wall make it suited to it; induction hot bending at 850–1000 °C is used for tighter radii, after which the properties of the bend must be re-verified because a thermomechanically rolled microstructure does not survive reheating unchanged. Tapping, threading and welded branch connections are made to the pipeline code, not freehand.

Applications: Onshore oil and gas transmission pipelines; Gathering lines and flowlines; Gas distribution mains at intermediate pressure; Water transmission and slurry lines; Offshore pipelines and risers (suffix O, Annex J); Sour-service lines (suffix S, Annex H); Piling and casing where a documented yield is required

Q: Is API 5L X52 the same as L360?
A: Yes. They are the two designations of one grade: the X number is the specified minimum yield in ksi and the L number is the same value in MPa, and 52 ksi is 360 MPa. API 5L lists both for every grade from X42 upward, and a certificate may print either or both. Grades A and B are the exception — they keep letter names rather than X numbers.

Q: What is the difference between X52 PSL1 and PSL2?
A: PSL2 adds requirements that PSL1 does not contain: a maximum yield as well as a minimum (360–530 MPa instead of 360 and up), a yield-to-tensile ratio capped at 0.93, a carbon equivalent limit, mandatory Charpy impact testing at a stated temperature, drop-weight tear testing on larger sizes, and sulphur held to 0.015 %. They are different products at the same strength level. An order for X52 that does not state the level is incomplete.

Q: What is the yield strength of X52?
A: 360 MPa, which is 52 ksi, as the specified minimum; minimum tensile is 460 MPa (66 ksi). Under PSL2 the yield is also capped, at 530 MPa. Typical modern thermomechanically rolled X52 tests at 400–470 MPa, but pipeline design uses the specified minimum because that is the figure the Barlow formula is built on.

Q: What is the equivalent of API 5L X52?
A: EN 10208-2 L360NB or L360MB is the direct European line-pipe equivalent, with the same 360 MPa minimum yield and a test regime broadly matching PSL2. ISO 3183 L360 is the same document as API 5L. EN 10219 S355J2H has almost the same strength and toughness but is a structural hollow-section specification with no pipeline requirements, and no ASTM pipe specification reaches this strength at all.

Q: Can A53 Grade B or A106 Grade B be used instead of X52?
A: No. Both are 240 MPa minimum yield, a third below X52, so a wall thickness designed for X52 would be undersized. Dual stencilling between A53 and API 5L applies at Grade B, where the strength levels coincide; there is no ASTM pipe grade corresponding to X52 and no substitution route.

Q: What chemistry does X52 have?
A: The specification sets ceilings rather than an analysis — for PSL2 seamless, carbon to 0.24 %, manganese to 1.40 %, phosphorus to 0.025 %, sulphur to 0.015 %, plus a carbon equivalent cap and up to 0.15 % combined niobium, vanadium and titanium. The mill may reach 360 MPa by any route. Older X52 was carbon-manganese steel near 0.26 % carbon; modern X52 is usually a microalloyed, controlled-rolled steel at 0.08–0.12 % carbon, which is tougher and more weldable at the same grade name.

Q: Why does X52 need a maximum yield strength?
A: Because a pipeline is a welded assembly designed with plastic reserve. A pipe that over-shoots on strength, welded to one that does not, puts the weakest material at the girth weld — the least inspected point in the line. And a high yield-to-tensile ratio means the steel runs out of plastic capacity shortly after yielding, so it cannot redistribute stress around a dent, a weld flaw or ground settlement. PSL2 therefore specifies a band and caps the ratio at 0.93.

Q: Is X52 suitable for sour service?
A: Only when ordered with the S suffix to Annex H of API 5L, which adds restrictions on composition, hardness, inclusion shape control and non-metallic cleanliness, plus HIC and SSC testing. Plain X52 PSL2 carries none of those and will crack in wet hydrogen sulphide. Weld and heat-affected-zone hardness limits of 250–300 HV apply to sour-service lines and must be qualified in the welding procedure.

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## P235GH (1.0345) — Non-alloy steel for pressure purposes with elevated-temperature properties
URL: https://steelstandart.com/grade/p235gh/
System: EN (European) | Family: Pressure vessel steel | Standard: EN 10028-2 | Verified against: EN 10028-2:2017
Aliases: p235gh, 1.0345, p235gh equivalent, p235gh tc1, p235gh vs s235jr, p235gh boiler plate

P235GH is where the pressure-vessel standards begin, and its designation says what it is for: P for pressure purposes, 235 for minimum yield in MPa, G for other specified characteristics and H for elevated temperature. Its Werkstoff number is 1.0345.

On paper it looks like S235JR — the same 235 MPa yield, the same low carbon — and it is a different product. Three things separate them. First, EN 10028-2 guarantees proof strength at temperature, tabulated from 50 °C to 400 °C, which is the number a vessel or pipe wall thickness is actually calculated from. A structural steel has no such data and therefore cannot be used in a pressure calculation at all. Second, the chemistry is held far tighter: phosphorus to 0.025 % and sulphur to 0.015 %, with a minimum aluminium that forces a fully killed, fine-grained steel. Third, the plate is supplied normalised, not as-rolled.

The grade is the workhorse of low-pressure and moderate-temperature equipment — boiler drums, heat exchanger shells, steam pipework, air receivers and process vessels — and it is the reference point from which P265GH, P295GH and P355GH step up in strength. It is also the answer to the most common designation error in this family: there is no such grade as S235GH. S belongs to the structural standard, P to the pressure standard, and the two letters are not interchangeable.

Chemical composition (mass %): C ≤ 0.16; Si ≤ 0.35; Mn 0.6 – 1.2; P ≤ 0.025 (tighter than any structural S235 grade); S ≤ 0.015 (less than half the S235JR limit); Al ≥ 0.02 (total aluminium — the grade is fully killed and grain refined); Cr ≤ 0.3; Ni ≤ 0.3; Mo ≤ 0.08; Cu ≤ 0.3
EN 10028-2:2017 ladle analysis. The residual elements are capped because they affect behaviour at temperature and in service ageing, and the aluminium minimum forces a fully killed, fine-grained steel. This is the same carbon level as S235JR bought under far tighter control.

Mechanical properties:
- ≤ 16 mm, room temperature: yield 235 MPa; tensile 360–480 MPa; elongation 24 %; hardness ≈ 110–150 HB (typical)
- > 16 ≤ 40 mm: yield 225 MPa; tensile 360–480 MPa; elongation 24 %; hardness —
- > 40 ≤ 60 mm: yield 215 MPa; tensile 360–480 MPa; elongation 24 %; hardness —
- > 60 ≤ 100 mm: yield 200 MPa; tensile 350–480 MPa; elongation 24 %; hardness —
- 0.2 % proof at 200 °C (≤ 16 mm): yield ≈ 165 MPa; tensile — MPa; elongation — %; hardness —
- 0.2 % proof at 300 °C (≤ 16 mm): yield ≈ 139 MPa; tensile — MPa; elongation — %; hardness —
- 0.2 % proof at 400 °C (≤ 16 mm): yield ≈ 121 MPa; tensile — MPa; elongation — %; hardness —
The elevated-temperature rows are the point of the grade and are approximate: the governing values are the minimum 0.2 % proof strengths tabulated by thickness in EN 10028-2 Table 5, and a pressure calculation must take them from the standard rather than from a summary. Delivery condition is normalised (+N).
Impact: 27 J at 20 °C (longitudinal; transverse values are lower and set separately)

Equivalents:
- P265GH (EN (European)) — near: The grade above in the same standard: 265 MPa yield and correspondingly higher proof strength at temperature. Same family, same delivery condition.
- P235TR1 (EN (European)) — near: 1.0345: the same 235 MPa strength level, but specified for **elevated temperature** with proof-strength values tabulated to 400 °C, a silicon minimum and mandatory impact testing. The GH grade is what a boiler or process line needs; the TR grades stop at room temperature.
- A516 Grade 70 (ASTM / ASME) — functional: ASTM A516 Gr. 70 is far stronger (260 MPa yield, 485–620 MPa tensile) and notch-toughness oriented; A285 Gr. C is the closer American match to P235GH.
- A106 Grade B (ASTM / ASME) — functional: The American seamless pressure pipe counterpart; comparable duty to P235GH TC1/TC2 tube, different property basis.
- S235JR (EN (European)) — functional: Same room-temperature yield and similar carbon, but no elevated-temperature proof values, looser P and S, and no normalising requirement. It cannot be substituted into a pressure calculation.

Superseded names:
- H I — DIN 17155 (withdrawn): The legacy German boiler plate designation; still quoted on older vessel drawings and in the Middle East.
- St 35.8 — DIN 17175 (withdrawn): The tube designation of the same class; St 35.8/I and St 35.8/III map onto P235GH TC1 and TC2.
- Fe 360-1 KW — EURONORM 28 (withdrawn): Pre-EN European designation for the same pressure quality.

Product forms: normalised plate and wide flat (EN 10028-2); seamless tube as P235GH TC1 and TC2 (EN 10216-2); welded tube as P235GH TC1 (EN 10217-2); pipe fittings and flanges (EN 10222-2 forgings); strip for welded pressure tube
Tolerances: plate: EN 10029; seamless tube: EN 10216-2 dimensional clauses; welded tube: EN 10217-2; surface condition: EN 10163-2 class A or B for plate

### P235GH yield strength
235 MPa minimum up to 16 mm at room temperature, 225 MPa to 40 mm, 215 MPa to 60 mm and 200 MPa to 100 mm, with tensile 360–480 MPa. The room-temperature figure is the familiar one; it is rarely the number that sizes the component.

### P235GH at temperature
The defining data. Minimum 0.2 % proof strength falls to roughly 165 MPa at 200 °C, 139 MPa at 300 °C and 121 MPa at 400 °C for material up to 16 mm, with the governing values tabulated by thickness in EN 10028-2. Above about 400 °C the grade runs out: creep governs, and the specification moves to 16Mo3 or a chromium-molybdenum steel.

### P235GH chemical composition
C ≤ 0.16 %, Si ≤ 0.35 %, Mn 0.60–1.20 %, P ≤ 0.025 %, S ≤ 0.015 %, Al ≥ 0.020 % total, with Cr, Ni, Cu each ≤ 0.30 % and Mo ≤ 0.08 %. The residual ceilings and the aluminium minimum are what make it a pressure grade rather than a structural one with the same carbon.

### P235GH TC1 and TC2
The tube designations from EN 10216-2 (seamless) and EN 10217-2 (welded). TC1 covers the standard test category and TC2 the enhanced one, with additional testing on each length. They correspond to the old DIN 17175 St 35.8/I and St 35.8/III, which is the equivalence most often asked for on boiler-tube enquiries.

### P235GH vs P265GH
P265GH is the same steel family with 265 MPa room-temperature yield and proportionally higher proof strength at every temperature, at the cost of slightly more carbon and manganese. The choice is a wall-thickness calculation: P265GH buys thinner walls for the same duty, P235GH welds a little more easily and costs slightly less.

### Weldability
P235GH is designed to be welded and is among the most forgiving pressure grades. Carbon equivalent is low, and preheat is generally unnecessary below about 30 mm; above that, 100–150 °C preheat is normal practice in restrained joints. Use consumables matched to the parent grade and qualified to the applicable vessel code — the procedure, not the material certificate, is what the inspector accepts. Post-weld heat treatment is governed by the design code and the thickness rather than by the steel: many thin-walled vessels in this grade are built without it. The tight sulphur ceiling is a direct welding benefit, reducing hot-cracking risk in heavy restrained welds.

### Machining, forming, heat treatment
Machinability is good and comparable to other low-carbon normalised steels. Cold forming — rolling shells, dishing heads, bending tube — is straightforward, and the normalised fine-grained structure gives consistent springback. Where cold forming exceeds the strain limits in the design code, re-normalising after forming is required; that is a code question rather than a material one, and it is the usual reason a dished end carries a heat-treatment certificate of its own.

Applications: Boiler drums, headers and low-pressure steam equipment; Heat exchanger shells, channels and tube sheets in moderate-temperature duty; Steam and hot-water pipework as P235GH TC1 or TC2 tube; Air receivers, compressed-air vessels and buffer tanks; Process vessels and reactors operating below about 400 °C; Pipe fittings, flanges and forged components to EN 10222-2

Q: What is P235GH steel?
A: P235GH (1.0345) is the entry grade of EN 10028-2, the European standard for non-alloy pressure-vessel steels with elevated-temperature properties. It has a 235 MPa minimum yield at room temperature and, crucially, guaranteed proof strength tabulated up to 400 °C.

Q: What is the difference between P235GH and S235JR?
A: P235GH has elevated-temperature proof strength data, tighter phosphorus and sulphur (0.025 % and 0.015 %), a minimum aluminium content and a normalised delivery condition. S235JR has none of these, so it cannot be used in a pressure calculation even though its room-temperature yield is the same.

Q: What does GH mean in P235GH?
A: G means other characteristics are specified and H means elevated-temperature properties. The P before the number marks the pressure-purposes standard EN 10028; a grade beginning with S, such as S235JR, belongs to the structural standard EN 10025 instead.

Q: Is there a grade called S235GH?
A: No. It is one of the most common designation errors on drawings, mixing the S of the structural standard with the GH of the pressure standard. The grade being asked for is almost always P235GH, or occasionally S235JR where no pressure duty exists.

Q: What is the maximum temperature for P235GH?
A: Design data runs to 400 °C, and that is the practical ceiling. Above it creep governs the design rather than proof strength, and the specification moves to a molybdenum-bearing grade such as 16Mo3 or to a chromium-molybdenum steel for higher duty.

Q: What is P235GH TC1?
A: The tube version, from EN 10216-2 for seamless and EN 10217-2 for welded pipe. TC1 is the standard test category and TC2 the enhanced one; they correspond to the withdrawn DIN 17175 grades St 35.8/I and St 35.8/III.

Q: What is the ASTM equivalent of P235GH?
A: A285 Grade C is the closest plate match on strength and duty. A516 Grade 70 is often quoted but is considerably stronger and toughness-oriented; for tube, A106 Grade B covers comparable service to P235GH TC1 and TC2.

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## P235TR1 (1.0254) — Welded non-alloy pressure tube, room-temperature properties
URL: https://steelstandart.com/grade/p235tr1/
System: EN (European) | Family: Pipe & tube steel | Standard: EN 10217-1 | Verified against: EN 10217-1:2019
Aliases: 1.0254, P235 TR1, P235TR2, 1.0255, P235TR1 material, P235TR1 tube, P235TR1 equivalent, P235GH TR1, St 37.0, St37.0, P195TR1, P265TR1, EN 10217-1 P235TR1

P235TR1 is the plain welded steel tube for pressure purposes in the European system, and the grade name is self-describing once the convention is read: P for pressure purposes, 235 for the minimum yield strength in MPa. Material number 1.0254. Tensile strength is bounded at both ends — 360–500 MPa — and minimum elongation is 25 %. Its predecessor on German drawings was St 37.0, and that name is still in daily use.

The whole substance of this grade lies in the suffix, and it is routinely misunderstood because TR1 and TR2 have the same mechanical property table. Identical yield, identical tensile range, identical elongation. Nothing in a tensile certificate tells them apart. What separates them is everything around the tensile test:

TR1 is the basic quality. No impact test. Non-destructive testing of the weld only if the order asks for it. Inspection document 2.2 (a non-specific test report) is sufficient. TR2 adds a mandatory Charpy test at 0 °C, mandatory non-destructive testing of the weld, tighter control of residual elements, and a 3.1 inspection certificate. That is why most national pressure-equipment rules — and the Pressure Equipment Directive route in practice — accept TR2 and not TR1 for a pressure-retaining part.

The second boundary worth fixing is temperature. TR means "specified room temperature properties". There is no proof-strength table above 20 °C anywhere in EN 10217-1, so the grade cannot be used for a hot line no matter how modest the pressure. The grade for that is P235GH in EN 10216-2 or EN 10217-2, which tabulates proof strength to 400 °C and requires impact testing. P235TR1, P235GH and the structural S235JRH all carry the number 235 and are three different products.

Across systems the closest match is ASTM A53 Grade B: almost the same strength, the same market, and the same absence of an impact requirement. The structural difference is how each specification subdivides its product — A53 by manufacturing type, EN 10217-1 by test quality.

Chemical composition (mass %): C ≤ 0.16; Si ≤ 0.35; Mn ≤ 1.2; P ≤ 0.025; S ≤ 0.02
EN 10217-1:2019, grade P235TR1 (1.0254). TR2 (1.0255) is the same base analysis with the residual elements more tightly controlled and, in some editions, a slightly lower carbon ceiling. The **P prefix means pressure purposes** and the number is the minimum yield strength in MPa — the same logic as P265GH and P355GH, and not to be confused with the S prefix of the structural grades.

Mechanical properties:
- P235TR1 / TR2 — specified, t ≤ 16 mm: yield 235 MPa; tensile 360–500 MPa; elongation 25 (longitudinal) %; hardness —
- P195TR1 / TR2 — specified: yield 195 MPa; tensile 320–440 MPa; elongation 27 (longitudinal) %; hardness —
- P265TR1 / TR2 — specified: yield 265 MPa; tensile 410–570 MPa; elongation 21 (longitudinal) %; hardness —
- P235TR1, typical mill result: yield 280–350 MPa; tensile 400–460 MPa; elongation 28–35 %; hardness 115–145 HB
- Leak tightness test: yield — MPa; tensile — MPa; elongation — %; hardness hydrostatic or eddy current, every tube
- Flattening and weld bend test: yield — MPa; tensile — MPa; elongation — %; hardness required by size and route
**TR1 and TR2 share the same mechanical table.** The yield, tensile and elongation figures are identical, which is precisely why the pair is so often confused — nothing in a tensile certificate distinguishes them. The difference is in the impact requirement, the non-destructive testing and the inspection document, all listed below. Older third-party data sheets quoting 215 MPa for P235 are reporting the **seamless** standard EN 10216-1, not EN 10217-1.
Impact: 40 J longitudinal average of three (27 J transverse) J at 0 °C °C (TR2 only. Tested on the parent metal; test frequency and specimen orientation follow the standard's tables, and sub-size specimens carry proportionally reduced requirements.)

Equivalents:
- A53 Grade B (ASTM / ASME) — near: ASTM A53 Grade B: 240 MPa minimum yield and 415 MPa minimum tensile with **no upper bound** on tensile, no silicon requirement and no impact test. Very close in strength to P235TR1 and the same market position; the differences are that A53 publishes no maximum tensile and splits its product by manufacturing type (F, E, S) while EN 10217-1 splits it by test quality (TR1, TR2).
- A106 Grade B (ASTM / ASME) — near: ASTM A106 Grade B at 240/415, seamless only, with a silicon minimum and published elevated-temperature allowables. Its EN counterpart is not this grade but **P235GH to EN 10216-2/10217-2**, whose property table runs to 400 °C. P235TR1 is a room-temperature specification — that is what the TR designation means.
- A53 Grade B (ASTM / ASME) — near: EN 10217-1 P235TR1: 235 MPa minimum yield, 360–500 MPa tensile — the European welded pipe for general service. Slightly lower strength, and TR1 carries no impact requirement while TR2 does; A53 carries none either, which makes TR1 the closer match.
- P235GH (EN (European)) — near: 1.0345: the same 235 MPa strength level, but specified for **elevated temperature** with proof-strength values tabulated to 400 °C, a silicon minimum and mandatory impact testing. The GH grade is what a boiler or process line needs; the TR grades stop at room temperature.
- STPG370 (JIS (Japan)) — near: JIS G3454 STPG370: 215 MPa minimum yield, 370 MPa minimum tensile, carbon steel pipe for ordinary pressure service, welded or seamless. The closest Japanese counterpart.
- S195T (EN (European)) — functional: EN 10255 S195T: the threadable general-purpose tube for water, gas and low-pressure service at 195 MPa minimum yield. One step below in both strength and test regime, and specified in light, medium and heavy series rather than by wall thickness.
- S235JRH (EN (European)) — functional: EN 10219 S235JRH: 235 MPa minimum yield **structural** hollow section. The same strength number, and a frequent source of error — the H grade carries no pressure-purpose requirements and the TR grade carries no section-property or structural tolerance guarantees. The prefix decides which one the drawing means.
- DC01 (EN (European)) — functional: EN 10130 DC01: the cold-rolled forming sheet that welded precision tube is often made from. Listed because enquiries confuse the two — DC01 is a forming grade with no strength guarantee, and a tube rolled from it is a precision tube to EN 10305-3, not a pressure tube.
- E355 (EN (European)) — functional: EN 10217-1 P235TR1: the welded pressure tube at 235 MPa yield. A pressure tube is specified for leak-tightness and wall integrity; a precision tube is specified for dimensions and finish. Neither substitutes for the other, and a precision tube should not be used as a pressure-retaining part without checking the design code.
- Q235 (GB/T (China)) — functional: Chinese welded pressure tube to GB/T 3091 and GB 9948 is usually rolled from Q235B, at a comparable carbon and strength level. The grade system and test regime differ, so an equivalence claim should be checked against the actual tube standard rather than the steel grade.

Superseded names:
- St 37.0 — DIN 1626 (withdrawn): The German welded pressure tube grade P235 descends from; the .0 suffix marked the pressure-purpose quality as distinct from structural St 37-2. Still written on older drawings and in stockist catalogues.
- St 37.4 — DIN 1630 (withdrawn): The seamless, higher-quality counterpart; its modern equivalent is EN 10216-1 P235TR2 or EN 10305-4 for precision tube.
- HFS 23 / ERW 23 — BS 3601 (withdrawn): The British pressure tube grades at a similar strength level.
- TU 37b — NF A 49-141: The French welded pressure tube designation.

Product forms: electric-welded tube (EW); submerged-arc welded tube (SAW) in larger diameters; black or galvanized; plain end, bevelled or threaded
Tolerances: diameter, wall thickness and length: EN 10217-1 with the size tables of EN 10220; every tube leak tested; TR2 adds non-destructive testing of the weld as a mandatory requirement; seamless counterpart: EN 10216-1, same grade designations, different property table

### P235TR1 mechanical properties
235 MPa minimum yield (ReH), 360–500 MPa tensile, 25 % minimum elongation longitudinal for wall up to 16 mm. The tensile upper bound is worth noting — unlike ASTM A53, EN 10217-1 caps it, because a pressure tube that must be bent, expanded or welded in the field should not be arbitrarily strong. Typical mill results run 280–350 MPa yield and 400–460 MPa tensile. The sister grades are P195TR1 at 195 MPa and P265TR1 at 265 MPa.

### TR1 against TR2 — the actual difference
The mechanical table is the same. TR2 adds four things: a mandatory Charpy impact test at 0 °C (40 J longitudinal average of three), mandatory non-destructive testing of the weld seam, tighter limits on residual elements, and a 3.1 inspection certificate rather than a 2.2 test report. TR1 has none of these. The practical consequence is regulatory: a pressure-retaining component normally needs TR2, and ordering TR1 to save a few per cent produces tube that cannot be used for the job. Ask for the suffix on every enquiry — a quotation for "P235" is not a quotation for either.

### What TR means and why it limits temperature
TR = specified properties at room temperature. EN 10217-1 contains no proof-strength values above 20 °C, so there is no basis on which to calculate a wall thickness for a hot line. The elevated-temperature family is separate: P235GH, P265GH, P355GH in EN 10216-2 (seamless) and EN 10217-2 (welded), each with a proof-strength table running to 400 °C, a silicon minimum and mandatory impact testing. A tube ordered as P235TR2 cannot be used where the design code calls for P235GH, and the substitution is not a matter of margin — the data simply does not exist.

### P235TR1, P235GH and S235JRH
Three grades, one number, constant confusion. P235TR1 / TR2 (EN 10217-1) — welded pressure tube, room temperature only. P235GH (EN 10216-2 / 10217-2) — pressure tube for elevated temperature, with hot proof strength tabulated. S235JRH (EN 10219) — structural hollow section, with section properties and structural tolerances but no pressure-purpose requirements at all. The 235 is the minimum yield in each case and tells you nothing about which document applies. The prefix is the specification; the number is only the strength.

### Welded against seamless: EN 10217-1 and EN 10216-1
The two standards use the same grade designations for different products: EN 10217-1 is welded, EN 10216-1 is seamless, and each has its own property table. This is the source of a persistent data error — third-party databases quoting 215 MPa yield for P235 are reporting the seamless standard's figure, not the 235 MPa of EN 10217-1. When comparing a certificate against a published figure, confirm which of the two standards the figure came from.

### Physical properties
Density 7.85 g/cm³, E = 210 GPa, thermal conductivity ≈ 52 W/m·K at 20 °C, expansion 12.0 × 10⁻⁶/K (20–100 °C). At 0.16 % maximum carbon the carbon equivalent is low — typically 0.25–0.35 — which is why the grade is welded without preheat in any normal wall thickness and is the usual choice where a tube will be fabricated on site.

### Weldability
Excellent weldability by every arc process with no preheat in normal wall thickness; the carbon ceiling of 0.16 % keeps the carbon equivalent at roughly 0.25–0.35. E6013/E7018 or ER70S-6 consumables, no post-weld heat treatment required below the code thickness limits. The tube's own longitudinal seam is made by high-frequency induction or submerged arc; on TR2 that seam is non-destructively tested as a matter of course, while on TR1 it is only leak tested unless the order says otherwise — relevant when a branch or support is welded near the seam. Galvanized tube must have the zinc removed from the weld zone before welding.

### Machining, forming, heat treatment
Machines easily, around 70–75 % relative to 1 % C free-cutting steel, and threads cleanly — though for threaded service the proper specification is EN 10255 rather than a pressure tube. Cold bending is straightforward at this carbon level and the capped upper tensile strength helps, since springback is predictable; mandrel bending down to about 2.5 D is routine. Expanding, flaring and swaging are practical. Cutting by saw, abrasive wheel or plasma; keep the heat-affected zone modest if a leak-tight joint will be made at the cut. For close-tolerance mechanical work the grade to use is a precision tube to EN 10305, not a pressure tube.

Applications: Water, compressed air and low-pressure steam service at ambient temperature; Heating circuits, chilled water and HVAC pipework; Pressure vessels and tanks — connections, nozzles and non-fired coils (TR2); Fire protection and sprinkler mains; Hydraulic and pneumatic lines in larger diameters; General fabrication where a leak-tight, weldable tube is needed; Fluid handling in food, chemical and process plant at room temperature

Q: What is the difference between P235TR1 and P235TR2?
A: Not the mechanical properties — those are identical, which is why the two are so often confused. TR2 adds a mandatory Charpy impact test at 0 °C, mandatory non-destructive testing of the weld seam, tighter control of residual elements and a 3.1 inspection certificate instead of a 2.2 test report. TR1 has none of these. Most national pressure-equipment rules accept TR2 and not TR1 for a pressure-retaining part, so the suffix must be on the order.

Q: What does TR mean in P235TR1?
A: Specified properties at room temperature. The standard contains no proof-strength values above 20 °C, so the grade cannot be used to size a hot line. For elevated temperature the corresponding grades are P235GH, P265GH and P355GH in EN 10216-2 and EN 10217-2, which tabulate proof strength up to 400 °C.

Q: What is the yield strength of P235TR1?
A: 235 MPa minimum, with tensile strength between 360 and 500 MPa and elongation at least 25 % for wall thickness up to 16 mm. Note that EN 10217-1 caps the tensile strength at the top as well as the bottom. Data sheets quoting 215 MPa are reporting the seamless standard EN 10216-1, not the welded EN 10217-1.

Q: Is P235TR1 the same as St 37.0?
A: It is the direct successor. St 37.0 to DIN 1626 was the welded pressure tube grade — the .0 suffix marking the pressure-purpose quality, distinct from the structural St 37-2 — and EN 10217-1 replaced it with P235TR1 and TR2. The two names refer to the same material in practice, and stockists still list both.

Q: What is the ASTM equivalent of P235TR1?
A: ASTM A53 Grade B is the nearest, at 240 MPa minimum yield and 415 MPa minimum tensile, with no impact requirement — the same absence as TR1. The structural difference is how each specification subdivides its product: A53 by manufacturing type (F, E, S) and EN 10217-1 by test quality (TR1, TR2). A106 Grade B is a seamless elevated-temperature pipe and corresponds to P235GH rather than to this grade.

Q: What is the difference between P235TR1 and S235JRH?
A: The prefix. P is for pressure purposes and S is for structural, and they lead to different standards: P235TR1 is a welded pressure tube to EN 10217-1, while S235JRH is a structural hollow section to EN 10219 with section properties, structural tolerances and a J-quality impact class but no pressure-purpose requirements. Both have a minimum yield of 235 MPa, which is all the number tells you.

Q: Can P235TR1 be used for a pressure vessel?
A: Generally not as a pressure-retaining part — that normally requires TR2, because the conformity route expects impact testing, non-destructive testing of the weld and a 3.1 certificate, none of which TR1 provides. TR1 is used for non-critical service lines, water, air and heating circuits. The design code or notified body determines what is acceptable, so the question should be settled before ordering rather than after.

Q: Is P235TR1 weldable without preheat?
A: Yes, in any normal wall thickness. With carbon capped at 0.16 % the carbon equivalent sits around 0.25–0.35, which is low enough for every arc process without preheat and without post-weld heat treatment below the code's thickness limits. That weldability is one of the main reasons the grade is specified for site-fabricated pipework.

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## P265GH (1.0425) — Non-alloy steel for pressure purposes with elevated-temperature properties
URL: https://steelstandart.com/grade/p265gh/
System: EN (European) | Family: Pressure vessel steel | Standard: EN 10028-2 | Verified against: EN 10028-2:2017
Aliases: P 265 GH, HII, H II, 1.0425, P265GH+N, Fe410-1KW, P265GH steel

P265GH is the standard carbon-steel plate for boilers, pressure vessels and heat exchangers in Europe: P for pressure, 265 for the minimum yield in MPa, G for 'other characteristics' and H for guaranteed high-temperature properties. Werkstoff number 1.0425; the pre-1992 name HII (DIN 17155) is still in wide use, especially in Turkey, Germany and the Gulf.

What separates it from a structural steel of the same strength is the guarantee package: yield strength tabulated from 50 to 400 °C, Charpy 27 J at −20 °C transverse, sulphur held to 0.010 %, full killing with aluminium, normalized microstructure, and mandatory testing per plate under the Pressure Equipment Directive (EN 10028-2 with EN 10204 3.1/3.2 certification). Tensile is 410–530 MPa, elongation 23 %.

The usual US counterpart is ASTM/ASME A516 Grade 60 (yield 220 MPa) — a 'near' match because yield is lower and elevated-temperature values are handled differently in ASME. JIS SB410, GB Q245R and IS 2002 Grade 2 are closer. For service above ~450 °C the next step is 16Mo3.

Chemical composition (mass %): C ≤ 0.2; Si ≤ 0.4; Mn 0.8 – 1.4; P ≤ 0.025; S ≤ 0.01 (very low sulphur for through-thickness ductility in vessels); Al ≥ 0.02 (total Al; fully killed); N ≤ 0.012; Cr ≤ 0.3; Cu ≤ 0.3; Mo ≤ 0.08; Nb ≤ 0.02; Ni ≤ 0.3; Ti ≤ 0.03; V ≤ 0.02
EN 10028-2:2017 Table 1; Cr + Cu + Mo + Ni ≤ 0.70 %. CEV max 0.40 % (≤ 60 mm), 0.42 % (60–100 mm). Normalized delivery (+N) is mandatory for plate > 16 mm.

Mechanical properties:
- ≤ 16 mm, +N: yield 265 MPa; tensile 410–530 MPa; elongation 23 %; hardness ≈ 120–160 HB (typ.)
- > 16 ≤ 40 mm: yield 255 MPa; tensile 410–530 MPa; elongation 23 %; hardness —
- > 40 ≤ 60 mm: yield 245 MPa; tensile 410–530 MPa; elongation 23 %; hardness —
- > 60 ≤ 100 mm: yield 215 MPa; tensile 400–520 MPa; elongation 22 %; hardness —
- > 100 ≤ 150 mm: yield 200 MPa; tensile 390–510 MPa; elongation 21 %; hardness —
- Rp0.2 at 100 °C (≤ 60 mm): yield 226 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 200 °C: yield 205 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 300 °C: yield 173 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 400 °C: yield 145 MPa; tensile — MPa; elongation — %; hardness —
EN 10028-2 Tables 2–4; transverse test pieces for plate. Elevated-temperature yield values decrease slightly for thickness > 60 mm. Creep data (EN 10028-2 Annex) allow use to about 480 °C for time-dependent design.
Impact: 27 J at -20 °C (transverse; ≥ 40 J longitudinal at −20 °C; ≥ 31 J transverse at 0 °C and ≥ 34 J at +20 °C)

Equivalents:
- Q245R (GB/T (China)) — identical: GB/T 713 Q245R: yield 245 MPa, Rm 400–520 MPa, 31 J at 0 °C; C ≤ 0.20, Mn 0.50–1.10 — the Chinese boiler and pressure-vessel plate matching P265GH/HII.
- IS 2002 Gr. 2 (IS (India)) — identical: IS 2002 Grade 2 pressure-vessel plate: yield 240 MPa, Rm 410–530 MPa.
- SB410 (JIS (Japan)) — identical: JIS G3103 SB410 boiler plate: yield ≥ 225 MPa, Rm 410–550 MPa, C ≤ 0.24; SPV235 (G3115) is the pressure-vessel equivalent.
- A516 Gr. 60 (ASTM / ASME) — near: ASTM A516 Grade 60 (SA-516-60): yield 220 MPa (32 ksi), Rm 415–550 MPa; C ≤ 0.21–0.27 by thickness, no elevated-temperature yield table (ASME Section II-D gives allowables). Closest US boiler-plate grade.
- A516 Gr. 65 (ASTM / ASME) — near: Yield 240 MPa, Rm 450–585 MPa — slightly stronger than P265GH.
- A516 Grade 70 (ASTM / ASME) — near: Yield 265 MPa, Rm 410–530 MPa — the EN grade most often substituted for A516-60/65; slightly weaker than Grade 70.
- P235GH (EN (European)) — near: 1.0345 (ex HI): yield 235 MPa, Rm 360–480 MPa — the lower class; common for tubes.
- P295GH (EN (European)) — near: 1.0481 (ex 17Mn4): yield 295 MPa, Rm 460–580 MPa.
- 16K / 20K (GOST (Russia/CIS)) — near: GOST 5520 16K (yield 245, Rm 400–490) and 20K (yield 245, Rm 410–520): Russian boiler plates.
- A285 Gr. C (ASTM / ASME) — functional: Yield 205 MPa, Rm 380–515 MPa; lower-quality pressure plate for low-pressure vessels.
- 16Mo3 (EN (European)) — functional: Mo-alloyed step for service above 400–450 °C.
- S275JR (EN (European)) — functional: Structural steel of similar strength without elevated-temperature or pressure-equipment certification (no PED compliance).

Superseded names:
- HII — DIN 17155 (withdrawn 1992): The classic German boiler-plate grade; still the ordering name in much of Europe and the Middle East.
- Fe410-1KW / Fe410-2KW — EN 10028-2:1992 / ISO 9328
- P265GH (1.0425) — EN 10028-2:1992: Name and number unchanged since 1992.
- 161 Gr 400 / 164 Gr 400 — BS 1501 (withdrawn): Grade 400 (≈ 410 MPa tensile) is the match.
- A42CP / A42AP — NF A 36-205

Product forms: plate (EN 10028-2, dominant); strip and sheet (EN 10028-2); seamless tube for pressure (EN 10216-2); welded tube (EN 10217-2); forgings (EN 10222-2 as P280GH); fittings (EN 10253-2)
Tolerances: plate: EN 10029 (class A/B thickness, flatness N); strip: EN 10051; tube: EN 10216-2 / EN ISO 1127

### P265GH yield strength
265 MPa (38.4 ksi) ≤ 16 mm, 255 MPa to 40 mm, 245 MPa to 60 mm, 215 MPa to 100 mm, 200 MPa to 150 mm. Elevated temperature (≤ 60 mm): 226 MPa at 100 °C, 205 at 200 °C, 173 at 300 °C, 145 MPa at 400 °C.

### P265GH tensile strength
410–530 MPa (59–77 ksi) up to 60 mm; 400–520 MPa to 100 mm; 390–510 MPa to 150 mm.

### P265GH hardness
Not specified in EN 10028-2; normalized plate is typically 120–160 HB. NACE MR0175 sour service: ≤ 22 HRC is comfortably met.

### Impact toughness
Transverse 27 J at −20 °C, 31 J at 0 °C, 34 J at +20 °C; longitudinal 40 / 47 / 55 J.

### Maximum service temperature
Design tables to 400 °C (time-independent); creep rupture data allow time-dependent design to about 480 °C. Above that use 16Mo3 or 13CrMo4-5.

### Physical properties
Density 7.85 g/cm³, E = 212 GPa at 20 °C (200 GPa at 300 °C), expansion 12.0 × 10⁻⁶/K (20–100 °C) to 13.5 (20–400 °C), conductivity ≈ 50 W/m·K.

### Weldability
Very good weldability (CEV ≤ 0.40 %): all arc processes, E42/G42 or E46 consumables with low hydrogen for pressure work. Preheat normally unnecessary below 30 mm; EN 1011-2 governs thicker joints. PWHT (stress relief 550–600 °C) is required by EN 13445 / AD 2000 above certain thicknesses (typically > 35 mm) or for specific services (H₂S, caustic). Welding procedures must be qualified per EN ISO 15614-1 for PED equipment.

### Machining, forming, heat treatment
Machines like a mild structural steel (index ≈ 70 %). Cold forming: dished ends and shells are cold-formed within EN 13445 strain limits (typically ≤ 5 % without post-forming normalizing); hot forming 900–1050 °C followed by re-normalizing 890–950 °C. Flame cutting is routine; grind cut edges for vessels in cyclic service.

Applications: Steam boilers, boiler drums and headers (low-pressure and firetube boilers); Pressure vessels, air receivers, LPG storage vessels (with impact requirements); Heat-exchanger shells, tubesheets (thin), channels; Hot-water storage tanks and district-heating equipment; Seamless pressure tubes (EN 10216-2 P265GH) for boilers and superheaters up to 400 °C; Autoclaves, sterilizers and process vessels in food and chemical plants

Q: Is P265GH the same as HII?
A: Yes. HII (DIN 17155) became P265GH (EN 10028-2) in 1992 with harmonized limits; material certified to EN 10028-2 P265GH fulfils an old HII requirement.

Q: What is the ASTM equivalent of P265GH?
A: ASTM/ASME A516 Grade 60 is the usual substitute (yield 220 MPa, Rm 415–550 MPa); Grade 65 is closer in strength. Neither has the EN elevated-temperature yield table, and for PED-marked equipment a European Approval for Materials or particular material appraisal is needed.

Q: What is the maximum temperature for P265GH?
A: 400 °C for design using the tabulated yield values, up to about 480 °C where creep-rupture data are applied. For higher temperatures switch to 16Mo3 (≈ 530 °C) or 13CrMo4-5 (≈ 570 °C).

Q: P265GH or S275JR — what is the difference?
A: Similar room-temperature strength, but P265GH is a pressure-equipment steel: certified per plate under EN 10028-2, with guaranteed yield at elevated temperature, low sulphur, −20 °C impact and normalized structure. S275JR is a structural steel and cannot be used for PED-scope pressure parts without specific appraisal.

Q: Does P265GH need PWHT?
A: Not for weldability, but the vessel code decides: EN 13445 and AD 2000 require stress-relief above threshold thicknesses (around 35 mm for carbon steel) and for services such as wet H₂S or caustic.

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## P355GH (1.0473) — Non-alloy steel for pressure purposes with elevated-temperature properties
URL: https://steelstandart.com/grade/p355gh/
System: EN (European) | Family: Pressure vessel steel | Standard: EN 10028-2 | Verified against: EN 10028-2:2017
Aliases: 17Mn4, HIII, S355GH (incorrect), 1.0473

P355GH is the strongest non-alloy grade in EN 10028-2 and the one specified when a pressure vessel has to carry more load than P265GH allows without moving to an alloyed or fine-grain steel. The G stands for *Gütestahl* qualities for pressure purposes and the H for elevated temperature: the standard publishes a guaranteed 0.2 % proof strength at 50 °C intervals up to 400 °C, and that table — not the room-temperature yield — is what a vessel designer calculates with.

The grade is a carbon-manganese steel: up to 0.22 % C with 1.10–1.70 % Mn, aluminium-killed and normalized. It is supplied mostly as plate from 5 to 150 mm, and also as seamless and welded tube, forgings and fittings, all carrying the same designation across EN 10216-2, EN 10222-2 and EN 10253-2 — which is why a complete vessel can be built in one grade.

A note on the name: S355GH does not exist. The S prefix belongs to structural steels in EN 10025, the P prefix to pressure steels in EN 10028. A drawing or enquiry that says S355GH almost always means P355GH, and a supplier who ships S355J2 against it has delivered a structural plate with no elevated-temperature data and no pressure certification.

Chemical composition (mass %): C ≤ 0.22 (≤ 0.20 for thickness ≤ 16 mm); Si ≤ 0.6; Mn 1.1 – 1.7; P ≤ 0.025; S ≤ 0.015; Cr ≤ 0.3; Cu ≤ 0.3; Mo ≤ 0.08; Ni ≤ 0.3; Nb ≤ 0.05; Ti ≤ 0.03; V ≤ 0.02; Al ≥ 0.02 (total Al, for grain refinement)
Cr + Cu + Mo + Ni ≤ 0.70 %. The manganese range is what separates P355GH from P265GH: more Mn, more strength, slightly more care in welding.

Mechanical properties:
- ≤ 16 mm, +N: yield 355 MPa; tensile 490–630 MPa; elongation 21 %; hardness ≈ 150–190 HB (typ.)
- > 16 ≤ 40 mm, +N: yield 345 MPa; tensile 490–630 MPa; elongation 21 %; hardness 
- > 40 ≤ 60 mm, +N: yield 335 MPa; tensile 490–630 MPa; elongation 21 %; hardness 
- > 60 ≤ 100 mm, +N: yield 315 MPa; tensile 480–620 MPa; elongation 20 %; hardness 
- > 100 ≤ 150 mm, +N: yield 295 MPa; tensile 470–610 MPa; elongation 20 %; hardness 
Transverse test pieces, normalized condition. Elevated-temperature proof strength is the reason the grade exists — see the properties section.
Impact: 27 J at −20 °C °C (longitudinal, ≤ 60 mm)

Equivalents:
- A516 Grade 70 (ASTM / ASME) — near: ASTM A516 Grade 70 (SA-516-70): yield 260 MPa (38 ksi), Rm 485–620 MPa. Similar tensile band and service role, but the yield is markedly lower and ASTM gives allowable stresses through ASME Section II-D rather than a guaranteed elevated-temperature proof strength.
- SPV355 (JIS (Japan)) — near: JIS G3115 SPV355: 355 MPa yield pressure-vessel plate; chemistry and impact regime differ in detail.
- A537 Cl. 1 (ASTM / ASME) — functional: Normalized C-Mn pressure plate with 345 MPa yield — the closest US grade by strength, used where A516-70 is not strong enough.
- P355NH (EN (European)) — functional: EN 10028-3 weldable fine-grain grade at the same yield. Choose NH where low-temperature toughness matters more than elevated-temperature service; GH where the vessel runs hot.
- 16Mo3 (EN (European)) — functional: Molybdenum-alloyed creep-resistant grade for service above 400 °C, where P355GH's guaranteed proof strength table ends.

Superseded names:
- 17Mn4 — DIN 17155: the German boiler-plate designation replaced in 1992
- HIII — DIN 17155: older trade name, still quoted in tenders
- Fe 510 KW — EURONORM: withdrawn

Product forms: plate (EN 10028-2, dominant); strip and sheet (EN 10028-2); seamless tube for pressure (EN 10216-2 as P355GH); welded tube (EN 10217-2); forgings (EN 10222-2 as P355GH); fittings (EN 10253-2)
Tolerances: Plate thickness to EN 10029 class A or B; flatness class N or S. Normalized (+N) delivery is standard above 16 mm.

### P355GH yield strength
355 MPa (51.5 ksi) ≤ 16 mm, 345 MPa to 40 mm, 335 MPa to 60 mm, 315 MPa to 100 mm, 295 MPa to 150 mm. Elevated temperature (≤ 60 mm): 306 MPa at 100 °C, 278 at 200 °C, 235 at 300 °C, 196 MPa at 400 °C.

### Tensile strength
490–630 MPa up to 60 mm, 480–620 MPa to 100 mm, 470–610 MPa to 150 mm. Elongation A ≥ 21 % (20 % above 60 mm), transverse.

### Impact toughness
27 J at −20 °C longitudinal as standard to 60 mm. Transverse values and lower test temperatures are agreed at order; for genuinely low-temperature service the fine-grain P355NL1 or P355NL2 grades of EN 10028-3 are the correct choice.

### Delivery condition
Normalized (+N) is standard and mandatory above 16 mm. Normalizing forming (+NR) is permitted by agreement. Simulated post-weld heat treatment data is supplied on request for vessels that will be stress-relieved.

### Density and physical data
7.85 kg/dm³; modulus of elasticity 212 GPa at 20 °C, 199 GPa at 200 °C, 186 GPa at 400 °C; thermal conductivity ≈ 46 W/mK; specific heat ≈ 460 J/kgK.

### Weldability
Readily weldable by all common processes. Carbon equivalent CEV ≤ 0.45 to 30 mm and ≤ 0.47 above, which puts preheat at 100–150 °C for thick sections and below 5 °C ambient. Use basic low-hydrogen consumables matched to the plate (for example E 46 4 B or S 46 4 for SAW); hydrogen control matters more here than on P265GH because the higher manganese raises hardenability in the heat-affected zone. Post-weld heat treatment at 530–620 °C is normal practice for pressure vessels and is required by most design codes above certain thicknesses; when PWHT is planned, order the plate with simulated PWHT test data so the mechanical values after heat treatment are documented rather than assumed.

### Machining, forming, heat treatment
Machines like a normalized C-Mn steel at 150–190 HB: cutting speeds roughly 15 % below mild steel, carbide tooling, generous coolant on drilling. Oxy-fuel and plasma cutting are routine; the cut edge should be ground back 1–2 mm before welding on thick plate. Cold forming is possible but the bending radius should be at least 2.5 × thickness, and heavy cold work before PWHT needs to be declared because it affects the final properties.

Applications: Pressure vessels, receivers and separators designed to EN 13445 or AD 2000; Steam drums, headers and boiler shells below the creep range; Heat exchanger shells and tube plates; Refinery and petrochemical vessels operating to 400 °C; Pipework and fittings in the same grade through EN 10216-2 and EN 10253-2; Storage tanks for hot media where P265GH would need a thicker wall

Q: Is S355GH the same as P355GH?
A: S355GH is not a designation in any current standard. The S prefix is for structural steels (EN 10025), the P prefix for pressure steels (EN 10028). An enquiry for S355GH is almost always meant as P355GH — confirm it before ordering, because S355J2 plate carries no elevated-temperature data.

Q: What is the difference between P265GH and P355GH?
A: Manganese and strength: P265GH has 0.50–1.40 % Mn and 265 MPa yield, P355GH has 1.10–1.70 % Mn and 355 MPa. At 400 °C the guaranteed proof strengths are 145 and 196 MPa, so P355GH lets a vessel wall be roughly a quarter thinner at the same pressure.

Q: What is the ASTM equivalent of P355GH?
A: A516 Grade 70 is the usual substitution by service, but its yield is 260 MPa against 355 MPa. Where the design needs the yield rather than the tensile, A537 Class 1 at 345 MPa is closer.

Q: Is P355GH the same as 17Mn4 or HIII?
A: Yes, in practice. 17Mn4 and HIII are the DIN 17155 designations replaced by P355GH in EN 10028-2; material certified to the EN grade satisfies an old 17Mn4 requirement.

Q: Does P355GH need post-weld heat treatment?
A: Most pressure design codes require PWHT above a thickness threshold, typically 30–35 mm for C-Mn steels. Stress relieving at 530–620 °C is standard; order plate with simulated PWHT test data if the vessel will be heat treated.

Q: Up to what temperature can P355GH be used?
A: The guaranteed proof strength table ends at 400 °C. Above that the grade is outside its design basis and a creep-resistant steel such as 16Mo3 or 13CrMo4-5 takes over.

---

## P355NH (1.0565) — Weldable fine-grain normalized steel for pressure purposes, elevated temperature
URL: https://steelstandart.com/grade/p355nh/
System: EN (European) | Family: Pressure vessel steel | Standard: EN 10028-3 | Verified against: EN 10028-3:2017
Aliases: P 355 NH, P355N, 1.0562, P355NL1, 1.0566, P355NL2, 1.1106, WStE355, TStE355, 1.0565, P355NH steel

P355NH is the 355 MPa class of EN 10028-3, the European standard for normalized, weldable fine-grain steels for pressure purposes. Grain refinement with aluminium, niobium and vanadium (Nb + Ti + V ≤ 0.12 %) gives the toughness that plain C-Mn steel cannot reach at this strength: 27 J at −20 °C transverse for the NH and N variants, −40 °C for NL1 and −50 °C for NL2. The H suffix adds a guaranteed yield table up to 400 °C (210 MPa at 400 °C). Werkstoff number 1.0565; the DIN 17102 name WStE355 is still common.

It is the standard plate for LPG spheres and bullets, air receivers, pressure vessels in refineries and chemical plants, and — as P355NL1/NL2 — for ammonia, propane and other refrigerated-gas storage. Because carbon stays ≤ 0.20 % and CEV ≤ 0.43 %, welding is straightforward for a 355 MPa steel.

The ASME counterparts are A516-70 (lower yield, 260 MPa) and A537 Class 1 (345 MPa, normalized) — both 'near'; JIS SPV355 is identical in intent.

Chemical composition (mass %): C ≤ 0.2; Si ≤ 0.5; Mn 1.1 – 1.7; P ≤ 0.025; S ≤ 0.01; Al ≥ 0.02 (total; fine-grain treatment); N ≤ 0.02; Cr ≤ 0.3; Cu ≤ 0.3; Mo ≤ 0.08; Nb ≤ 0.05; Ni ≤ 0.5; Ti ≤ 0.03; V ≤ 0.1 (Nb + Ti + V ≤ 0.12)
EN 10028-3:2017 Table 1; Cr + Cu + Mo ≤ 0.45. CEV max 0.43 % (≤ 60 mm), 0.45 % (60–100 mm). P355N (1.0562) same chemistry without elevated-temperature yield; P355NL1 (1.0566): P/S 0.025/0.010, impact −40 °C; P355NL2 (1.1106): Ni ≤ 0.50, impact −50 °C.

Mechanical properties:
- ≤ 16 mm, +N: yield 355 MPa; tensile 490–630 MPa; elongation 22 %; hardness ≈ 150–190 HB (typ.)
- > 16 ≤ 40 mm: yield 345 MPa; tensile 490–630 MPa; elongation 22 %; hardness —
- > 40 ≤ 60 mm: yield 335 MPa; tensile 490–630 MPa; elongation 22 %; hardness —
- > 60 ≤ 100 mm: yield 315 MPa; tensile 480–620 MPa; elongation 21 %; hardness —
- > 100 ≤ 150 mm: yield 295 MPa; tensile 470–610 MPa; elongation 21 %; hardness —
- Rp0.2 at 100 °C (≤ 60 mm): yield 314 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 200 °C: yield 284 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 300 °C: yield 250 MPa; tensile — MPa; elongation — %; hardness —
- Rp0.2 at 400 °C: yield 210 MPa; tensile — MPa; elongation — %; hardness —
EN 10028-3 Tables 2–4; transverse for plate. Impact (transverse): NH/N ≥ 27 J at −20 °C, ≥ 40 J at 0 °C, ≥ 55 J at +20 °C; NL1 ≥ 27 J at −40 °C; NL2 ≥ 27 J at −50 °C. Longitudinal values are ~15 J higher.
Impact: 27 J at -20 °C (transverse (P355NH / P355N); NL1 −40 °C, NL2 −50 °C)

Equivalents:
- IS 2041 R355 (IS (India)) — identical: IS 2041 (pressure-vessel plate) grade R355.
- SPV355 (JIS (Japan)) — identical: JIS G3115 SPV355: yield 355 MPa, Rm 520–640 MPa; SPV355N (normalized).
- A516 Grade 70 (ASTM / ASME) — near: ASTM/ASME A516-70: yield 260 MPa, Rm 485–620 MPa, C ≤ 0.27–0.31 — the common US vessel plate, but lower yield and no micro-alloy fine-grain guarantee. Order normalized with Charpy (S5) for a closer match.
- A537 Cl. 1 (ASTM / ASME) — near: Normalized C-Mn-Si vessel plate: yield 345 MPa (≤ 65 mm), Rm 485–620 MPa — the nearest US equivalent by yield and condition.
- A737 Gr. B (ASTM / ASME) — near: Nb micro-alloyed vessel plate, yield 345 MPa, Rm 485–620 MPa.
- P355GH (EN (European)) — near: 1.0473 (ex 19Mn6): EN 10028-2 non-fine-grain grade with the same strength; higher C (0.22), CEV 0.45.
- S355N (EN (European)) — near: EN 10025-3 structural fine-grain twin without pressure-equipment certification.
- Q345R / 16MnDR (GB/T (China)) — near: GB/T 713 Q345R: yield 345 MPa, Rm 510–640 MPa, impact 0 °C; 16MnDR (GB/T 3531) for −40 °C ≈ P355NL1.
- 09G2S (GOST (Russia/CIS)) — near: GOST 5520 09G2S vessel plate: yield 305–345 MPa, Rm 460–490 MPa.
- P355QH (EN (European)) — functional: EN 10028-6 quenched & tempered version for thick sections.

Superseded names:
- WStE355 — DIN 17102 (withdrawn 1996): W = warmfest (elevated temperature) → P355NH.
- StE355 — DIN 17102: → P355N (1.0562).
- TStE355 — DIN 17102: T = tieftemperatur → P355NL1 (−40 °C).
- EStE355 — DIN 17102: → P355NL2 (−50 °C).
- Fe E 355 KG / KW / KT — EN 10028-3:1992 (ISO 9328)
- BS 1501-225-490B / LT — BS 1501 (withdrawn)

Product forms: plate (EN 10028-3); seamless tube (EN 10216-3 P355NH); welded tube (EN 10217-3); forgings (EN 10222-4 P355QH); fittings (EN 10253-2)
Tolerances: plate: EN 10029; tube: EN 10216-3 / EN ISO 1127

### P355NH yield strength
355 MPa (51.5 ksi) ≤ 16 mm, 345 MPa to 40 mm, 335 MPa to 60 mm, 315 MPa to 100 mm, 295 MPa to 150 mm. Elevated temperature (≤ 60 mm): 314 MPa at 100 °C, 284 at 200 °C, 250 at 300 °C, 210 MPa at 400 °C.

### P355NH tensile strength
490–630 MPa (71–91 ksi) to 60 mm, 480–620 MPa to 100 mm, 470–610 MPa to 150 mm.

### P355NH impact toughness
Transverse 27 J at −20 °C, 40 J at 0 °C, 55 J at +20 °C; P355NL1 27 J at −40 °C; P355NL2 27 J at −50 °C (and 40 J at −20 °C).

### P355NH hardness
Not specified; normalized plate ≈ 150–190 HB. HAZ hardness after welding ≤ 350 HV with proper procedure; NACE MR0175 ≤ 22 HRC is met in the base metal.

### Physical properties
Density 7.85 g/cm³, E = 212 GPa (20 °C), expansion 12.2 × 10⁻⁶/K (20–100 °C), conductivity ≈ 45 W/m·K.

### Heat treatment
Delivery +N (normalized 890–950 °C or normalizing rolled). PWHT / stress relief 550–600 °C; do not exceed 620 °C (loss of Nb/V precipitation strengthening). Hot forming requires re-normalizing.

### Weldability
Good weldability (CEV ≤ 0.43 %): E46/G46 low-hydrogen consumables; preheat per EN 1011-2 above ~25 mm (typically 75–125 °C). PWHT at 550–600 °C where the vessel code requires it (EN 13445 thickness thresholds, or H₂S/caustic service). Limit heat input to ~3.5 kJ/mm to keep HAZ toughness; for NL1/NL2 qualify procedures with impact tests at the design temperature.

### Machining, forming, heat treatment
Machinability ≈ 60 % (similar to S355). Cold forming of heads and shells within EN 13445 limits (≤ 5 % strain without re-normalizing); hot forming 1050–900 °C then normalize 890–950 °C. Flame cutting with 100 °C preheat above 30 mm.

Applications: LPG storage spheres, bullets and road tankers; Air receivers and compressed-gas vessels; Refinery and chemical process vessels, columns, separators; Refrigerated gas storage (ammonia, propane, ethylene at −50 °C as P355NL2); Heat-exchanger shells and channels; Seamless pressure tubes for boilers and pipelines (EN 10216-3); Hydraulic accumulators and high-pressure cylinders (as P355NH or P355QH)

Q: What is the difference between P355N, P355NH, P355NL1 and P355NL2?
A: Same chemistry and strength. N = normalized, impact 27 J at −20 °C; NH adds guaranteed yield up to 400 °C; NL1 guarantees 27 J at −40 °C; NL2 guarantees 27 J at −50 °C (with Ni ≤ 0.50 %). Choose by service temperature range.

Q: Is P355NH the same as WStE355?
A: Yes. WStE355 (DIN 17102) became P355NH (1.0565) in EN 10028-3:1992. StE355 → P355N, TStE355 → P355NL1, EStE355 → P355NL2.

Q: What is the ASTM equivalent of P355NH?
A: ASTM/ASME A537 Class 1 (normalized, 345 MPa yield) is the closest; A516 Grade 70 is commonly substituted but has only 260 MPa yield, so wall thickness must be re-checked.

Q: What is the yield strength of P355NH at 400 °C?
A: 210 MPa (≤ 60 mm). At 100/200/300 °C: 314/284/250 MPa.

Q: Can P355NH be used below −20 °C?
A: Not on its own guarantee. Order P355NL1 (−40 °C) or P355NL2 (−50 °C); for −100 °C and below, nickel steels (EN 10028-4) are required.

---

## Q235 — Carbon structural steel (Chinese national standard)
URL: https://steelstandart.com/grade/q235/
System: GB/T (China) | Family: Structural steel | Standard: GB/T 700-2006 | Verified against: GB/T 700-2006
Aliases: q235, q235b, q235 steel, q235b equivalent, gb/t 700, q235 vs s235jr

Q235 is the workhorse structural steel of Chinese production, and the grade most often seen on a mill certificate arriving from Asia. The designation is literal: Q is *qufu diandian*, the yield point, and 235 is that yield in MPa up to 16 mm. It is defined in GB/T 700, the Chinese carbon structural steel standard.

What confuses buyers is the letter that follows. Q235A, Q235B, Q235C and Q235D are not strength classes — the strength is identical — they are quality classes defined by the impact test, exactly as JR, J0 and J2 are in the European system. Q235A is tested not at all, Q235B at +20 °C, Q235C at 0 °C and Q235D at −20 °C, each to 27 J.

In practice Q235B is what the market means by Q235: it is the stock grade, the one rolled into sections and coil, and the one that maps directly onto S235JR. A and D are order grades.

The equivalence to S235JR is close but not an identity. Q235B's tensile band is 370–500 MPa against 360–510, and — the detail that matters on a welding procedure — Q235B specifies a *minimum* carbon of 0.12 %, where S235JR only sets a ceiling. A European welding procedure qualified on low-carbon S235JR is not automatically valid on material that has to contain carbon.

Chemical composition (mass %): C 0.12 – 0.2 (Q235B; Q235A allows 0.14–0.22 %, Q235C and D cap at 0.17 % with no minimum); Si ≤ 0.35; Mn ≤ 1.4; P ≤ 0.045 (0.040 % for Q235C, 0.035 % for Q235D); S ≤ 0.045 (0.040 % for Q235C, 0.035 % for Q235D)
GB/T 700-2006 ladle analysis. The quality letter changes the chemistry as well as the test: A and B carry a carbon minimum, C and D do not and are supplied killed or special killed. A carbon minimum is the structural difference from the European S235 family, which only caps carbon.

Mechanical properties:
- ≤ 16 mm: yield 235 MPa; tensile 370–500 MPa; elongation 26 %; hardness ≈ 110–145 HB (typical)
- > 16 ≤ 40 mm: yield 225 MPa; tensile 370–500 MPa; elongation 26 %; hardness —
- > 40 ≤ 60 mm: yield 215 MPa; tensile 370–500 MPa; elongation 25 %; hardness —
- > 60 ≤ 100 mm: yield 215 MPa; tensile 370–500 MPa; elongation 24 %; hardness —
- > 100 ≤ 150 mm: yield 195 MPa; tensile 370–500 MPa; elongation 22 %; hardness —
- > 150 ≤ 200 mm: yield 185 MPa; tensile 370–500 MPa; elongation 21 %; hardness —
The tensile floor is 370 MPa against 360 MPa for S235JR, and the ceiling is 500 against 510 — a narrower band sitting slightly higher. Yield steps down with thickness on the same pattern as the European grade.
Impact: 27 J at 20 °C (Q235B; longitudinal)

Equivalents:
- A36 (ASTM / ASME) — near: A36 yield is 250 MPa with no impact requirement; close on strength, different on quality class.
- S235JR (EN (European)) — near: Q235B is the direct counterpart: same 235 MPa yield, same 27 J at +20 °C. Tensile floor is 10 MPa higher and Q235B carries a carbon minimum that S235JR does not.
- S235J0 (EN (European)) — near: Q235C matches it — 27 J at 0 °C with tightened phosphorus and sulphur.
- St3sp (GOST (Russia/CIS)) — near: Q235B: 235 MPa yield, 370–500 MPa tensile, carbon minimum present in both. The two grades occupy the same position in their national systems.
- E250 (IS (India)) — near: Q235B is 235 MPa yield and 370–500 MPa tensile; E250 sits one small step above it on both counts, with a carbon equivalent limit that Q235 does not carry.
- SS400 (JIS (Japan)) — near: JIS G3101 SS400: 245 MPa yield to 16 mm, 400–510 MPa tensile, no impact test — the Japanese commodity structural grade of the same tier.
- Q355 (GB/T (China)) — functional: The grade below in the Chinese system: 235 MPa yield under GB/T 700. Q235 to Q355 is the Chinese equivalent of the S235 to S355 step.

Superseded names:
- A3 / A3F — GB 700-1979 (withdrawn): The pre-1988 Chinese designation; still heard in workshops and occasionally seen on old drawings.
- Q235-A·F — GB/T 700-1988: The suffix marked the deoxidation practice: F rimmed, b semi-killed, Z killed, TZ special killed. The 2006 edition dropped the suffix from the grade name.

Product forms: hot-rolled plate and coil; sections: H beam, channel, angle, flat bar; welded and seamless tube (often certified to GB/T 3091 or GB/T 8162); merchant bar and round bar; cold-formed hollow sections
Tolerances: plate: GB/T 709; sections: GB/T 706 (channel and angle), GB/T 11263 (H beam); hot-rolled coil: GB/T 709; round bar: GB/T 702

### Q235 yield strength
235 MPa minimum up to 16 mm, stepping to 225 MPa at 16–40 mm, 215 MPa at 40–100 mm, 195 MPa at 100–150 mm and 185 MPa above that. The steps and the values follow the same pattern as the European S235 family, which is what makes the substitution workable.

### Q235A, B, C and D
The letters grade the impact test, not the strength. A: no Charpy requirement, carbon up to 0.22 %. B: 27 J at +20 °C, carbon 0.12–0.20 %. C: 27 J at 0 °C, carbon ≤ 0.17 %, P and S to 0.040 %. D: 27 J at −20 °C, carbon ≤ 0.17 %, P and S to 0.035 %, special killed. Q235B is the commercial default.

### Q235 chemical composition
For Q235B: C 0.12–0.20 %, Si ≤ 0.35 %, Mn ≤ 1.40 %, P ≤ 0.045 %, S ≤ 0.045 %. The carbon *minimum* is the feature to notice — European structural grades cap carbon without requiring any, so a Q235B plate can be harder and less forgiving in a restrained weld than an S235JR plate of the same nominal grade.

### Q235 and Q355
Q355 is the grade above, and it replaced Q345 when GB/T 1591 was revised in 2018. Q235 to Q355 is the Chinese equivalent of the S235 to S355 step: same standard family, same product forms, roughly 50 % more yield. A drawing that still says Q345 is working from the pre-2018 edition.

### Accepting Q235 against an S235JR specification
Technically the substitution works and is made daily. Three things should be checked rather than assumed: that the certificate names the quality letter and not just 'Q235'; that the impact test appears on it if the design needs one; and that the welding procedure covers the carbon range actually declared, not the European ceiling.

### Weldability
Q235B is readily weldable by all arc processes without preheat in normal thicknesses, and the carbon equivalent is comparable to S235JR. The caution is the carbon minimum: material at the top of the 0.12–0.20 % band behaves differently from a typical European S235JR heat running near 0.10 %, and in thick restrained joints that shows up as a harder heat-affected zone. Use E43xx / ER70S-class consumables. Q235A may be supplied rimmed or semi-killed under older practice, which is a further reason it is not the grade to weld in critical work — specify B as a minimum, and C or D where toughness matters.

### Machining, forming, heat treatment
Machinability is good in the as-rolled condition and comparable to other low-carbon structural steels. Cold forming behaviour is acceptable but less predictable than a forming grade, since the standard sets no yield ceiling: a plate at the top of the strength band springs back further. For bending and roll forming from Chinese supply, the forming grades in GB/T 912 or GB/T 3274 are the better specification than the structural one.

Applications: General building steelwork: columns, beams, bracing and purlins in Chinese and export construction; Welded frames, platforms, ladders and stairs; Structural hollow sections and fabricated tube structures; Machine bases, guards and non-critical load-bearing weldments; Plate for tanks, hoppers and chutes with no pressure duty; Export sections and coil sold against an S235JR requirement

Q: What is Q235 steel?
A: Q235 is the Chinese carbon structural steel of GB/T 700, with a 235 MPa minimum yield up to 16 mm and a 370–500 MPa tensile band. The Q stands for yield point and 235 is that yield in MPa; it is the most widely rolled structural grade in Chinese production.

Q: What is the difference between Q235A, Q235B, Q235C and Q235D?
A: The impact test and the chemistry that supports it, not the strength. A has no Charpy requirement, B is tested at +20 °C, C at 0 °C and D at −20 °C, all to 27 J; C and D also tighten phosphorus, sulphur and carbon and are supplied killed.

Q: Is Q235 the same as S235JR?
A: Q235B is the close counterpart — same yield, same 27 J at +20 °C — but they are not identical. Q235B's tensile band is 370–500 MPa against 360–510, and Q235B specifies a minimum carbon of 0.12 % where S235JR only caps it, which can matter for a welding procedure.

Q: What is the ASTM equivalent of Q235?
A: A36 is the usual match, with a higher 250 MPa yield and no impact requirement. It is an equivalence of class rather than of specification: a project that calls for A36 with a mill test report will accept Q235B in most commercial work but not where a code names the standard explicitly.

Q: Can Q235 be welded?
A: Yes, by all arc processes without preheat at normal thicknesses. Specify Q235B as a minimum for welded work — Q235A may be supplied rimmed or semi-killed — and qualify the procedure against the carbon actually declared rather than against a European ceiling.

Q: What replaced Q345?
A: Q355, in the 2018 revision of GB/T 1591. It is the grade above Q235 in the Chinese system, equivalent in role to S355 in the European one. Drawings still calling for Q345 are working from the pre-2018 edition of the standard.

Q: Is Q235 good quality steel?
A: For its class, yes — it is a commodity structural steel with a national standard behind it, and the quality letter tells you exactly what was tested. The risk in importing it is not the grade but the certificate: material sold simply as 'Q235' with no letter has no defined impact class.

---

## Q355 — High-strength low-alloy structural steel (Chinese national standard)
URL: https://steelstandart.com/grade/q355/
System: GB/T (China) | Family: Structural steel | Standard: GB/T 1591 | Verified against: GB/T 1591-2018
Aliases: q355, q355b, q355c, q355d, q345, q345b, q355 steel, q355 equivalent, gb/t 1591, 16mn, q355 vs s355

Q355 is the Chinese low-alloy structural steel that carries the load wherever Q235 is not strong enough — bridges, heavy frames, crane runways, offshore modules. It is defined in GB/T 1591, the Chinese HSLA standard, and it is the grade most often offered against an S355 enquiry from Asian supply.

The name follows the same rule as Q235: Q is *qufu dian*, the yield point, and 355 is that yield in MPa up to 16 mm. The letter after it — B, C or D — grades the impact test and not the strength, which is identical across all three.

The single most important fact about this grade is a date. Q355 did not exist before 2018. The 2018 revision of GB/T 1591 replaced Q345 with Q355, raising the guaranteed yield by 10 MPa and bringing the grade into line with the international 355 MPa class. Drawings, catalogues and stock lists across the industry still say Q345, and mills supply Q355B against them. A certificate for Q345 issued after 2018 is working from a withdrawn edition, and the 2018 revision also withdrew quality class A — there is no Q355A.

Against S355 the match is unusually clean. Same yield at the first step, the same 470–630 MPa tensile band, and a quality ladder that maps one to one onto JR, J0 and J2. Two differences deserve attention: the Chinese impact requirement is 34 J where the European is 27 J, and the thickness ladders diverge above 63 mm.

Chemical composition (mass %): C ≤ 0.24 (Q355B; 0.20 % for Q355C and Q355D); Si ≤ 0.55; Mn ≤ 1.6; P ≤ 0.035 (0.030 % for Q355C, 0.025 % for Q355D); S ≤ 0.035 (0.030 % for Q355C, 0.020 % for Q355D); Nb ≤ 0.05 (microalloying, optional); V ≤ 0.1 (microalloying, optional); Ti ≤ 0.05 (microalloying, optional); Al ≥ 0.015 (acid-soluble, minimum where fine grain is required)
GB/T 1591-2018 ladle analysis for the as-rolled Q355 grades. Carbon, phosphorus and sulphur all tighten with the quality letter, exactly as they do in the European J0 / J2 ladder. Niobium, vanadium and titanium are permitted as microalloying additions rather than required, so two conforming Q355B plates can be strengthened by quite different routes.

Mechanical properties:
- ≤ 16 mm: yield 355 MPa; tensile 470–630 MPa; elongation 22 %; hardness ≈ 150–190 HB (typical)
- > 16 ≤ 40 mm: yield 345 MPa; tensile 470–630 MPa; elongation 21 %; hardness —
- > 40 ≤ 63 mm: yield 335 MPa; tensile 470–630 MPa; elongation 20 %; hardness —
- > 63 ≤ 80 mm: yield 325 MPa; tensile 470–630 MPa; elongation 20 %; hardness —
- > 80 ≤ 100 mm: yield 315 MPa; tensile 470–630 MPa; elongation 18 %; hardness —
- > 100 ≤ 150 mm: yield 295 MPa; tensile 450–600 MPa; elongation 18 %; hardness —
The thickness ladder is close to EN 10025-2 but not identical: Q355 steps down at 16 mm where S355 holds 355 MPa to 16 mm and then 345 MPa to 40 mm — the two agree at the first two steps and diverge above 63 mm. The tensile band 470–630 MPa is the same as the European one, which is unusual and makes the comparison unusually clean.
Impact: 34 J at 20 °C (Q355B longitudinal; C at 0 °C, D at −20 °C)

Equivalents:
- A572 Grade 50 (ASTM / ASME) — near: ASTM A572 Grade 50 is 345 MPa yield and 450 MPa minimum tensile — a hair below on both counts, with no impact requirement as standard.
- S355JR (EN (European)) — near: Q355B is the counterpart: same 355 MPa yield to 16 mm, same 470–630 MPa tensile band, both tested at +20 °C. Q355B is tested to 34 J against 27 J, and allows carbon to 0.24 % against 0.24 % for S355JR in thick product — the closest cross-system match in the structural range.
- s355j0 (EN (European)) — near: Q355C matches it: 0 °C impact test with phosphorus and sulphur tightened to 0.030 %.
- S355J2 (EN (European)) — near: Q355D matches it: −20 °C impact test, P ≤ 0.025 % and S ≤ 0.020 %, and a fine-grain aluminium requirement.
- 09G2S (GOST (Russia/CIS)) — near: The CIS grade of the same tier: 345 MPa yield, 490 MPa tensile floor, tested far colder but reporting KCU on a U-notch rather than KV on a V-notch.
- L360 / X52 (API (line pipe)) — functional: GB/T 1591 Q355: 355 MPa minimum yield structural steel, and the plate from which much Chinese line pipe is rolled. The yield level matches, but Q355 is a structural specification — Chinese line pipe is properly specified to GB/T 9711, which mirrors API 5L.
- Q235 (GB/T (China)) — functional: The grade below in the Chinese system: 235 MPa yield under GB/T 700. Q235 to Q355 is the Chinese equivalent of the S235 to S355 step.

Superseded names:
- Q345 — GB/T 1591-2008 (superseded): The direct predecessor. The 2018 revision raised the guaranteed yield by 10 MPa and renamed the grade; a drawing that still says Q345B is working from the old edition, and mills supply Q355B against it.
- 16Mn — GB 1591-1979 (withdrawn): The pre-1988 name, read as 0.16 % carbon with manganese. Still heard in Chinese workshops and seen on old equipment drawings.
- Q345A — GB/T 1591-2008: Quality class A — no impact requirement — was withdrawn when the standard was revised. There is no Q355A.

Product forms: hot-rolled plate and heavy plate; sections: H beam (GB/T 11263), channel, angle; hot-rolled coil and strip; cold-formed and welded hollow sections (GB/T 6728, GB/T 8162); round and flat bar
Tolerances: plate and coil: GB/T 709; H beam: GB/T 11263; channel and angle: GB/T 706; round bar: GB/T 702

### Q355 yield strength
355 MPa minimum up to 16 mm, then 345 MPa to 40 mm, 335 MPa to 63 mm, 325 MPa to 80 mm, 315 MPa to 100 mm and 295 MPa to 150 mm. The first two steps are identical to EN 10025-2; above 63 mm the European grade holds its strength slightly better.

### Q355 tensile strength
470–630 MPa up to 100 mm, falling to 450–600 MPa above. This is the same band EN 10025-2 specifies for S355, which makes tensile the one property where the two standards agree exactly — and it is worth noticing that both set a ceiling, unlike GOST 19281.

### Q355B, C and D
The letters grade the Charpy test. B: 34 J at +20 °C, C ≤ 0.24 %, P and S ≤ 0.035 %. C: 34 J at 0 °C, C ≤ 0.20 %, P ≤ 0.030 %, S ≤ 0.030 %. D: 34 J at −20 °C, C ≤ 0.20 %, P ≤ 0.025 %, S ≤ 0.020 %, with an aluminium minimum for fine grain. Q355B is the commercial stock grade.

### Q345 became Q355
The 2018 revision of GB/T 1591 replaced Q345 with Q355 and raised the guaranteed yield from 345 to 355 MPa at the first thickness step. Quality class A disappeared at the same time. Material offered as Q345B today is almost always Q355B on the certificate; where a drawing specifies Q345, confirm which edition the design was checked against before accepting the substitution upwards.

### N and M delivery conditions
The 2018 edition added Q355N (normalised or normalised-rolled) and Q355M (thermomechanically rolled) alongside the as-rolled grade, with their own chemistry and toughness tables and quality letters up to F at −60 °C. They correspond to the European EN 10025-3 and EN 10025-4 families. Plain Q355 without a suffix is the as-rolled grade.

### Accepting Q355 against S355
Three checks. The quality letter must be on the certificate, not just "Q355". The impact temperature must match the design — B, C and D are +20, 0 and −20 °C. And above 63 mm the yield ladders diverge, so the governing thickness has to be checked rather than assumed. The tensile band and the 355 MPa first step need no adjustment at all.

### Weldability
Q355B welds like any 355 MPa structural steel of its generation. Carbon equivalent is limited by the standard and normally runs 0.40–0.45 for plate in the common thicknesses, so preheat is unnecessary below about 25 mm and 100–150 °C is the usual figure above it. All arc processes apply, with E50xx / ER70S-class consumables. The point requiring attention is the optional microalloying: GB/T 1591 permits niobium, vanadium and titanium but does not require them, so two conforming heats can reach 355 MPa by different metallurgical routes and behave differently in the heat-affected zone. Where the joint is thick and restrained, qualify on the declared analysis rather than on the grade name, and prefer C or D where the design allows — their carbon ceiling is 0.20 % against 0.24 %.

### Machining, forming, heat treatment
Machinability is moderate, comparable with S355 and noticeably harder work than Q235: expect roughly 30 % higher cutting forces than a 235 MPa steel at the same hardness. Cold forming is acceptable for the strength class, with elongation from 22 % at thin gauge down to 18 % above 80 mm, but the tensile ceiling of 630 MPa still leaves a wide band and spring-back varies between heats. For cold-formed sections and press work the better Chinese specification is the forming series of GB/T 3274 or the cold-rolled grades, not the structural one.

Applications: Bridges, crane runways and heavy building frames in Chinese and export construction; Offshore and industrial module steelwork; Pressure-bearing structural components and heavy welded fabrications; Mining, earthmoving and heavy vehicle structures; Plate for silos, hoppers and large tank shells; Sections and plate exported against an S355JR, S355J0 or S355J2 requirement

Q: What is Q355 steel?
A: Q355 is the Chinese low-alloy structural steel of GB/T 1591, with a 355 MPa minimum yield to 16 mm and a 470–630 MPa tensile band. It is supplied in quality classes B, C and D, which are separated by the impact test temperature rather than by strength.

Q: Is Q355 the same as Q345?
A: Q355 replaced Q345 in the 2018 revision of GB/T 1591, raising the guaranteed yield by 10 MPa. They are the same grade in the same position of the same standard, one edition apart; mills supply Q355B against drawings that still specify Q345B.

Q: Is Q355 equivalent to S355?
A: Q355B is the closest cross-system match there is in the structural range: identical 355 MPa yield at the first step and an identical 470–630 MPa tensile band. The differences are that Q355 is tested to 34 J rather than 27 J, and that the yield ladders diverge above 63 mm.

Q: What is the difference between Q355B, Q355C and Q355D?
A: The impact test and the chemistry supporting it. B is tested at +20 °C, C at 0 °C and D at −20 °C, all to 34 J; C and D also tighten carbon to 0.20 % and progressively reduce phosphorus and sulphur. There is no Q355A — class A was withdrawn in 2018.

Q: What is 16Mn steel?
A: The pre-1988 Chinese name for what became Q345 and is now Q355: roughly 0.16 % carbon with manganese as the principal alloy. The name is withdrawn but still used in Chinese workshops and on older equipment drawings.

Q: What do Q355N and Q355M mean?
A: The delivery condition. N is normalised or normalised-rolled, M is thermomechanically rolled, and each has its own chemistry and toughness table with quality letters down to −60 °C. They correspond to the European EN 10025-3 and EN 10025-4 grades; plain Q355 is as-rolled.

Q: Can Q355 be used where S355J2 is specified?
A: Q355D is the matching class — −20 °C impact test, tightened phosphorus and sulphur, aluminium for fine grain. Check the certificate names the letter, check the governing thickness against both ladders, and confirm the carbon equivalent if the joint is thick and restrained.

---

## S195T (1.0026) — Non-alloy steel for welded and threaded tubes (water, gas, sprinkler, GI pipe)
URL: https://steelstandart.com/grade/s195t/
System: EN (European) | Family: Pipe & tube steel | Standard: EN 10255 | Verified against: EN 10255:2004+A1:2007
Aliases: S 195 T, 1.0026, St33-2, St 33, S195, BS 1387 steel, EN 10255 M, EN 10255 H, medium series pipe, heavy series pipe, Class B pipe, Class C pipe

S195T is the only steel grade in EN 10255, the European standard for water, gas and sprinkler pipe that is screwed or welded — the pipe the trade calls GI pipe, black pipe, gas pipe or, by its old British name, BS 1387 Class B and C. The designation reads S (structural steel), 195 (minimum yield in MPa), T (tube). Werkstoff number 1.0026. Its strength is modest on purpose: the pipe is defined by its wall series — light (L), medium (M, old Class B) and heavy (H, old Class C) — and by a 50 bar leak test on every length, not by the steel.

Most S195T tube is high-frequency welded from S235JR-quality strip, hot-dip galvanized to EN 10240 A1 (≥ 55 µm zinc inside and out) and threaded BSPT to EN 10226-1 with a socket per bar. Sizes run DN 6 (⅛") to DN 150 (6"), 6 m long. Medium series is the potable-water and fire-sprinkler standard; heavy series adds wall for pressure and deeper threads.

ASTM A53 Grade A/B, GOST 3262 ВГП, JIS SGP and GB/T 3091 are the equivalents in their markets; where the tube is a structural member rather than a line, EN 10219 S235JRH is the right specification.

Chemical composition (mass %): C ≤ 0.2; Mn ≤ 1.4; P ≤ 0.035; S ≤ 0.03
Ladle analysis, EN 10255:2004 Table 1. Si is not limited; the steel is normally semi- or fully killed. Only one grade is specified in the standard — the series (L/M/H) defines the wall, not the steel.

Mechanical properties:
- All series, all sizes: yield 195 MPa; tensile 320–520 MPa; elongation 20 %; hardness ≈ 100–130 HB (typ.)
- ASTM A53 Grade A (for comparison): yield 205 MPa; tensile 330 min MPa; elongation — %; hardness —
- ASTM A53 Grade B: yield 240 MPa; tensile 415 min MPa; elongation — %; hardness —
EN 10255 Table 3: ReH ≥ 195 MPa, Rm 320–520 MPa, A ≥ 20 % (L0 = 5.65√S0). Leak-tightness test on every tube: hydrostatic at 50 bar (or eddy-current). Threadable series (M, H) must accept EN 10226-1 taper threads; flattening test to 2/3 D for welded tube.

Equivalents:
- A53 Grade A (Type E/F) (ASTM / ASME) — near: ASTM A53 Grade A: 205 MPa yield, 330 MPa tensile, welded or seamless, black or galvanized — the US water/gas pipe; Grade B (240/415) is stronger and usually what is stocked.
- S235JR (EN (European)) — near: The strip from which most S195T tube is actually made; S235JR coil certified to EN 10255 requirements.
- Q195 / Q235 (GB/T 3091) (GB/T (China)) — near: Chinese welded pipe for low-pressure liquid delivery on Q195–Q235 steel.
- Ст2сп / Ст3сп (GOST 3262) (GOST (Russia/CIS)) — near: GOST 3262 water-gas pipe (ВГП, обыкновенная/усиленная) on Ст2–Ст3 steel: the CIS equivalent of medium/heavy series.
- SGP (JIS G3452) (JIS (Japan)) — near: JIS G3452 carbon steel pipe for ordinary piping, Rm ≥ 290 MPa; galvanized SGP-W.
- A53 Grade B (ASTM / ASME) — functional: EN 10255 S195T: the threadable general-purpose tube used across Europe for water, gas and low-pressure service, at 195 MPa minimum yield. It occupies the same place in the market as galvanized threaded A53, with lighter and heavier series instead of schedules.
- S235JRH (EN (European)) — functional: Structural hollow-section grade (EN 10219) with 235 MPa yield — the alternative when the pipe is a column or frame member, not a pressure line.
- P235TR1 (EN (European)) — functional: EN 10217-1 pressure-purpose welded tube with specified elevated-temperature use; choose when the line is above 50 bar or a pressure code applies.

Superseded names:
- St33-2 / St 33 — DIN 17100 / DIN 1626: German general steel used for DIN 2440/2441 gas pipe (mittelschwer / schwer).
- BS 1387 steel (Class A/B/C) — BS 1387:1985 (withdrawn): Class A = light, B = medium, C = heavy; the names survive in every GI-pipe market (Gulf, India, Africa).
- Fe 330 — UNI 8863: Italian threadable tube steel.

Product forms: welded (HFI/ERW) tube DN 6–150 (½"–6"), light (L, L1, L2), medium (M) and heavy (H) series; seamless tube in the same series (rare); black, varnished or hot-dip galvanized per EN 10240 (A1–B3); plain, bevelled or threaded ends (EN 10226-1) with socket
Tolerances: outside diameter: EN 10255 Table 2 (e.g. 33.7 +0.4/−0.5 mm for DN 25); wall thickness: medium/heavy −10 % (no plus tolerance stated; mass ±7.5 %); length: 4–8 m random, 6 m usual; exact length ±25 mm

### S195T yield strength
≥ 195 MPa (28 ksi). Actual tube made from S235JR strip usually tests 240–300 MPa.

### S195T tensile strength
320–520 MPa (46–75 ksi).

### S195T elongation
≥ 20 % (L0 = 5.65√S0).

### Working pressure
The standard guarantees a 50 bar hydrostatic test; typical working pressures used by installers are 16 bar (medium) and 25 bar (heavy) for cold water, subject to the joint and code. Threads are cut after galvanizing.

### Wall series (examples)
DN 15 (½", 21.3 mm): L 2.0 · M 2.6 · H 3.2 mm. DN 25 (1", 33.7 mm): L 2.6 · M 3.2 · H 4.0 mm. DN 50 (2", 60.3 mm): L 2.9 · M 3.6 · H 4.5 mm. DN 100 (4", 114.3 mm): M 4.5 · H 5.4 mm. Galvanized mass adds about 3–4 %.

### Weldability
Readily weldable (C ≤ 0.20, no preheat); bevelled ends 30° for butt welds. Galvanized tube must be ground back 20–30 mm from the joint, welded with fume extraction and repaired with zinc-rich paint — or joined by threads or grooved couplings to keep the coating intact.

### Machining, forming, heat treatment
Threading BSPT/NPT, grooving (roll-groove for fire systems), cutting, drilling and bending (cold, radius ≥ 3 D with mandrel for medium series) are routine. Heavy series is preferred for deep threads and repeated re-threading.

Applications: Potable-water and irrigation lines (medium series, galvanized); Fire-sprinkler and hydrant mains (grooved or threaded, red-painted); Gas and compressed-air lines at low pressure; Scaffold tube 48.3 × 3.2 (also EN 39), fence posts, handrail; Greenhouse, canopy and light structural frames (or S235JRH); Electrical conduit and cable protection; Street-light and sign posts

Q: What is S195T?
A: The steel grade of EN 10255 tubes for water, gas and sprinkler lines: 195 MPa minimum yield, 320–520 MPa tensile, 20 % elongation, delivered in light, medium or heavy wall series, black or galvanized, threadable.

Q: Is S195T the same as BS 1387 Class B / Class C?
A: Effectively yes. BS 1387 was withdrawn in favour of EN 10255; Class B corresponds to the medium series and Class C to the heavy series, with the same outside diameters and walls. "Class B GI pipe" in the Gulf or India means EN 10255 M galvanized.

Q: What is the difference between medium and heavy series?
A: Wall thickness only: e.g. 1" pipe is 3.2 mm (medium) vs 4.0 mm (heavy). Heavy gives more pressure margin, deeper threads and longer corrosion life; the steel is the same S195T.

Q: What is the ASTM equivalent of EN 10255 pipe?
A: ASTM A53 Grade A (205 MPa) is the direct equivalent; Grade B (240 MPa, 415 MPa tensile) is what most mills stock and dual-certify with EN 10255 where dimensions coincide (Schedule 40 walls are slightly different from medium series).

Q: Can EN 10255 pipe be used for structures?
A: For handrail, fences and light frames yes; for designed structural members specify EN 10219 S235JRH or S355J2H (cold-formed hollow sections), which guarantee structural properties and tolerances rather than a leak test.

---

## S235J0 (1.0114) — Non-alloy hot-rolled structural steel
URL: https://steelstandart.com/grade/s235j0/
System: EN (European) | Family: Structural steel | Standard: EN 10025-2 | Verified against: EN 10025-2:2019
Aliases: s235j0, s235 j0, 1.0114, st 37-3 u, s235j0 equivalent, s235j0 vs s235jr

S235J0 is the middle member of the S235 family in EN 10025-2, and the only thing that separates it from S235JR is the temperature at which the steel has to absorb 27 joules in a Charpy test: 0 °C instead of +20 °C. Strength is identical — 235 MPa minimum yield up to 16 mm, 360–510 MPa tensile — and so is the carbon ceiling.

The tighter numbers are on phosphorus and sulphur, capped at 0.030 % against 0.035 % for S235JR. Those two elements are what embrittle steel at low temperature, so the specification does not ask for a different steel; it asks for a cleaner one.

In practice S235J0 is specified for structures that will be erected, handled or loaded in cold weather, and for welded assemblies where a brittle failure at a notch is the risk being designed against. If the structure lives indoors or in a temperate climate and sees no dynamic load, S235JR is the correct and cheaper answer. If the design temperature goes below about −10 °C, the grade to jump to is S235J2, tested at −20 °C and supplied fully killed.

Chemical composition (mass %): C ≤ 0.17 (≤ 0.17 % for all product thicknesses; same ceiling as S235JR); Mn ≤ 1.4; P ≤ 0.03 (0.005 % tighter than S235JR); S ≤ 0.03 (0.005 % tighter than S235JR); N ≤ 0.012; Cu ≤ 0.55
Ladle analysis per EN 10025-2:2019 Table 2. Silicon is not limited. CEV maximum 0.35 % up to 30 mm and 0.38 % above 40 mm — identical to S235JR. The whole chemical difference between the two grades is 0.005 % on phosphorus and 0.005 % on sulphur.

Mechanical properties:
- ≤ 16 mm: yield 235 MPa; tensile 360–510 MPa; elongation 26 %; hardness ≈ 100–140 HB (typical)
- > 16 ≤ 40 mm: yield 225 MPa; tensile 360–510 MPa; elongation 26 %; hardness —
- > 40 ≤ 63 mm: yield 215 MPa; tensile 360–510 MPa; elongation 25 %; hardness —
- > 63 ≤ 80 mm: yield 215 MPa; tensile 360–510 MPa; elongation 24 %; hardness —
- > 80 ≤ 100 mm: yield 215 MPa; tensile 360–510 MPa; elongation 24 %; hardness —
- > 100 ≤ 150 mm: yield 195 MPa; tensile 350–500 MPa; elongation 22 %; hardness —
- > 150 ≤ 200 mm: yield 185 MPa; tensile 340–490 MPa; elongation 21 %; hardness —
Identical to S235JR at every thickness — the J suffix changes the impact test, not the strength. Elongation is for L0 = 5.65√S0, longitudinal; transverse values are two points lower on flat products.
Impact: 27 J at 0 °C (longitudinal, ≥ 10 mm thick)

Equivalents:
- A36 (ASTM / ASME) — near: A36 has a higher yield (250 MPa) and no Charpy requirement at all, so it does not substitute where the 0 °C toughness is the reason for the specification.
- S235JR (EN (European)) — near: Same chemistry ceiling and identical mechanical properties; only the impact test temperature differs (+20 °C against 0 °C) plus 0.005 % on P and S.
- Q235 (GB/T (China)) — near: Q235C is the Chinese quality tested at 0 °C and is the closest GB/T 700 match; Q235B corresponds to S235JR.
- St3sp (GOST (Russia/CIS)) — near: St3sp category 4 or 5 is the closer match where low-temperature testing is required — tested at −20 °C, against 0 °C for S235J0.
- SS400 (JIS (Japan)) — functional: JIS G3101 SS400 has comparable strength but no impact requirement, so it matches S235J0 on strength only.

Superseded names:
- St 37-3 U — DIN 17100 (withdrawn 1994): The unalloyed, non-normalised quality; the closest legacy German name and still seen on older drawings.
- Fe 360 C — EN 10025:1990: The pre-1993 European designation; C corresponded to the 0 °C impact class.
- E 24-3 — NF A 35-501 (France, withdrawn): French legacy designation of the same quality class.
- Fe 360 C — UNI 7070 (Italy, withdrawn): Italian legacy designation.

Product forms: hot-rolled plate and wide flat; sections (IPE, HEA/HEB, UPN, angles); merchant bar and flat bar; hot-rolled coil and sheet; welded hollow sections (as S235J0H, EN 10219)
Tolerances: plate: EN 10029; sections: EN 10034 (I/H), EN 10279 (channels), EN 10056-2 (angles); hot-rolled coil/sheet: EN 10051; flat bar: EN 10058

### S235J0 yield strength
The minimum yield strength (ReH) of S235J0 is 235 MPa up to 16 mm thickness, falling stepwise to 215 MPa between 40 and 100 mm and 185 MPa between 150 and 200 mm. These are exactly the S235JR values — choosing J0 buys toughness, not strength, and a design calculation does not change.

### S235J0 impact energy
27 J minimum at 0 °C, on a longitudinal specimen from material at least 10 mm thick. This single line is the reason the grade exists. Sub-size specimens are used below 10 mm with proportionally reduced energy, as set out in EN 10025-1.

### S235J0 chemical composition
C ≤ 0.17 %, Mn ≤ 1.40 %, P ≤ 0.030 %, S ≤ 0.030 %, N ≤ 0.012 %, Cu ≤ 0.55 %. Silicon is unrestricted, which matters when the steel will be hot-dip galvanized: silicon content drives coating thickness and appearance, and it has to be agreed separately with the mill.

### S235J0 weldability
CEV is capped at 0.35 % up to 30 mm, so S235J0 welds without preheat by every arc process up to roughly 40 mm. Use E42/G42 consumables. The lower phosphorus and sulphur also give slightly cleaner weld metal and less risk of solidification cracking than S235JR.

### When S235J0 is worth the premium
The price step over S235JR is small — usually a few per cent, sometimes only a mill minimum quantity. It is worth paying where the service temperature approaches 0 °C, where the member carries dynamic or impact load, where thickness exceeds about 30 mm with notches or welded attachments, or where a design code sets a minimum service temperature that S235JR cannot satisfy.

### Weldability
S235J0 is fully weldable by all arc processes (MMA, MAG, SAW, TIG) without preheat up to about 40 mm, on the same CEV limit as S235JR (≤ 0.35 % to 30 mm). Use E42/G42 class consumables matched to the parent strength. The tighter sulphur ceiling reduces the risk of hot cracking in restrained joints, which is a secondary but real benefit in heavy welded fabrication. Where a welded joint has to carry the 0 °C toughness requirement as well, the welding procedure should be qualified with impact testing at the design temperature rather than relying on the parent certificate alone.

### Machining, forming, heat treatment
Machinability is good in the as-rolled condition, at roughly the same index as S235JR (≈ 70 % relative to 1212 free-cutting steel). Minimum inside bend radii follow EN 10025-2 Annex C, unchanged from S235JR. Flame and plasma cutting need no preheat at normal thicknesses; on sections over 40 mm with restrained geometry, a modest preheat reduces the hardness of the cut edge before welding.

Applications: Outdoor steel structures in climates where erection and service temperatures reach 0 °C; Welded frames and gantries carrying dynamic or impact load; Bridge secondary steelwork and walkway structures where a toughness class is specified; Crane runway supports and machine frames with notched or welded attachments; Storage and silo structures in continental and northern European locations; Any structure whose design code sets a minimum service temperature below +10 °C

Q: What is the difference between S235JR and S235J0?
A: The Charpy test temperature and two chemistry limits. S235JR is tested at +20 °C, S235J0 at 0 °C, both to 27 J; and S235J0 caps phosphorus and sulphur at 0.030 % against 0.035 %. Yield, tensile and elongation are identical at every thickness.

Q: Is S235J0 stronger than S235JR?
A: No. Both have 235 MPa minimum yield up to 16 mm and 360–510 MPa tensile, and both step down the same way with thickness. The J suffix in EN 10025-2 grades the impact test, never the strength.

Q: What does J0 mean in S235J0?
A: J means a 27 J minimum Charpy energy and 0 means the test temperature in degrees Celsius. The family runs JR at +20 °C, J0 at 0 °C and J2 at −20 °C, all to the same 27 J.

Q: What is the old name for S235J0?
A: St 37-3 U under the withdrawn DIN 17100, and Fe 360 C under the 1990 version of EN 10025. Drawings in Turkey, Poland and the Middle East still carry the St 37-3 designation, which is why the equivalence is asked for so often.

Q: Can S235J0 replace S235JR?
A: Always, technically — it meets every S235JR requirement and one more. The reverse is not true: S235JR cannot be substituted where the 0 °C impact class was specified, because the certificate will not carry the test.

Q: When should S235J2 be used instead?
A: When the design temperature goes below roughly −10 °C, when the section is thick and heavily notched, or when a code calls up a −20 °C toughness class. S235J2 is tested at −20 °C and is supplied fully killed with a finer grain, which is what the lower temperature requires.

Q: Is S235J0 available as hollow section?
A: Yes, as S235J0H to EN 10219 for cold-formed welded sections and EN 10210 for hot-finished ones. The H suffix marks the hollow-section standard; the strength and impact class are the same as the plate grade.

---

## S235JR (1.0038) — Non-alloy hot-rolled structural steel
URL: https://steelstandart.com/grade/s235jr/
System: EN (European) | Family: Structural steel | Standard: EN 10025-2 | Verified against: EN 10025-2:2019
Aliases: S235JR+AR, S235JR+N, S 235 JR, St37-2, Fe360B, 1.0038

S235JR is the entry grade of EN 10025-2, the European standard for hot-rolled non-alloy structural steels. The designation encodes everything a buyer needs: S = structural, 235 = minimum yield strength in MPa for thicknesses up to 16 mm, J = 27 J Charpy energy, R = tested at room temperature (+20 °C). Its Werkstoff number is 1.0038.

It is a low-carbon (≤ 0.17 %) steel supplied as-rolled (+AR) or normalized/normalizing-rolled (+N). Because the carbon equivalent is capped at 0.35 %, it welds without preheat in all common thicknesses, which is why S235JR is the default material for secondary steelwork, general fabrication, light frames and any part where stiffness rather than strength governs the design.

S235JR replaced DIN St37-2 and BS 4360 40B in 1994; the old names survive on legacy drawings, so this page lists them alongside the ASTM, JIS, GB and GOST cross-references.

Chemical composition (mass %): C ≤ 0.17 (≤ 40 mm nominal thickness; 0.20 % above 40 mm (product analysis +0.03)); Mn ≤ 1.4; P ≤ 0.035; S ≤ 0.035; N ≤ 0.012 (may be exceeded if Al ≥ 0.020 % or other N-binding elements are present); Cu ≤ 0.55
Ladle analysis per EN 10025-2:2019 Table 2. Si is not limited for S235JR; CEV maximum 0.35 % up to 30 mm, 0.38 % up to 150 mm.

Mechanical properties:
- ≤ 16 mm: yield 235 MPa; tensile 360–510 MPa; elongation 26 %; hardness ≈ 100–140 HB (typical)
- > 16 ≤ 40 mm: yield 225 MPa; tensile 360–510 MPa; elongation 26 %; hardness —
- > 40 ≤ 63 mm: yield 215 MPa; tensile 360–510 MPa; elongation 25 %; hardness —
- > 63 ≤ 80 mm: yield 215 MPa; tensile 360–510 MPa; elongation 24 %; hardness —
- > 80 ≤ 100 mm: yield 215 MPa; tensile 360–510 MPa; elongation 24 %; hardness —
- > 100 ≤ 150 mm: yield 195 MPa; tensile 350–500 MPa; elongation 22 %; hardness —
- > 150 ≤ 200 mm: yield 185 MPa; tensile 340–490 MPa; elongation 21 %; hardness —
Rm range applies to 3–100 mm; elongation for L0 = 5.65√S0, longitudinal; transverse values are 2 points lower for flat products. Hardness is not specified by the standard — the HB figure is typical for as-rolled material.
Impact: 27 J at 20 °C (longitudinal, ≥ 10 mm thick)

Equivalents:
- St37-2 (DIN (superseded German)) — identical: Direct successor (1.0038). S235JR guarantees 27 J at +20 °C which St37-2 did not; ordering S235JR always satisfies an St37-2 requirement.
- S235JRH (EN (European)) — identical: Same steel as flat/long product to EN 10025-2; the H suffix only marks the hollow-section delivery standard.
- A36 (ASTM / ASME) — near: A36 yield 250 MPa (36 ksi) and Rm 400–550 MPa are slightly higher; no impact requirement. Widely accepted as the US counterpart.
- A283 Gr. C (ASTM / ASME) — near: Yield 205 MPa, Rm 380–515 MPa; plate only, no Charpy requirement.
- S235J0 (EN (European)) — near: Same chemistry limits with P/S 0.030 %; impact 27 J at 0 °C instead of +20 °C.
- S195T (EN (European)) — near: The strip from which most S195T tube is actually made; S235JR coil certified to EN 10255 requirements.
- Q235 (GB/T (China)) — near: GB/T 700 Q235B: yield 235 MPa, Rm 370–500 MPa, 27 J at +20 °C — the closest Chinese match; C max 0.20 %.
- Q235 (GB/T (China)) — near: Q235B is the direct counterpart: same 235 MPa yield, same 27 J at +20 °C. Tensile floor is 10 MPa higher and Q235B carries a carbon minimum that S235JR does not.
- St3sp (GOST (Russia/CIS)) — near: GOST 380 St3sp (killed): yield 245 MPa ≤ 20 mm, Rm 370–480 MPa; impact tested at +20 °C.
- IS 2062 E250 BR (IS (India)) — near: Yield 250 MPa, Rm 410 MPa min; BR = impact tested at room temperature.
- E250 (IS (India)) — near: The usual counterpart on quality structure: E250BR is tested to 27 J at room temperature as S235JR is at +20 °C. E250 is 250 MPa yield against 235 and 410 MPa tensile floor against 360, so it is the stronger of the two at both limits.
- SS400 (JIS (Japan)) — near: JIS G3101 SS400: yield 245 MPa (≤16 mm), Rm 400–510 MPa; no chemistry limits beyond P and S, no impact test.
- St 22 (DIN (superseded German)) — functional: Often offered as a substitute and often wrong: S235JR is a structural grade with a guaranteed yield and impact test, and it is less formable. Use it only if the part is structural rather than formed.
- S275JR (EN (European)) — functional: Next strength class (275 MPa); substitutes upward for strength but is not identical.
- C15 (EN (European)) — functional: Structural steel of similar carbon; not a case-hardening quality (no hardenability or cleanliness control).
- DC01 (EN (European)) — functional: Hot-rolled structural steel of similar chemistry; not a cold-rolled forming grade and not interchangeable in surface or gauge.
- DD11 (EN (European)) — functional: Structural steel of similar chemistry with guaranteed 235 MPa yield and impact; DD11 has no minimum yield guarantee for structural design.
- P235GH (EN (European)) — functional: Same room-temperature yield and similar carbon, but no elevated-temperature proof values, looser P and S, and no normalising requirement. It cannot be substituted into a pressure calculation.
- S250GD (EN (European)) — functional: Uncoated hot-rolled structural steel of similar strength for members that will be post-galvanized.

Superseded names:
- St37-2 — DIN 17100 (withdrawn 1994): Most common legacy name; still on many drawings and in Turkish, Polish and Middle-East specifications.
- Fe360B — EN 10025:1990 / UNI 7070: Renamed S235JR in EN 10025:1993.
- 40A / 40B — BS 4360 (withdrawn 1994): 40B is the closer match (impact at +20 °C).
- E24-2 — NF A 35-501 (withdrawn): French designation.
- S235JRG2 — EN 10025:1993: Fully killed variant; merged into S235JR (1.0038) in EN 10025-2:2004.

Product forms: hot-rolled plate and wide flat; hot-rolled coil and sheet; sections (IPE, HEA/HEB, UPN, angles); merchant bar and flat bar; welded hollow sections (as S235JRH, EN 10219)
Tolerances: plate: EN 10029; hot-rolled coil/sheet: EN 10051; sections: EN 10034 (I/H), EN 10279 (channels), EN 10056-2 (angles); flat bar: EN 10058

### S235JR yield strength
The minimum yield strength (ReH) of S235JR is 235 MPa (34.1 ksi) for thicknesses up to 16 mm, dropping stepwise to 215 MPa at 40–100 mm and 185 MPa at 150–200 mm. Design codes (EN 1993-1-1) use fy = 235 MPa for t ≤ 40 mm and 215 MPa for 40–80 mm.

### S235JR tensile strength
Tensile strength (Rm) is 360–510 MPa (52–74 ksi) for 3–100 mm. Mill certificates for coil typically show 400–440 MPa.

### S235JR hardness
EN 10025-2 does not specify hardness. As-rolled S235JR measures roughly 100–140 HB (≈ 110–150 HV), which is why it is easily drilled, sheared and punched.

### Density, modulus and thermal properties
Density 7.85 g/cm³, Young's modulus 210 GPa, shear modulus 81 GPa, Poisson's ratio 0.30, coefficient of thermal expansion 12 × 10⁻⁶/K (20–100 °C), thermal conductivity ≈ 50 W/m·K. These are the EN 1993-1-1 design values common to all structural carbon steels.

### Carbon equivalent (CEV)
Maximum CEV is 0.35 % for t ≤ 30 mm, 0.35 % for 30–40 mm, 0.38 % for 40–150 mm and 0.40 % for 150–250 mm (EN 10025-2 Table 4).

### Weldability
S235JR is fully weldable by all arc processes (MMA, MAG, SAW, TIG) without preheat up to about 40 mm thickness thanks to its low CEV (≤ 0.35 %). Use E42 / G42 class consumables (EN ISO 2560 / 14341). For thick sections or high restraint, follow EN 1011-2 for preheat and interpass control; hydrogen-controlled electrodes are recommended above 25 mm.

### Machining, forming, heat treatment
Machinability is good in the as-rolled condition (index ≈ 70 % relative to 1212 free-cutting steel). Cold forming: minimum inside bend radius per EN 10025-2 Table 7 is 1.0 t for t ≤ 2.5 mm up to 2.0 t for 8–16 mm (transverse); most mills achieve 1 t on coil. Hot forming 900–1100 °C. Normalizing 890–930 °C is possible but rarely needed. S235JR is not intended for hardening; case-hardening is not applicable because of the low carbon content.

Applications: General steel construction: purlins, bracing, secondary beams, platforms and stairs; Welded frames, machine bases and guards; Storage racks and shelving profiles; Hollow sections for fences, handrails and light structures (as S235JRH); Base plates, cleats and gusset plates; Pre-painted and hot-dip galvanized steelwork (good galvanizing response when Si is controlled)

Q: What does S235JR mean?
A: S = structural steel, 235 = minimum yield strength in MPa (up to 16 mm), J = 27 J Charpy impact energy, R = tested at room temperature (+20 °C). The full designation may carry a delivery condition, e.g. S235JR+AR (as rolled) or S235JR+N (normalized).

Q: What is the ASTM equivalent of S235JR?
A: ASTM A36 is the usual substitute: 250 MPa yield and 400–550 MPa tensile, slightly stronger and without a Charpy requirement. For plate, A283 Grade C is also used. Neither is identical, so the match is graded 'near'.

Q: Is S235JR the same as St37?
A: Practically yes. St37-2 (DIN 17100) was replaced by S235JR in 1994. St37-2 had no guaranteed impact value while S235JR guarantees 27 J at +20 °C, so S235JR always satisfies an St37-2 requirement, but not strictly the other way round.

Q: Can S235JR be hardened?
A: No. With ≤ 0.17 % carbon it does not respond to quench hardening and it is not a case-hardening grade. Choose C45 or 42CrMo4 for hardened parts.

Q: What is the difference between S235JR and S235J2?
A: Same strength; the impact test temperature differs: +20 °C for JR, 0 °C for J0, −20 °C for J2. S235J2 also has lower P and S limits (0.025 %) and is always fully killed.

Q: Is S235 stainless steel?
A: No. S235JR is a non-alloy structural steel with no chromium added, so it rusts in open air and needs paint, galvanizing or another coating. Stainless steels carry at least 10.5 % chromium and sit in a different standard, EN 10088 — the closest stainless in role, not in properties, is 1.4301 (304). The confusion comes from EN 10025-2 and EN 10088 sharing the same S-prefix style of designation in some catalogues.

Q: Does S235JR rust?
A: Yes, at the ordinary rate of unprotected carbon steel: a visible red film within days outdoors and roughly 0.05–0.10 mm of section loss per year in a normal urban atmosphere. In practice it is always delivered oiled, painted or galvanized; for exposed structures without a coating the grade to consider is S355J2W weathering steel, not S235.

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## S235JRH (1.0039) — Non-alloy structural steel for cold-formed (EN 10219) and hot-finished (EN 10210) hollow sections
URL: https://steelstandart.com/grade/s235jrh/
System: EN (European) | Family: Structural steel | Standard: EN 10219 | Verified against: EN 10219-1:2019
Aliases: S 235 JRH, 1.0039, S235JRH (EN 10219), S235JRH (EN 10210), St37-2 hollow section, RSt37-2 Hohlprofil, Fe360BH, S235JR hollow section, MS square tube, box section grade

S235JRH is what a box section, MS square tube or CHS made in Europe is certified to: the general structural steel S235JR delivered as a hollow section, H for hollow, under EN 10219 (cold-formed, welded) or EN 10210 (hot-finished). Werkstoff number 1.0039. Yield 235 MPa, tensile 360–510 MPa, 27 J at room temperature — the same numbers as the flat product, with the hollow-section standards adding the geometry, tolerances and sectional properties a designer needs.

Cold-formed EN 10219 sections are made on a tube mill from S235JR-quality strip, high-frequency welded, then sized square or rectangular; the corners work-harden, which is why EN 10219 quotes 24 % elongation against 26 % for the hot-finished EN 10210 product and assigns buckling curve c instead of a. For fences, furniture, canopies, racking, greenhouse and light building frames S235JRH is the default; for columns, trusses, cranes and anything designed to 355 MPa or needing −20 °C toughness, S355J2H is specified.

ASTM A500 Grade B, JIS STKR400 and GB Q235B are the market equivalents; all are slightly stronger on paper because of how their yield is measured on the formed section.

Chemical composition (mass %): C ≤ 0.17; Mn ≤ 1.4; P ≤ 0.04; S ≤ 0.04; N ≤ 0.009 (not applicable if Al ≥ 0.020)
Ladle analysis, EN 10219-1:2019 Table B.1 (same as S235JR of EN 10025-2). CEV max 0.35 %. Deoxidation: at manufacturer's discretion (FN for JR).

Mechanical properties:
- EN 10219 cold-formed, t ≤ 16 mm: yield 235 MPa; tensile 360–510 MPa; elongation 24 %; hardness ≈ 100–140 HB (typ.)
- EN 10210 hot-finished, t ≤ 16 mm: yield 235 MPa; tensile 360–510 MPa; elongation 26 %; hardness —
- EN 10210 hot-finished, > 16 ≤ 40 mm: yield 225 MPa; tensile 360–510 MPa; elongation 25 %; hardness —
- S275J0H / J2H (for comparison): yield 275 MPa; tensile 410–560 MPa; elongation 20 (10219) / 22 (10210) %; hardness —
- S355J2H / K2H: yield 355 MPa; tensile 470–630 MPa; elongation 20 (10219) / 22 (10210) %; hardness —
EN 10219-1:2019 Table B.3 and EN 10210-1:2006 Table A.3; A longitudinal, L0 = 5.65√S0. Cold forming raises the yield in the corners; EN 1993-1-3 / EN 1993-1-1 give the design values (fy = 235 MPa) and the cold-formed sections are assigned buckling curve c (hot-finished: a).
Impact: 27 J at 20 °C (longitudinal)

Equivalents:
- S235JR (EN (European)) — identical: Same steel as flat/long product to EN 10025-2; the H suffix only marks the hollow-section delivery standard.
- A500 Grade B (ASTM / ASME) — near: ASTM A500 Grade B cold-formed welded HSS: 290 MPa yield (round) / 317 MPa (shaped), 400 MPa tensile — the US box-section grade, slightly stronger than S235JRH; Grade C (345 MPa) ≈ S355J2H.
- Q235B (GB/T 6728) (GB/T (China)) — near: Chinese cold-formed hollow sections on Q235B: 235 MPa yield, 370–500 MPa tensile, 27 J at +20 °C.
- Ст3сп/пс (GOST 30245 / 8639) (GOST (Russia/CIS)) — near: CIS square and rectangular tube on Ст3 steel, 245 MPa yield class.
- STKR400 / STK400 (JIS (Japan)) — near: JIS G3466 (rectangular) / G3444 (circular) structural tube: yield ≥ 245 MPa, tensile ≥ 400 MPa.
- S355J2H (EN (European)) — functional: The high-strength hollow-section grade for primary members and EN 1090 EXC2/3 components.
- S195T (EN (European)) — functional: EN 10255 pipe steel for water/gas lines — not a structural grade; use S235JRH when the tube is a member.
- P235TR1 (EN (European)) — functional: EN 10219 S235JRH: 235 MPa minimum yield **structural** hollow section. The same strength number, and a frequent source of error — the H grade carries no pressure-purpose requirements and the TR grade carries no section-property or structural tolerance guarantees. The prefix decides which one the drawing means.

Superseded names:
- RSt37-2 (Hohlprofil) — DIN 17100 / DIN 59411: German cold-formed hollow sections in RSt37-2.
- Fe360BH — EN 10219:1997 (draft names) / EN 10025:1990
- 43C hollow — BS 6363 / BS 4360: British cold-formed hollow sections.

Product forms: cold-formed welded square, rectangular and circular hollow sections (EN 10219): SHS 20×20–400×400, RHS to 500×300, CHS to 508 mm, wall 1.5–16 mm; hot-finished hollow sections (EN 10210) in the same grade, wall to 40 mm; lengths 6–18 m
Tolerances: EN 10219-2: outside dimension ±1 % (min ±0.5 mm), wall ±10 %, squareness 90° ±1°, straightness 0.2 % of length, corner radius 1.6–3.0 t depending on wall; EN 10210-2 (hot-finished): corner radius ≤ 3 t, mass ±6 %; sectional properties tabulated in Part 2 of each standard

### S235JRH yield strength
≥ 235 MPa (34 ksi) up to 16 mm wall; 225 MPa for 16–40 mm (hot-finished). Corner regions of cold-formed sections test 280–350 MPa.

### S235JRH tensile strength
360–510 MPa (52–74 ksi).

### S235JRH elongation
≥ 24 % cold-formed (EN 10219) / ≥ 26 % hot-finished (EN 10210), longitudinal.

### Impact toughness
27 J at +20 °C (JR). No J0/J2 variant exists for S235 hollow sections — step to S275J0H or S355J2H for cold climates.

### Design values (EN 1993)
fy = 235 MPa, fu = 360 MPa; buckling curve c (cold-formed) or a (hot-finished) for flexural buckling; cross-section class depends on b/t — e.g. 100×100×4 is class 1 in S235.

### Physical properties
Density 7.85 g/cm³, E = 210 GPa, G = 81 GPa; mass per metre and section properties per EN 10219-2 tables (e.g. SHS 40×40×2: 2.31 kg/m; 100×100×4: 11.9 kg/m).

### Weldability
Excellent weldability (CEV ≤ 0.35): MAG, MMA, TIG and submerged-arc without preheat at any wall thickness in the range. Cold-formed corners may be welded in S235JRH without restriction (EN 1993-1-8 limits on welding in cold-formed zones apply from r/t ratios that S235 sections normally satisfy). Galvanized sections: remove zinc 20–30 mm from the joint, ventilate.

### Machining, forming, heat treatment
Sawing, drilling, punching, laser tube cutting (holes, slots, mitres to DXF), bending on section benders (radius ≥ 5–8 × section depth) and swaging are routine. Cold forming of the finished section (further bending) is allowed within EN 1993-1-3 limits; hot bending changes properties and is not permitted without re-certification.

Applications: Square and rectangular hollow sections for fences, gates, handrail and furniture; Canopy, greenhouse, shed and light building frames; Racking, mezzanines and platforms; Machine frames, conveyor structures; Scaffold and formwork components (also S195T / EN 39); Sign posts, lighting columns, guardrail posts; Secondary members in EN 1090 EXC1/EXC2 structures

Q: What does the H in S235JRH mean?
A: Hollow section: the same S235JR steel delivered as a structural hollow section under EN 10219 (cold-formed welded) or EN 10210 (hot-finished), which add the dimensional tolerances and sectional properties.

Q: Is S235JRH the same as S235JR?
A: Same chemistry and strength. S235JRH is the designation printed on the certificate of a hollow section; S235JR on plate, strip, bar and sections.

Q: What is the ASTM equivalent of S235JRH?
A: ASTM A500 Grade B (290–317 MPa yield, 400 MPa tensile) is the nearest cold-formed HSS grade; JIS STKR400 and GB Q235B are the Asian equivalents.

Q: S235JRH or S355J2H — which should I specify?
A: S235JRH for fences, furniture, racking, light frames and non-critical members; S355J2H when the design uses 355 MPa yield, for primary members, cranes, cold climates (27 J at −20 °C) and EN 1090 EXC2/3 components.

Q: EN 10219 or EN 10210 hollow sections?
A: EN 10219 = cold-formed welded (tighter corners, buckling curve c, cheaper, the usual choice); EN 10210 = hot-finished (larger corner radii, stress-relieved, buckling curve a, better for fatigue and dynamic loads). Both use the same grade names.

Q: Can S235JRH hollow sections be galvanized?
A: Yes — pre-galvanized strip (Z275) for light sections, or hot-dip galvanizing after fabrication to EN ISO 1461 for structural members; vent holes are required for closed sections.

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## S250GD (1.0242) — Hot-dip coated structural steel, guaranteed 250 MPa yield
URL: https://steelstandart.com/grade/s250gd/
System: EN (European) | Family: Cold-rolled & coated sheet | Standard: EN 10346 | Verified against: EN 10346:2015
Aliases: S250GD+Z, S250GD+Z275, S250GD+ZM, S250GD+AZ, S 250 GD, 1.0242, FeE250G, StE250-2Z, S250GD+ZF

S250GD is the first of the structural hot-dip galvanized grades in EN 10346 — the ones ordered when a roll-formed profile has to carry load and the engineer needs a yield value to design to. The designation reads S (structural steel), 250 (minimum yield in MPa), G (hot-dip coated), D (for cold forming); the coating code follows, usually +Z275 (275 g/m² zinc both faces) or, increasingly, +ZM zinc-magnesium at ZM90–ZM120 for the same corrosion life at half the mass. Werkstoff number 1.0242.

Against the forming grade DX51D, S250GD trades some ductility (19 % vs 22 % elongation) for a guaranteed 250 MPa yield and 330 MPa tensile — enough for purlins, girts, light-gauge framing, composite floor deck and cable trays designed to EN 1993-1-3. The ladder continues S280GD (the usual purlin grade), S320GD, S350GD (deck and long-span profiles), up to S550GD full-hard for roofing sheets that only need stiffness.

ASTM A653 SS Grade 37 and JIS SGC340 are the nearest equivalents; Chinese and Indian standards use the EN name or the yield number directly.

Chemical composition (mass %): C ≤ 0.2; Si ≤ 0.6; Mn ≤ 1.7; P ≤ 0.1; S ≤ 0.045
EN 10346:2015 Table 2 (S220GD to S350GD share these limits). Strength comes from carbon/manganese and cold work, not micro-alloying; typical coil C 0.05–0.10, Mn 0.30–0.60.

Mechanical properties:
- S250GD, all thicknesses (longitudinal): yield 250 MPa; tensile 330 MPa; elongation 19 %; hardness ≈ 65–80 HRB (typ.)
- S220GD (for comparison): yield 220 MPa; tensile 300 MPa; elongation 20 %; hardness —
- S280GD: yield 280 MPa; tensile 360 MPa; elongation 18 %; hardness —
- S320GD: yield 320 MPa; tensile 390 MPa; elongation 17 %; hardness —
- S350GD: yield 350 MPa; tensile 420 MPa; elongation 16 %; hardness —
- S390GD: yield 390 MPa; tensile 460 MPa; elongation 16 %; hardness —
- S450GD: yield 450 MPa; tensile 510 MPa; elongation 14 %; hardness —
- S550GD: yield 550 MPa; tensile 560 MPa; elongation — %; hardness —
EN 10346 Table 5: minimum yield ReH (or Rp0.2), minimum tensile Rm, minimum A80 longitudinal. Values apply to the base steel; for thickness < 0.7 mm elongation minus 2 points. S550GD has no elongation requirement (full-hard).

Equivalents:
- S250GD+Z (GB/T (China)) — identical: GB/T 2518 adopts the EN designation (also listed as 250 by yield).
- IS 277 Grade 250 (IS (India)) — identical: Indian galvanized sheet with 250 MPa yield.
- SS Grade 37 (A653) (ASTM / ASME) — near: ASTM A653 Structural Steel Grade 37 [255]: 255 MPa yield, 360 MPa tensile — the closest US structural galvanized grade; SS Grade 33 [230] sits just below.
- S280GD (EN (European)) — near: Next class up (280 MPa); the common purlin grade when S250GD is not stocked.
- SGC340 (JIS (Japan)) — near: JIS G3302 SGC340: yield ≥ 245 MPa, tensile ≥ 340 MPa, A ≥ 20 % — Japanese structural galvanized.
- S350GD (EN (European)) — functional: Same chemistry family, 350 MPa yield; used where span tables require it.
- DX51D (EN (European)) — functional: Same substrate family without a guaranteed yield — for bending and profiling that is not load-bearing.
- S235JR (EN (European)) — functional: Uncoated hot-rolled structural steel of similar strength for members that will be post-galvanized.
- DX52D (EN (European)) — functional: Same standard and coatings but a structural grade with a 250 MPa minimum yield — specified when the sheet carries load rather than being formed.

Superseded names:
- FeE250G — EN 10147:1992: Structural galvanized designation before the S…GD names (EN 10147:2000).
- StE250-2Z — DIN 17162 (withdrawn): German structural galvanized grade; ≈ S250GD+Z.
- Z25 / Z28 — BS 2989: British structural galvanized qualities by yield in kgf/mm².

Product forms: hot-dip galvanized coil and sheet 0.40–4.0 mm (+Z, +ZM, +AZ, +ZA, +ZF); slit strip for purlin, deck and profile lines; pre-painted (EN 10169) on S250GD base
Tolerances: thickness/width/flatness: EN 10143; coating mass per EN 10346 (Z275 = 275 g/m² both faces, ≈ 20 µm per face); surface quality A or B; finish N or M

### S250GD yield strength
≥ 250 MPa (36 ksi), longitudinal, ReH or Rp0.2. Typical measured values 270–320 MPa.

### S250GD tensile strength
≥ 330 MPa (48 ksi). No upper limit is specified; typical 350–400 MPa.

### S250GD elongation
≥ 19 % (A80, longitudinal); 17 % below 0.7 mm.

### Design values
EN 1993-1-3 uses fyb = 250 MPa and fu = 330 MPa for cold-formed members in S250GD; the cold-forming strength increase (fya) may be used for fully effective sections. E = 210 GPa, density 7.85 g/cm³.

### Coating and corrosion life
Z275 ≈ 20 µm/face: roughly 20–40 years in rural C2 air, 10–20 in urban C3, 3–8 near the coast (EN ISO 14713-1 guidance). ZM120 gives about twice the life of Z275 at equal mass and is the trend for solar mounting and agricultural framing.

### Weldability
Spot welding and MAG welding as for DX51D+Z: zinc fume extraction, 10–20 % higher current for spot welds, zinc-rich repair paint on heat-affected areas. Structural connections in light-gauge framing are usually self-drilling screws, blind rivets or bolts rather than welds, to keep the coating intact.

### Machining, forming, heat treatment
Roll forming, punching and slitting are routine; minimum inside bend radius about 1 t (transverse) — the coating passes the EN 10346 T-bend test without flaking. Not a drawing grade (no r-value). Cut edges are protected sacrificially by the zinc up to about 2 mm thickness.

Applications: C and Z purlins, girts and eaves beams (S250GD–S350GD); Light-gauge steel framing studs and tracks for load-bearing walls; Composite floor deck and roof deck (usually S280GD–S350GD); Cable trays, ladders and support channels; Solar-panel mounting rails and ground-mount frames (+ZM preferred); Guardrail, agricultural and greenhouse structures; Racking uprights and beams (higher grades for heavy racks)

Q: What is the difference between DX51D and S250GD?
A: DX51D is a forming grade with no guaranteed yield (tensile 270–500 MPa, 22 % elongation); S250GD is a structural grade with a guaranteed 250 MPa yield and 330 MPa tensile at 19 % elongation. Order S250GD when the profile is load-bearing and designed to EN 1993-1-3.

Q: What does S250GD+Z275 mean?
A: Structural (S) steel with 250 MPa minimum yield, hot-dip coated (G) for cold forming (D), zinc coating of 275 g/m² total on both faces (+Z275, about 20 µm per side).

Q: Is S250GD the same as SS Grade 37 or SGC340?
A: Near-equivalent: ASTM A653 SS Grade 37 [255] has 255 MPa yield and 360 MPa tensile; JIS G3302 SGC340 has 245 MPa yield and 340 MPa tensile. All three serve the same purlin and framing applications.

Q: Which grade for purlins — S250GD, S280GD or S350GD?
A: S280GD is the most common purlin grade in Europe; S250GD is used for light spans and where stock dictates; S350GD where the span table needs it or for deck. Higher yield means smaller sections but slightly less ductility.

Q: Can S250GD be supplied pre-painted?
A: Yes — pre-painted (PPGI) profiles to EN 10169 are usually on S250GD–S320GD substrate for purlins that stay visible, and on DX51D for non-structural cladding.

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## S275JR (1.0044) — Non-alloy hot-rolled structural steel
URL: https://steelstandart.com/grade/s275jr/
System: EN (European) | Family: Structural steel | Standard: EN 10025-2 | Verified against: EN 10025-2:2019
Aliases: S275JR+AR, S 275 JR, St44-2, Fe430B, 1.0044

S275JR sits between S235JR and S355 in the EN 10025-2 family: a non-alloy structural steel with 275 MPa minimum yield up to 16 mm and a tensile range of 410–560 MPa, impact tested to 27 J at +20 °C. Its Werkstoff number is 1.0044.

In practice S275JR is the British and Irish default for hot-rolled sections (the successor to BS 4360 43A/43B), while continental Europe tends to jump from S235 directly to S355. Buyers see it most in universal beams and columns, angles, flats and hollow sections. Carbon is allowed up to 0.21 % and CEV up to 0.40 %, so preheat is still unnecessary in ordinary thicknesses.

When a drawing says St44-2 or Fe430B, S275JR is the grade to order; when it says A36, check the design — A36 yield is 250 MPa, so S275JR is the safe upward substitute but A36 is not a downward one.

Chemical composition (mass %): C ≤ 0.21 (≤ 40 mm; 0.25 % above 40 mm); Mn ≤ 1.5; P ≤ 0.035; S ≤ 0.035; N ≤ 0.012; Cu ≤ 0.55
Ladle analysis, EN 10025-2:2019 Table 2. CEV max 0.40 % up to 30 mm, 0.42 % 40–150 mm.

Mechanical properties:
- ≤ 16 mm: yield 275 MPa; tensile 410–560 MPa; elongation 23 %; hardness ≈ 120–160 HB (typical)
- > 16 ≤ 40 mm: yield 265 MPa; tensile 410–560 MPa; elongation 23 %; hardness —
- > 40 ≤ 63 mm: yield 255 MPa; tensile 410–560 MPa; elongation 22 %; hardness —
- > 63 ≤ 80 mm: yield 245 MPa; tensile 410–560 MPa; elongation 21 %; hardness —
- > 80 ≤ 100 mm: yield 235 MPa; tensile 410–560 MPa; elongation 21 %; hardness —
- > 100 ≤ 150 mm: yield 225 MPa; tensile 400–540 MPa; elongation 19 %; hardness —
Rm range for 3–100 mm; elongation L0 = 5.65√S0, longitudinal.
Impact: 27 J at 20 °C (longitudinal)

Equivalents:
- A572 Gr. 42 (ASTM / ASME) — near: Yield 290 MPa (42 ksi), Rm 415 MPa min — slightly stronger, HSLA chemistry.
- Q275B (GB/T (China)) — near: GB/T 700 Q275: yield 275 MPa, Rm 410–540 MPa; B = 27 J at +20 °C.
- IS 2062 E275 BR (IS (India)) — near: Yield 275 MPa, Rm 430 MPa min, room-temperature impact.
- A36 (ASTM / ASME) — functional: A36 yield 250 MPa is below 275 MPa; A36 is not a drop-in replacement where the design used fy = 275.
- S235JR (EN (European)) — functional: Lower class; S275JR can replace S235JR, not vice versa.
- S355JR (EN (European)) — functional: Higher class; same delivery conditions.
- P265GH (EN (European)) — functional: Structural steel of similar strength without elevated-temperature or pressure-equipment certification (no PED compliance).
- S280GD (EN (European)) — functional: Uncoated hot-rolled equivalent by yield for members that will be hot-dip galvanized after fabrication.
- E250 (IS (India)) — functional: Matches on tensile — S275JR is 410–560 MPa — but E250's yield is 250 MPa against 275. Where the design is tensile-governed the substitution works; where it is yield-governed it does not.
- SS400 (JIS (Japan)) — functional: Yield 245 MPa, below S275; SM400 is closer on impact but also 245 MPa.

Superseded names:
- St44-2 — DIN 17100 (withdrawn): Legacy German name, still used in Turkey and the Gulf.
- Fe430B — EN 10025:1990
- 43A / 43B — BS 4360: 43B matches the +20 °C impact requirement.
- E28-2 — NF A 35-501

Product forms: hot-rolled plate; hot-rolled coil and sheet; sections and merchant bar; hollow sections (S275JRH, EN 10210/10219)
Tolerances: plate: EN 10029; coil/sheet: EN 10051; sections: EN 10034 / EN 10279

### S275JR yield strength
Minimum ReH is 275 MPa (39.9 ksi) ≤ 16 mm, 265 MPa to 40 mm, 255 MPa to 63 mm, 245 MPa to 80 mm and 235 MPa to 100 mm. EN 1993-1-1 design value fy = 275 MPa (t ≤ 40 mm) / 255 MPa (40–80 mm).

### S275JR tensile strength
Rm is 410–560 MPa (59–81 ksi); typical certificates show 430–470 MPa.

### S275JR hardness
Not specified in the standard; as-rolled material is about 120–160 HB.

### Density and modulus
7.85 g/cm³ and E = 210 GPa — identical to all EN 10025 carbon steels.

### Weldability
Weldable by all processes without preheat up to ~30 mm (CEV ≤ 0.40 %). Match with E42 / G42 consumables; for thick, restrained joints use EN 1011-2 to set preheat.

### Machining, forming, heat treatment
Slightly harder to machine than S235JR but still free-cutting with HSS or carbide. Minimum bend radius (transverse) 1.0 t ≤ 2.5 mm to 2.5 t at 8–16 mm per EN 10025-2 Table 7. Not hardenable.

Applications: Hot-rolled sections for buildings (UK/IE practice: UB, UC, PFC); Hollow sections for architectural and light industrial frames; Trailer chassis and agricultural equipment frames; Crane runway secondary members; Galvanized structural steelwork

Q: What is S275JR equivalent to in ASTM?
A: There is no exact ASTM match. A572 Grade 42 (290 MPa yield) is the nearest by strength; A36 (250 MPa) is weaker and only a functional substitute after a design check.

Q: Is S275JR the same as St44-2?
A: S275JR replaced St44-2 (DIN 17100) in 1994 with an added 27 J impact guarantee at +20 °C. For ordering purposes they are treated as the same grade.

Q: What is the difference between S275JR and S355JR?
A: Yield strength: 275 vs 355 MPa. S355JR also allows more carbon (0.24 %) and has a higher CEV limit (0.45 %), so it needs more welding care in thick sections.

Q: Where is S275JR used instead of S235JR?
A: Wherever the design is strength-governed rather than deflection-governed: beams and columns, trailer frames, lifting-equipment secondary members. UK/Irish section stock is mostly S275 or S355, rarely S235.

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## S280GD (1.0244) — Hot-dip coated structural steel, guaranteed 280 MPa yield — the purlin grade
URL: https://steelstandart.com/grade/s280gd/
System: EN (European) | Family: Cold-rolled & coated sheet | Standard: EN 10346 | Verified against: EN 10346:2015
Aliases: S280GD+Z, S280GD+Z275, S280GD+ZM, S280GD+AZ, S 280 GD, 1.0244, FeE280G, StE280-2Z, S280GD+ZF

S280GD is the grade most European purlin and light-gauge framing lines run on: a hot-dip galvanized structural sheet with a guaranteed 280 MPa yield and 360 MPa tensile that still bends and roll-forms cleanly at 18 % elongation. Werkstoff number 1.0244; ordered as S280GD+Z275 for enclosed buildings, +Z350 or +ZM120 where the frame is exposed or in humid climates, and as the substrate under pre-painted purlins.

Within EN 10346 it sits between S250GD (light purlins, cable trays) and S320GD/S350GD (deck, long spans, racking). Compared with the forming grade DX51D there is no formability loss that matters for open profiles, but the guaranteed yield lets the designer use EN 1993-1-3 section tables instead of a conservative assumption.

ASTM A653 SS Grade 40 and JIS SGC400 are the working equivalents; span tables published by purlin manufacturers in the Gulf and Africa are commonly based on S280GD or S350GD.

Chemical composition (mass %): C ≤ 0.2; Si ≤ 0.6; Mn ≤ 1.7; P ≤ 0.1; S ≤ 0.045
EN 10346:2015 Table 2, common to S220GD–S350GD. Mills reach 280 MPa with C 0.06–0.12 and Mn 0.40–0.80 plus temper rolling; no Nb/V in this class.

Mechanical properties:
- S280GD, all thicknesses (longitudinal): yield 280 MPa; tensile 360 MPa; elongation 18 %; hardness ≈ 70–85 HRB (typ.)
- S250GD (for comparison): yield 250 MPa; tensile 330 MPa; elongation 19 %; hardness —
- S320GD: yield 320 MPa; tensile 390 MPa; elongation 17 %; hardness —
- S350GD: yield 350 MPa; tensile 420 MPa; elongation 16 %; hardness —
EN 10346 Table 5, minimum values, A80 longitudinal; minus 2 points below 0.7 mm. Typical S280GD coil tests 300–340 MPa yield.

Equivalents:
- S280GD+Z (GB/T (China)) — identical: GB/T 2518 adopts the EN designation.
- SS Grade 40 (A653) (ASTM / ASME) — near: ASTM A653 Structural Steel Grade 40 [275]: 275 MPa yield, 380 MPa tensile — the US purlin and deck grade.
- S250GD (EN (European)) — near: One class lower; interchangeable for light purlins if the span table allows.
- S350GD (EN (European)) — near: One class higher; chosen for deck and long-span purlins.
- IS 277 Grade 275 (IS (India)) — near: Indian galvanized sheet, 275 MPa yield.
- SGC400 (JIS (Japan)) — near: JIS G3302 SGC400: yield ≥ 295 MPa, tensile ≥ 400 MPa, A ≥ 18 %; slightly stronger.
- S275JR (EN (European)) — functional: Uncoated hot-rolled equivalent by yield for members that will be hot-dip galvanized after fabrication.

Superseded names:
- FeE280G — EN 10147:1992: Pre-2000 designation.
- StE280-2Z — DIN 17162 (withdrawn): German structural galvanized grade.
- Z28 — BS 2989: British structural galvanized quality, 28 kgf/mm² ≈ 275 MPa.

Product forms: hot-dip galvanized coil and sheet 0.50–4.0 mm (+Z, +ZM, +AZ); slit strip for C/Z purlin, sigma and deck lines; pre-painted (EN 10169) base for visible purlins and trays
Tolerances: thickness/width/flatness: EN 10143; coating mass per EN 10346 (Z275 standard for structural use; Z350/Z450 for exposed frames); surface A or B, finish N or M

### S280GD yield strength
≥ 280 MPa (41 ksi), longitudinal. Typical 300–340 MPa.

### S280GD tensile strength
≥ 360 MPa (52 ksi); typical 380–430 MPa.

### S280GD elongation
≥ 18 % (A80, longitudinal); 16 % below 0.7 mm.

### Design values
EN 1993-1-3: fyb = 280 MPa, fu = 360 MPa; average yield fya may be increased for cold-forming in fully effective sections. E = 210 GPa.

### Coating and corrosion life
Z275 (≈ 20 µm/face) — 10–20 years in urban C3, 20–40 in rural C2; Z450 or ZM140 for coastal or agricultural exposure. Cut edges under 2 mm are protected by the zinc's sacrificial action.

### Weldability
Weldable as DX51D+Z with fume extraction and zinc-rich repair; purlin systems normally use bolted cleats, sleeves and self-drilling screws so the coating stays intact. Spot welding needs 10–20 % more current and electrode dressing.

### Machining, forming, heat treatment
Roll forming, punching (bolt holes on the line), swaging and slitting are routine; inside bend radius ≥ 1 t transverse recommended, EN 10346 T-bend test guaranteed. Not intended for drawing.

Applications: C, Z and sigma purlins and girts (the reference grade); Light-gauge steel framing (LSF) studs, tracks and joists; Composite and roof deck (with S350GD); Cable trays, ladders, strut channels; Solar mounting rails and trackers (+ZM); Shelving and light racking; Highway and agricultural fencing posts

Q: What is S280GD used for?
A: Mainly C/Z purlins, girts, light-gauge framing and deck: any roll-formed galvanized profile that carries load and is designed with a 280 MPa yield to EN 1993-1-3.

Q: S280GD or S350GD for purlins?
A: S280GD is the standard; S350GD gives about 20 % more moment capacity from the same section and is chosen for long spans, deck and heavy racking. Ductility drops from 18 % to 16 %, which is irrelevant for open profiles.

Q: What is the ASTM equivalent of S280GD?
A: ASTM A653 SS Grade 40 [275] — 275 MPa yield, 380 MPa tensile. JIS SGC400 (295 MPa) is slightly stronger.

Q: What coating should I specify for purlins?
A: Z275 for enclosed buildings in dry inland climates; Z350–Z450 or ZM120–ZM140 for exposed frames, coastal sites and agricultural buildings; pre-painted on S280GD where purlins remain visible.

Q: Is S280GD available thicker than 3 mm?
A: Yes, to about 4.0 mm from continuous galvanizing lines; heavier purlins (4–6 mm) are usually hot-rolled S275JR/S355JR profiles hot-dip galvanized after forming.

---

## S350GD (1.0529) — Hot-dip coated structural steel, guaranteed 350 MPa yield — deck and long-span profiles
URL: https://steelstandart.com/grade/s350gd/
System: EN (European) | Family: Cold-rolled & coated sheet | Standard: EN 10346 | Verified against: EN 10346:2015
Aliases: S350GD+Z, S350GD+Z275, S350GD+ZM, S350GD+AZ, S 350 GD, 1.0529, FeE350G, StE350-2Z, S350GD+ZF

S350GD is the structural galvanized grade for members that are designed to their limit: composite floor deck, long-span roof deck, heavy-duty purlins, pallet-racking uprights, highway guardrail and solar trackers. EN 10346 guarantees 350 MPa yield and 420 MPa tensile at 16 % elongation; Werkstoff number 1.0529. Ordered as S350GD+Z275 (Z350–Z600 or +ZM for exposed frames) and, for deck, usually with a surface quality B and a minimized spangle so the concrete-side embossing is uniform.

It is the top of the plain carbon-manganese structural class in EN 10346 — S390GD and above are micro-alloyed — and roughly 20 % stronger than S280GD from the same section, which is why deck manufacturers publish their span tables on S350GD. Ductility is lower (16 %); bend radii on deck ribs and racking hooks are sized accordingly.

ASTM A653 SS Grade 50 Class 1 and JIS SGC440 are the equivalents used in North American and Asian deck catalogues.

Chemical composition (mass %): C ≤ 0.2; Si ≤ 0.6; Mn ≤ 1.7; P ≤ 0.1; S ≤ 0.045
EN 10346:2015 Table 2 (S220GD–S350GD). Some mills reach 350 MPa with a small Nb or Ti addition within these limits; above S350GD the micro-alloyed classes (S390GD–S450GD) apply.

Mechanical properties:
- S350GD, all thicknesses (longitudinal): yield 350 MPa; tensile 420 MPa; elongation 16 %; hardness ≈ 80–90 HRB (typ.)
- S320GD (for comparison): yield 320 MPa; tensile 390 MPa; elongation 17 %; hardness —
- S390GD: yield 390 MPa; tensile 460 MPa; elongation 16 %; hardness —
- S420GD: yield 420 MPa; tensile 480 MPa; elongation 15 %; hardness —
- S450GD: yield 450 MPa; tensile 510 MPa; elongation 14 %; hardness —
- S550GD: yield 550 MPa; tensile 560 MPa; elongation — %; hardness —
EN 10346 Table 5, minimum values, A80 longitudinal; minus 2 points below 0.7 mm. S550GD (full-hard) has no elongation requirement and is for stiffness-only roofing sheet, not for designed members.

Equivalents:
- S350GD+Z (GB/T (China)) — identical: GB/T 2518 adopts the EN designation (also 350 by yield).
- SS Grade 50 (A653) (ASTM / ASME) — near: ASTM A653 Structural Steel Grade 50 [340] Class 1: 340 MPa yield, 450 MPa tensile — the US deck and framing grade.
- S280GD (EN (European)) — near: One class lower — the general purlin grade.
- S390GD (EN (European)) — near: First micro-alloyed class above S350GD, for heavy racking and structural deck.
- IS 277 Grade 340 (IS (India)) — near: Indian galvanized sheet, 340 MPa yield.
- SGC440 (JIS (Japan)) — near: JIS G3302 SGC440: yield ≥ 335 MPa, tensile ≥ 440 MPa, A ≥ 18 %.
- S355JR (EN (European)) — functional: Uncoated hot-rolled equivalent by yield, for profiles hot-dip galvanized after forming.
- S250GD (EN (European)) — functional: Same chemistry family, 350 MPa yield; used where span tables require it.

Superseded names:
- FeE350G — EN 10147:1992: Pre-2000 designation.
- StE350-2Z — DIN 17162 (withdrawn): German structural galvanized grade.
- Z35 — BS 2989: British structural galvanized quality, 35 kgf/mm² ≈ 345 MPa.

Product forms: hot-dip galvanized coil and sheet 0.60–4.0 mm (+Z, +ZM, +AZ); slit strip for deck, purlin and racking lines; pre-painted (EN 10169) base
Tolerances: thickness/width/flatness: EN 10143; coating mass per EN 10346 (Z275 standard; Z350–Z600 or ZM for exposed use); surface A or B, finish N or M

### S350GD yield strength
≥ 350 MPa (51 ksi), longitudinal. Typical 370–420 MPa.

### S350GD tensile strength
≥ 420 MPa (61 ksi); typical 440–500 MPa.

### S350GD elongation
≥ 16 % (A80, longitudinal); 14 % below 0.7 mm.

### Design values
EN 1993-1-3: fyb = 350 MPa, fu = 420 MPa. For composite slabs EN 1994-1-1 uses the deck yield as fyp = 350 MPa. E = 210 GPa.

### Coating and corrosion life
Z275 ≈ 20 µm/face for interior deck and purlins; Z450–Z600 or ZM140–ZM200 for guardrail, agricultural and coastal frames (EN ISO 14713-1 categories C3–C5). Hot-dip galvanizing after forming (EN ISO 1461, 70–85 µm) is the alternative for heavy exposed members.

### Weldability
Shear studs on composite deck are welded through the deck to the beam (EN 1994-1-1, stud welding through galvanized sheet ≤ 1.25 mm total zinc-coated thickness). Other joints are screwed, riveted or bolted; MAG welding needs fume extraction and zinc-rich repair paint.

### Machining, forming, heat treatment
Roll forming with embossing (deck), punching and slitting are routine; recommended inside bend radius ≥ 1.5 t transverse. The higher yield increases springback — profile tooling is set for S350GD specifically. Not a drawing grade.

Applications: Composite floor deck and steel roof deck (the reference grade); Long-span and heavy-duty C/Z/sigma purlins; Pallet-racking uprights and beams; Highway guardrail W-beam and posts (often Z600 or post-galvanized); Solar trackers and ground-mount structures (+ZM); Light-gauge framing joists for longer spans; Silo and tank wall panels (with S390GD–S450GD)

Q: What is S350GD used for?
A: Composite and roof deck, long-span purlins, racking, guardrail and solar structures — galvanized profiles designed with a 350 MPa yield to EN 1993-1-3 or EN 1994-1-1.

Q: What is the ASTM equivalent of S350GD?
A: ASTM A653 SS Grade 50 [340] Class 1 (340 MPa yield, 450 MPa tensile); JIS G3302 SGC440 (335 MPa) is the Japanese counterpart.

Q: S350GD vs S355JR — what is the difference?
A: Same nominal yield, different product: S350GD is a continuously galvanized thin sheet (0.6–4 mm) for roll forming to EN 10346; S355JR is uncoated hot-rolled plate, strip and sections to EN 10025-2 that would be galvanized after fabrication.

Q: Can S350GD be bent as tightly as S280GD?
A: Not quite — elongation is 16 % vs 18 % and springback is higher. Use an inside radius of at least 1.5 t and set tooling for the grade; deck ribs and racking hooks are designed around this.

Q: Which zinc coating for guardrail in S350GD?
A: Most highway specifications call for Z600 continuous coating or, more commonly, hot-dip galvanizing after forming to EN ISO 1461 with 70–85 µm; the sheet grade stays S350GD or S420GD.

---

## S355J2 (1.0577) — Non-alloy hot-rolled structural steel, −20 °C impact
URL: https://steelstandart.com/grade/s355j2/
System: EN (European) | Family: Structural steel | Standard: EN 10025-2 | Verified against: EN 10025-2:2019
Aliases: S355J2+N, S355J2+AR, S355J2G3, St52-3 N, Fe510D, 1.0577, S355J2+M

S355J2 is the plate grade engineers actually specify when they write "S355": 355 MPa minimum yield, 470–630 MPa tensile and a Charpy guarantee of 27 J at −20 °C, Werkstoff number 1.0577. The J2 suffix also brings tighter cleanliness (P, S ≤ 0.025 %) and mandatory full killing, so the steel is more uniform than S355JR from the same mill.

Most S355J2 plate is delivered normalized or normalizing-rolled (+N), giving a fine ferrite–pearlite structure that keeps toughness in thicknesses up to 250 mm. Crane makers, bridge fabricators and machinery builders standardize on it because it covers most temperate-climate service without moving to the fine-grain S355N/NL family of EN 10025-3.

Old drawings call it St52-3 N or Fe510D; in the United States ASTM A572 Grade 50 with Charpy supplement (or A709-50 for bridges) is the practical equivalent, and in China Q355D.

Chemical composition (mass %): C ≤ 0.22 (≤ 30 mm; 0.22 % above 30 mm); Si ≤ 0.55; Mn ≤ 1.6; P ≤ 0.025; S ≤ 0.025; Cu ≤ 0.55
Ladle analysis, EN 10025-2:2019 Table 2. Fully killed (FF). No N limit because Al-killed. CEV max 0.45 % (≤ 30 mm) to 0.47 % (40–150 mm).

Mechanical properties:
- ≤ 16 mm: yield 355 MPa; tensile 470–630 MPa; elongation 22 %; hardness ≈ 150–190 HB (typical)
- > 16 ≤ 40 mm: yield 345 MPa; tensile 470–630 MPa; elongation 22 %; hardness —
- > 40 ≤ 63 mm: yield 335 MPa; tensile 470–630 MPa; elongation 21 %; hardness —
- > 63 ≤ 80 mm: yield 325 MPa; tensile 470–630 MPa; elongation 20 %; hardness —
- > 80 ≤ 100 mm: yield 315 MPa; tensile 470–630 MPa; elongation 20 %; hardness —
- > 100 ≤ 150 mm: yield 295 MPa; tensile 450–600 MPa; elongation 18 %; hardness —
- > 150 ≤ 200 mm: yield 285 MPa; tensile 450–600 MPa; elongation 17 %; hardness —
- > 200 ≤ 250 mm: yield 275 MPa; tensile 450–600 MPa; elongation 17 %; hardness —
Same strength table as S355JR/J0/K2. Elongation longitudinal, L0 = 5.65√S0.
Impact: 27 J at -20 °C (longitudinal)

Equivalents:
- St52-3 (DIN (superseded German)) — identical: Successor of St52-3 N (1.0577); same yield table, tensile 470–630 MPa, 27 J at −20 °C, cleaner P/S.
- S355J2H (EN (European)) — identical: Same steel as plate, strip and sections to EN 10025-2; H marks the hollow-section standard.
- A572 Grade 50 (ASTM / ASME) — near: Yield 345 MPa, Rm 450 MPa min; order with supplementary S5 (Charpy) to approach J2 toughness.
- A709 Gr. 50 (ASTM / ASME) — near: Bridge version of A572-50 with Charpy requirement by zone; closest US match for bridge plate.
- S355JR (EN (European)) — near: Same strength; JR tested at +20 °C, higher P/S allowed.
- S355N (EN (European)) — near: EN 10025-3 normalized fine-grain steel, same strength up to 16 mm, better guaranteed toughness and weldability (Nb/V/Ti grain refinement).
- E355 (EN (European)) — near: EN 10025-2 S355J2: effectively the same analysis and, in the +N condition, the same 355 MPa yield and 490–630 MPa tensile. The difference is what else each standard demands — S355J2 guarantees 27 J at −20 °C and structural tolerances, while E355 guarantees dimensional precision and surface finish and requires no impact test at all.
- Q355 (GB/T (China)) — near: GB/T 1591 Q355D: 355 MPa yield, 34 J at −20 °C; quality D is the −20 °C class matching J2.
- Q355 (GB/T (China)) — near: Q355D matches it: −20 °C impact test, P ≤ 0.025 % and S ≤ 0.020 %, and a fine-grain aluminium requirement.
- 09G2S-12 (GOST (Russia/CIS)) — near: Category 12 = impact at −40 °C; low-alloy 09G2S exceeds S355J2 toughness but yield is 325–345 MPa.
- 09G2S (GOST (Russia/CIS)) — near: The usual counterpart: 345 MPa yield against 355 at the first thickness step and a 490 MPa tensile floor against 470. 09G2S is tested colder than S355J2 but reports KCU on a U-notch rather than KV on a V-notch.
- IS 2062 E350 C (IS (India)) — near: Yield 350 MPa, quality C = impact at −20 °C.
- SM490B (JIS (Japan)) — near: Yield 325 MPa, Rm 490–610 MPa, 27 J at 0 °C (not −20 °C); SM490YB is closer on yield (365 MPa).
- S355J2W (EN (European)) — functional: Same mechanical properties without the weathering alloying — use where the steel is painted or galvanized.
- S355MC (EN (European)) — functional: Normalized/as-rolled structural steel of the same yield; heavier chemistry (C ≤ 0.22), larger bend radii, chosen for plate and sections rather than cold-formed parts.
- AR400 (Proprietary (trade names)) — functional: EN 10025-2 S355J2 at roughly 150 HBW. Listed as the benchmark: in sliding abrasion AR400 lasts about **three to four times** as long, which is the whole economic case for wear plate. S355J2 is what the surrounding structure is made of.
- AR450 (Proprietary (trade names)) — functional: EN 10025-2 S355J2 at roughly 150 HBW — the reference point for wear calculations. AR450 lasts roughly four to five times as long in sliding abrasion.
- AR500 (Proprietary (trade names)) — functional: EN 10025-2 S355J2 at roughly 150 HBW — the reference point. AR500 lasts about five to six times as long in sliding abrasion, and that multiplier is the whole reason to accept its fabrication penalties.

Superseded names:
- St52-3 N — DIN 17100: Normalized St52-3; the direct predecessor.
- Fe510D / Fe510D1 — EN 10025:1990
- S355J2G3 — EN 10025:1993: G3 = normalized delivery; merged into S355J2 in the 2004 edition.
- 50D — BS 4360
- E36-4 — NF A 35-501

Product forms: hot-rolled plate (most common, usually +N); hot-rolled coil; sections; bar and flat; hollow sections (S355J2H)
Tolerances: plate: EN 10029 class A (thickness), flatness class N; coil/sheet: EN 10051; sections: EN 10034

### S355J2 yield strength
Minimum ReH 355 MPa (51.5 ksi) to 16 mm, 345 MPa to 40 mm, 335 MPa to 63 mm, 325 MPa to 80 mm, 315 MPa to 100 mm, 295 MPa to 150 mm and 275 MPa up to 250 mm.

### S355J2 tensile strength
Rm 470–630 MPa (68–91 ksi) to 100 mm, 450–600 MPa from 100 to 250 mm.

### S355J2 hardness
Not a standard requirement; normalized plate is typically 150–190 HB. Flame-cut edges can locally reach 250–300 HV and should be ground before cold bending.

### Impact energy
27 J at −20 °C (longitudinal, full-size specimen). Transverse values, if ordered, are typically ≥ 20 J.

### Weldability
Good weldability with E46 / G46 consumables. CEV up to 0.45–0.47 %; for t > 25 mm calculate preheat with EN 1011-2 (typically 50–125 °C). Low-hydrogen consumables (≤ 5 ml/100 g) are standard for cranes and bridges. PWHT not usually required; if performed, 550–600 °C.

### Machining, forming, heat treatment
Machines like S355JR (index ≈ 60 %). Cold bending of +N plate: minimum radius 1.5–3 t transverse depending on thickness (EN 10025-2 Table 7). Hot forming 950–1100 °C followed by re-normalizing 880–920 °C to restore J2 toughness. Flame cutting: preheat 100 °C above 30 mm to avoid edge cracking.

Applications: Crane girders, booms and structural parts of lifting equipment; Bridge plate girders and orthotropic decks (+N); Machinery frames and earthmoving-equipment structures; Wind-turbine tower shells; Heavy plate for shipbuilding secondary structure and offshore modules; Hollow sections S355J2H for exposed architectural steelwork

Q: What does J2 mean in S355J2?
A: J = 27 J minimum Charpy V-notch energy, 2 = test temperature −20 °C. Compare JR (+20 °C), J0 (0 °C) and K2 (40 J at −20 °C).

Q: Is S355J2 the same as S355J2+N?
A: +N is the delivery condition (normalized or normalizing-rolled). S355J2 without a suffix may be supplied +AR, +N or +M at the mill's choice; specify +N when you need guaranteed toughness through thickness.

Q: What is the difference between S355J2 and S355N?
A: S355N (EN 10025-3) is a normalized fine-grain steel with Nb/V/Ti additions and a guaranteed 40 J at −20 °C (S355NL: 27 J at −50 °C). It is used where toughness matters more than cost.

Q: What is the ASTM equivalent of S355J2?
A: ASTM A572 Grade 50 with supplementary requirement S5 (Charpy), or A709 Grade 50 for bridges. Neither is identical — yield is 345 MPa and Charpy values are by agreement.

Q: Can S355J2 be used at −30 °C?
A: The guarantee is at −20 °C. For −30 °C and below, order S355K2 or S355N/NL (EN 10025-3) or S355ML (EN 10025-4).

---

## S355J2H (1.0576) — Non-alloy structural steel for hollow sections, 355 MPa, −20 °C impact
URL: https://steelstandart.com/grade/s355j2h/
System: EN (European) | Family: Structural steel | Standard: EN 10219 | Verified against: EN 10219-1:2019
Aliases: S 355 J2H, 1.0576, S355J2H (EN 10219), S355J2H (EN 10210), S355J0H, S355K2H, St52-3 hollow section, St52-3 Hohlprofil, Fe510DH, S355 hollow section, S355J2 tube

S355J2H is the grade engineers write on the drawing when a hollow section is a primary member: columns, truss chords, crane and stadium structures, offshore and machinery frames. It is S355J2 — 355 MPa yield, 470–630 MPa tensile, 27 J at −20 °C — delivered as a structural hollow section (H) under EN 10219 (cold-formed welded) or EN 10210 (hot-finished). Werkstoff number 1.0576. The −20 °C toughness is what separates it from S355J0H (0 °C) and makes it the default in EN 1090 EXC2/EXC3 components and in cold-climate export markets.

Cold-formed EN 10219 sections are roll-formed and HF-welded from S355J2 strip; the corners work-harden, elongation is 20 % (22 % hot-finished) and buckling curve c applies. For fatigue-loaded or dynamically loaded members, EN 10210 hot-finished sections — stress-relieved, larger corner radii, curve a — are preferred, at a premium. Thermomechanical S420MH/S460MH exist in EN 10219 for weight-critical trusses.

ASTM A500 Grade C and A1085, JIS STKR490, GB Q355B/D and GOST 09Г2С tube are the market equivalents.

Chemical composition (mass %): C ≤ 0.22; Si ≤ 0.55; Mn ≤ 1.6; P ≤ 0.03; S ≤ 0.03
Ladle analysis, EN 10219-1:2019 Table B.1 (as S355J2 of EN 10025-2). Fully killed (FF); CEV max 0.45 % (≤ 16 mm). S355J0H has the same chemistry with P/S ≤ 0.035; S355K2H requires 40 J at −20 °C.

Mechanical properties:
- EN 10219 cold-formed, t ≤ 16 mm: yield 355 MPa; tensile 470–630 MPa; elongation 20 %; hardness ≈ 150–190 HB (typ.)
- EN 10210 hot-finished, t ≤ 16 mm: yield 355 MPa; tensile 470–630 MPa; elongation 22 %; hardness —
- EN 10210 hot-finished, > 16 ≤ 40 mm: yield 345 MPa; tensile 470–630 MPa; elongation 21 %; hardness —
- S275J2H (for comparison): yield 275 MPa; tensile 410–560 MPa; elongation 20 / 22 %; hardness —
- S420MH / S460MH (EN 10219, TM): yield 420 / 460 MPa; tensile 500–660 / 530–720 MPa; elongation 19 %; hardness —
EN 10219-1:2019 Table B.3 and EN 10210-1:2006 Table A.3; A longitudinal, L0 = 5.65√S0. Design per EN 1993-1-1 with fy = 355 MPa; cold-formed sections take buckling curve c, hot-finished curve a. EN 1993-1-8 restricts welding within 5 t of cold-formed corners for r/t < 1.5–3 depending on wall.
Impact: 27 J at -20 °C (longitudinal)

Equivalents:
- S355J2 (EN (European)) — identical: Same steel as plate, strip and sections to EN 10025-2; H marks the hollow-section standard.
- L360 / X52 (API (line pipe)) — near: EN 10219 S355J2H: 355 MPa minimum yield with 27 J at −20 °C — almost the same strength and toughness, but it is a **structural** hollow section specification with no pipeline requirements: no yield ceiling, no carbon equivalent cap, no fracture-arrest testing. Suitable for a structural pipe, not for a transmission line.
- A500 Grade C (ASTM / ASME) — near: ASTM A500 Grade C cold-formed welded HSS: 317 MPa (round) / 345 MPa (shaped) yield, 427 MPa tensile — the US structural box-section grade; A1085 (345 MPa, tighter tolerances, 25 J at 4 °C) is closer to EN 10219 S355J2H.
- A1085 (ASTM / ASME) — near: ASTM A1085 HSS: 345 MPa yield, 450 MPa tensile, Charpy option, tolerances aligned with EN 10219 — the closest US specification.
- S420MH (EN (European)) — near: Thermomechanical high-strength hollow-section grade of EN 10219 for weight-critical trusses.
- Q355B / Q355D (GB/T 6728) (GB/T (China)) — near: Chinese cold-formed hollow sections on Q355: 355 MPa yield; D quality has 27 J at −20 °C like J2H.
- 09Г2С (GOST 30245) (GOST (Russia/CIS)) — near: CIS square and rectangular tube on 09Г2С low-alloy steel, 345 MPa yield, −40 °C impact.
- STKR490 / STK490 (JIS (Japan)) — near: JIS G3466 / G3444 structural tube: yield ≥ 325 MPa, tensile ≥ 490 MPa.
- S235JRH (EN (European)) — functional: The general-purpose hollow-section grade for light frames and fences.

Superseded names:
- St52-3 (Hohlprofil) — DIN 17100 / DIN 59411: German hollow sections in St52-3; direct predecessor.
- Fe510DH — EN 10025:1990 / EN 10219:1997 draft
- 50D hollow — BS 6363 / BS 4360: British cold-formed hollow sections.
- S355J2G3H — EN 10210:1994: Normalized hot-finished variant; merged into S355J2H.

Product forms: cold-formed welded square, rectangular and circular hollow sections (EN 10219): SHS 40×40–400×400, RHS to 500×300, CHS to 508 mm, wall 2–16 mm; hot-finished hollow sections (EN 10210), wall to 40 mm (larger sizes to 500×500 / 1 016 mm CHS); lengths 6–18 m
Tolerances: EN 10219-2: outside dimension ±1 % (min ±0.5 mm), wall ±10 %, squareness 90° ±1°, straightness 0.2 %, corner radius 1.6–3.0 t; EN 10210-2: corner radius ≤ 3 t, mass ±6 %; sectional properties tabulated in Part 2

### S355J2H yield strength
≥ 355 MPa (51 ksi) up to 16 mm wall; 345 MPa for 16–40 mm (hot-finished). Cold-formed corners test 400–450 MPa.

### S355J2H tensile strength
470–630 MPa (68–91 ksi).

### S355J2H elongation
≥ 20 % cold-formed (EN 10219) / ≥ 22 % hot-finished (EN 10210), longitudinal.

### Impact toughness
27 J at −20 °C (Charpy V, longitudinal). S355K2H: 40 J at −20 °C.

### Design values (EN 1993)
fy = 355 MPa, fu = 470 MPa; buckling curve c (cold-formed) or a (hot-finished); many common sizes (e.g. 150×150×5) are class 2–3 in S355 where they were class 1 in S235 — check b/t limits.

### Physical properties
Density 7.85 g/cm³, E = 210 GPa, G = 81 GPa; section properties per EN 10219-2 / EN 10210-2 (e.g. SHS 100×100×4: 11.9 kg/m, Wel = 36.0 cm³; RHS 200×100×6: 26.4 kg/m).

### Weldability
Good weldability (CEV ≤ 0.45): preheat rarely needed below 20 mm wall; use consumables of 470 MPa class (G 46 / E 46, or G 42 for under-matching at nodes). EN 1993-1-8 §4.14 limits welding in the cold-formed corner zone unless r/t satisfies the table (e.g. r/t ≥ 3 for t ≤ 12 mm) or the section is hot-finished. Galvanized sections: grind zinc back before welding, provide vent holes for closed members.

### Machining, forming, heat treatment
Sawing, drilling, laser tube cutting (mitres, slots, notches to DXF), section bending (radius ≥ 6–10 × depth for S355) and end preparation are routine; punching thick walls needs more press force than S235. Hot bending or normalizing after cold forming requires re-testing.

Applications: Columns, beams and bracing in steel buildings (EN 1090 EXC2/3); Roof and space trusses, stadium and airport roofs; Crane girders, gantries and machinery frames; Bridges and footbridges (often hot-finished EN 10210); Offshore and marine structures (with impact-tested K2H / fine-grain grades); Truck, trailer and agricultural machine frames; Wind-turbine internals, transmission towers

Q: What is the difference between S355J2H and S355J2?
A: Same steel; H means it is delivered as a structural hollow section under EN 10219 or EN 10210, which add the geometry, tolerances and sectional properties. The certificate of a box section or CHS reads S355J2H.

Q: What is the ASTM equivalent of S355J2H?
A: ASTM A500 Grade C (345 MPa shaped) is the common cold-formed HSS equivalent; ASTM A1085 (345 MPa, tighter tolerances, Charpy option) matches EN 10219 S355J2H more closely.

Q: When do I need S355J2H instead of S235JRH?
A: When the design uses 355 MPa yield (smaller sections for the same load), for primary members, cranes and dynamic loads, for cold climates (27 J at −20 °C), and for EN 1090 EXC2/EXC3 CE-marked components.

Q: Cold-formed (EN 10219) or hot-finished (EN 10210) S355J2H?
A: Cold-formed is cheaper, more available and fine for static structures; hot-finished has larger corner radii, no residual stresses, buckling curve a and better fatigue performance — specified for bridges, cranes and offshore work.

Q: Can I weld at the corners of cold-formed S355J2H sections?
A: Only within EN 1993-1-8 limits: welding in the cold-formed zone (5 t either side of the corner) needs r/t above the tabulated value (e.g. ≥ 3 for t ≤ 12 mm) or the section must be hot-finished or normalized. Most EN 10219 S355J2H sections meet this for t ≤ 12 mm.

Q: Is S355J2H suitable for galvanizing?
A: Yes — hot-dip galvanizing after fabrication (EN ISO 1461) is standard for outdoor structures; Si and P are within the ranges that give a normal zinc layer, and vent/drain holes are required on closed sections.

---

## S355J2W (1.8965) — Weathering (atmospheric-corrosion-resistant) structural steel, −20 °C impact
URL: https://steelstandart.com/grade/s355j2w/
System: EN (European) | Family: Structural steel | Standard: EN 10025-5 | Verified against: EN 10025-5:2019
Aliases: S355J2W+N, S355J2W+AR, S355J2G2W, S355J2G1W, WTSt52-3, WT St 52-3, 1.8965, Corten B, COR-TEN B, weathering steel, S355J0W, S355K2W

S355J2W is the weathering structural steel of EN 10025-5 — the grade Europe buys when the drawing says Corten B (the ArcelorMittal/US Steel trade name) or the old German WTSt52-3. A copper-chromium-nickel addition (Cu 0.25–0.55, Cr 0.40–0.80, Ni ≤ 0.65 %) makes the rust that forms in wet-dry cycles dense and adherent instead of flaky, so an unpainted bridge girder, façade panel, chimney or sculpture stabilises at a 0.1–0.2 mm patina and then corrodes at a tenth of the rate of plain carbon steel. Werkstoff number 1.8965. The mechanical table is that of S355J2: 355 MPa yield, 470–630 MPa tensile, 27 J at −20 °C.

The patina needs alternating wet and dry exposure; permanently damp details, chloride-rich coastal air (> 2 km from the sea is the usual limit), and sheltered crevices do not form it and corrode as ordinary steel. Design details therefore avoid water traps, and run-off is managed because early rust stains concrete and glass. Thin façade sheet (1.5–3 mm) is delivered pre-rusted or blasted; plate for bridges is normally +N.

ASTM A588 Grade A/B is the direct US equivalent; A242 and A606 Type 4 cover the thin, phosphorus-bearing variants (EN S355J2WP); JIS SMA490 and GB Q355NH are the Asian counterparts.

Chemical composition (mass %): C ≤ 0.16; Si ≤ 0.5; Mn 0.5 – 1.5; P ≤ 0.03; S ≤ 0.03; Cr 0.4 – 0.8; Cu 0.25 – 0.55; Ni ≤ 0.65; Mo ≤ 0.3; Zr ≤ 0.15
Ladle analysis, EN 10025-5:2019 Table 2. Fully killed; N ≤ 0.009 unless Al-bound. Copper and chromium (with nickel) form the dense, adherent oxide layer; the WP variants (S355J0WP/J2WP) instead use P 0.06–0.15 % and are limited to ≤ 12 mm. CEV max 0.52 % (≤ 16 mm).

Mechanical properties:
- ≤ 16 mm: yield 355 MPa; tensile 470–630 MPa; elongation 22 %; hardness ≈ 150–190 HB (typ.)
- > 16 ≤ 40 mm: yield 345 MPa; tensile 470–630 MPa; elongation 22 %; hardness —
- > 40 ≤ 63 mm: yield 335 MPa; tensile 470–630 MPa; elongation 21 %; hardness —
- > 63 ≤ 80 mm: yield 325 MPa; tensile 470–630 MPa; elongation 20 %; hardness —
- > 80 ≤ 100 mm: yield 315 MPa; tensile 470–630 MPa; elongation 20 %; hardness —
- > 100 ≤ 150 mm: yield 295 MPa; tensile 450–600 MPa; elongation 18 %; hardness —
EN 10025-5:2019 Table 4 — identical strength table to S355J2 (EN 10025-2). Elongation longitudinal, L0 = 5.65√S0; transverse values 2 points lower.
Impact: 27 J at -20 °C (longitudinal)

Equivalents:
- A588 Grade A / B (ASTM / ASME) — near: ASTM A588: 345 MPa yield, 485 MPa tensile, Cu-Cr-Ni(-V) weathering steel for bridges — the US Corten B; Grade A is Cr-rich, Grade B Ni-rich, both within S355J2W chemistry ranges.
- S235J2W (EN (European)) — near: Lower-strength weathering grade (235 MPa) for façades and non-critical members.
- Q355NH (GB/T (China)) — near: GB/T 4171 weathering structural steel, 355 MPa yield; Q355NH (Cu-Cr-Ni) ≈ S355J2W, Q355GNH ≈ WP type.
- 10ХНДП / 14ХГНДЦ (GOST (Russia/CIS)) — near: GOST 19281 weathering (Cu-Ni-P and Cu-Cr-Ni) structural steels of 345–355 MPa class.
- SMA490BW / CW (JIS (Japan)) — near: JIS G3114 welded structural weathering steel, 355 MPa yield (≤ 16 mm), 490–610 MPa tensile; B = 0 °C, C = −5 °C impact.
- A242 Type 1 (ASTM / ASME) — functional: ASTM A242: the original Cu-P weathering steel (345 MPa ≤ 19 mm) — closer to S355J2WP; used for sheet and light sections.
- A606 Type 4 (ASTM / ASME) — functional: ASTM A606 Type 4 sheet and strip with enhanced corrosion resistance (345 MPa) — the thin-gauge façade equivalent.
- S355J2 (EN (European)) — functional: Same mechanical properties without the weathering alloying — use where the steel is painted or galvanized.

Superseded names:
- WTSt52-3 — DIN 17100 / SEW 087: German weathering structural steel; direct predecessor.
- S355J2G1W / S355J2G2W — EN 10155:1993: G1 = as-rolled, G2 = normalized; merged into S355J2W in EN 10025-5:2004.
- Fe510D2K1 — EN 10155:1993 (Fe designation)
- WR50B / WR50C — BS 4360: British weathering grades.

Product forms: hot-rolled plate 2–150 mm (+AR or +N); hot-rolled coil and sheet 1.5–12 mm (façade and cladding); sections, flats and bar; hollow sections as S355J2WH (EN 10219/10210)
Tolerances: plate: EN 10029 class A, flatness N; coil/sheet: EN 10051; sections: EN 10034 / EN 10279

### S355J2W yield strength
≥ 355 MPa (51 ksi) up to 16 mm, stepping down to 295 MPa at 150 mm — same table as S355J2.

### S355J2W tensile strength
470–630 MPa (68–91 ksi) up to 100 mm; 450–600 MPa above.

### S355J2W elongation
≥ 22 % (longitudinal, ≤ 40 mm); 18 % at 150 mm.

### Impact toughness
27 J at −20 °C (Charpy V, longitudinal). Order S355K2W for 40 J at −20 °C.

### Corrosion rate
After patina formation (1–3 years, C2–C3 atmospheres): about 5 µm/year vs 30–50 µm/year for unprotected S355J2; EN 1993-1-1 / EN 1993-2 allow a 1 mm per exposed face corrosion allowance over 100 years in suitable environments. Not for permanently wet, buried, marine (C5) or de-icing-salt-splashed positions without paint.

### Physical properties
Density 7.85 g/cm³, E = 210 GPa, thermal expansion 12 × 10⁻⁶/K — identical to carbon structural steel.

### Weldability
Weldable by all arc processes with the same preheat rules as S355J2 (CEV ≤ 0.52; preheat 50–100 °C above ~25 mm combined thickness). For exposed welds use matching weathering consumables (e.g. EN ISO 2560 E 42 4 Z B / AWS E8018-W2, or Cu-Ni-bearing wires) so the weld patinates with the plate; for painted or multi-pass root runs, ordinary S355 consumables are acceptable except the cap. Remove mill scale beside the weld for uniform patina.

### Machining, forming, heat treatment
Cut by plasma, laser and oxy-fuel as S355; the Cr-Cu content slightly increases tool wear when drilling. Cold bending radius ≥ 2 t (plate) / 1.5 t (sheet); hot forming 850–1 100 °C. Blasting to Sa 2½ before exposure gives an even patina; pre-weathering (accelerated rusting) is offered for façade sheet.

Applications: Highway and railway bridges (unpainted girders, cross-beams); Building façades, cladding and screens in pre-weathered sheet; Transmission and lighting towers, masts, guardrail; Chimneys, silos, hoppers, conveyor structures; Shipping containers (thin A606/S355J2WP-type sheet); Sculpture, landscape and garden elements; Rail wagons and truck bodies (with S355J2WP)

Q: Is S355J2W the same as Corten B?
A: For specification purposes yes: Corten B is a trade name; its chemistry and 345–355 MPa yield fall within ASTM A588 Grade A/B and EN 10025-5 S355J2W. Corten A is the phosphorus type, closer to S355J2WP / A242.

Q: How long does weathering steel take to form its patina?
A: Typically 1–3 years in a temperate C2–C3 atmosphere with wet-dry cycling; faster with pre-weathering treatment. During that period rust run-off can stain adjacent surfaces.

Q: Can S355J2W be used near the sea?
A: Not unpainted within about 2 km of the coast or where de-icing salt is splashed: chlorides prevent a stable patina and the steel corrodes like ordinary S355. Paint it or choose stainless there.

Q: Does weathering steel need painting?
A: No, that is its purpose — but details must drain, avoid crevices and allow drying. Painted weathering steel still benefits: coating life is longer because under-film corrosion is slower.

Q: What is the difference between S355J2W and S355J2WP?
A: J2W is the Cu-Cr-Ni type for all thicknesses (bridges, plate); J2WP is the Cu-P type (P 0.06–0.15 %) limited to ≤ 12 mm, mainly sheet for façades and containers, with slightly better patina but poorer weldability in thick sections.

Q: What welding consumable for S355J2W?
A: Matching weathering-grade consumables (AWS E8018-W2 / EN ISO 2560 with Cu-Ni) for exposed cap passes; standard S355 consumables are acceptable for root and fill or where the joint will be painted.

---

## S355JR (1.0045) — Non-alloy hot-rolled structural steel
URL: https://steelstandart.com/grade/s355jr/
System: EN (European) | Family: Structural steel | Standard: EN 10025-2 | Verified against: EN 10025-2:2019
Aliases: S355JR+AR, S 355 JR, St52-3 U, Fe510B, 1.0045, S355

S355JR is the strength workhorse of European structural steel: 355 MPa minimum yield, 470–630 MPa tensile, 27 J Charpy at +20 °C, Werkstoff number 1.0045. It is still a non-alloy steel — strength comes from up to 0.24 % C and 1.60 % Mn rather than micro-alloying — which is why the carbon equivalent limit rises to 0.45 % and welding thick sections calls for a preheat check.

The S355 family (JR, J0, J2, K2) shares one strength table and differs only in impact temperature and cleanliness. JR is the coil and section grade for mild climates; plate for cranes, bridges and offshore is almost always ordered as J2 or K2. If a specification simply says "S355", ask which suffix — the difference decides whether the steel is accepted at −20 °C.

S355JR replaced DIN St52-3 U and BS 4360 50B; the US counterpart is ASTM A572 Grade 50, the Chinese Q355B (formerly Q345B).

Chemical composition (mass %): C ≤ 0.24 (≤ 40 mm; 0.24 % above 40 mm); Si ≤ 0.55; Mn ≤ 1.6; P ≤ 0.035; S ≤ 0.035; N ≤ 0.012; Cu ≤ 0.55
Ladle analysis, EN 10025-2:2019 Table 2. CEV max 0.45 % up to 30 mm, 0.47 % 30–40 mm, 0.47 % 40–150 mm.

Mechanical properties:
- ≤ 16 mm: yield 355 MPa; tensile 470–630 MPa; elongation 22 %; hardness ≈ 140–190 HB (typical)
- > 16 ≤ 40 mm: yield 345 MPa; tensile 470–630 MPa; elongation 22 %; hardness —
- > 40 ≤ 63 mm: yield 335 MPa; tensile 470–630 MPa; elongation 21 %; hardness —
- > 63 ≤ 80 mm: yield 325 MPa; tensile 470–630 MPa; elongation 20 %; hardness —
- > 80 ≤ 100 mm: yield 315 MPa; tensile 470–630 MPa; elongation 20 %; hardness —
- > 100 ≤ 150 mm: yield 295 MPa; tensile 450–600 MPa; elongation 18 %; hardness —
Rm range for 3–100 mm; longitudinal elongation, L0 = 5.65√S0.
Impact: 27 J at 20 °C (longitudinal)

Equivalents:
- A572 Grade 50 (ASTM / ASME) — near: Yield 345 MPa (50 ksi), Rm 450 MPa min; HSLA with Nb/V, no impact requirement unless supplementary S5 is ordered.
- A992 (ASTM / ASME) — near: Yield 345–450 MPa, Rm 450 MPa min; shapes only, with a yield/tensile ratio cap of 0.85.
- St52-3 (DIN (superseded German)) — near: Successor of St52-3 U (impact at +20 °C).
- S355J2 (EN (European)) — near: Same strength; impact at −20 °C, P/S ≤ 0.025 %, fully killed.
- Q355 (GB/T (China)) — near: GB/T 1591 Q355B: yield 355 MPa, Rm 470–630 MPa, 34 J at +20 °C — the direct successor of Q345B and the closest Chinese match.
- Q355 (GB/T (China)) — near: Q355B is the counterpart: same 355 MPa yield to 16 mm, same 470–630 MPa tensile band, both tested at +20 °C. Q355B is tested to 34 J against 27 J, and allows carbon to 0.24 % against 0.24 % for S355JR in thick product — the closest cross-system match in the structural range.
- 09G2S (GOST (Russia/CIS)) — near: GOST 19281 09G2S: yield 325–345 MPa, Rm 470–490 MPa; low-alloy Mn-Si steel, better cold toughness.
- IS 2062 E350 BR (IS (India)) — near: Yield 350 MPa, Rm 490 MPa min, room-temperature impact.
- SM490A (JIS (Japan)) — near: JIS G3106 SM490A: yield 325 MPa (≤ 16 mm), Rm 490–610 MPa; A = no impact requirement, B = 27 J at 0 °C.
- S275JR (EN (European)) — functional: Higher class; same delivery conditions.
- S350GD (EN (European)) — functional: Uncoated hot-rolled equivalent by yield, for profiles hot-dip galvanized after forming.

Superseded names:
- St52-3 U — DIN 17100: St52-3 U (unkilled-tested at +20 °C) ≈ S355JR; St52-3 N ≈ S355J2.
- Fe510B — EN 10025:1990
- 50B — BS 4360
- E36-2 — NF A 35-501

Product forms: hot-rolled plate; hot-rolled coil and sheet; sections (IPE, HE, UPN, angles); bar; hollow sections (S355JRH)
Tolerances: plate: EN 10029; coil/sheet: EN 10051; sections: EN 10034 / EN 10279

### S355JR yield strength
Minimum ReH 355 MPa (51.5 ksi) ≤ 16 mm, 345 MPa to 40 mm, 335 MPa to 63 mm, 325 MPa to 80 mm, 315 MPa to 100 mm. EN 1993-1-1: fy = 355 MPa (t ≤ 40 mm), 335 MPa (40–80 mm).

### S355JR tensile strength
Rm 470–630 MPa (68–91 ksi) for 3–100 mm; typical mill values 510–560 MPa.

### S355JR hardness
Not specified; as-rolled S355 measures about 140–190 HB (150–200 HV).

### Carbon equivalent
CEV max 0.45 % ≤ 30 mm, 0.47 % for 30–150 mm. Above ~25 mm or with high restraint, preheat 50–100 °C is common practice per EN 1011-2.

### Weldability
Weldable with E46 / G46 consumables (EN ISO 2560 / 14341). Because CEV may reach 0.45 %, calculate preheat with EN 1011-2 Method A for t > 25 mm; low-hydrogen processes are standard. Post-weld heat treatment is not normally required.

### Machining, forming, heat treatment
Machinability index ≈ 60 %; carbide tooling recommended for sections above 20 mm. Minimum transverse bend radius per EN 10025-2 Table 7: 1.0 t (≤ 2.5 mm) to 3.0 t (8–16 mm). Hot forming 950–1100 °C; normalizing 880–920 °C restores properties after hot work. Not hardenable in the useful sense — it is not a heat-treatable grade.

Applications: Primary steel structures: beams, columns, trusses, portal frames; Crane girders and lifting-equipment structures (as S355J2/K2); Bridges (S355J2+N, S355K2+N or S355N/NL); Heavy transport and trailer chassis; Wind-tower sections and offshore secondary steel (S355J2 or S355ML); Hollow sections S355J2H for architectural structures

Q: What is the difference between S355JR and S355J2?
A: Strength is identical. S355J2 is impact tested at −20 °C (JR at +20 °C), has P and S limited to 0.025 % and is always fully killed. Plate for cranes, bridges and cold climates is ordered as J2.

Q: What is the ASTM equivalent of S355JR?
A: ASTM A572 Grade 50 (345 MPa / 50 ksi yield) is the standard substitute; A992 for rolled shapes. Both are HSLA steels without a default Charpy requirement, so they are graded 'near'.

Q: Is S355 the same as St52?
A: Yes in ordering practice: St52-3 (DIN 17100) became S355 in EN 10025:1993. St52-3 U corresponds to S355JR and St52-3 N to S355J2.

Q: Does S355JR need preheat for welding?
A: Not below ~25 mm in ordinary joints. Above that, or with high restraint and CEV near 0.45 %, EN 1011-2 typically gives 50–100 °C preheat with low-hydrogen consumables.

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## S355MC (1.0976) — Thermomechanically rolled HSLA steel for cold forming
URL: https://steelstandart.com/grade/s355mc/
System: EN (European) | Family: Structural steel | Standard: EN 10149-2 | Verified against: EN 10149-2:2013
Aliases: S 355 MC, 1.0976, QStE380TM, QStE 380 TM, Domex 355 MC, S355MC+P, HSLA 355, S355 MC

S355MC is the workhorse of EN 10149-2, the European standard for thermomechanically rolled high-strength steels for cold forming. The designation reads S (structural), 355 (minimum yield, MPa), M (thermomechanical rolling), C (suitable for cold forming). Werkstoff number 1.0976; the old German name QStE380TM and the SSAB trade name Domex 355 MC are still used at the shop floor.

What separates it from ordinary S355J2 is the metallurgy: carbon is held to 0.12 %, sulphur to 0.020 %, and strength comes from niobium/vanadium/titanium micro-alloying plus controlled rolling, giving a fine ferrite grain. The result is a strip that bends to 0.5 t radius in thin gauge without cracking, welds without preheat, and punches cleanly — which is why trailer chassis, truck frames, crane booms, agricultural implements and cold-formed structural profiles are made from it rather than from normalized plate.

The EN 10149-2 ladder runs S315MC → S355MC → S420MC → S460MC → S500MC → S550MC → S600MC → S650MC → S700MC (and S900/S960MC); each step raises yield and tightens the allowable bend radius. ASTM A1011 HSLAS-F Grade 50 and JIS SAPH440 are the sheet equivalents.

Chemical composition (mass %): C ≤ 0.12; Si ≤ 0.5; Mn ≤ 1.5; P ≤ 0.025; S ≤ 0.02; Al ≥ 0.015; Nb ≤ 0.09; V ≤ 0.2; Ti ≤ 0.15
Ladle analysis, EN 10149-2:2013 Table 1. Fully killed, fine-grain (Al ≥ 0.015 total); Nb + V + Ti ≤ 0.22 %. Low carbon and sulphur are what give the grade its cold-forming and welding behaviour; CEV typically 0.25–0.35.

Mechanical properties:
- < 3 mm (A80): yield 355 MPa; tensile 430–550 MPa; elongation 19 %; hardness ≈ 130–170 HB (typ.)
- ≥ 3 mm (A5): yield 355 MPa; tensile 430–550 MPa; elongation 23 %; hardness —
- S315MC (for comparison): yield 315 MPa; tensile 390–510 MPa; elongation 20 / 24 %; hardness —
- S420MC: yield 420 MPa; tensile 480–620 MPa; elongation 16 / 19 %; hardness —
- S460MC: yield 460 MPa; tensile 520–670 MPa; elongation 14 / 17 %; hardness —
- S500MC: yield 500 MPa; tensile 550–700 MPa; elongation 12 / 14 %; hardness —
- S600MC: yield 600 MPa; tensile 650–820 MPa; elongation 11 / 13 %; hardness —
- S700MC: yield 700 MPa; tensile 750–950 MPa; elongation 10 / 12 %; hardness —
EN 10149-2:2013 Table 2, longitudinal; A80 for t < 3 mm, A (L0 = 5.65√S0) for t ≥ 3 mm. Transverse tensile allowed up to 20 MPa lower. Minimum inside bend radius (transverse to rolling): S355MC 0.5 t for t ≤ 3 mm, 1.0 t for 3–6 mm, 1.5 t above 6 mm.
Impact: 40 J at -20 °C (longitudinal, option)

Equivalents:
- A1011 HSLAS-F Grade 50 (ASTM / ASME) — near: ASTM A1011 High-Strength Low-Alloy with improved Formability, Grade 50 [340]: 340 MPa yield, 410 MPa tensile, inclusion-controlled for bending — the US sheet equivalent.
- S420MC (EN (European)) — near: Next class in EN 10149-2 (420 MPa) — the usual step up for trailer chassis.
- S355MC (EN 10149-2) vs S355NC (EN 10149-3) (EN (European)) — near: NC is the normalized-rolled version with the same yield but slightly larger bend radii.
- Q355 (QStE380TM-type) (GB/T (China)) — near: GB/T 1591 Q355 or the automotive GB/T 3273 grades of 355–380 MPa class.
- SAPH440 (JIS (Japan)) — near: JIS G3113 hot-rolled automotive structural sheet: yield ≥ 305 MPa, tensile ≥ 440 MPa, good formability.
- A572 Grade 50 (ASTM / ASME) — functional: Same yield class (345 MPa) as plate/sections, but not thermomechanically rolled and without the guaranteed bend radii.
- S355J2 (EN (European)) — functional: Normalized/as-rolled structural steel of the same yield; heavier chemistry (C ≤ 0.22), larger bend radii, chosen for plate and sections rather than cold-formed parts.
- S700MC (EN (European)) — functional: The general cold-forming HSLA grade — roughly half the yield, twice the elongation.
- 09G2S (GOST (Russia/CIS)) — functional: Similar yield, different route: S355MC is thermomechanically rolled for forming, with much tighter carbon and a bend requirement. Substitute only where the design is about strength rather than about forming.

Superseded names:
- QStE380TM — SEW 092 (withdrawn): German thermomechanical HSLA grade; direct predecessor with 380 MPa yield.
- FeE355TM — EN 10149-2:1995 (draft names)
- Domex 355 MC — SSAB trade name: Widely used as a generic term for S355MC in Northern Europe.

Product forms: hot-rolled coil and strip 1.5–20 mm (+P pickled and oiled usual); cut-to-length sheet and plate to 20 mm; slit strip for roll forming and tube mills
Tolerances: thickness/width/flatness: EN 10051 (special class often ordered); surface: as-rolled or pickled; EN 10163 not applicable to strip

### S355MC yield strength
≥ 355 MPa (51 ksi), longitudinal, all thicknesses 1.5–20 mm. Typical 380–430 MPa.

### S355MC tensile strength
430–550 MPa (62–80 ksi).

### S355MC elongation
≥ 19 % (A80, t < 3 mm) / ≥ 23 % (A5, t ≥ 3 mm).

### Minimum bend radius (transverse)
0.5 t for t ≤ 3 mm, 1.0 t for 3 < t ≤ 6 mm, 1.5 t for t > 6 mm (EN 10149-2 Table 3). Longitudinal bends may need one step larger.

### Impact toughness
Option: 40 J at −20 °C longitudinal (27 J transverse) for t ≥ 6 mm; mills typically supply 40 J at −40 °C on request.

### Physical properties
Density 7.85 g/cm³, E = 210 GPa; CEV 0.25–0.35 (very good weldability).

### Weldability
Excellent: no preheat up to about 20 mm combined thickness thanks to C ≤ 0.12 and CEV ≈ 0.30. Use consumables matching 355–420 MPa (e.g. G 42 / G 46, E 42); keep heat input moderate (≤ 1.5 kJ/mm on thin gauge) so the fine TM grain is not coarsened in the HAZ. Post-weld heat treatment is not required and normalizing must be avoided — it destroys the TM properties.

### Machining, forming, heat treatment
Punching, shearing, laser and plasma cutting are routine and give clean edges suitable for bending without cracking. Cold forming is the purpose of the grade: press braking, roll forming, flanging; keep the bend axis transverse to rolling where radii are tight. Hot forming above 600 °C is not permitted (TM steel).

Applications: Trailer, semi-trailer and truck chassis longitudinal members; Crane and aerial-platform booms (S355MC–S700MC); Agricultural and construction machinery frames and buckets; Cold-formed structural profiles, C/Z sections and welded box sections; Tube mills for high-strength structural and mechanical tube; Automotive wheels, seat frames, brackets; Racking uprights and mezzanine floors

Q: What is the difference between S355MC and S355J2?
A: Same 355 MPa yield, different product: S355MC is thermomechanically rolled strip (C ≤ 0.12, Nb/V/Ti) made for cold forming with guaranteed tight bend radii and easy welding; S355J2 is as-rolled or normalized structural plate/sections (C ≤ 0.22) to EN 10025-2. MC must not be normalized or hot-formed.

Q: What does MC mean in S355MC?
A: M = thermomechanical rolling, C = suitable for cold forming (with specified minimum bend radii). The NC grades of EN 10149-3 are normalized-rolled.

Q: What is the minimum bend radius of S355MC?
A: 0.5 t up to 3 mm, 1.0 t from 3 to 6 mm and 1.5 t above 6 mm, transverse to the rolling direction (EN 10149-2 Table 3).

Q: Is S355MC the same as QStE380TM or Domex 355?
A: QStE380TM (SEW 092) was the German predecessor with 380 MPa yield; Domex 355 MC is SSAB's brand meeting S355MC. Both are treated as S355MC in practice.

Q: What is the ASTM equivalent of S355MC?
A: ASTM A1011 HSLAS-F Grade 50 [340] for sheet and strip (340 MPa yield, improved formability); A572 Grade 50 is the plate/section counterpart by yield but without the cold-forming guarantees.

Q: Does S355MC need preheating for welding?
A: Not up to about 20 mm combined thickness; keep heat input moderate to preserve the fine grain, and never normalize after welding.

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## S700MC (1.8974) — Thermomechanically rolled ultra-high-strength steel for cold forming
URL: https://steelstandart.com/grade/s700mc/
System: EN (European) | Family: Structural steel | Standard: EN 10149-2 | Verified against: EN 10149-2:2013
Aliases: S 700 MC, 1.8974, QStE690TM, QStE 690 TM, Domex 700 MC, Strenx 700 MC, S700MC+P, HSLA 700, S700 MC

S700MC is the strongest grade most cold-forming shops will ever roll: an EN 10149-2 thermomechanically rolled strip with 700 MPa minimum yield and 750–950 MPa tensile, still weldable and bendable at 10–12 % elongation. Werkstoff number 1.8974; QStE690TM in the old German nomenclature, Domex/Strenx 700 MC in the trade. The metallurgy is a very low carbon (≤ 0.12, typically 0.06 %) fine-grained ferrite–bainite matrix strengthened by Ti, Nb, V and Mo precipitates and, in some mills, boron — controlled rolling and accelerated cooling do the rest.

It exists to take weight out of structures: a crane boom, trailer chassis rail or tipper body in S700MC is 40–50 % lighter than the S355 equivalent for the same load, which is payload, fuel and reach. The price is stricter forming rules (bend radius ≥ 1.5–2.5 t, no hot forming, springback compensation), stricter welding heat input, and a fatigue design that respects the higher stresses.

There is no exact ASTM equivalent in A1011 (Grade 80 stops at 550 MPa); SAE J1392 100XF and mill grades cover the US market. For plate above about 12 mm the quenched-and-tempered S690QL (EN 10025-6) is the alternative.

Chemical composition (mass %): C ≤ 0.12; Si ≤ 0.6; Mn ≤ 2.1; P ≤ 0.025; S ≤ 0.015; Al ≥ 0.015; Nb ≤ 0.09; V ≤ 0.2; Ti ≤ 0.22; Mo ≤ 0.5; B ≤ 0.005
Ladle analysis, EN 10149-2:2013 Table 1 (S600MC–S700MC). Nb + V + Ti ≤ 0.22 %. Mills typically use C 0.05–0.08, Mn 1.6–2.0, Ti 0.10–0.15 with Nb/Mo/B for precipitation and bainitic strengthening; CEV about 0.35–0.45 despite the low carbon.

Mechanical properties:
- < 3 mm (A80): yield 700 MPa; tensile 750–950 MPa; elongation 10 %; hardness ≈ 240–290 HB (typ.)
- ≥ 3 mm (A5): yield 700 MPa; tensile 750–950 MPa; elongation 12 %; hardness —
- S600MC (for comparison): yield 600 MPa; tensile 650–820 MPa; elongation 11 / 13 %; hardness —
- S650MC: yield 650 MPa; tensile 700–880 MPa; elongation 10 / 12 %; hardness —
- S900MC: yield 900 MPa; tensile 930–1 200 MPa; elongation 8 / 10 %; hardness —
- S960MC: yield 960 MPa; tensile 980–1 250 MPa; elongation 7 / 10 %; hardness —
EN 10149-2:2013 Table 2, longitudinal; A80 for t < 3 mm, A (L0 = 5.65√S0) for t ≥ 3 mm; for t > 8 mm the minimum yield may be 20 MPa lower. Minimum inside bend radius (transverse): S700MC 1.5 t for t ≤ 3 mm, 2.0 t for 3–6 mm, 2.5 t above 6 mm (mill grades such as Strenx 700 MC Plus guarantee tighter).
Impact: 40 J at -20 °C (longitudinal, option)

Equivalents:
- A1011 HSLAS Grade 80 (ASTM / ASME) — near: ASTM A1011 High-Strength Low-Alloy Grade 80 [550] gives 550 MPa yield / 620 MPa tensile — the highest standard A1011 class; 700 MPa strip in the US is usually sold to mill specifications (e.g. HSLA 100) or SAE J1392 100XF.
- S650MC (EN (European)) — near: One class lower in EN 10149-2; interchangeable where 650 MPa suffices.
- Q690 (GB/T 16270 / 1591) (GB/T (China)) — near: Chinese 690 MPa class high-strength structural steel; TM versions for cold forming are mill-specific.
- SAE J1392 100XF (sae) — near: SAE J1392 100XF: 690 MPa yield HSLA sheet with improved formability — the automotive-frame equivalent.
- S690QL (EN (European)) — functional: EN 10025-6 quenched-and-tempered plate with 690 MPa yield: same strength class for heavy plate (> 12 mm), but Q&T instead of TM, larger bend radii and stricter welding.
- S355MC (EN (European)) — functional: The general cold-forming HSLA grade — roughly half the yield, twice the elongation.

Superseded names:
- QStE690TM — SEW 092 (withdrawn): German thermomechanical grade with 690 MPa yield; the direct predecessor.
- Domex 700 MC / Strenx 700 MC — SSAB trade names: The brand names most buyers use; Strenx 700 MC meets S700MC with tighter bend guarantees.

Product forms: hot-rolled coil and strip 2–12 mm (+P pickled and oiled usual; to 20 mm from some mills); cut-to-length sheet and plate; slit strip for high-strength tube and profiles
Tolerances: thickness/width/flatness: EN 10051, special class common; surface: pickled and oiled; as-rolled on request

### S700MC yield strength
≥ 700 MPa (102 ksi) longitudinal; 680 MPa permitted above 8 mm. Typical 730–800 MPa.

### S700MC tensile strength
750–950 MPa (109–138 ksi).

### S700MC elongation
≥ 10 % (A80, t < 3 mm) / ≥ 12 % (A5, t ≥ 3 mm).

### Minimum bend radius (transverse)
1.5 t (t ≤ 3 mm), 2.0 t (3–6 mm), 2.5 t (> 6 mm) per EN 10149-2; mill brands guarantee 1.0–1.5 t. Longitudinal bends: add one step. Expect 10–15° springback.

### Impact toughness
Option 40 J at −20 °C (EN); typical mill guarantee 40 J at −40 °C longitudinal.

### Physical properties
Density 7.85 g/cm³, E = 210 GPa; hardness about 240–290 HB — cutting tools and punches are sized for it.

### Weldability
Weldable with all arc processes; keep heat input low (0.5–1.5 kJ/mm) and interpass ≤ 200 °C so the HAZ does not soften below the base strength — softening of 10–15 % in the HAZ is normal and is allowed for in design. Preheat is generally unnecessary below 12 mm (CEV ≈ 0.40) but hydrogen control (dry consumables, H ≤ 5 ml/100 g) is mandatory. Consumables: matching (G 69 / E 69) for full-strength joints or under-matched (G 46) for better toughness where design allows. Never normalize; PWHT only with the mill's agreement.

### Machining, forming, heat treatment
Laser and plasma cutting are routine (edge hardness rises slightly); punching needs 20–30 % more press force than S355 and sharp tools to avoid edge cracks before bending. Press-brake with radius ≥ 1.5–2 t and generous die opening (≥ 10 t); avoid bending across shear-cut edges with burrs. No hot forming above 580 °C.

Applications: Crane, aerial-platform and concrete-pump booms; Trailer and truck chassis rails, tipper and dump bodies; Lightweight agricultural and forestry machinery; Container and rail-wagon frames; High-strength welded box sections and tube; Safety and roll-over structures; Mining and material-handling equipment

Q: What is S700MC used for?
A: Weight-critical welded structures: crane booms, trailer chassis, tipper bodies, agricultural and mining equipment — anywhere a 700 MPa yield lets the designer halve plate thickness against S355.

Q: Can S700MC be bent?
A: Yes, that is what the C in MC means, but with radii of at least 1.5–2.5 t (transverse), clean edges and springback compensation. Mill brands such as Strenx 700 MC guarantee tighter radii than the EN minimum.

Q: How is S700MC welded?
A: Low heat input, hydrogen-controlled consumables, interpass ≤ 200 °C, no normalizing afterwards. Expect a softened HAZ of 10–15 %; use matching 690-class consumables for full-strength joints.

Q: What is the difference between S700MC and S690QL?
A: Both are 690–700 MPa class. S700MC is thermomechanically rolled strip (to ~12–20 mm) for cold forming, low carbon, cheaper; S690QL (EN 10025-6) is quenched-and-tempered plate to 150 mm with guaranteed −40 °C toughness for heavy structures.

Q: Is there an ASTM equivalent of S700MC?
A: Not in A1011 (HSLAS Grade 80 stops at 550 MPa yield). SAE J1392 100XF and mill grades (HSLA 100) are the US counterparts; for plate, ASTM A514 (Q&T, 690 MPa) is the functional equivalent.

Q: Why is S700MC not hot formed?
A: Its strength comes from a fine thermomechanical microstructure and precipitates that dissolve above about 580 °C; hot forming or normalizing drops the yield towards 400 MPa permanently.

---

## SPHC — Hot-rolled mild steel sheet and strip for commercial and drawing quality
URL: https://steelstandart.com/grade/sphc/
System: JIS (Japan) | Family: Cold-rolled & coated sheet | Standard: JIS G3131 | Verified against: JIS G3131:2018
Aliases: JIS G3131 SPHC, SPHD, SPHE, hot rolled commercial quality

SPHC is the workhorse hot-rolled sheet of Japanese and wider East Asian practice, and the grade most often written on an enquiry that simply means *ordinary hot-rolled coil*. The letters decode as Steel Plate Hot Commercial: JIS G3131 covers three grades in one family — SPHC for commercial use, SPHD for drawing and SPHE for deep drawing — separated by how clean the steel is and how far it will stretch before it tears.

What matters when reading a G3131 certificate is what is *not* there. No yield strength is guaranteed, no impact energy, no carbon equivalent. The standard fixes a minimum tensile strength of 270 MPa, an elongation band and four chemical limits, and nothing else. That is entirely adequate for a bracket, a duct or a pressed panel, and entirely inadequate for a structural member — which is why substituting SPHC for SS400 or S235JR is a specification error, even though the plates look identical.

The practical range is 1.2 to 14 mm; below that the product becomes cold-rolled SPCC and above it hot-rolled plate. Pickled and oiled material carries the suffix P and is what a press shop or a laser cutter should be ordering, because mill scale interferes with both.

Chemical composition (mass %): C ≤ 0.15; Mn ≤ 0.6; P ≤ 0.05; S ≤ 0.05
SPHC, SPHD and SPHE share one chemistry table in G3131 with the limits tightening down the list: SPHD is C ≤ 0.10, Mn ≤ 0.50, and SPHE is C ≤ 0.10, Mn ≤ 0.50 with P ≤ 0.030 and S ≤ 0.035. Nothing else is specified — this is a plain low-carbon steel.

Mechanical properties:
- SPHC, ≥ 1.2 mm: yield not specified MPa; tensile ≥ 270 MPa; elongation 27–31 %; hardness ≈ 100–120 HB (typ.)
- SPHD, ≥ 1.2 mm: yield not specified MPa; tensile ≥ 270 MPa; elongation 30–36 %; hardness 
- SPHE, ≥ 1.2 mm: yield not specified MPa; tensile ≥ 270 MPa; elongation 31–39 %; hardness 
Elongation depends on thickness: the lower figure applies at 1.2–1.6 mm, the higher above 3.2 mm. No yield strength is guaranteed in any of the three grades — typical values run 210–280 MPa.
Impact: 0 J at  °C ()

Equivalents:
- A1011 CS Type B (ASTM / ASME) — near: ASTM A1011 Commercial Steel Type B: hot-rolled sheet with C ≤ 0.10–0.20 and no guaranteed yield. The US equivalent by role; the grade families are organised differently (CS, DS, SS, HSLAS).
- St 22 (DIN (superseded German)) — near: JIS G3131 SPHC is the Japanese commercial hot-rolled forming grade at the same level: C ≤ 0.15, tensile ≥ 270 MPa, no guaranteed yield.
- DD11 (EN (European)) — near: EN 10111 DD11: hot-rolled mild steel for cold forming, Rm ≤ 440 MPa, A80 ≥ 24 %, C ≤ 0.12. The direct European counterpart of SPHC; the EN grade caps tensile strength where JIS sets a minimum, so a certificate should be read in both directions.
- DD12 (EN (European)) — near: EN 10111 DD12 corresponds to SPHD: cleaner chemistry, higher elongation, for drawn parts.
- DD13 (EN (European)) — near: EN 10111 DD13 corresponds to SPHE: the deep-drawing member of the family.
- DX52D (EN (European)) — functional: Uncoated hot-rolled commercial sheet; comparable base metal but no coating and no yield band. The coated JIS counterpart is SGCD1 in G3302.
- Q195 / Q235 (GB/T (China)) — functional: GB/T 700 carbon structural steels often supplied against SPHC enquiries in East Asian trade. Q195 is close in chemistry but is a structural grade with a declared yield.

Superseded names:
- SPHC — JIS G3131:1996: the designation is unchanged in the 2018 edition
- SS400 (confused with) — JIS G3101: a structural grade with 245 MPa guaranteed yield — not a substitute for a forming grade

Product forms: hot-rolled coil (1.2–14 mm, dominant); cut sheet; slit strip; pickled and oiled (SPHC-P)
Tolerances: Thickness and width to JIS G3193; the pickled variant carries the suffix P (SPHC-P). Ordinary, cut-edge and mill-edge widths are all covered.

### SPHC tensile strength
≥ 270 MPa minimum, typically 300–380 MPa in practice. No maximum is specified, which is the main difference from EN 10111, where DD11 is capped at 440 MPa.

### Yield strength
Not specified. Typical values are 210–280 MPa. If a design needs a guaranteed yield, the grade is wrong: use SS400 (245 MPa) from JIS G3101 or S235JR from EN 10025-2.

### Elongation
SPHC 27 % at 1.2–1.6 mm rising to 31 % above 3.2 mm; SPHD 30–36 %; SPHE 31–39 %. The elongation band is the real difference between the three grades.

### Thickness range
1.2 to 14 mm as coil, sheet and strip. The pickled variant SPHC-P is normal above 2 mm for parts that will be welded, painted or laser cut.

### Surface
As-rolled with mill scale, or pickled and oiled (P). There is no surface class system comparable to the A/B classes of EN 10130 — surface expectations are agreed between buyer and mill.

### Weldability
Welds without difficulty by every common process. Carbon is capped at 0.15 % and manganese at 0.60 %, so the carbon equivalent sits around 0.25 and neither preheat nor post-weld heat treatment is needed at any thickness in the range. Mill scale should be removed from the weld zone on as-rolled material; on pickled sheet the surface is ready. Spot, MAG and laser welding are all routine, and the grade is used in exhaust, chassis and enclosure fabrication precisely because it is so tolerant.

### Machining, forming, heat treatment
Soft and gummy rather than hard: 100–120 HB, prone to built-up edge at low speeds. Use positive-rake tooling and higher cutting speeds than the hardness suggests. Punching, shearing and roll forming are all straightforward; the low carbon means cut edges stay ductile and can be bent without cracking.

Applications: Pressed and formed parts: brackets, housings, covers; Automotive chassis components, wheel rims and exhaust parts; Welded tube and pipe as feedstock; Ducting, enclosures and general fabrication; Drums, containers and light tanks; Substrate for pickling, galvanizing and further processing

Q: What is JIS G3131 SPHC?
A: The commercial grade of the Japanese hot-rolled mild steel sheet standard: tensile ≥ 270 MPa, elongation 27–31 %, C ≤ 0.15 %, with no guaranteed yield strength. SPHD and SPHE in the same standard are the drawing and deep-drawing grades.

Q: What is the equivalent of JIS G3131 in EN?
A: EN 10111: SPHC ≈ DD11, SPHD ≈ DD12, SPHE ≈ DD13. The correspondence is by role and chemistry; note that EN caps tensile strength while JIS sets a minimum.

Q: What is the ASTM equivalent of SPHC?
A: ASTM A1011 CS Type B (Commercial Steel) is the closest hot-rolled sheet grade. For drawing quality, A1011 DS Type B corresponds to SPHD.

Q: Is SPHC the same as SS400?
A: No. SPHC is a forming grade with no guaranteed yield; SS400 (JIS G3101) is a structural grade with 245 MPa minimum yield. They are not interchangeable on a structural drawing even when the chemistry looks similar.

Q: What does SPHC stand for?
A: Steel Plate Hot Commercial. SPHD is Hot Drawing and SPHE is Hot deep-drawing (Extra). The cold-rolled family in JIS G3141 uses SPCC, SPCD and SPCE in the same pattern.

Q: What thickness does SPHC come in?
A: 1.2 to 14 mm as hot-rolled coil, sheet and strip. Thinner material is cold-rolled SPCC; thicker is hot-rolled plate to another standard.

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## SS400 — Rolled steel for general structure (Japanese national standard)
URL: https://steelstandart.com/grade/ss400/
System: JIS (Japan) | Family: Structural steel | Standard: JIS G3101 | Verified against: JIS G3101:2020
Aliases: ss400, ss 400, ss400 steel, ss400 equivalent, jis ss400, jis g3101, ss41, ss400 vs s235jr, ss400 vs a36

SS400 is the default structural steel of Japanese production and one of the most frequently quoted grade names in Asian trade. The designation is read in two parts: SS is *steel structure* — rolled steel for general structure — and 400 is the minimum tensile strength in MPa. It is not a yield figure, which is the single commonest misreading of the name.

What makes SS400 unusual among structural grades is what JIS G3101 leaves out. The standard specifies phosphorus at 0.050 % and sulphur at 0.050 % and stops there: carbon, silicon and manganese are not controlled, there is no carbon equivalent limit, and no impact test is required at any temperature. Everything the standard guarantees is mechanical — 245 MPa yield to 16 mm, a 400–510 MPa tensile band, and elongation.

That is a deliberate design. SS400 exists for general fabrication where the load path is simple and the joint is not restrained, and Japanese practice moves to JIS G3106 SM400 — same strength, full chemistry, carbon equivalent and a graded Charpy test — the moment welding matters. Treating SS400 and SM400 as interchangeable is the mistake the two standards exist to prevent.

Against European practice, SS400 sits between S235JR and S275JR on strength and below both on specification. A substitution in either direction works on the numbers and should be checked on the certificate, because an SS400 plate can legitimately arrive with a carbon content that no S235JR plate would be allowed to carry.

Chemical composition (mass %): C — (not specified); Si — (not specified); Mn — (not specified); P ≤ 0.05; S ≤ 0.05
JIS G3101 controls only phosphorus and sulphur on SS400 — carbon, silicon and manganese are left to the mill. That is the defining feature of the grade and the reason it is a general structural steel rather than a weldable structural steel. Where composition matters, JIS G3106 SM400 is the grade to specify: same strength, full chemistry and a carbon equivalent limit.

Mechanical properties:
- ≤ 16 mm: yield 245 MPa; tensile 400–510 MPa; elongation 17 %; hardness ≈ 120–140 HB (typical)
- > 16 ≤ 40 mm: yield 235 MPa; tensile 400–510 MPa; elongation 21 %; hardness —
- > 40 mm: yield 215 MPa; tensile 400–510 MPa; elongation 23 %; hardness —
Yield point (not proof stress) by thickness; tensile band applies to all thicknesses. Elongation depends on the test piece as well as the thickness — JIS uses No. 1A, No. 5 and No. 4 pieces over different ranges, so a certificate can show different percentages for the same material. The 400 in the name is the tensile floor in MPa; it is not a yield figure.
Impact:  J at  °C (no requirement)

Equivalents:
- A36 (ASTM / ASME) — near: The closest single match: A36 is 250 MPa yield and 400–550 MPa tensile, and it too has no impact requirement for plate. A36 does cap carbon and manganese, which SS400 does not.
- St37-2 (DIN (superseded German)) — near: JIS G3101 SS400: yield 245 MPa, Rm 400–510 MPa; often listed as St37 equivalent in Asian catalogues.
- S235JR (EN (European)) — near: Yield 245 MPa against 235, tensile 400–510 against 360–510. SS400 is marginally stronger, but S235JR is tested to 27 J at +20 °C and specifies full chemistry with a carbon equivalent, which SS400 does not.
- Q235 (GB/T (China)) — near: Q235B is the Chinese grade of the same tier — 235 MPa yield, 370–500 MPa tensile — but it carries a chemistry specification and a 27 J impact test at +20 °C.
- St3sp (GOST (Russia/CIS)) — near: St3sp is 245 MPa yield to 20 mm and 370–480 MPa tensile with full chemistry; the strength tier matches, the specification depth does not.
- E250 (IS (India)) — near: IS 2062 E250 is 250 MPa yield and 410 MPa minimum tensile — the same commodity structural tier, with a carbon equivalent limit that SS400 lacks.
- S235J0 (EN (European)) — functional: JIS G3101 SS400 has comparable strength but no impact requirement, so it matches S235J0 on strength only.
- S275JR (EN (European)) — functional: Yield 245 MPa, below S275; SM400 is closer on impact but also 245 MPa.

Superseded names:
- SS41 — JIS G3101 (before 1995): The number was the tensile floor in kgf/mm²: 41 kgf/mm² ≈ 400 MPa. Old Japanese drawings and second-hand machine plates still carry it.
- SS34 / SS50 / SS55 — JIS G3101 (before 1995): Renamed SS330, SS490 and SS540 in the same revision.

Product forms: hot-rolled plate and sheet; sections: H beam (JIS G3192), channel, angle, flat bar; hot-rolled coil and strip; round and square bar; cold-formed and welded hollow sections certified separately to JIS G3466
Tolerances: plate and sheet: JIS G3193; sections: JIS G3192; bar: JIS G3191; hot-rolled coil: JIS G3193

### SS400 yield strength
245 MPa minimum up to 16 mm, 235 MPa from 16 to 40 mm and 215 MPa above 40 mm. JIS specifies a yield *point* rather than a 0.2 % proof stress, which is appropriate for a low-carbon steel with a defined yield plateau but is not strictly the same quantity as the European Rₑₕ.

### SS400 tensile strength
400–510 MPa across all thicknesses. The band is narrower than the European S235JR band of 360–510 MPa and sits 40 MPa higher at the floor, which is why SS400 material normally satisfies an S235JR tensile requirement without difficulty.

### SS400 chemical composition
Only P ≤ 0.050 % and S ≤ 0.050 % are specified. Typical mill analysis runs 0.15–0.20 % C, 0.30–0.60 % Mn and low silicon, but none of that is guaranteed. A buyer who needs a composition should ask for the ladle analysis before accepting the heat, not after.

### SS400 and SM400
SM400 (JIS G3106) is the weldable equivalent: identical strength, but with carbon, silicon, manganese, phosphorus and sulphur all limited, a carbon equivalent ceiling, and a Charpy test graded A (none), B (27 J at 0 °C) and C (47 J at 0 °C). Japanese structural codes call up SM grades for welded work; SS400 is for general and lightly loaded fabrication.

### SS400 against S235JR on a certificate
Three checks decide whether the substitution holds. Impact: if the design needs 27 J at +20 °C, SS400 does not guarantee it. Carbon equivalent: S235JR caps CEV at 0.35–0.40 depending on thickness; SS400 sets none. Thickness: above 40 mm the SS400 yield drops to 215 MPa, below the S235JR floor of 215 MPa at 80–100 mm — the two ladders do not step at the same points.

### The SS grade ladder
SS330 (330–430 MPa tensile, 205 MPa yield), SS400, SS490 (490–610 MPa, 285 MPa yield), SS540 and SS590. The numbers are all tensile minimums in MPa. SS540 and SS590 are not intended for welding at all — the standard says so explicitly.

### Weldability
SS400 is welded routinely by all arc processes, and in thin sections with simple joints it causes no trouble. The risk is structural rather than metallurgical: because the standard limits neither carbon nor the carbon equivalent, two heats of conforming SS400 can behave very differently in a restrained thick joint. A welding procedure qualified on one heat is not evidence for the next. Where the joint is thick, restrained or fatigue-loaded, specify SM400B or SM400C instead, or order SS400 with a maximum carbon equivalent agreed as a supplementary requirement. Consumables are the ordinary mild-steel classes — E4316 / E7016 or ER70S-6 equivalents.

### Machining, forming, heat treatment
Machinability is good and comparable with other low-carbon structural steels, but it is not consistent between heats for the same reason the weldability is not: the carbon and manganese are whatever the mill ran. Cold forming and bending are acceptable in thin sections; there is no yield ceiling, so spring-back varies. For press work and deep drawing the correct Japanese specification is JIS G3131 SPHC, SPHD or SPHE, not SS400.

Applications: General building steelwork and light structural frames in Japanese and export construction; Machine frames, bases, guards and non-critical weldments; Platforms, walkways, stairs and handrails; Plate for hoppers, chutes, tanks and covers with no pressure duty; Sections and coil exported against an S235JR or A36 requirement; Shipbuilding ancillary structure (hull steel is classification-society grade, not SS400)

Q: What is SS400 steel?
A: SS400 is the Japanese general structural steel of JIS G3101, with a 400–510 MPa tensile band and a 245 MPa minimum yield up to 16 mm. The standard controls only phosphorus and sulphur and requires no impact test, which makes it a mechanical specification rather than a metallurgical one.

Q: Is SS400 the same as S235JR?
A: They are close on strength and not equivalent on specification. SS400 is 245 MPa yield against 235 and has a higher tensile floor, but S235JR guarantees 27 J at +20 °C, full chemistry and a carbon equivalent limit, none of which SS400 provides.

Q: Is SS400 the same as A36?
A: It is the closest single match. A36 is 250 MPa yield and 400–550 MPa tensile, and like SS400 it carries no plate impact requirement. A36 does specify carbon and manganese, so it is the better-defined of the two.

Q: Does the 400 in SS400 mean yield strength?
A: No — it is the minimum tensile strength in MPa. The yield is 245 MPa up to 16 mm. The confusion is common because European grades such as S235 and S355 are named after their yield instead.

Q: What is the difference between SS400 and SM400?
A: SM400 (JIS G3106) has the same strength but adds a full chemical specification, a carbon equivalent limit and a graded Charpy test. Japanese design codes call up SM grades for welded structure and leave SS400 for general fabrication.

Q: What was SS41?
A: The same grade under the pre-1995 designation, when the number was the tensile floor in kgf/mm²: 41 kgf/mm² is about 400 MPa. SS41 and SS400 describe the same material.

Q: Can SS400 be used for pressure vessels?
A: No. It has no impact requirement, no carbon equivalent limit and no elevated-temperature properties. Japanese pressure-vessel plate is JIS G3115 SPV or JIS G3103 SB; the European counterparts are the EN 10028 P-grades.

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## St 22 (1.0332) — Withdrawn DIN designation for hot-rolled mild steel sheet for cold forming
URL: https://steelstandart.com/grade/st22/
System: DIN (superseded German) | Family: Cold-rolled & coated sheet | Standard: DIN 17100 | Verified against: DIN 1614-1 (withdrawn); EN 10111:2008 for the replacement
Aliases: StW 22, St22, DIN 1614 St 22, 1.0332

St 22 is not a steel you can order any more — it is a designation from DIN 1614, the German standard for hot-rolled sheet for cold forming, withdrawn when EN 10111 took over across Europe in the 1990s. It keeps appearing on drawings, in old tenders and in enquiries from workshops working to archived documentation, which is why it still needs an answer rather than a shrug.

The historic family ran StW 22, StW 23 and StW 24 in ascending order of formability, exactly as EN 10111 now runs DD11, DD12 and DD13. St 22 was the general grade: soft, low carbon, suitable for bending, roll forming and moderate pressing, with no guaranteed yield strength and no impact requirement. The W stood for *Weichstahl*, mild steel, and the number was a quality index rather than a property.

Order DD11 today. The chemistry envelope is the same, the role is the same, and every European mill rolls it as stock. If the part has been splitting in production, the modern ladder gives you DD12 and DD13 to move up, which is a cleaner conversation than trying to source a designation that no mill certifies.

Chemical composition (mass %): C ≤ 0.12; Mn ≤ 0.6; P ≤ 0.045; S ≤ 0.045
The historic DIN limits. A modern DD11 certificate to EN 10111 caps C at 0.12, Mn at 0.60, P at 0.045 and S at 0.045 — the same envelope, which is why the substitution is clean.

Mechanical properties:
- St 22 (historic): yield ≈ 240 MPa; tensile 340–420 MPa; elongation 26 %; hardness ≈ 100–115 HB
- DD11 (EN 10111, today): yield 170–360 MPa; tensile ≤ 440 MPa; elongation 24 %; hardness ≈ 100–120 HB
DIN 1614 specified a tensile band and a minimum elongation; EN 10111 specifies a yield range and a maximum tensile. The steels are the same, the way the standard describes them is not.
Impact: 0 J at  °C ()

Equivalents:
- DD11 (EN (European)) — identical: EN 10111 DD11 is the direct replacement: same chemistry envelope, same role as the general hot-rolled forming sheet. Any supplier asked for St 22 today will quote DD11, and the certificate will say DD11.
- A1011 CS Type B (ASTM / ASME) — near: ASTM A1011 Commercial Steel Type B covers the same ground in US practice.
- SPHC (JIS (Japan)) — near: JIS G3131 SPHC is the Japanese commercial hot-rolled forming grade at the same level: C ≤ 0.15, tensile ≥ 270 MPa, no guaranteed yield.
- S235JR (EN (European)) — functional: Often offered as a substitute and often wrong: S235JR is a structural grade with a guaranteed yield and impact test, and it is less formable. Use it only if the part is structural rather than formed.
- DD12 / DD13 (EN (European)) — functional: The next two forming levels in EN 10111, for parts that split in DD11. The historic ladder ran St 22 → St 23 → St 24 in the same way.

Superseded names:
- StW 22 — DIN 1614-1: the full historic designation — W for Weichstahl (mild steel)
- St 22 — DIN 1614: the short form seen on older drawings
- RSt 22 — DIN 1614: the rimmed-steel variant, no longer produced

Product forms: hot-rolled sheet and strip (historic); supplied today as DD11 to EN 10111
Tolerances: Historic tolerances were to DIN 1016. Material ordered today follows EN 10051 for thickness, width and flatness.

### What St 22 meant
Hot-rolled mild steel sheet for cold forming to DIN 1614-1, material number 1.0332: C ≤ 0.12 %, Mn ≤ 0.60 %, tensile roughly 340–420 MPa, elongation ≥ 26 %. No guaranteed yield, no impact test.

### What to order instead
DD11 to EN 10111 — yield 170–360 MPa, tensile ≤ 440 MPa, A80 ≥ 24 %, same chemical limits. Thickness 1.5–20 mm as hot-rolled coil, sheet or strip, pickled and oiled on request.

### If the part splits in DD11
Move up the ladder: DD12 (A80 ≥ 27 %) then DD13 (A80 ≥ 30 %, tighter C and P). The historic equivalents were StW 23 and StW 24.

### If the part is structural
The forming grades have no guaranteed yield. For a load-bearing part order S235JR to EN 10025-2, which carries a 235 MPa yield and a 27 J impact test — and accept that it forms less readily.

### Physical data
Density 7.85 kg/dm³; modulus 210 GPa; thermal conductivity ≈ 50 W/mK. Identical to any plain low-carbon steel.

### Weldability
Weldable by every common process without preheat or post-weld heat treatment; the carbon equivalent is around 0.20–0.25. Mill scale should be removed from the weld zone on as-rolled material. Modern DD11 behaves identically, so weld procedures written against St 22 remain valid — only the material designation on the WPS needs updating.

### Machining, forming, heat treatment
Soft and ductile at 100–115 HB, with the same built-up-edge tendency as any low-carbon forming steel. Sharp positive-rake tooling and high surface speeds; punching and shearing are straightforward and cut edges stay ductile enough to bend.

Applications: Legacy drawings and archived technical documentation; Replacement parts for older machinery and vehicles; General pressed and roll-formed parts (as DD11 today); Welded tube and profile feedstock; Enclosures, brackets and ducting

Q: What is St 22 steel?
A: A withdrawn DIN 1614 designation (material number 1.0332) for hot-rolled mild steel sheet for cold forming: C ≤ 0.12 %, Mn ≤ 0.60 %, tensile about 340–420 MPa, no guaranteed yield.

Q: What is the equivalent of St 22?
A: DD11 to EN 10111 is the direct replacement and what any mill will supply today. JIS G3131 SPHC and ASTM A1011 CS Type B are the Japanese and American counterparts.

Q: Is St 22 the same as S235JR?
A: No. St 22 was a forming grade with no guaranteed yield strength; S235JR is a structural grade with 235 MPa yield and an impact test. Substituting one for the other changes both the formability and the structural basis.

Q: Can I still buy St 22?
A: Not as a certified designation — DIN 1614 is withdrawn. Order DD11 and the certificate will satisfy any specification written for St 22.

Q: What does the W in StW 22 mean?
A: Weichstahl — mild steel. The historic family was StW 22, StW 23 and StW 24 in ascending order of formability, matching today's DD11, DD12 and DD13.

---

## St37-2 (1.0037) — General structural steel (DIN 17100, withdrawn) — today S235JR
URL: https://steelstandart.com/grade/st37/
System: DIN (superseded German) | Family: Structural steel | Standard: DIN 17100 | Verified against: DIN 17100:1980 (withdrawn) and EN 10025-2:2019
Aliases: St37, St 37, St 37-2, St37-2, ST37, RSt37-2, USt37-2, 1.0037, 1.0038 St37, St37 steel

St37 is the most-searched steel name that no longer exists in any current standard. DIN 17100 defined St37-2 (number 1.0037) as a general structural steel with 37 kp/mm² — about 360 MPa — minimum tensile strength and 235 MPa yield; the standard was withdrawn in 1994 when EN 10025 replaced it with S235JR (1.0038). Thirty years later the old name survives on drawings, in Turkish, Polish, Iranian and Gulf specifications, and in everyday speech across the German-speaking world.

This page exists to make the translation exact. DIN 17100 had five St37 variants that differed in deoxidation and impact testing — USt37-2 (rimmed), RSt37-2 (killed), St37-2 (either), St37-3 U (27 J at +20 °C) and St37-3 N (27 J at −20 °C) — and EN 10025 mapped them onto S235JRG1, S235JRG2, S235JR, S235J0 and S235J2. Since 2004 only S235JR, S235J0 and S235J2 remain.

The practical rule: a requirement for St37-2 is met by S235JR, for St37-3 U by S235J0 and for St37-3 N by S235J2. The tables below give the original DIN values, the current EN values, and the graded ASTM, JIS, GB and GOST cross-references.

Chemical composition (mass %): C ≤ 0.17 (DIN 17100: 0.17 % ≤ 16 mm, 0.20 % > 16 mm (St37-2); RSt37-2 identical, USt37-2 (rimmed) 0.17 %); P ≤ 0.05 (St37-2: 0.050 (0.040 ladle); RSt37-2: 0.050; St37-3: 0.040); S ≤ 0.05 (St37-3: 0.040); N ≤ 0.009 (St37-2 and RSt37-2; not limited for St37-3 (killed))
DIN 17100:1980 Table 1 (product analysis). No Mn, Si or Cu limits were given for St37-2. S235JR today: C ≤ 0.17/0.20, Mn ≤ 1.40, P/S ≤ 0.035, N ≤ 0.012, Cu ≤ 0.55.

Mechanical properties:
- < 16 mm (DIN 17100): yield 235 MPa; tensile 340–470 MPa; elongation 26 %; hardness ≈ 100–140 HB
- 16–40 mm: yield 225 MPa; tensile 340–470 MPa; elongation 25 %; hardness —
- 40–63 mm: yield 215 MPa; tensile 340–470 MPa; elongation 24 %; hardness —
- 63–80 mm: yield 215 MPa; tensile 340–470 MPa; elongation 24 %; hardness —
- 80–100 mm: yield 215 MPa; tensile 340–470 MPa; elongation 24 %; hardness —
- S235JR today, ≤ 16 mm (for comparison): yield 235 MPa; tensile 360–510 MPa; elongation 26 %; hardness —
DIN 17100:1980 Table 2 (Rm for 3–100 mm). The EN 10025-2 successor raised the tensile window to 360–510 MPa and added a guaranteed 27 J impact at +20 °C (St37-2 had none; St37-3 U/N had 27 J at +20/0 °C).
Impact: 27 J at 20 °C (St37-3 U only; St37-2 had no impact requirement)

Equivalents:
- S235JR (EN (European)) — identical: Direct successor (1.0038). S235JR guarantees 27 J at +20 °C which St37-2 did not; ordering S235JR always satisfies an St37-2 requirement.
- A36 (ASTM / ASME) — near: Yield 250 MPa, Rm 400–550 MPa — slightly stronger; the usual US substitute on St37 drawings.
- 40B (BS (superseded British)) — near: BS 4360 40B (withdrawn).
- Q235 (GB/T (China)) — near: GB/T 700 Q235B: 235 MPa yield, 370–500 MPa tensile, 27 J at +20 °C.
- St3sp / St3ps (GOST (Russia/CIS)) — near: GOST 380 St3: yield 245 MPa (≤ 20 mm), Rm 370–480 MPa; the Russian/CIS 'St37'.
- E250 (IS (India)) — near: Yield 250 MPa, Rm 410 MPa min.
- SS400 (JIS (Japan)) — near: JIS G3101 SS400: yield 245 MPa, Rm 400–510 MPa; often listed as St37 equivalent in Asian catalogues.
- DD11 (EN (European)) — functional: Hot-rolled forming sheet often bought 'as St37' in Turkey/Middle East — but it has no guaranteed minimum yield.

Superseded names:
- St37-2 → S235JR (1.0038) — EN 10025:1993 / EN 10025-2:2004: The direct replacement. Old number 1.0037 (St37-2) merged into 1.0038 (RSt37-2 / S235JRG2).
- USt37-2 → S235JRG1 (1.0036) — EN 10025:1993: Rimmed grade; deleted in EN 10025-2:2004.
- RSt37-2 → S235JRG2 → S235JR (1.0038) — EN 10025:1993 → 2004
- St37-3 U → S235J0 (1.0114) — EN 10025: Impact temperature moved from +20 °C to 0 °C.
- St37-3 N → S235J2G3 → S235J2 (1.0117) — EN 10025
- St37.0 / St37.4 (tubes) — DIN 1629 / DIN 1630 → EN 10216-1 P235TR1/TR2: Tube grades are a separate lineage.

Product forms: historically: plate, coil, sections, bar, tube (St37-2 also as St37.0 for tubes per DIN 1629); today: order as S235JR (EN 10025-2) in all forms
Tolerances: current: EN 10029 (plate), EN 10051 (coil), EN 10034 (sections) — DIN 1543/1016 are withdrawn

### St37 yield strength
235 MPa (34 ksi) below 16 mm, 225 MPa at 16–40 mm, 215 MPa at 40–100 mm — identical to S235JR today.

### St37 tensile strength
DIN 17100: 340–470 MPa (49–68 ksi) for 3–100 mm; the '37' is 37 kp/mm² ≈ 363 MPa. EN 10025-2 S235JR: 360–510 MPa.

### St37 hardness
Not specified; as-rolled material measures about 100–140 HB (≈ 110–150 HV), same as S235JR.

### St37 vs St37-2 vs St37-3
'St37' alone is incomplete. St37-2 = no impact requirement (S235JR today, which does guarantee 27 J at +20 °C). St37-3 U = impact at +20 °C → S235J0 (now tested at 0 °C). St37-3 N = normalized, impact at −20 °C → S235J2.

### Material numbers
St37-2 = 1.0037; RSt37-2 = 1.0038 (the number S235JR inherited); USt37-2 = 1.0036; St37-3 U = 1.0114; St37-3 N = 1.0116 (later S235J2G3 1.0116 → S235J2 1.0117).

### Weldability
As for S235JR: fully weldable without preheat (CEV ≤ 0.35 %). Old USt37-2 rimmed steel had higher nitrogen and was more prone to strain ageing at welds — one reason the rimmed grades were deleted.

### Machining, forming, heat treatment
As for S235JR: easily machined, punched and bent (0.5–1 t radius). Not hardenable. Galvanizes well.

Applications: Any drawing or specification that still calls up St37-2 — order S235JR; General construction, machine frames, tanks and light structures; Tube: DIN 1629 St37.0 / DIN 2448 → EN 10216-1 P235TR2 or EN 10255 S195T (gas/water pipe); Turkish and Middle-East practice: 'St37 sac' = S235JR or DD11 hot-rolled sheet — confirm which is meant

Q: What is St37 steel?
A: St37-2 is the DIN 17100 general structural steel with 235 MPa minimum yield and 340–470 MPa tensile ('37' = 37 kp/mm²). DIN 17100 was withdrawn in 1994; the current equivalent is S235JR (EN 10025-2, material number 1.0038).

Q: Is St37 the same as S235JR?
A: Yes for ordering purposes. S235JR is the direct successor with the same yield strength; it additionally guarantees 27 J impact at +20 °C and a slightly higher tensile window (360–510 MPa). Material certified as S235JR fulfils an St37-2 requirement.

Q: What is the difference between St37 and St52?
A: Strength class: St37-2 has 235 MPa yield / 340–470 MPa tensile, St52-3 has 355 MPa yield / 490–630 MPa tensile. Today they are S235JR and S355J2 respectively.

Q: What is St37 equivalent to in ASTM?
A: ASTM A36 (250 MPa yield, 400–550 MPa tensile) is the standard American substitute. It is slightly stronger and has no impact requirement.

Q: What does the 37 in St37 mean?
A: The minimum tensile strength in kilopond per square millimetre: 37 kp/mm² ≈ 363 MPa. St52 = 52 kp/mm² ≈ 510 MPa. EN designations switched to yield strength in MPa (S235, S355).

---

## St3sp — Carbon structural steel of ordinary quality (GOST / CIS)
URL: https://steelstandart.com/grade/st3sp/
System: GOST (Russia/CIS) | Family: Structural steel | Standard: GOST 380 | Verified against: GOST 380-2005; mechanical values per GOST 535-2005 and GOST 14637-89
Aliases: st3sp, st3ps, st3kp, ct3cn, st3sp steel, st3sp equivalent, gost 380, ст3сп, st3sp vs s235jr, st3 steel

St3sp — Ст3сп in Cyrillic — is the ordinary-quality carbon structural steel that carries most of the structural steelwork produced in Russia, Kazakhstan, Belarus and the wider CIS. It appears on almost every mill certificate arriving from the region, and it is the grade an S235JR enquiry is normally answered with.

The name has three parts. St is *stal* (steel), 3 is the position on the GOST 380 ladder from St0 to St6, and sp is *spokoynaya* — killed steel. The suffix matters: kp is rimmed, ps semi-killed and sp fully killed, and only the silicon content changes between them. Structural work outside a heated building is ordered sp, because rimmed steel has neither the silicon nor the consistency for a welded structure.

The second thing to know is that GOST 380 contains no mechanical properties at all. It defines grades and chemistry. Yield, tensile, elongation and impact come from the product standard — GOST 535 for sections and bar, GOST 14637 for heavy plate — which is why a complete certificate names two standards and an incomplete one names only the first.

The third is the category number. St3sp and St3sp5 are not the same order: the digit sets what was tested. Category 1 requires no impact test, category 3 is tested at +20 °C, category 4 at −20 °C and category 5 at −20 °C after mechanical ageing. Reading an S235J2 requirement across to "St3sp" without a category is reading half of it.

Chemical composition (mass %): C 0.14 – 0.22; Si 0.15 – 0.3 (the sp (killed) practice; ps semi-killed is 0.05–0.15 %, kp rimmed ≤ 0.05 %); Mn 0.4 – 0.65; P ≤ 0.04; S ≤ 0.05; Cr ≤ 0.3 (residual); Ni ≤ 0.3 (residual); Cu ≤ 0.3 (residual)
GOST 380-2005 ladle analysis for St3sp. The suffix is the deoxidation practice and it changes only the silicon: **sp** (спокойная, killed) 0.15–0.30 %, **ps** (полуспокойная, semi-killed) 0.05–0.15 %, **kp** (кипящая, rimmed) ≤ 0.05 %. Carbon, manganese, phosphorus and sulphur are the same across all three. Like Q235 and unlike S235JR, St3sp carries a carbon *minimum*.

Mechanical properties:
- ≤ 20 mm: yield 245 MPa; tensile 370–480 MPa; elongation 26 %; hardness ≈ 115–150 HB (typical)
- > 20 ≤ 40 mm: yield 235 MPa; tensile 370–480 MPa; elongation 25 %; hardness —
- > 40 ≤ 100 mm: yield 225 MPa; tensile 370–480 MPa; elongation 23 %; hardness —
- > 100 mm: yield 215 MPa; tensile 370–480 MPa; elongation 23 %; hardness —
Mechanical values are not in GOST 380 at all — they come from the product standard that calls the grade up: GOST 535 for sections and bar, GOST 14637 for heavy plate, GOST 16523 for thin sheet. That is why a genuine St3sp certificate always names two standards, and why a certificate quoting GOST 380 alone is incomplete.
Impact: 27 J at 20 °C (category 3 and above; KCU converted from J/cm²)

Equivalents:
- A36 (ASTM / ASME) — near: A36 is 250 MPa yield and 400–550 MPa tensile — slightly stronger at both ends, with no impact requirement for plate.
- St37-2 (DIN (superseded German)) — near: DIN 17100 St37-2 is the withdrawn German grade of the same tier; both map onto S235JR and both are still written on drawings.
- S235JR (EN (European)) — near: The standard counterpart: 245 MPa yield against 235 to the first thickness step, 370–480 MPa tensile against 360–510. St3sp specifies a carbon minimum and states impact as KCU in J/cm², which S235JR does not.
- S235J0 (EN (European)) — near: St3sp category 4 or 5 is the closer match where low-temperature testing is required — tested at −20 °C, against 0 °C for S235J0.
- Q235 (GB/T (China)) — near: Q235B: 235 MPa yield, 370–500 MPa tensile, carbon minimum present in both. The two grades occupy the same position in their national systems.
- E250 (IS (India)) — near: St3sp is 245 MPa yield and 370–480 MPa tensile — the same tier, with mechanical values that come from a separate product standard rather than from the grade standard itself.
- SS400 (JIS (Japan)) — near: Same strength tier, but SS400 controls only phosphorus and sulphur while St3sp carries a full composition.

Superseded names:
- St3 — GOST 380 (all editions): The bare grade name without a deoxidation suffix is incomplete; drawings that say only St3 leave the silicon and therefore the weldability open.
- VSt3sp — GOST 380-71 / -88: The В (V) prefix marked steel supplied to both chemical and mechanical requirements — group В. The 2005 edition dropped the prefix and made that the default.
- St3sp5 — GOST 535 (current usage): The trailing digit is the category, which sets the test scope. St3sp5 is the common structural order: killed, tested for impact at −20 °C and after ageing.

Product forms: hot-rolled sections: I beam (GOST 8239 / 26020), channel, angle; heavy plate to GOST 14637; thin sheet and coil to GOST 16523; round, square and flat bar to GOST 2590 / 2591 / 103; welded pipe to GOST 10704 (chemistry called up from GOST 380)
Tolerances: heavy plate: GOST 19903; thin sheet: GOST 19904 (cold) / GOST 19903 (hot); I beam: GOST 8239, wide-flange GOST 26020; round bar: GOST 2590

### St3sp yield strength
245 MPa minimum up to 20 mm, stepping to 235 MPa at 20–40 mm, 225 MPa at 40–100 mm and 215 MPa above. Note that the first step is at 20 mm and not at 16 mm as in EN 10025-2 — the two ladders do not line up, and in the 16–20 mm band St3sp is nominally the stronger of the two.

### St3sp tensile strength
370–480 MPa. The band is tighter than the European 360–510 MPa and sits inside it, so St3sp material satisfies an S235JR tensile requirement on both limits.

### St3sp chemical composition
C 0.14–0.22 %, Si 0.15–0.30 %, Mn 0.40–0.65 %, P ≤ 0.040 %, S ≤ 0.050 %, with Cr, Ni and Cu each limited to 0.30 % as residuals. The carbon *minimum* of 0.14 % is the practical difference from S235JR, which only caps carbon at 0.17–0.24 % by product and thickness.

### kp, ps and sp — what the suffix changes
Only the silicon, and therefore the deoxidation. kp (rimmed, Si ≤ 0.05 %) has a clean surface skin and a segregated core; it is sheet and light-gauge material, not structural. ps (semi-killed, 0.05–0.15 %) is a compromise used for sections. sp (killed, 0.15–0.30 %) is the structural and weldable choice, and the only one that should be accepted against a European structural grade.

### The category digit
Written after the grade — St3sp5 — it sets the test scope, not the strength. 1: chemistry and tensile only. 2: plus elongation. 3: plus impact at +20 °C. 4: impact at −20 °C. 5: impact at −20 °C and after mechanical ageing. 6: impact at −40 °C. Category 5 is the usual structural order in the CIS and the one to ask for against S235J2.

### KCU and KV are different tests
GOST reports impact energy as KCU in J/cm² on a U-notched specimen; EN reports KV in joules on a V-notched one. There is no exact conversion — the U-notch is blunter and absorbs more energy — so a GOST impact figure cannot be placed directly beside an EN one. Where a design needs 27 J KV, ask the mill for a V-notch test to EN 10045 / ISO 148 as a supplementary requirement.

### Weldability
St3sp is fully weldable by all arc processes in normal structural thicknesses and needs no preheat below about 25 mm at ordinary ambient temperatures. Two cautions carry over from the specification. The carbon minimum of 0.14 % means material can legitimately sit harder than a typical European S235JR heat, so a procedure qualified on European plate should be re-checked on the declared analysis. And the suffix must be sp: rimmed St3kp has a segregated, low-silicon core and is not a structural welding material whatever the yield figure says. Consumables are the ordinary mild-steel classes; CIS practice uses UONI-13/45 and equivalents, which correspond to E7015/E7016.

### Machining, forming, heat treatment
Machinability is good and predictable for a low-carbon steel — better than S235JR on average, because the carbon minimum keeps the material out of the very soft range where low-carbon steel smears. Cold bending and roll forming are acceptable in the killed variants; GOST sets no yield ceiling, so spring-back varies between heats. For pressing and deep drawing the correct GOST specification is the 08kp / 08ps / 08Yu forming grades of GOST 16523, not St3.

Applications: Building and industrial steelwork across Russia, Kazakhstan, Belarus and Central Asia; Welded frames, platforms, stairs, ladders and gantries; Heavy plate for hoppers, chutes, silos and tank shells with no pressure duty; Hot-rolled sections rolled to GOST 8239 and GOST 26020 profiles; Welded pipe for structural and low-pressure service (GOST 10704); Material offered against an S235JR or A36 requirement on export orders

Q: What is St3sp steel?
A: St3sp is the killed carbon structural steel of GOST 380, the standard grade of Russian and CIS structural production. Yield is 245 MPa up to 20 mm and tensile 370–480 MPa; the mechanical values come from GOST 535 or GOST 14637, not from GOST 380 itself.

Q: Is St3sp equivalent to S235JR?
A: It is the accepted counterpart and the substitution is made daily, but the two are not identical. St3sp is 245 MPa yield against 235, carries a carbon minimum that S235JR does not, and states impact as KCU in J/cm² on a U-notch rather than KV in joules on a V-notch.

Q: What does the sp in St3sp mean?
A: It is the deoxidation practice: sp is spokoynaya, killed steel, with 0.15–0.30 % silicon. The alternatives are ps (semi-killed, 0.05–0.15 %) and kp (rimmed, ≤ 0.05 %). Only sp should be accepted for welded structural work.

Q: What does the number after St3sp mean, as in St3sp5?
A: It is the category, and it sets what was tested rather than how strong the steel is. Category 3 is impact-tested at +20 °C, category 4 at −20 °C, category 5 at −20 °C and after mechanical ageing, category 6 at −40 °C. Category 5 is the usual structural order.

Q: Can I compare a GOST impact value with a European one?
A: Not directly. GOST uses KCU in J/cm² on a U-notched specimen; EN uses KV in joules on a V-notched one, which is the more severe test. Where a design calls for 27 J KV, ask for a V-notch test to ISO 148 as a supplementary requirement on the order.

Q: What is the difference between St3sp and 09G2S?
A: Strength class. St3sp is the 245 MPa ordinary-quality carbon grade of GOST 380; 09G2S is the 345 MPa low-alloy grade of GOST 19281, with manganese near 1.5 % and genuine low-temperature toughness. The step is the CIS equivalent of S235 to S355.

Q: Is St3 the same as St3sp?
A: Not as a complete specification. St3 names the strength tier but leaves the deoxidation open, and with it the silicon content and the weldability. An order or a drawing should always carry the suffix, and a structural one should carry sp.

---

## St52-3 (1.0570) — General structural steel (DIN 17100, withdrawn) — today S355J2 / S355JR
URL: https://steelstandart.com/grade/st52/
System: DIN (superseded German) | Family: Structural steel | Standard: DIN 17100 | Verified against: DIN 17100:1980 (withdrawn) and EN 10025-2:2019
Aliases: St52, St 52, St 52-3, St52-3 N, St52-3 U, ST52, 1.0570, St52 steel, St52.3

St52-3 was DIN 17100's higher-strength structural steel: 52 kp/mm² (≈ 510 MPa) minimum tensile and 355 MPa yield, material number 1.0570. It came in two impact classes — St52-3 U tested at +20 °C and St52-3 N (normalized) at −20 °C — and, together with St37-2, it made up almost the whole German structural market for forty years. DIN 17100 was withdrawn in 1994, but 'St52' remains the everyday name for S355 in Germany, Austria, Turkey, Poland and much of the Middle East, and 'ST52' appears in countless hydraulic-cylinder and crane specifications.

The EN 10025 mapping is straightforward: St52-3 N → S355J2 (1.0577), St52-3 U → S355JR (1.0045). The yield table is unchanged; EN lowered the minimum tensile to 470 MPa, tightened P and S to 0.025 % for J2, and dropped the DIN N-limit. Cold-drawn hydraulic tube sold as 'ST52' is the tube lineage (DIN 2391 St52 → EN 10305-1 E355), not the plate grade — a frequent source of confusion.

Internationally, ASTM A572 Grade 50, JIS SM490, GB Q355B and GOST 09G2S are the 'near' matches; none carries exactly the St52-3 N combination of 355 MPa and −20 °C impact.

Chemical composition (mass %): C ≤ 0.2 (DIN 17100 St52-3: 0.20 % (product analysis 0.22)); Si ≤ 0.55; Mn ≤ 1.6; P ≤ 0.04; S ≤ 0.04; N ≤ 0.009 (St52-3 U only; St52-3 N (killed) not limited)
DIN 17100:1980 Table 1. S355J2 today: C ≤ 0.22 (≤ 30 mm) / 0.22, Si ≤ 0.55, Mn ≤ 1.60, P/S ≤ 0.025, Cu ≤ 0.55 — cleaner on P and S, otherwise the same window.

Mechanical properties:
- < 16 mm (DIN 17100): yield 355 MPa; tensile 490–630 MPa; elongation 22 %; hardness ≈ 150–190 HB
- 16–40 mm: yield 345 MPa; tensile 490–630 MPa; elongation 21 %; hardness —
- 40–63 mm: yield 335 MPa; tensile 490–630 MPa; elongation 20 %; hardness —
- 63–80 mm: yield 325 MPa; tensile 490–630 MPa; elongation 19 %; hardness —
- 80–100 mm: yield 315 MPa; tensile 490–630 MPa; elongation 18 %; hardness —
- S355J2 today, ≤ 16 mm (for comparison): yield 355 MPa; tensile 470–630 MPa; elongation 22 %; hardness —
DIN 17100:1980 Table 2. EN 10025-2 lowered the minimum tensile from 490 to 470 MPa and kept the yield table; elongation minimums are 1–2 points higher in EN.
Impact: 27 J at -20 °C (St52-3 N (normalized); St52-3 U: 27 J at +20 °C)

Equivalents:
- S355J2 (EN (European)) — identical: Successor of St52-3 N (1.0577); same yield table, tensile 470–630 MPa, 27 J at −20 °C, cleaner P/S.
- A572 Grade 50 (ASTM / ASME) — near: Yield 345 MPa, Rm 450 MPa min; HSLA — the usual US replacement on St52 drawings.
- 50B / 50D (BS (superseded British)) — near: BS 4360 50B (+20 °C) and 50D (−20 °C).
- S355JR (EN (European)) — near: Successor of St52-3 U (impact at +20 °C).
- Q355B / Q345B (GB/T (China)) — near: GB/T 1591 Q355B (355 MPa, 470–630 MPa) — formerly Q345B; commonly quoted as the Chinese St52.
- 09G2S / 17GS (GOST (Russia/CIS)) — near: GOST 19281 09G2S (yield 325–345 MPa) and 17GS (yield 345 MPa) are the CIS 'St52' equivalents.
- IS 2062 E350 (IS (India)) — near: Yield 350 MPa, Rm 490 MPa min.
- SM490B / SM490YB (JIS (Japan)) — near: JIS G3106 SM490B: yield 325 MPa, Rm 490–610 MPa, 27 J at 0 °C; SM490YB yield 365 MPa.

Superseded names:
- St52-3 N → S355J2G3 → S355J2 (1.0577) — EN 10025:1993 → EN 10025-2:2004: The direct replacement for normalized plate; number changed from 1.0570 to 1.0577.
- St52-3 U → S355JR (1.0045) / S355J0 (1.0553) — EN 10025: Impact at +20 °C → S355JR; EN also introduced S355J0 at 0 °C.
- St52-3 → S355J2G3 (1.0570) — EN 10025:1993: In the 1993 edition S355J2G3 kept number 1.0570; the 2004 edition merged it into S355J2 (1.0577).
- St52.0 / St52.4 (tubes) — DIN 1629/1630 → EN 10216-1 P355N-type / EN 10210 S355J2H
- Fe510C / Fe510D — EN 10025:1990

Product forms: historically: plate, coil, sections, bar; tubes as St52.0 (DIN 1629) / St52-3 hollow sections (DIN 17120); today: order as S355J2 (plate, −20 °C) or S355JR/J0 (sections, coil)
Tolerances: current: EN 10029 (plate), EN 10051 (coil), EN 10034 (sections)

### St52 yield strength
355 MPa (51.5 ksi) below 16 mm, 345 MPa 16–40 mm, 335 MPa 40–63 mm, 325 MPa 63–80 mm, 315 MPa 80–100 mm — the same table S355 uses today.

### St52 tensile strength
DIN 17100: 490–630 MPa (71–91 ksi); '52' = 52 kp/mm² ≈ 510 MPa. EN 10025-2 S355: 470–630 MPa.

### St52 hardness
Not specified; as-rolled/normalized ≈ 150–190 HB. Cold-drawn ST52 (E355) tube is harder: 190–230 HB.

### St52-3 U vs St52-3 N
U = impact tested at +20 °C, may be supplied as-rolled → S355JR. N = normalized, 27 J at −20 °C → S355J2 (+N). When a drawing says only 'St52-3', N was usually intended for plate.

### 'ST52' hydraulic tube
Cold-drawn seamless tube marked ST52 follows DIN 2391 → EN 10305-1 E355 (1.0580): C ≤ 0.22, yield ≥ 355 MPa (+N) and up to 450–520 MPa in +C/+SR conditions — different standard, different numbers (1.0580), similar chemistry.

### Weldability
As for S355J2/JR: weldable with E46/G46 consumables; CEV up to 0.45–0.47 %, so calculate preheat (EN 1011-2) for t > 25 mm; low-hydrogen processes standard.

### Machining, forming, heat treatment
As S355: machinability ≈ 60 %, carbide tooling above 20 mm; bend radius 1.5–3 t; normalize after hot forming.

Applications: Any legacy drawing calling St52-3 — order S355J2 (plate, −20 °C) or S355JR/J0 (sections); Cranes, lifting equipment, machinery frames; Bridges and heavy structures (S355J2+N / S355K2); Hydraulic cylinders: 'ST52' honed tube → EN 10305-1 E355+SR; Trailer chassis and heavy transport

Q: What is St52 steel?
A: St52-3 is the DIN 17100 structural steel with 355 MPa yield and 490–630 MPa tensile ('52' = 52 kp/mm²). The standard was withdrawn in 1994; today's equivalents are S355J2 (for St52-3 N) and S355JR (for St52-3 U).

Q: Is St52 the same as S355?
A: Yes in strength; S355J2 is the direct successor of St52-3 N. EN tightened P and S to 0.025 % and lowered the minimum tensile to 470 MPa. Material certified S355J2 fulfils an St52-3 requirement.

Q: What is St52 in ASTM?
A: ASTM A572 Grade 50 (345 MPa / 50 ksi yield) is the standard US substitute; A709-50 for bridges. Add Charpy supplement S5 to match St52-3 N toughness.

Q: Is ST52 tube the same as St52-3 plate?
A: No. Cold-drawn precision tube sold as ST52 follows DIN 2391 / EN 10305-1 as E355 (1.0580) — similar chemistry, different standard and delivery conditions (+C, +SR, +N). Hollow structural sections are S355J2H (EN 10210/10219).

Q: What is the difference between St52 and St37?
A: Yield 355 vs 235 MPa and tensile 490–630 vs 340–470 MPa. St52-3 always had an impact requirement; St37-2 did not.

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## 1.4301 vs 1.4404
URL: https://steelstandart.com/compare/1-4301-vs-1-4404/

In German-speaking and Northern European practice the 304/316 question is asked with material numbers — 1.4301 or 1.4404? — or with the old Krupp names V2A or V4A. The metallurgy is the same as for the ASTM grades: 1.4404 (X2CrNiMo17-12-2) carries 2–2.5 % molybdenum and about 3 % more nickel than 1.4301 (X5CrNi18-10), which lifts the pitting resistance equivalent from about 18 to 24 and lets the steel survive chlorides — coastal air, road salt, pool water, brines — that stain and pit 1.4301. Mechanically, magnetically and in fabrication the two are twins.

The EN twist is that 1.4404 is already the low-carbon (≤ 0.03 %) grade, so it also solves weld sensitization in thick sections, whereas 1.4301 (C ≤ 0.07 %) has its own low-carbon sister 1.4307. The table compares the EN 10088-2 flat-product values and gives the cost and decision rules.

- EN name: 1.4301 = X5CrNi18-10 | 1.4404 = X2CrNiMo17-12-2
- Trade name: 1.4301 = V2A (18/8, 18/10) | 1.4404 = V4A
- ASTM / UNS twin: 1.4301 = 304 / S30400 | 1.4404 = 316L / S31603
- Chromium: 1.4301 = 17.5–19.5 % | 1.4404 = 16.5–18.5 %
- Nickel: 1.4301 = 8.0–10.5 % | 1.4404 = 10.0–13.0 %
- Molybdenum: 1.4301 = — | 1.4404 = 2.0–2.5 %
- Carbon max: 1.4301 = 0.07 % | 1.4404 = 0.030 %
- PREN: 1.4301 = ≈ 18–19 | 1.4404 = ≈ 23.5–25
- CPT (6 % FeCl₃): 1.4301 = ≈ 5–10 °C | 1.4404 = ≈ 15–20 °C
- Rp0.2 min, hot-rolled plate (+AT): 1.4301 = 210 MPa | 1.4404 = 220 MPa
- Rp0.2 min, cold-rolled sheet (+AT): 1.4301 = 230 MPa | 1.4404 = 240 MPa
- Rm, plate: 1.4301 = 520–720 MPa | 1.4404 = 520–670 MPa
- Elongation A: 1.4301 = ≥ 45 % | 1.4404 = ≥ 40 %
- Hardness max (annealed): 1.4301 = 215 HB | 1.4404 = 215 HB
- Magnetic (annealed): 1.4301 = no | 1.4404 = no
- Weld sensitization risk: 1.4301 = moderate (> 6 mm: use 1.4307) | 1.4404 = none in practical thickness
- Filler metal: 1.4301 = 19 9 L (308L) | 1.4404 = 19 12 3 L (316L)
- Machinability: 1.4301 = ≈ 45 % | 1.4404 = ≈ 40 %
- Polish / decorative finish: 1.4301 = excellent | 1.4404 = excellent
- Corrosion class (EN 1993-1-4 CRC): 1.4301 = CRC II | 1.4404 = CRC III
- Fastener class (ISO 3506): 1.4301 = A2 | 1.4404 = A4
- Relative price (2026, sheet): 1.4301 = 1.00 | 1.4404 = ≈ 1.25–1.40

Verdict: 1.4404 (V4A) for coastal and urban-industrial facades, swimming pools and spas, de-icing-salt exposure, chemical and pharmaceutical process equipment, brine and seawater splash, medical devices, and any outdoor part that is crevice-prone or rarely washed. EN 1993-1-4 puts it in corrosion resistance class III.

1.4301 (V2A) for kitchens, catering, food and beverage plant, inland architecture and interiors, water tanks, automotive trim, appliance panels and fasteners indoors — corrosion resistance class II is ample and the 25–40 % saving is real.

If 1.4301 parts in the target environment show tea staining within a year, the answer is 1.4404. For warm chloride water (indoor pools, hot brine) neither is adequate — go to 1.4462 duplex or 1.4539.

Q: What is the difference between 1.4301 and 1.4404?
A: 1.4404 contains 2–2.5 % molybdenum (and more nickel) and is limited to 0.03 % carbon; 1.4301 has no molybdenum and up to 0.07 % carbon. Molybdenum raises chloride pitting resistance from PREN ≈ 18 to ≈ 24. Strength, formability, weldability and magnetism are essentially identical.

Q: What do V2A and V4A mean?
A: Krupp trade names from 1912: V2A = the 18/8 Cr-Ni austenitic (today 1.4301/1.4307), V4A = the Mo-bearing Cr-Ni-Mo austenitic (today 1.4401/1.4404/1.4571). They are colloquial, not standard designations.

Q: Is 1.4404 stronger than 1.4301?
A: Marginally on paper (Rp0.2 220 vs 210 MPa for plate), but not in any way that changes a design. Choose between them on corrosion resistance.

Q: Is 1.4404 the same as 1.4401?
A: 1.4401 is the 316 with up to 0.07 % C; 1.4404 is the 316L with ≤ 0.03 % C. Same corrosion class; 1.4404 is preferred for welded equipment and is usually what stockists hold (dual-certified 1.4401/1.4404).

Q: Which should I use for a balcony railing?
A: Inland: 1.4301 with a smooth (≤ Ra 0.5 µm) brushed or polished finish. Within a few kilometres of the sea, or where road salt reaches: 1.4404 (or 1.4571). Grind-marks and rough finishes pit first whatever the grade.

Q: Are 1.4301 and 1.4404 magnetic?
A: No in the annealed state; both may show slight magnetism after heavy cold work, 1.4404 less so because of its higher nickel.

---

## SAE 1010 vs SAE 1018
URL: https://steelstandart.com/compare/1010-vs-1018/

Two low-carbon steels separated by eight hundredths of a percent of carbon, and the market treats them as different products. 1010 is a forming steel: sheet, strip, wire and welded tube, chosen because it bends, draws and welds without argument. 1018 is the bar stock of the machine shop: the default for turned parts, shafts, pins and anything that will be carburised.

The carbon does the work in both directions. More carbon in 1018 means higher strength, chips that break instead of tearing, and enough carbon to take a case. Less carbon in 1010 means better elongation, a cleaner weld and less springback.

One caution before substituting: the product form matters as much as the grade. Cold-drawn 1018 and hot-rolled 1018 differ more from each other than 1018 differs from 1010 in the same condition.

- Standard: SAE 1010 = SAE J403 / ASTM A29 | SAE 1018 = SAE J403 / ASTM A29
- Carbon: SAE 1010 = 0.08–0.13 % | SAE 1018 = 0.15–0.20 %
- Manganese: SAE 1010 = 0.30–0.60 % | SAE 1018 = 0.60–0.90 %
- Max P / S: SAE 1010 = 0.040 / 0.050 % | SAE 1018 = 0.040 / 0.050 %
- Yield, hot rolled: SAE 1010 = ≈ 180 MPa | SAE 1018 = ≈ 220 MPa
- Tensile, hot rolled: SAE 1010 = ≈ 325 MPa | SAE 1018 = ≈ 400 MPa
- Yield, cold drawn: SAE 1010 = ≈ 305 MPa | SAE 1018 = ≈ 370 MPa
- Tensile, cold drawn: SAE 1010 = ≈ 365 MPa | SAE 1018 = ≈ 440 MPa
- Elongation, cold drawn: SAE 1010 = ≈ 20 % | SAE 1018 = ≈ 15 %
- Hardness, cold drawn: SAE 1010 = ≈ 105 HB | SAE 1018 = ≈ 126 HB
- Machinability (B1112 = 100): SAE 1010 = ≈ 55 % | SAE 1018 = ≈ 78 %
- Weldability: SAE 1010 = Excellent, no preheat | SAE 1018 = Very good, no preheat below 20 mm
- Case hardening: SAE 1010 = Possible, soft core | SAE 1018 = The standard carburising grade of its class
- Cold forming: SAE 1010 = Very good — deep draws, tight bends | SAE 1018 = Moderate — springs back and cracks sooner
- Usual product form: SAE 1010 = Sheet, strip, wire, welded tube | SAE 1018 = Round, square and flat bar; cold-drawn and turned
- EN equivalent: SAE 1010 = C10 / 1.0301 | SAE 1018 = C15 / 1.0401 (near; C15E for a closer match)
- JIS equivalent: SAE 1010 = S10C | SAE 1018 = S20C (S15C for the low end)
- Heat treatment response: SAE 1010 = Little — too little carbon to harden through | SAE 1018 = Case hardens well; will not through-harden
- Where it fails: SAE 1010 = Anything needing strength or a clean machined finish | SAE 1018 = Anything needing a deep draw or a tight bend
- Typical price: SAE 1010 = Base commodity | SAE 1018 = Small premium as cold-drawn bar; similar as coil

Verdict: 1018 for anything held in a chuck, 1010 for anything held in a die. The machine shop answer is 1018 almost every time: it turns cleanly, holds a tolerance after cold drawing, and takes a carburised case for a wear surface. The press and tube shop answer is 1010, because carbon is exactly what makes a part crack at the radius and spring away from the form.

Neither is a structural specification in the European sense — for a load calculation the grade to name is S235JR or S355JR, not a SAE carbon number.

Q: What is the difference between 1010 and 1018 steel?
A: Carbon and manganese: 1010 carries 0.08–0.13 % C with 0.30–0.60 % Mn, 1018 carries 0.15–0.20 % C with 0.60–0.90 % Mn. That gives 1018 roughly 20 % more strength and much better machinability, while 1010 forms and welds more easily.

Q: Is 1018 stronger than 1010?
A: Yes, by roughly 20 %. In the cold-drawn condition 1018 runs about 370 MPa yield and 440 MPa tensile against about 305 and 365 MPa for 1010. Both figures shift downward in the hot-rolled condition, so the product form has to be compared like for like.

Q: Which machines better, 1010 or 1018?
A: 1018, clearly — about 78 % on the B1112 scale against roughly 55 % for 1010. The extra carbon and manganese give chips that break instead of tearing, which is why 1018 is the default bar stock in a machine shop and 1010 is not.

Q: Can 1010 be case hardened?
A: It can be carburised, but the core stays soft because there is not enough carbon to support it. Where a hard case over a load-bearing core is needed, 1018 is the grade of this pair to use, and 8620 or 16MnCr5 above it if the core has to carry more.

Q: What is the European equivalent of 1018?
A: C15 (1.0401) is the usual match, with C15E (1.1141) closer on the controlled-sulphur side. It is an equivalence rather than an identity: the SAE and EN systems specify different sulphur ranges and different delivery conditions, so the certificate should be read rather than assumed.

Q: Which welds better?
A: 1010, marginally. Both are well below the carbon level that needs preheat, so in practice either welds with standard procedures; 1010's lower carbon simply gives a slightly softer heat-affected zone, which matters on thin sheet welded to thin sheet.

---

## 1018 vs 4140
URL: https://steelstandart.com/compare/1018-vs-4140/

1018 and 4140 are the two bar steels every North American shop keeps in the rack, and they sit at opposite ends of the decision: 1018 is the cheap, weldable, low-carbon steel for parts that carry little stress; 4140 is the chromoly alloy that can be heat-treated to three or four times the strength. The chemistry tells the story — 1018 has 0.18 % carbon and no alloying, 4140 has 0.40 % carbon plus 1 % Cr and 0.2 % Mo — and everything downstream follows: hardenability, strength, machinability, weldability and price.

Many designers reach for 4140 by reflex; many others use 1018 where it will later fail. The table gives the numbers in the conditions actually sold (cold-drawn 1018; annealed, pre-hard and Q&T 4140), and the verdict says which to buy for which job.

- Type: 1018 = plain low-carbon steel | 4140 = Cr-Mo low-alloy steel (chromoly)
- UNS: 1018 = G10180 | 4140 = G41400
- Carbon: 1018 = 0.15–0.20 % | 4140 = 0.38–0.43 %
- Alloying: 1018 = Mn 0.60–0.90 % | 4140 = Mn 0.75–1.00, Cr 0.80–1.10, Mo 0.15–0.25 %
- Usual supply condition: 1018 = cold-drawn (CRS) bar | 4140 = annealed, or pre-hardened 28–32 HRC (HT/PH)
- Yield, as supplied: 1018 = ≈ 370 MPa (54 ksi) cold-drawn; ≈ 220 MPa hot-rolled | 4140 = ≈ 415 MPa (60 ksi) annealed; ≈ 690–760 MPa pre-hard
- Tensile, as supplied: 1018 = ≈ 440 MPa (64 ksi) | 4140 = ≈ 655 MPa annealed; ≈ 930–1000 MPa pre-hard
- Max. heat-treated tensile: 1018 = ≈ 500 MPa (cannot through-harden) | 4140 = ≈ 1770 MPa (257 ksi) tempered 205 °C
- Hardness, as supplied: 1018 = ≈ 126 HB | 4140 = ≈ 197 HB annealed; 28–32 HRC pre-hard
- Max. hardness: 1018 = carburized case 58–62 HRC only | 4140 = 54–59 HRC as-quenched; 50 HRC in service
- Through-hardening: 1018 = no | 4140 = yes, to ≈ 50–75 mm in oil
- Elongation: 1018 = ≈ 15 % cold-drawn, 25 % hot-rolled | 4140 = ≈ 25 % annealed; 10–16 % Q&T
- Impact toughness: 1018 = high (soft) | 4140 = good at ≤ 40 HRC; falls at high hardness
- Machinability (vs B1112): 1018 = ≈ 70–78 % | 4140 = ≈ 65 % annealed; ≈ 55–60 % pre-hard
- Weldability: 1018 = excellent, no preheat | 4140 = poor: 250–350 °C preheat + post-weld temper
- Carbon equivalent: 1018 = ≈ 0.30 | 4140 = ≈ 0.80
- Fatigue strength (rotating bend, typical): 1018 = ≈ 200 MPa | 4140 = ≈ 450–550 MPa (Q&T)
- Surface hardening: 1018 = carburize/carbonitride | 4140 = induction/flame (50–55 HRC), nitride (55–60 HRC)
- Relative price per kg (bar, 2026): 1018 = 1.00 | 4140 = ≈ 1.6–2.0 (pre-hard ≈ 2.0–2.5)
- EN equivalent: 1018 = C15 / C22 (near) | 4140 = 42CrMo4 (identical)
- Typical use: 1018 = spacers, pins, brackets, fixtures, low-stress shafts | 4140 = shafts, gears, bolts, tooling, hydraulic rods, high-stress parts

Verdict: Use 4140 when the part carries real stress, will be heat-treated, or must resist wear and fatigue: shafts, gears, bolts above Grade 5, hydraulic rods, tooling, anything that would bend or wear in 1018. Buy it pre-hardened (28–32 HRC) to skip heat treatment.

Use 1018 when the part is a spacer, pin, bracket, fixture, guide or low-stress shaft, or when it must be welded: it is half the price, machines to a bright finish, welds with no preheat, and can be carburized for a hard skin if a wear surface is needed.

The common mistake is welding 4140 like 1018 — it cracks — and the opposite one is using 1018 for a shaft that then yields or fatigues. If in doubt and the part is not welded, 4140 pre-hard is the safe choice; if it is welded, 1018 or a weldable 4130.

Q: Which is stronger, 1018 or 4140?
A: 4140 — even annealed it exceeds cold-drawn 1018 (≈ 415 vs 370 MPa yield), pre-hard 4140 is about twice as strong, and Q&T 4140 reaches 900–1600 MPa yield. 1018 cannot be strengthened by heat treatment.

Q: Can 1018 be hardened like 4140?
A: No. 1018's 0.18 % carbon is too low to form hard martensite through the section. It can only be case-hardened (carburized) for a thin 58–62 HRC skin over a soft core.

Q: Is 4140 harder to machine than 1018?
A: Somewhat: annealed 4140 rates about 65 % versus 70–78 % for cold-drawn 1018, and pre-hard 4140 (28–32 HRC) about 55–60 %. In practice 4140 pre-hard gives better chip control and surface finish than 'gummy' 1018 with carbide tooling.

Q: Can I weld 4140 like 1018?
A: No. 1018 welds with no preheat by any process. 4140 (CE ≈ 0.8) needs 250–350 °C preheat, low-hydrogen filler and post-weld tempering, and pre-hard/Q&T 4140 loses its properties in the heat-affected zone. Use 4130 for welded chromoly structures.

Q: How much more does 4140 cost than 1018?
A: Roughly 1.6–2× per kilogram for annealed bar and 2–2.5× for pre-hardened bar, depending on size and market. The premium is small next to the cost of a failed shaft.

Q: What are 1018 and 4140 called in Europe?
A: 1018 has no exact EN twin — C15/C22 or S235JRC bright bar are the substitutes. 4140 is identical to EN 42CrMo4 (1.7225), JIS SCM440 and GB 42CrMo.

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## 1045 vs 4140
URL: https://steelstandart.com/compare/1045-vs-4140/

1045 and 4140 both contain about 0.4–0.45 % carbon, so in thin sections they quench to almost the same hardness — which is why the question 'which is stronger?' has a subtle answer. The difference is hardenability: 4140's 1 % chromium and 0.2 % molybdenum let it through-harden in bars of 50–75 mm, while 1045 hardens only to a depth of about 10 mm and through-hardens only below ~20–25 mm. 4140 also tempers to a tougher structure at the same strength and resists softening at temperature, and it costs 1.5–2× more.

In practice 1045 is the surface-hardened shaft and general medium-strength steel; 4140 is the through-hardened, higher-strength part. The table compares the conditions in which each is actually bought (hot-rolled/cold-drawn 1045, pre-hard 4140) and their heat-treated maxima; the European twins C45 and 42CrMo4 follow the same logic.

- Type: 1045 = plain medium-carbon steel | 4140 = Cr-Mo low-alloy steel
- UNS / EN twin: 1045 = G10450 / C45 (1.0503) | 4140 = G41400 / 42CrMo4 (1.7225)
- Carbon: 1045 = 0.43–0.50 % | 4140 = 0.38–0.43 %
- Alloying: 1045 = Mn 0.60–0.90 % | 4140 = Mn 0.75–1.00, Cr 0.80–1.10, Mo 0.15–0.25 %
- Yield, as supplied: 1045 = ≈ 310 MPa hot-rolled; ≈ 530 MPa cold-drawn | 4140 = ≈ 415 MPa annealed; ≈ 690–760 MPa pre-hard
- Tensile, as supplied: 1045 = ≈ 565 MPa hot-rolled; ≈ 625 MPa cold-drawn | 4140 = ≈ 655 MPa annealed; ≈ 930–1000 MPa pre-hard
- Q&T tensile, 25 mm, 540 °C temper: 1045 = ≈ 760 MPa (surface); core lower | 4140 = ≈ 1035 MPa (through)
- Max. Q&T tensile (thin section): 1045 = ≈ 960 MPa (315 °C temper) | 4140 = ≈ 1770 MPa (205 °C temper)
- As-quenched hardness: 1045 = 55–60 HRC (water, surface) | 4140 = 54–59 HRC (oil)
- Through-hardening limit: 1045 = ≈ 20–25 mm (water) | 4140 = ≈ 50–75 mm (oil)
- Quench medium: 1045 = water/brine (cracking risk) | 4140 = oil (low distortion)
- Toughness at 30 HRC (Charpy, typical): 1045 = ≈ 20–30 J | 4140 = ≈ 40–50 J
- Fatigue strength (rotating bend, Q&T): 1045 = ≈ 300–350 MPa | 4140 = ≈ 450–550 MPa
- Surface hardening: 1045 = induction/flame 55–58 HRC (excellent) | 4140 = induction 50–55 HRC; nitride 55–60 HRC
- Machinability (vs B1112): 1045 = ≈ 55–60 % | 4140 = ≈ 65 % annealed; 55–60 % pre-hard
- Weldability: 1045 = limited: 200–300 °C preheat + temper | 4140 = poor: 250–350 °C preheat + temper
- Carbon equivalent: 1045 = ≈ 0.55–0.65 | 4140 = ≈ 0.80
- Temper resistance / hot strength: 1045 = low | 4140 = good to ~450 °C
- Relative price per kg (bar): 1045 = 1.00 | 4140 = ≈ 1.5–2.0
- Typical use: 1045 = TGP shafting, induction-hardened shafts, Grade 5 bolts, gears, hand tools | 4140 = high-stress shafts, gears, Grade 8 / 10.9 bolts, hydraulic rods, drill collars, tooling

Verdict: Choose 4140 when the part is thicker than about 20 mm and must be strong or hard through the section, when it sees fatigue or shock, when it runs warm, or when you need a predictable oil quench with low distortion: gearbox shafts, heavy bolts, hydraulic rods, tooling, anything over 1000 MPa.

Choose 1045 when strength is needed only at the surface or in a thin section, and cost matters: induction-hardened shafting, small gears and sprockets, spindles, hand tools, Grade 5 bolts, general machine parts under 25 mm. Its water quench and shallow hardening are fine for a hard skin over a soft core.

The classic error is specifying 1045 for a 40 mm shaft that must be 30 HRC through — it will be hard outside and pearlite inside. The opposite error, using 4140 for a linear shaft that only needs an induction-hardened case, wastes money but at least works.

Q: Which is stronger, 1045 or 4140?
A: 4140. In thin sections both quench to ~55–58 HRC, but 4140 keeps that hardness through 50–75 mm bars and tempers to 1000–1600 MPa with better toughness; 1045 through-hardens only to about 20–25 mm and tops out around 960 MPa in thin sections. As supplied, pre-hard 4140 (≈ 950 MPa) is far stronger than cold-drawn 1045 (≈ 625 MPa).

Q: Is 1045 the same as 4140?
A: No. They share the ~0.45 % carbon level, but 4140 adds 1 % chromium and 0.2 % molybdenum, which change hardenability, toughness and price. 1045 = EN C45; 4140 = EN 42CrMo4.

Q: Can 1045 replace 4140?
A: Only for parts thinner than ~20 mm that need surface hardness rather than through-strength, and that are not fatigue- or shock-critical. For a through-hardened shaft or a Grade 8 bolt, no.

Q: Which is easier to weld, 1045 or 4140?
A: Neither is easy, but 1045 (CE ≈ 0.6) is somewhat less critical than 4140 (CE ≈ 0.8). Both need preheat (200–300 °C for 1045, 250–350 °C for 4140), low-hydrogen filler and post-weld tempering; weld before hardening.

Q: Which machines better?
A: Roughly equal; 1045 hot-rolled rates 55–60 %, annealed 4140 about 65 % and pre-hard 4140 55–60 %. Pre-hard 4140 gives the best surface finish and chip control with carbide.

Q: What about C45 vs 42CrMo4?
A: Same comparison in EN terms: C45 (1.0503) ≈ 1045 and 42CrMo4 (1.7225) ≈ 4140. EN 10083 gives the same picture — 42CrMo4 +QT 900–1300 MPa versus C45 +QT 630–850 MPa at ≤ 16 mm.

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## 304 vs 316
URL: https://steelstandart.com/compare/304-vs-316/

304 and 316 are the two austenitic stainless steels that cover about 75 % of all stainless use, and the question of which one to buy comes up on every project that sees water, food or weather. The metallurgical difference is one element: 316 contains 2–3 % molybdenum (and about 2 % more nickel), which roughly triples its resistance to pitting and crevice corrosion by chlorides — salt water, road salt, brine, pool chemicals, many process streams. Everything else — strength, formability, weldability, hygiene, temperature range, non-magnetism — is essentially the same.

The cost of that molybdenum and nickel is 20–40 % on the material price. So the decision is an environment question, not a strength question: if chlorides are present and the surface stays wet, 316 pays for itself; if not, 304 does the job. The table below gives the numbers for both ASTM and EN designations (304 = 1.4301, 316 = 1.4401, 316L = 1.4404).

- ASTM / UNS: 304 = A240 304 / S30400 (304L: S30403) | 316 = A240 316 / S31600 (316L: S31603)
- EN material number: 304 = 1.4301 (304L: 1.4307) | 316 = 1.4401 (316L: 1.4404)
- Chromium: 304 = 18–20 % | 316 = 16–18 %
- Nickel: 304 = 8–10.5 % | 316 = 10–14 %
- Molybdenum: 304 = — | 316 = 2–3 %
- PREN (Cr + 3.3 Mo + 16 N): 304 = ≈ 18–20 | 316 = ≈ 24–26
- Critical pitting temperature (6 % FeCl₃): 304 = ≈ 5–10 °C | 316 = ≈ 15–20 °C
- Min. yield (annealed): 304 = 205 MPa (30 ksi) | 316 = 205 MPa (30 ksi)
- Min. tensile: 304 = 515 MPa (75 ksi) | 316 = 515 MPa (75 ksi)
- Elongation: 304 = ≥ 40 % | 316 = ≥ 40 %
- Hardness (annealed max): 304 = 201 HB / 92 HRB | 316 = 217 HB / 95 HRB
- Magnetic (annealed): 304 = No | 316 = No (even less after cold work)
- Max. service temperature (oxidation): 304 = 870 °C continuous | 316 = 870 °C continuous
- Chloride SCC threshold: 304 = ≈ 60 °C in chloride water | 316 = ≈ 60 °C (marginally better)
- Seawater / marine atmosphere: 304 = tea staining, pitting | 316 = good (splash zone); crevice attack if immersed and stagnant
- Sulphuric acid, dilute: 304 = poor | 316 = fair (to ~5 % at ambient)
- Nitric acid: 304 = excellent | 316 = good
- Weldability: 304 = excellent (ER308L) | 316 = excellent (ER316L)
- Machinability (vs B1112): 304 = ≈ 45 % | 316 = ≈ 40 %
- Density: 304 = 8.0 g/cm³ | 316 = 8.0 g/cm³
- Thermal expansion (0–100 °C): 304 = 17.2 × 10⁻⁶/K | 316 = 16.0 × 10⁻⁶/K
- Relative price (2026, sheet): 304 = 1.00 | 316 = ≈ 1.25–1.40
- Fastener class (ISO 3506): 304 = A2 | 316 = A4

Verdict: Buy 316 (or 316L) when chlorides are present and the surface stays wet or is rarely cleaned: coastal buildings within a few kilometres of the sea, marine hardware, swimming-pool and spa fittings, de-icing-salt exposure, brine and pickling lines, most chemical and pharmaceutical process equipment, and anything embedded or crevice-prone outdoors.

Buy 304 (or 304L) everywhere else: kitchens, food and dairy equipment, brewing, inland architecture, water tanks, automotive trim, indoor railings, fasteners in dry service. It is cheaper, marginally easier to machine and polish, and equally strong.

A useful rule: if a 304 part in that location would show 'tea staining' within a year, it should be 316. If you are unsure, the price of 316 is cheaper than the cost of replacing a pitted 304 part.

Q: What is the main difference between 304 and 316 stainless steel?
A: 316 contains 2–3 % molybdenum (304 has none) and slightly more nickel. Molybdenum raises resistance to pitting and crevice corrosion by chlorides — salt water, road salt, brine — from PREN ≈ 18 to ≈ 24. Mechanical properties are the same.

Q: Is 316 stronger than 304?
A: No. Both have 205 MPa minimum yield and 515 MPa tensile in the annealed state; 316 is marginally stronger at high temperature and slightly harder (217 vs 201 HB max). Choose between them on corrosion, not strength.

Q: How can I tell 304 from 316?
A: Not by eye or magnet — both are non-magnetic and look identical. Use a molybdenum spot test (a drop reagent that turns dark on Mo-bearing steel), an XRF analyser, or the mill certificate / stencil.

Q: Is 316 worth the extra cost?
A: Where chlorides are present and surfaces stay wet — yes; a pitted 304 part costs far more to replace than the 25–40 % premium. Inland, indoor and food-contact uses without chlorides gain nothing from 316.

Q: What about 304L and 316L?
A: The L versions limit carbon to 0.03 % to avoid sensitization in welds thicker than about 6 mm. Most coil today is dual-certified 304/304L and 316/316L, so you get the low carbon anyway; the 304-vs-316 decision is unchanged.

Q: Which is better for outdoor use?
A: 316 near the coast or road salt; 304 inland with normal rainfall washing. Both will 'tea stain' in unwashed sheltered marine locations; for the worst cases (indoor pools, warm seawater) use duplex 2205 instead.

Q: Is 316 more magnetic than 304?
A: No — 316 is if anything less magnetic after cold work, because its higher nickel content stabilizes the austenite.

---

## 304 vs 430
URL: https://steelstandart.com/compare/304-vs-430/

The question behind almost every 304-versus-430 enquiry is price, and the answer is nickel. 304 is 18 % chromium with 8 % nickel, which makes it austenitic: non-magnetic, deep-drawable, and resistant enough for food, outdoor and mildly chemical service. 430 is around 17 % chromium with no nickel at all, which makes it ferritic: magnetic, cheaper, dimensionally stable in heat — and noticeably less corrosion resistant.

Nickel is also why the price gap moves. 304 tracks the nickel market and 430 mostly does not, so the ratio between them widens and narrows through the cycle rather than sitting at a fixed percentage.

The practical dividing line is water and chlorides. Indoors, dry, wiped clean, 430 does the job and looks the same. Outdoors, near the sea, or anywhere salt and standing moisture meet the surface, 430 will stain and pit while 304 will not.

- Structure: 304 = Austenitic | 430 = Ferritic
- EN number: 304 = 1.4301 | 430 = 1.4016
- Chromium: 304 = 17.5–19.5 % | 430 = 16.0–18.0 %
- Nickel: 304 = 8.0–10.5 % | 430 = None specified
- Max carbon: 304 = 0.07 % | 430 = 0.08 %
- Magnetic: 304 = No in the annealed condition; slightly after heavy cold work | 430 = Yes, strongly
- Yield Rp0.2: 304 = 210 MPa min. (EN) | 430 = 260 MPa min. (EN)
- Tensile Rm: 304 = 520–720 MPa | 430 = 450–600 MPa
- Elongation: 304 = 45 % min. | 430 = 20 % min.
- Deep drawing: 304 = Excellent — the reference material for sinks and hollowware | 430 = Limited; prone to ridging and roping
- Work hardening: 304 = High — plan for it in tooling | 430 = Low
- Weldability: 304 = Good with standard austenitic filler | 430 = Poor to fair — grain growth and brittleness in the HAZ
- Thermal expansion: 304 = ≈ 17 × 10⁻⁶ /K | 430 = ≈ 10.5 × 10⁻⁶ /K — closer to carbon steel
- Corrosion, indoor dry: 304 = Excellent | 430 = Good
- Corrosion, outdoor / coastal: 304 = Good to fair; 316 for marine | 430 = Poor — will tea-stain and pit
- Chloride tolerance: 304 = Moderate | 430 = Low
- Typical uses: 304 = Food plant, sinks, façades, tanks, handrail | 430 = Appliance panels, trim, indoor cladding, exhaust parts
- ASTM designation: 304 = A240 Type 304 | 430 = A240 Type 430
- Price driver: 304 = Nickel — moves with LME nickel | 430 = Chromium and scrap only
- Typical price: 304 = Reference; the benchmark stainless price | 430 = Roughly 55–70 % of 304, widening when nickel rises

Verdict: 430 where it will stay dry and be seen; 304 where it will get wet and has to last. In an appliance panel, a lift interior, indoor trim or a decorative sheet, 430 is the correct commercial choice and spending on 304 buys nothing visible. As soon as the part faces weather, handles food and cleaning chemicals, gets welded into a fabrication, or has to be deep drawn, 304 stops being the expensive option and starts being the only one that works.

If the environment is coastal or chlorinated, neither is the answer — that is 316 territory.

Q: Is 430 stainless steel as good as 304?
A: Not for corrosion. 430 has no nickel and around 17 % chromium, which is enough for dry indoor service but not for weather, chlorides or wash-down. Indoors and dry the two are hard to tell apart; outdoors 430 tea-stains and pits while 304 does not.

Q: Why is 430 stainless magnetic and 304 not?
A: Because of crystal structure. 430 is ferritic, which is magnetic; 304 is austenitic, which is not — although heavy cold work such as deep drawing can make a 304 part slightly magnetic at the formed areas. Magnetism is not a test of whether steel is stainless.

Q: Can 430 stainless be used outdoors?
A: Only in sheltered, inland, low-pollution situations, and it will still stain. Anything exposed to rain, road salt or sea air should be 304 as a minimum, and 316 within a few kilometres of the coast.

Q: Is 430 cheaper than 304?
A: Typically 55–70 % of the 304 price, and the ratio moves with the nickel market. 304 carries 8–10.5 % nickel, whose LME price drives the alloy surcharge; 430 has none, so its price is set by chromium and scrap.

Q: Can 430 stainless be welded?
A: It can be, but it is the weak point of the grade: the heat-affected zone coarsens and loses toughness, and corrosion resistance drops at the weld. Where welded ferritic stainless is needed, a stabilised grade such as 441 or 430Ti is the better specification.

Q: Which is better for a kitchen?
A: 304 for anything that holds water or food — sinks, worktops, splashbacks behind a hob. 430 is perfectly adequate for appliance fronts, cabinet panels and trim, which is exactly where manufacturers use it.

---

## 316 vs 316L
URL: https://steelstandart.com/compare/316-vs-316l/

The L is low carbon, and that is the entire difference: 316 allows up to 0.08 % carbon, 316L up to 0.030 %. Chromium, nickel and molybdenum are the same in both, so corrosion resistance in the base metal is the same in both.

The carbon matters when the steel is held between roughly 425 and 815 °C — which is what a weld does to the metal beside it. At those temperatures chromium and carbon combine at the grain boundaries, and the chromium that goes into carbides is no longer available to protect the steel. The result, sensitisation, shows up as corrosion in a narrow band parallel to the weld rather than in the weld itself. Less carbon means less to precipitate, which is why 316L is the default for welded fabrication.

In practice most modern material settles the argument for you: it is dual certified 316/316L, meaning the carbon is below 0.030 % and the mechanical properties still meet the higher 316 minimums.

- EN number: 316 = 1.4401 | 316L = 1.4404
- Max carbon: 316 = 0.08 % | 316L = 0.030 %
- Chromium: 316 = 16.5–18.5 % | 316L = 16.5–18.5 %
- Nickel: 316 = 10.0–13.0 % | 316L = 10.0–13.0 %
- Molybdenum: 316 = 2.0–2.5 % | 316L = 2.0–2.5 %
- Yield Rp0.2 (ASTM min.): 316 = 205 MPa | 316L = 170 MPa
- Tensile Rm (ASTM min.): 316 = 515 MPa | 316L = 485 MPa
- Elongation: 316 = 40 % min. | 316L = 40 % min.
- PREN (approx.): 316 = 24–25 | 316L = 24–25
- Corrosion, base metal: 316 = Same as 316L | 316L = Same as 316
- Corrosion after welding: 316 = Risk of sensitisation in the heat-affected zone | 316L = Effectively immune at normal section thicknesses
- Post-weld solution anneal: 316 = Recommended on heavy sections | 316L = Not required
- Service above 500 °C: 316 = Better — higher creep strength | 316L = Lower creep strength; avoid for sustained high temperature
- Preferred for: 316 = Unwelded parts, high temperature, where strength governs | 316L = Welded fabrication, thick sections, pharmaceutical and food plant
- Machining: 316 = Marginally easier — slightly higher carbon | 316L = Slightly gummier
- Cost: 316 = Effectively identical | 316L = Effectively identical
- Grade above for heat: 316 = 316H (0.04–0.10 % C) | 316L = 316H (a 316 variant, not a 316L one)
- JIS equivalent: 316 = SUS 316 | 316L = SUS 316L
- Common delivery: 316 = Often supplied as dual-certified 316/316L | 316L = Often supplied as dual-certified 316/316L
- Typical price: 316 = Same class; surcharge follows nickel and molybdenum | 316L = Same class; surcharge follows nickel and molybdenum

Verdict: Specify 316L for anything welded and 316 for anything hot. For tanks, pipework, pharmaceutical and food plant, handrail and any fabrication going into service without a post-weld solution anneal, 316L removes a failure mode for no cost. For unwelded machined parts, and for sustained service above about 500 °C where creep strength governs, 316 — or 316H — is the correct choice.

If the certificate says 316/316L dual, the material satisfies both and the question does not arise.

Q: What does the L mean in 316L?
A: Low carbon: a maximum of 0.030 % against 0.08 % for 316. Everything else in the alloy — 16.5–18.5 % chromium, 10–13 % nickel, 2–2.5 % molybdenum — is the same, so the L affects welding behaviour, not base-metal corrosion resistance.

Q: Is 316L more corrosion resistant than 316?
A: Not in the base metal, where they are identical. The difference appears beside a weld: 316's higher carbon can precipitate chromium carbides at the grain boundaries, leaving a chromium-depleted band that corrodes. 316L has too little carbon for that to matter.

Q: Is 316 stronger than 316L?
A: Slightly, on paper. ASTM A240 gives 316 a minimum yield of 205 MPa and tensile of 515 MPa, against 170 and 485 MPa for 316L. Real material usually exceeds both, which is why dual-certified stock meeting the 316 minimums at 316L carbon is common.

Q: What is dual certified 316/316L?
A: Material whose carbon is below 0.030 % — satisfying 316L — while its mechanical properties still meet the higher 316 minimums. One certificate then covers both specifications, which is why most 316 sold today is supplied this way.

Q: Which should be used for welded pipework?
A: 316L, unless the fabrication will be solution annealed after welding. It removes the sensitisation risk in the heat-affected zone at effectively no price difference, which is why process, food and pharmaceutical pipework is specified in 316L as a matter of routine.

Q: Can 316L be used at high temperature?
A: For short excursions, yes; for sustained service above about 500 °C, no. Low carbon means lower creep strength, so the grade to specify for hot service is 316 or, where a design code allows it, 316H with its deliberately raised carbon range.

---

## 4140 vs 4340
URL: https://steelstandart.com/compare/4140-vs-4340/

Both carry 0.40 % carbon, both are quenched and tempered, and both are bought for shafts and highly stressed parts. The difference is a single alloying element with a large consequence.

4140 is chromium-molybdenum: around 1 % chromium and 0.2 % molybdenum, the workhorse engineering steel of every machine shop, stocked in every size and priced as a commodity.

4340 adds 1.65–2.00 % nickel on top of a similar chromium-molybdenum base. Nickel does two things that nothing else in this price bracket does: it pushes hardenability deeper into the section, and it raises toughness at a given strength — including at low temperature, where 4140 starts to lose it.

The practical question is therefore almost always about section size. In a 40 mm shaft the two behave close enough that 4140 wins on price. In a 150 mm shaft, 4140 does not harden to the core and 4340 does, and no amount of tempering closes that gap.

- Standard: 4140 = SAE J404 / ASTM A29 (alloy) | 4340 = SAE J404 / ASTM A29 (alloy)
- Type: 4140 = Chromium-molybdenum | 4340 = Nickel-chromium-molybdenum
- Carbon: 4140 = 0.38–0.43 % | 4340 = 0.38–0.43 %
- Nickel: 4140 = Not specified | 4340 = 1.65–2.00 %
- Chromium: 4140 = 0.80–1.10 % | 4340 = 0.70–0.90 %
- Molybdenum: 4140 = 0.15–0.25 % | 4340 = 0.20–0.30 %
- Manganese: 4140 = 0.75–1.00 % | 4340 = 0.60–0.80 %
- EN equivalent: 4140 = 42CrMo4 / 1.7225 | 4340 = 34CrNiMo6 / 1.6582 (near)
- Tensile, Q&T typical: 4140 = 850–1 000 MPa | 4340 = 1 000–1 300 MPa
- Yield, Q&T typical: 4140 = 700–900 MPa | 4340 = 900–1 200 MPa
- Hardness range, Q&T: 4140 = 28–34 HRC typical, up to ~50 HRC | 4340 = 30–40 HRC typical, up to ~53 HRC
- Through-hardening section: 4140 = Roughly to 65–75 mm | 4340 = Roughly to 150 mm and beyond
- Toughness at strength: 4140 = Good | 4340 = Better — the reason to pay for it
- Low-temperature toughness: 4140 = Falls away | 4340 = Retained; nickel is what does it
- Weldability: 4140 = Poor without preheat and PWHT | 4340 = Poorer still; higher carbon equivalent
- Machinability: 4140 = Good in the annealed condition | 4340 = Slightly harder work at the same hardness
- Nitriding: 4140 = Excellent; the standard nitriding base | 4340 = Also good
- Availability: 4140 = Stocked everywhere, every form | 4340 = Order item in most sizes outside aerospace supply
- Typical uses: 4140 = Shafts, gears, spindles, tooling, hydraulic parts | 4340 = Landing gear, heavy crankshafts, high-integrity shafts, large gears
- Typical price: 4140 = Commodity alloy steel | 4340 = Roughly 1.5–2× 4140, moving with nickel

Verdict: 4140 until the section is too big for it, then 4340. For parts up to roughly 65–75 mm ruling section, 4140 reaches the required properties through the wall and costs a fraction as much; it is also stocked, which for a repair or a one-off shaft matters more than a data sheet.

Move to 4340 when the section is heavier than that, when the design needs high strength *and* toughness together rather than a trade between them, when the part will be loaded at low temperature, or when a failure would be expensive enough to justify the metallurgy. Aerospace and heavy machinery specify it for exactly those reasons.

Neither is a welding grade. If the part has to be welded, that decision should push the design toward a quenched and tempered structural plate such as S690QL instead.

Q: What is the difference between 4140 and 4340 steel?
A: Nickel. Both carry about 0.40 % carbon with chromium and molybdenum, but 4340 adds 1.65–2.00 % nickel, which deepens hardenability and raises toughness at a given strength. The chemistry difference translates almost entirely into how large a section can be hardened through.

Q: Is 4340 stronger than 4140?
A: In practice yes, though the headline reason is depth rather than peak strength. Quenched and tempered, 4140 typically runs 850–1 000 MPa tensile and 4340 1 000–1 300 MPa — but the decisive difference is that 4340 reaches those numbers at the centre of a heavy section where 4140 does not.

Q: Which should be used for a shaft?
A: 4140 up to roughly 65–75 mm diameter, where it hardens through and costs far less; 4340 above that, and for any shaft that is fatigue-critical or works at low temperature. Section size decides this more often than load does.

Q: What is the European equivalent of 4140 and 4340?
A: 4140 corresponds to 42CrMo4 (1.7225) and 4340 to 34CrNiMo6 (1.6582), the second being a near equivalence rather than an identity — 34CrNiMo6 runs slightly lower carbon and higher chromium. Compare the certificate rather than assuming the substitution.

Q: Can 4140 and 4340 be welded?
A: Both can be, neither should be casually. They need preheat, controlled interpass temperature, low-hydrogen consumables and post-weld heat treatment, and 4340 is the more difficult of the two because of its higher carbon equivalent. A design that requires welding is usually better served by a quenched and tempered structural grade.

Q: Why is 4340 so much more expensive?
A: Nickel at 1.65–2.00 %, and a smaller, more specialised market. The price runs roughly 1.5 to 2 times 4140 and moves with the nickel market, which is why the substitution question is asked so often — and why the honest answer is to check the ruling section before paying it.

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## A36 vs 1018
URL: https://steelstandart.com/compare/a36-vs-1018/

'Are A36 and 1018 the same?' is one of the most-asked steel questions in North America, and the honest answer is: they are the same *kind* of steel bought under two different *kinds* of rules. ASTM A36 is a performance specification — it guarantees 250 MPa (36 ksi) minimum yield and 400–550 MPa tensile for structural plate, shapes and bar, and lets carbon float up to 0.25–0.29 %. AISI/SAE 1018 is a chemistry designation — 0.15–0.20 % carbon, 0.6–0.9 % manganese — with no guaranteed strength at all; what you get depends on the condition, and it is almost always sold as cold-drawn bar with about 370 MPa yield.

In a hot-rolled bar the two are practically interchangeable; the difference shows up in what is certified (strength vs chemistry), in the surface and tolerance (A36 mill-scale vs 1018 bright cold-drawn), in weldability (1018's lower carbon is marginally better) and in what a code inspector will accept.

- Type of designation: A36 = ASTM performance specification (A36/A36M) | 1018 = AISI/SAE chemistry grade (ASTM A29 / A108)
- What is guaranteed: A36 = yield ≥ 250 MPa, tensile 400–550 MPa, elongation | 1018 = chemistry only; strength by condition/agreement
- Carbon: A36 = ≤ 0.25–0.29 % (by product/thickness) | 1018 = 0.15–0.20 %
- Manganese: A36 = 0.60–1.20 % (varies; often unspecified ≤ 20 mm) | 1018 = 0.60–0.90 %
- P / S max: A36 = 0.030 / 0.030 % | 1018 = 0.040 / 0.050 %
- Usual product forms: A36 = plate, angles, channels, flats, W/S shapes, hot-rolled bar | 1018 = cold-drawn rounds, squares, hexes, flats; hot-rolled bar; DOM tube
- Usual surface: A36 = hot-rolled with mill scale | 1018 = bright cold-drawn (CRS); hot-rolled available
- Yield strength: A36 = ≥ 250 MPa (36 ksi) min; typ. 280–340 | 1018 = ≈ 370 MPa (54 ksi) cold-drawn; ≈ 220 MPa hot-rolled (not guaranteed)
- Tensile strength: A36 = 400–550 MPa (58–80 ksi) | 1018 = ≈ 440 MPa cold-drawn; ≈ 400 MPa hot-rolled
- Elongation: A36 = ≥ 20 % (200 mm) / 23 % (50 mm) | 1018 = ≈ 15 % cold-drawn; ≈ 25 % hot-rolled
- Hardness (typical): A36 = 119–159 HB | 1018 = ≈ 126 HB cold-drawn
- Dimensional tolerance: A36 = ASTM A6 (hot-rolled, wide) | 1018 = ASTM A108 (cold-finished, tight; h10–h11)
- Weldability: A36 = excellent (CE ≈ 0.3–0.4; AWS D1.1 prequalified) | 1018 = excellent (CE ≈ 0.3); HAZ loses cold-work strength
- Machinability (vs B1112): A36 = ≈ 72 % (hot-rolled) | 1018 = ≈ 70–78 % (cold-drawn)
- Case hardening: A36 = possible but not controlled | 1018 = yes — standard carburizing grade
- Accepted for structural design (AISC): A36 = yes (Fy = 36 ksi) | 1018 = no (not a listed structural material)
- Price basis: A36 = per tonne, structural | 1018 = per kg, cold-finished bar (≈ 1.2–1.5× hot-rolled)
- EN cross-reference: A36 = S235JR / S275JR (near) | 1018 = C15 / C22 / S235JRC (near)
- Typical use: A36 = structures, base plates, brackets, weldments, plate parts | 1018 = shafts, pins, spacers, fixtures, machined and carburized parts

Verdict: Specify A36 when the part is structural, made from plate or shapes, welded, or must satisfy a building/bridge/equipment code: it is what AISC, AWS D1.1 and every fabricator expect, and the strength is certified.

Specify 1018 when the part is machined from bar and needs a bright surface, tight tolerance, or a carburized skin: shafts, pins, spacers, guides, fixtures. Its higher cold-drawn yield is a bonus, not a guarantee.

For a hot-rolled round or flat bar in a non-code application, either name will get you essentially the same steel; write 'A36' for plate and structural shapes and '1018 CRS' for cold-finished bar, and do not claim A36 structural properties for 1018 or 1018 chemistry for A36.

Q: Are A36 and 1018 the same steel?
A: Chemically they overlap (both low-carbon mild steels), but A36 is an ASTM structural specification guaranteeing 250 MPa yield with loose chemistry, while 1018 is an AISI chemistry grade (0.15–0.20 % C) with no guaranteed strength, usually sold cold-drawn. Hot-rolled 1018 and A36 bar behave alike; they are not interchangeable on paper.

Q: Which is stronger, A36 or 1018?
A: Cold-drawn 1018 is typically stronger (≈ 370 MPa yield, thanks to cold work) than A36's 250 MPa minimum, but 1018's strength is not guaranteed and disappears in weld heat-affected zones. Hot-rolled 1018 is about the same as A36 or slightly weaker.

Q: Can I weld 1018 to A36?
A: Yes, easily — both are low-carbon steels welded with ER70S-6 / E7018 without preheat. Design the joint on hot-rolled (≈ 220–250 MPa) properties because cold-drawn 1018 softens in the HAZ.

Q: Which is easier to machine?
A: Cold-drawn 1018 (≈ 70–78 %) is marginally better than hot-rolled A36 (≈ 72 %) and gives a cleaner finish; both are 'gummy' low-carbon steels that benefit from sharp tooling and chip breakers.

Q: Can A36 be case hardened like 1018?
A: It can be carburized, but A36's chemistry is not controlled for it (carbon may be up to 0.29 %, Mn variable), so results are less predictable. Use 1018 (or 8620 for higher core strength) when a specified case is required.

Q: What do I order for a round bar — A36 or 1018?
A: For a bright, accurate bar to machine: 1018 CRS. For a hot-rolled bar in a welded structure: A36 (hot-rolled merchant bar is often dual-certified A36/1018-type anyway).

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## A36 vs A572 Grade 50
URL: https://steelstandart.com/compare/a36-vs-a572/

A36 and A572 Grade 50 are the two structural steels an American fabricator quotes on almost every job. A36 is the plain carbon steel with 36 ksi (250 MPa) yield that has defined 'mild steel' since 1960; A572 Grade 50 is the high-strength low-alloy steel with 50 ksi (345 MPa) yield, micro-alloyed with niobium and vanadium so that the extra strength costs only a few percent per tonne and almost nothing in weldability. Since W-shapes moved to A992 (a 50 ksi grade) around 2000, the A36-vs-A572 question is mostly about plate, bar, angles and channels.

The arithmetic is simple: 39 % more yield for 3–8 % more money means A572-50 wins whenever strength governs the member size. A36 keeps its place where stiffness, buckling of slender elements, heavy cold forming or plain habit govern — and in bar and small-angle sizes where A572 is not stocked. The table gives the full comparison; A992's differences from A572-50 are noted for shapes.

- Type: A36 = carbon structural steel | A572 Grade 50 = HSLA (Nb/V micro-alloyed) structural steel
- UNS: A36 = K02600 | A572 Grade 50 = K02303
- Min. yield: A36 = 250 MPa (36 ksi); 220 MPa > 200 mm plate | A572 Grade 50 = 345 MPa (50 ksi), plate ≤ 100 mm
- Tensile: A36 = 400–550 MPa (58–80 ksi) | A572 Grade 50 = ≥ 450 MPa (65 ksi), no max (A992: 450–620)
- Elongation (200 mm / 50 mm): A36 = ≥ 20 % / 23 % | A572 Grade 50 = ≥ 18 % / 21 %
- Yield/tensile ratio (typ.): A36 = ≈ 0.65–0.75 | A572 Grade 50 = ≈ 0.75–0.85 (A992 caps at 0.85)
- Carbon max: A36 = 0.25–0.29 % (by product/thickness) | A572 Grade 50 = 0.23 %
- Mn: A36 = 0.80–1.20 % (plate > 20 mm) | A572 Grade 50 = ≤ 1.35 % (1.65 % Gr 60/65)
- Micro-alloy: A36 = none | A572 Grade 50 = Nb 0.005–0.05 and/or V 0.01–0.15 %
- Carbon equivalent (typ.): A36 = 0.30–0.40 | A572 Grade 50 = 0.35–0.45
- Impact toughness: A36 = not required (S5 optional) | A572 Grade 50 = not required (S5 optional; A709-50 has zones)
- Plate thickness limit: A36 = none (yield drops > 200 mm) | A572 Grade 50 = 100 mm (Grade 50)
- Preheat (AWS D1.1 Table 3.3): A36 = category A/B: none ≤ 19 mm … 110 °C > 64 mm | A572 Grade 50 = category B: same schedule, low-hydrogen mandatory
- Consumables: A36 = E70XX / ER70S-6 (over-matching) | A572 Grade 50 = E70XX / ER70S-6 (matching)
- Cold-bend inside radius (transverse): A36 = ≈ 1.5 t | A572 Grade 50 = ≈ 1.5–2 t
- Hardness (typ.): A36 = 119–159 HB | A572 Grade 50 = 135–185 HB
- Fatigue (AISC/AASHTO categories): A36 = same detail categories | A572 Grade 50 = same detail categories — no benefit from higher yield
- Price (2026, plate): A36 = 1.00 | A572 Grade 50 = ≈ 1.03–1.08
- Weight for equal strength: A36 = 1.00 | A572 Grade 50 = ≈ 0.72
- W-shapes: A36 = rare today | A572 Grade 50 = dual-certified A992/A572-50
- EN cross-reference: A36 = S235JR / S275JR | A572 Grade 50 = S355J2 / S355M

Verdict: A572 Grade 50 when strength sets the section: plate girders, columns, crane runways, lifting structures, truck and trailer frames, transmission towers, any design where a thinner plate or lighter section pays back the 3–8 % premium. For rolled beams simply specify A992.

A36 when it does not: deflection-limited floor beams and platforms (E is identical), slender compression members, gusset and base plates sized by geometry, heavy cold forming, small bar and angle sizes that stockists carry only in A36, and low-volume shops that want one steel in the yard.

Fatigue does not favour either — AISC detail categories are independent of grade — so fatigue-governed members gain nothing from Grade 50. And neither has an impact requirement: for cold-climate or dynamically loaded structures add supplementary S5 or move to A709.

Q: What is the difference between A36 and A572 Grade 50?
A: Yield strength: 250 MPa (36 ksi) vs 345 MPa (50 ksi). A572-50 is an HSLA steel with niobium/vanadium micro-alloying; A36 is plain carbon steel. Tensile is 400–550 vs ≥ 450 MPa. A572 saves 25–30 % weight in strength-governed members for 3–8 % more per tonne.

Q: Is A572 harder to weld than A36?
A: Marginally: its carbon equivalent is a little higher, so AWS D1.1 puts it in preheat category B with low-hydrogen consumables mandatory, but the preheat schedule by thickness is the same as for A36 and both are prequalified with 70 ksi consumables.

Q: Is A572 Grade 50 the same as A992?
A: Nearly. A992 is written for rolled W-shapes: same 50 ksi minimum yield plus a 65 ksi yield cap, a maximum yield/tensile ratio of 0.85 and a CE limit, for predictable seismic behaviour. W-shapes are dual-certified A992/A572-50; plate cannot be A992.

Q: Does A572 deflect less than A36?
A: No. Both have E = 200 GPa (29 × 10⁶ psi); a member of the same size deflects identically. A572 only allows a smaller section when strength — not deflection — governs.

Q: How much more does A572 cost?
A: Typically 3–8 % more per tonne for plate and about the same for shapes (where A992 is the default anyway). Per unit of capacity it is about 25 % cheaper.

Q: Which has better fatigue performance?
A: Neither. AISC and AASHTO fatigue design uses detail categories that do not depend on grade; higher yield does not raise fatigue resistance of welded details.

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## A36 vs Q235
URL: https://steelstandart.com/compare/a36-vs-q235/

These two meet on import documents more often than in a design office. ASTM A36 is the American structural commodity: 250 MPa minimum yield, a wide tensile band, no Charpy requirement and a chemistry that leaves the mill considerable freedom. Q235 is its Chinese counterpart from GB/T 700: 235 MPa minimum yield, 370–500 MPa tensile, and — the important structural difference — four quality classes A to D graded by impact test, exactly as the European system grades JR, J0 and J2.

The substitution is made constantly and usually works. Where it goes wrong is in the two details nobody reads on the certificate. First, the quality letter: material sold simply as "Q235" with no letter has no defined impact class at all, and Q235A may be supplied rimmed or semi-killed. Second, the carbon: Q235B specifies a minimum carbon of 0.12 %, while A36 only sets a ceiling. A welding procedure qualified on a low-carbon A36 heat is not automatically valid on material that has to contain carbon.

On strength the gap is small and in A36's favour; on documented toughness the advantage runs the other way, because A36 has none to document.

- Standard: A36 = ASTM A36/A36M | Q235 = GB/T 700-2006
- System: A36 = ASTM (United States) | Q235 = GB/T (China)
- Designation logic: A36 = A36 = 36 ksi minimum yield | Q235 = Q235 = 235 MPa yield point (Q = qufu diandian)
- Yield, ≤ 16 mm: A36 = 250 MPa (36 ksi) | Q235 = 235 MPa
- Yield, > 40 mm: A36 = 220 MPa above 8 in. plate | Q235 = 215 MPa (40–100 mm)
- Tensile Rm: A36 = 400–550 MPa | Q235 = 370–500 MPa
- Elongation: A36 = 20 % (200 mm) / 23 % (50 mm) | Q235 = 26 % (≤ 40 mm)
- Carbon: A36 = 0.25–0.29 % max by thickness, no minimum | Q235 = 0.12–0.20 % for Q235B — a minimum and a maximum
- Manganese: A36 = 0.80–1.20 % on thicker plate; not specified on thin | Q235 = ≤ 1.40 %
- Silicon: A36 = 0.40 % max (plate) | Q235 = 0.35 % max
- Max P / S: A36 = 0.030 / 0.030 % | Q235 = 0.045 / 0.045 % (B); 0.035 / 0.035 % (D)
- Impact test: A36 = None specified | Q235 = Q235A none · B +20 °C · C 0 °C · D −20 °C, 27 J
- Quality classes: A36 = One grade only | Q235 = Four: A, B, C, D
- Deoxidation: A36 = Killed or semi-killed by thickness | Q235 = A and B may be rimmed or semi-killed; C and D killed
- Product forms: A36 = Plate, bar, sections, sheet piling | Q235 = Plate, coil, sections, bar, tube
- EN counterpart: A36 = S235JR (near) | Q235 = S235JR for Q235B, S235J0 for Q235C
- JIS counterpart: A36 = SS400 (near) | Q235 = SS400 (near)
- Where it is bought: A36 = North America, projects on US codes | Q235 = Chinese production and its export markets
- Weldability: A36 = Good, no preheat at normal thickness | Q235 = Good on B and above; qualify against declared carbon
- Typical price: A36 = Commodity, priced against US plate index | Q235 = Commodity, priced against Chinese export offers

Verdict: Accept Q235B against an A36 requirement in ordinary commercial work, and check the letter before you do. The strength difference — 250 against 235 MPa — is within what most commercial designs absorb, and every other property is comparable. Two conditions make the substitution safe: the certificate names a quality class of B or higher, and the welding procedure covers the carbon actually declared rather than an assumed low value.

Do not substitute where a code names ASTM A36 explicitly, where a project requires US mill certification, or where material has been offered simply as "Q235" with no letter — that last case is not a grade, it is a family.

Q: Is Q235 the same as A36?
A: They are the same class of structural steel and are substituted routinely, but not identical. A36 has a higher minimum yield (250 against 235 MPa) and no impact requirement; Q235 has four quality classes graded by Charpy test and, in the B grade, a minimum carbon content that A36 does not impose.

Q: Which is stronger, A36 or Q235?
A: A36, by 15 MPa on minimum yield — 250 against 235 MPa up to 16 mm — with a tensile band of 400–550 MPa against 370–500. The gap is small enough that most commercial designs absorb it, but it is the reason the substitution runs one way more comfortably than the other.

Q: Can Q235B be used where A36 is specified?
A: In ordinary commercial work, usually yes, provided the certificate names quality class B or higher and the welding procedure covers the carbon actually declared. Where a design code names ASTM A36 explicitly or US mill certification is contractual, it cannot.

Q: What does the letter after Q235 mean?
A: The impact test, not the strength. Q235A has no Charpy requirement, B is tested at +20 °C, C at 0 °C and D at −20 °C, all to 27 J; C and D also tighten phosphorus, sulphur and carbon. Material sold as plain "Q235" has no defined class.

Q: Why does Q235B have a minimum carbon content?
A: Because GB/T 700 specifies the range 0.12–0.20 % rather than a ceiling alone, which is the opposite approach to A36 and to the European S235 family. In a thick restrained weld, material at the top of that range gives a harder heat-affected zone than a low-carbon A36 heat would.

Q: What is the European equivalent of both?
A: S235JR to EN 10025-2 sits between them: the same 235 MPa yield as Q235 with a 27 J impact test at +20 °C, matching Q235B. Q235C corresponds to S235J0 and Q235D to S235J2; A36 maps onto S235JR on strength but has no impact class to match.

---

## A36 vs S235JR
URL: https://steelstandart.com/compare/a36-vs-s235jr/

A36 and S235JR are the everyday structural steels of the two largest engineering traditions, and projects that cross the Atlantic — or use American drawings with European supply — need to know exactly how they differ. A36 is slightly stronger (250 vs 235 MPa yield, 400–550 vs 360–510 MPa tensile) but has no impact requirement and a looser chemistry (carbon up to 0.25–0.29 %); S235JR guarantees 27 J at +20 °C, caps carbon at 0.17 % and CEV at 0.35 %, which makes it marginally more weldable and tougher.

The practical consequences: S235JR can replace A36 only if the designer accepts a 6 % lower yield (or the design was not strength-critical); A36 can replace S235JR only where no Charpy value is required. Where an exact-or-better European substitute is wanted, S275JR (275 MPa) is the safe choice. The table lays out every number.

- Standard: A36 = ASTM A36/A36M-19 | S235JR = EN 10025-2:2019
- Number: A36 = UNS K02600 | S235JR = 1.0038
- Product forms: A36 = plate, shapes (W/S/C/L), bar | S235JR = plate, coil, sections, bar, hollow (S235JRH)
- Min. yield: A36 = 250 MPa (36 ksi) ≤ 200 mm; 220 MPa above | S235JR = 235 MPa ≤ 16 mm; 225 to 40; 215 to 100 mm
- Tensile: A36 = 400–550 MPa (58–80 ksi) | S235JR = 360–510 MPa (52–74 ksi)
- Elongation: A36 = ≥ 20 % (200 mm) / 23 % (50 mm) | S235JR = ≥ 26 % (L0 = 5.65√S0, ≤ 40 mm)
- Impact toughness: A36 = not required (S5 optional) | S235JR = 27 J at +20 °C (J0: 0 °C, J2: −20 °C)
- Carbon max: A36 = 0.25 % (plate ≤ 40 mm) to 0.29 % | S235JR = 0.17 % (≤ 40 mm) / 0.20 %
- Mn: A36 = 0.80–1.20 % (plate > 20 mm) | S235JR = ≤ 1.40 %
- P / S max: A36 = 0.030 / 0.030 % | S235JR = 0.035 / 0.035 %
- Carbon equivalent: A36 = not limited (typ. 0.30–0.40) | S235JR = ≤ 0.35 % (≤ 30 mm)
- Deoxidation / grain size: A36 = not specified (semi-killed allowed) | S235JR = FN (killed optional), fine grain optional
- Typical hardness: A36 = 119–159 HB | S235JR = 100–140 HB
- Design value: A36 = Fy = 36 ksi (AISC) | S235JR = fy = 235 MPa (EN 1993-1-1)
- Yield ratio (typical): A36 = ≈ 0.65–0.75 | S235JR = ≈ 0.60–0.70
- Weldability: A36 = excellent; AWS D1.1 preheat by thickness | S235JR = excellent; no preheat to ~40 mm
- Old / related names: A36 = A7 (predecessor), A709-36, SA-36 | S235JR = St37-2, Fe360B, 40B, S235JRG2
- Nearest exact-or-better EU substitute: A36 = — | S235JR = S275JR (275 MPa)
- Nearest exact-or-better US substitute: A36 = A572 Gr. 42 / A36 for S235 | S235JR = —

Verdict: Replacing A36 with a European grade: use S275JR to be at or above A36 on every strength value; use S235JR only if the design allows 235 MPa (many do, since A36 is often used where deflection governs) and note that you gain a Charpy guarantee.

Replacing S235JR with a US grade: A36 covers the strength with margin. If the European drawing calls S235J0/J2 or specifies impact values, order A36 with supplementary S5 (Charpy at the required temperature) or use A709 Grade 36.

Welding across the pair is unproblematic — both use E70XX / E42 class consumables — but on thick A36 (> 40 mm, C up to 0.29 %) apply AWS D1.1 preheat; S235JR rarely needs it.

Q: Is A36 equivalent to S235JR?
A: They are near equivalents, not identical. A36 has 250 MPa yield and 400–550 MPa tensile with no impact requirement; S235JR has 235 MPa yield, 360–510 MPa tensile and a guaranteed 27 J at +20 °C. S235JR is graded 'near' to A36; S275JR is the European grade that meets or exceeds A36 in strength.

Q: Can S235JR replace A36?
A: Only where the design does not need the full 250 MPa (about 6 % less yield), or after a check. For a like-for-like or better substitute, use S275JR (275 MPa yield, 410–560 MPa tensile).

Q: Can A36 replace S235JR?
A: Yes for strength. If the European specification requires impact toughness (S235JR's 27 J at +20 °C, or J0/J2), order A36 with supplementary requirement S5 for Charpy testing.

Q: Which is more weldable, A36 or S235JR?
A: S235JR marginally: carbon ≤ 0.17 % and CEV ≤ 0.35 % versus A36's carbon up to 0.25–0.29 % with no CEV limit. Both are prequalified for standard procedures; thick A36 needs AWS D1.1 preheat above 19 mm.

Q: What is A36 in DIN and JIS?
A: DIN St37-2 (now S235JR) and JIS SS400 (245 MPa yield) are the usual cross-references; GB Q235B and GOST St3sp likewise. None is identical.

Q: Is S235J2 the same as A36?
A: No — S235J2 has the same strength as S235JR but is impact tested at −20 °C and is fully killed with lower P/S. A36 has no Charpy requirement, so it is 'near' at best; use A36 + S5 or A709 Grade 36 with zone requirements.

---

## DC01 vs DD11
URL: https://steelstandart.com/compare/dc01-vs-dd11/

Both are forming steels, both are low carbon, and neither has a guaranteed minimum yield to design against. The difference is where the sheet was made thin. DC01 (EN 10130) is cold reduced: rolled at room temperature, then annealed and skin-passed, which gives a smooth bright surface and tolerances measured in hundredths of a millimetre. DD11 (EN 10111) is hot rolled: formed at over 900 °C, so it arrives with mill scale, wider tolerances and a lower price.

The practical line between them sits at about 2 mm and at the question of whether the finished part will be seen.

- Standard: DC01 = EN 10130:2006 | DD11 = EN 10111:2008
- Material number: DC01 = 1.0330 | DD11 = 1.0332
- Process: DC01 = Cold reduced, annealed, skin-passed | DD11 = Hot rolled, coiled hot
- Old name: DC01 = St 12, FeP01 | DD11 = StW22
- Usual thickness: DC01 = 0.30–3.0 mm | DD11 = 1.5–11 mm (up to 20 mm by agreement)
- Yield ReH: DC01 = ≤ 280 MPa (ceiling, no minimum) | DD11 = 170–360 MPa (range, no minimum)
- Tensile Rm: DC01 = 270–410 MPa | DD11 = ≤ 440 MPa
- Elongation A80: DC01 = ≥ 28 % | DD11 = ≥ 24 %
- Max C: DC01 = 0.12 % | DD11 = 0.12 %
- Max Mn: DC01 = 0.60 % | DD11 = 0.60 %
- Surface: DC01 = Bright, oiled, class A or B | DD11 = Mill scale, or pickled and oiled
- Thickness tolerance, 1.5 mm: DC01 = ± 0.05 mm (EN 10131) | DD11 = ± 0.17 mm (EN 10051)
- Flatness: DC01 = Tight — suitable for visible panels | DD11 = Wider — needs levelling for precision work
- Paintability: DC01 = Excellent as delivered | DD11 = Needs pickling or blasting first
- Price index: DC01 = 115–130 | DD11 = 100
- Formability family: DC01 = DC01 → DC03 → DC04 → DC06 (improving) | DD11 = DD11 → DD12 → DD13 → DD14 (improving)
- Typical parts: DC01 = Enclosures, appliance panels, brackets, tubes | DD11 = Tube and profile mills, silo bodies, chassis parts
- JIS closest: DC01 = SPCC | DD11 = SPHC
- ASTM closest: DC01 = A1008 CS Type B | DD11 = A1011 CS Type B
- Structural use: DC01 = No guaranteed yield — not for design | DD11 = No guaranteed yield — not for design

Verdict: DC01 below about 2 mm, or wherever the surface will be seen or painted without preparation. DD11 above about 2 mm, or wherever the part is welded, galvanized or hidden — the price advantage is real and the surface is irrelevant once it is coated. In the 1.5–3 mm overlap both are available and the decision is usually made by the finish, not the thickness: a visible enclosure panel in DC01, the same part inside a machine in DD11.

Q: What is the difference between DC01 and DD11?
A: DC01 is cold-reduced sheet to EN 10130 with a bright surface and tight tolerances; DD11 is hot-rolled sheet to EN 10111 with mill scale, wider tolerances and a lower price. Both are forming steels without a guaranteed minimum yield.

Q: Which is stronger?
A: Neither, in a way you can design with. DC01 caps yield at 280 MPa and DD11 gives a 170–360 MPa range; both are specified for how they form, not for load capacity. For a structural sheet, use S235JR or S355MC.

Q: Can DD11 be used below 2 mm?
A: It exists down to about 1.5 mm but the tolerance and flatness are looser and the surface still carries scale. Below 1.5 mm, cold-reduced grades are the practical choice.

Q: Is DC01 the same as SPCC?
A: Functionally, yes — SPCC is the JIS cold-reduced commercial quality. The chemistry limits and the tolerance tables differ slightly, so treat it as near-equivalent rather than identical.

Q: Which galvanizes better?
A: For continuous coil coating the base grades are DX51D and DX52D, not these two. For batch galvanizing of a formed part, DD11 is the usual base: its scale is removed in the pickling stage anyway.

Q: What if I need more formability?
A: Move up within the same family rather than across: DC03, DC04 and DC06 for cold reduced; DD12, DD13 and DD14 for hot rolled. Each step tightens the carbon and improves the draw.

---

## DC01 vs DX51D
URL: https://steelstandart.com/compare/dc01-vs-dx51d/

DC01 and DX51D are, at the substrate level, close to the same low-carbon cold-rolled steel; the practical difference is that DX51D leaves the mill with a hot-dip zinc (or ZM/AZ) coating applied on a continuous line, while DC01 is bare and would be galvanized or painted after fabrication. Because the galvanizing line also anneals the strip, EN 10346 writes DX51D's mechanical guarantees differently — no yield minimum, 22 % elongation, tensile 270–500 MPa — versus DC01's 140–280 MPa yield window and 28 % elongation under EN 10130.

The buying decision is therefore about corrosion protection and process: parts that must not rust, will not be painted immediately, or are roll-formed into building products are DX51D+Z (or +ZM); parts that are welded heavily, painted or powder-coated indoors, or need the best drawability at the lowest price are DC01. Cut-edge protection, weld fume and the availability of drawing qualities (DX52D–DX56D vs DC03–DC06) are the details that decide the rest.

- Standard: DC01 = EN 10130 (cold-rolled for cold forming) | DX51D = EN 10346 (hot-dip coated for cold forming)
- Material number: DC01 = 1.0330 | DX51D = 1.0226
- Old name: DC01 = St12 (DIN 1623) | DX51D = St02Z (DIN 17162)
- Coating: DC01 = none (or +ZE electro-zinc 2.5–7.5 µm per EN 10152) | DX51D = +Z (zinc), +ZF, +ZA, +AZ, +ZM — e.g. Z275 = 275 g/m² both faces ≈ 20 µm/face
- Substrate: DC01 = cold-rolled, skin-passed, annealed | DX51D = cold-rolled (or hot-rolled) and annealed on the coating line
- Thickness: DC01 = 0.35–3.0 mm | DX51D = 0.30–3.0 mm (thicker on request)
- Yield strength: DC01 = 140–280 MPa (window) | DX51D = not specified (typ. 200–320)
- Tensile strength: DC01 = 270–410 MPa | DX51D = 270–500 MPa
- Elongation A80: DC01 = ≥ 28 % | DX51D = ≥ 22 %
- Carbon max: DC01 = 0.12 % | DX51D = 0.18 %
- Drawing qualities in the family: DC01 = DC03 / DC04 / DC05 / DC06 | DX51D = DX52D / DX53D / DX54D / DX56D / DX57D
- Structural qualities in the family: DC01 = — (bright bar S235JRC; EN 10346 for coated) | DX51D = S220GD … S550GD (guaranteed yield)
- Surface: DC01 = quality A/B; finish b/g/m/r; oiled | DX51D = quality A/B/C; spangle N/M; passivated C, oiled O, phosphated P
- Corrosion protection as delivered: DC01 = none (rusts in days if unprotected) | DX51D = Z275: 10–40 years depending on atmosphere; ZM ≈ 2× at equal mass
- Cut-edge protection: DC01 = none | DX51D = zinc sacrificial protection up to ~2 mm
- Spot welding: DC01 = ideal | DX51D = good; +10–20 % current, electrode wear
- Arc/laser welding: DC01 = clean | DX51D = zinc fume, porosity risk; extraction needed; zinc lost at weld
- Painting: DC01 = after phosphating / primer | DX51D = after conversion coating; or pre-painted (EN 10169)
- Bending: DC01 = 0 t radius possible | DX51D = 0.5–1 t; coating holds (T-bend test)
- Price (2026, coil): DC01 = 1.00 | DX51D = ≈ 1.15–1.25 (Z275)
- Typical use: DC01 = enclosures, appliances, furniture, painted panels | DX51D = roofing, cladding, ducting, drywall profiles, cable trays, cabinets

Verdict: DX51D+Z whenever the part will meet moisture and will not be fully painted: roofing and cladding, ventilation ducts, drywall track, cable trays, outdoor cabinets, agricultural and storage equipment. The coating is cheaper and more uniform than post-galvanizing, and cut edges are protected up to about 2 mm. Use +ZM for coastal or agricultural atmospheres, DX52D–DX54D for pressed parts.

DC01 for parts that are welded extensively, e-coated/powder-coated indoors, drawn deeply (DC04+), or where a bright, paint-ready bare surface is needed at the lowest price: appliance housings, office furniture, electrical enclosures, automotive interior brackets. Add +ZE if a light zinc layer under paint is wanted.

Do not treat them as interchangeable: DX51D has no yield guarantee (order DX52D or an S-grade if the design needs one), and welding DX51D without fume extraction is a health issue as well as a quality one.

Q: What is the difference between DC01 and DX51D?
A: DC01 (EN 10130) is bare cold-rolled sheet for forming; DX51D (EN 10346) is the same class of steel supplied hot-dip galvanized (or with ZM/AZ coating) from a continuous line. DC01 has a yield window of 140–280 MPa and 28 % elongation; DX51D has no yield minimum and 22 % elongation. The choice is about corrosion protection and downstream process.

Q: Is DX51D just galvanized DC01?
A: Practically yes — the substrate is a low-carbon cold-rolled (sometimes hot-rolled) steel of DC01 type, annealed and zinc-coated in one pass. The standards and guarantees differ because the coating line changes the mechanical properties and adds the coating specification.

Q: Which is stronger, DC01 or DX51D?
A: Neither is guaranteed stronger: DC01 must be 140–280 MPa yield, DX51D has no yield requirement (typically 200–320 MPa) and a wider tensile range (270–500 MPa). If strength matters, order DX52D (140–300 MPa) or the structural galvanized grades S250GD–S350GD.

Q: Can I weld DX51D?
A: Yes: resistance spot welding is standard with slightly higher current; MAG and laser welding need zinc-fume extraction and produce some porosity. The zinc burns off around the weld and must be repaired with zinc-rich paint. DC01 welds cleaner.

Q: Can I galvanize DC01 after fabrication instead of using DX51D?
A: Yes (batch hot-dip galvanizing, EN ISO 1461) — typical for welded frames and thick parts. It gives a thicker (50–85 µm), less uniform coating and can distort thin sheet; for sheet products DX51D from the coil is cheaper and flatter.

Q: What are DC01 and DX51D called in old DIN and JIS?
A: DC01 = St12 (DIN 1623) = SPCC (JIS G3141); DX51D+Z = St02Z (DIN 17162) = SGCC (JIS G3302).

---

## DC01 vs S235JR
URL: https://steelstandart.com/compare/dc01-vs-s235jr/

DC01 and S235JR confuse buyers because their chemistry overlaps almost completely — both are plain low-carbon steels with about 0.05–0.15 % C — yet they are ordered from different standards, in different forms, for different reasons. DC01 (EN 10130) is a cold-rolled sheet bought for its surface, flatness, gauge accuracy and formability; the standard gives a yield *window* (140–280 MPa) and no impact value. S235JR (EN 10025-2) is a hot-rolled structural steel bought for a guaranteed *minimum* yield of 235 MPa and 27 J Charpy toughness, in plate, coil, sections and bar.

In practice the choice is settled by product form: below about 3 mm with a smooth surface you are buying DC01 (or DD11 hot-rolled if scale is acceptable); for anything load-bearing or thicker than 3 mm you are buying S235JR. The table shows exactly what each standard promises.

- Standard: DC01 = EN 10130 (cold-rolled products for cold forming) | S235JR = EN 10025-2 (hot-rolled structural steels)
- Material number: DC01 = 1.0330 | S235JR = 1.0038
- Old name: DC01 = St12 (DIN 1623) | S235JR = St37-2 (DIN 17100)
- Rolling: DC01 = cold-rolled, skin-passed | S235JR = hot-rolled (+AR) or normalized (+N)
- Thickness range: DC01 = 0.35–3.0 mm | S235JR = ≥ 1.5 mm coil; plate to 400 mm; sections
- Surface: DC01 = smooth, bright/matt, scale-free (A or B quality) | S235JR = mill scale as rolled (pickled on request)
- Yield strength: DC01 = 140–280 MPa (window; upper limit only 8 days after skin-pass) | S235JR = ≥ 235 MPa (minimum, ≤ 16 mm)
- Tensile strength: DC01 = 270–410 MPa | S235JR = 360–510 MPa
- Elongation: DC01 = ≥ 28 % (A80) | S235JR = ≥ 26 % (A, L0 = 5.65√S0)
- Impact toughness: DC01 = not specified | S235JR = 27 J at +20 °C
- Carbon max: DC01 = 0.12 % | S235JR = 0.17 % (≤ 40 mm)
- Mn max: DC01 = 0.60 % | S235JR = 1.40 %
- P / S max: DC01 = 0.045 / 0.045 % | S235JR = 0.035 / 0.035 %
- r / n values: DC01 = not guaranteed (DC04+ only) | S235JR = not applicable
- Structural design (EN 1993): DC01 = not a listed structural grade | S235JR = fy = 235 MPa
- Weldability: DC01 = excellent (spot, MAG, laser) | S235JR = excellent (all arc processes, no preheat)
- Coating options: DC01 = +ZE electro-galvanized (EN 10152); hot-dip as DX51D | S235JR = hot-dip after fabrication; coil as S250GD+Z
- Typical price basis: DC01 = per tonne, cold-rolled coil (≈ 10–15 % above hot-rolled) | S235JR = per tonne, hot-rolled coil/plate/sections
- Typical use: DC01 = enclosures, panels, appliances, furniture, drums | S235JR = frames, beams, plates, brackets, structures

Verdict: Order DC01 when the part is thin (≤ 3 mm), pressed or bent, and the surface matters — enclosures, panels, cabinets, drums, brackets that will be painted or powder-coated. You are paying for surface and gauge control, and you accept that yield is a window, not a minimum.

Order S235JR when the part carries load, is designed to a structural code, is thicker than 3 mm, or needs an impact guarantee — frames, base plates, beams, welded structures. If you need both a smooth surface and a guaranteed yield in thin gauge, the structural galvanized grades S250GD/S280GD+Z (EN 10346) or hot-rolled pickled S235JR+P are the answer.

Substituting DC01 for S235JR in a structural drawing is a specification error even if the measured yield happens to be above 235 MPa; substituting S235JR for DC01 is usually impossible in thin gauge and gives a scaled surface.

Q: Is DC01 the same as S235?
A: No. They are similar low-carbon steels, but DC01 (EN 10130) is a cold-rolled forming sheet with a yield window of 140–280 MPa and no impact guarantee, while S235JR (EN 10025-2) is a hot-rolled structural steel with a guaranteed minimum yield of 235 MPa and 27 J at +20 °C. They are ordered, priced and used differently.

Q: Which is stronger, DC01 or S235JR?
A: S235JR is guaranteed ≥ 235 MPa yield and 360–510 MPa tensile; DC01 may be anywhere from 140 to 280 MPa yield and 270–410 MPa tensile. Typical DC01 coil tests around 180–220 MPa, so S235JR is usually stronger and always the one with a guarantee.

Q: Can I use DC01 for a structural part?
A: Not where a structural code applies — DC01 is not a listed structural grade in EN 1993 and has no minimum yield. For thin structural sheet use S235JR/S275JR hot-rolled coil, or the galvanized structural grades S250GD–S350GD (EN 10346).

Q: Is S235JR available cold-rolled?
A: Not under EN 10025-2, which is a hot-rolled standard. Thin cold-rolled sheet with structural guarantees is sold as S235JRC-type bright products (EN 10277 bar) or as the cold-rolled/galvanized structural grades of EN 10346 (S220GD…S550GD).

Q: What is the German / Polish name for these grades?
A: DC01 was St12 (DIN 1623) and S235JR was St37-2 (DIN 17100) — 'St12 vs St37' is the same question. In Polish practice DC01 replaced St0S/St1S-type cold-rolled sheet and S235JR replaced St3S.

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## DD11 vs S235JR
URL: https://steelstandart.com/compare/dd11-vs-s235jr/

These two look interchangeable on a stock list and are not. S235JR is a structural steel to EN 10025-2: the mill guarantees a minimum yield of 235 MPa, because the number is what an engineer designs against. DD11 is a forming steel to EN 10111: the mill guarantees elongation and a yield *ceiling* of 170–360 MPa, because what matters is that the sheet bends and draws without cracking or springing back unpredictably.

The practical consequence is blunt. You cannot substitute DD11 into a structural calculation, because there is no minimum yield to calculate with. You can usually substitute S235JR into a forming job, but it will spring back more and may crack at the tight radii DD11 tolerates.

- Standard: DD11 = EN 10111:2008 | S235JR = EN 10025-2:2019
- Material number: DD11 = 1.0332 | S235JR = 1.0038
- Purpose: DD11 = Hot-rolled sheet and strip for cold forming | S235JR = Hot-rolled structural steel
- Old name: DD11 = StW22, St W 22 | S235JR = St37-2, Fe360B
- Yield ReH: DD11 = 170–360 MPa (range, not a minimum) | S235JR = 235 MPa minimum, ≤ 16 mm
- Tensile Rm: DD11 = 440 MPa maximum | S235JR = 360–510 MPa
- Elongation A80 / A: DD11 = 24 % min. (t < 3 mm) / 28 % min. | S235JR = 26 % min. (≥ 3 mm)
- Max C: DD11 = 0.12 % | S235JR = 0.17 %
- Max Mn: DD11 = 0.60 % | S235JR = 1.40 %
- Max P / S: DD11 = 0.045 / 0.045 % | S235JR = 0.035 / 0.035 %
- Impact test: DD11 = Not required | S235JR = 27 J at +20 °C (JR)
- Delivery forms: DD11 = Sheet, strip, coil, 1.5–11 mm typical | S235JR = Sections, plate, bar, hollow sections, sheet
- Surface: DD11 = Pickled or black, oiled on request | S235JR = Mill scale, pickled on request
- Bend radius, transverse: DD11 = 0.5–1 × thickness | S235JR = 1.5–2 × thickness
- Designed against: DD11 = Formability — draw, bend, roll | S235JR = Yield strength — beams, frames, brackets
- Structural design use: DD11 = Not permitted: no guaranteed minimum yield | S235JR = Yes, EN 1993 design value 235 MPa
- Family above it: DD11 = DD12, DD13, DD14 (progressively better forming) | S235JR = S275JR, S355JR (progressively stronger)
- JIS closest: DD11 = SPHC / SPHD | S235JR = SS400 / SM400A
- ASTM closest: DD11 = A1011 CS Type B / A569 (withdrawn) | S235JR = A283 Gr C, A36 with caveats
- Typical price: DD11 = Baseline for hot-rolled sheet | S235JR = 0–3 % over DD11 in sheet, same coil

Verdict: DD11 for anything that gets bent, rolled or drawn — tube and profile mills, enclosure panels, brackets pressed in a die, silo bodies. S235JR for anything that has to carry a calculated load, because it is the grade the structural code recognises. Where a part is both formed and structural, the honest answer is neither: specify S235JR with a bend test agreed at order, or move up to a forming grade with a guaranteed minimum yield such as S315MC in EN 10149-2.

Q: What is the difference between DD11 and S235JR?
A: DD11 is a forming steel with a yield *range* of 170–360 MPa and no guaranteed minimum; S235JR is a structural steel with a guaranteed minimum yield of 235 MPa and a Charpy test at +20 °C. DD11 bends more readily, S235JR is what structural design uses.

Q: Can I use DD11 instead of S235JR?
A: Not in a structural calculation. A DD11 coil can legitimately be delivered at 180 MPa yield, which is below the 235 MPa the design assumes. For non-structural formed parts the substitution is normal.

Q: Can I use S235JR instead of DD11?
A: Usually yes for mild forming, but expect more springback and a larger minimum bend radius; the higher manganese and carbon make the steel stiffer in the die. For deep drawing, use DD13 or DD14.

Q: Is DD11 the same as StW22?
A: Yes. StW22 is the withdrawn DIN 1614 designation; EN 10111 replaced it with DD11 and the material number 1.0332 carried over.

Q: What is DD11 used for?
A: Welded tube and hollow sections, roll-formed profiles, pressed enclosures, silo and tank bodies, automotive brackets and agricultural equipment panels — anything shaped cold from hot-rolled sheet.

Q: Is DD11 weldable?
A: Very. Carbon is capped at 0.12 % and manganese at 0.60 %, so the carbon equivalent sits around 0.15–0.25 and no preheat is needed in normal thicknesses.

---

## DX51D vs DX52D
URL: https://steelstandart.com/compare/dx51d-vs-dx52d/

Every hot-dip galvanized coil in EN 10346 starts from this family, and the two lowest classes cover almost all of the volume. DX51D is the commercial grade: it bends, roll-forms and profiles happily. DX52D is the drawing grade: tighter carbon, better elongation, and the class a press shop asks for when a part has a deep radius or a stretched corner.

Neither has a guaranteed minimum yield — they are forming grades, not structural ones. If a drawing needs a yield value on a galvanized coil, the family to read is S220GD to S550GD, not DX.

- Standard: DX51D = EN 10346:2015 | DX52D = EN 10346:2015
- Material number: DX51D = 1.0917 | DX52D = 1.0350
- Class: DX51D = Commercial forming | DX52D = Drawing quality
- Yield Re: DX51D = 140–320 MPa (typical, not guaranteed) | DX52D = 140–300 MPa (typical, not guaranteed)
- Tensile Rm: DX51D = 270–500 MPa | DX52D = 270–420 MPa
- Elongation A80, min.: DX51D = 22 % | DX52D = 26 %
- r90 value (deep draw): DX51D = Not specified | DX52D = Not specified (DX53D and above: ≥ 1.3)
- Max C: DX51D = 0.12 % | DX52D = 0.12 %
- Max Mn: DX51D = 0.60 % | DX52D = 0.60 %
- Max P / S: DX51D = 0.10 / 0.045 % | DX52D = 0.08 / 0.040 %
- Typical bend radius: DX51D = 1.0–1.5 × thickness | DX52D = 0.5–1.0 × thickness
- Ageing resistance: DX51D = Not guaranteed | DX52D = Guaranteed 6 months (as DX52D+Z)
- Coating options: DX51D = Z, ZF, ZM, AZ, AS | DX52D = Z, ZF, ZM, AZ, AS
- Surface classes: DX51D = A or B, MB / MC / MA spangle | DX52D = A or B, usually MB minimum
- Common thicknesses: DX51D = 0.25–3.0 mm | DX52D = 0.30–3.0 mm
- Price index: DX51D = 100 | DX52D = 103–108
- Typical use: DX51D = Roofing, purlins, ducting, profiles, tube | DX52D = Pressed panels, appliance parts, deeper draws
- Next class up: DX51D = DX52D | DX52D = DX53D, then DX54D (best draw)
- JIS closest: DX51D = SGCC | DX52D = SGCD1
- ASTM closest: DX51D = A653 CS Type B | DX52D = A653 FS / DS Type B

Verdict: DX51D for anything bent, rolled or profiled — which is the overwhelming majority of galvanized coil sold. DX52D when the part is pressed and the radius is tight, or when the coil will sit in stock for months and stretcher-strain marks would be unacceptable. The price difference is small; the cost of scrapping a pressed batch is not. If DX52D still cracks, the problem is the class, not the supplier: go to DX53D or DX54D.

Q: What is the difference between DX51D and DX52D?
A: Forming class. DX52D has a higher guaranteed elongation (26 % against 22 %), tighter phosphorus and sulphur, guaranteed ageing resistance and a smaller minimum bend radius. Both are galvanized coil to EN 10346 with no guaranteed minimum yield.

Q: What does the D in DX51D mean?
A: It marks the family for hot-dip coating: D for coated flat products, X for a hot- or cold-rolled base at the mill's choice, and the trailing D for hot-dip coating. DX52D is the same convention one class up.

Q: Can I substitute DX52D for DX51D?
A: Yes — every forming property is equal or better. The reverse is a downgrade and should not be accepted on pressed parts without a trial.

Q: Which one do I use for roofing sheet?
A: DX51D+Z is the standard choice, usually in Z100 to Z275 depending on the environment. The forming in a roll-formed profile is well within its class.

Q: Do these grades have a yield strength?
A: Not a guaranteed minimum. Typical values are quoted for information only. If the design needs a yield figure, use the structural galvanized family: S220GD, S250GD, S280GD, S320GD or S350GD.

Q: What does the +Z suffix mean?
A: The coating type: Z is pure zinc, ZF is galvannealed, ZM is zinc-magnesium, AZ is aluzinc and AS is aluminium-silicon. It is written after the grade, as in DX51D+Z275.

---

## P355GH vs S355J2
URL: https://steelstandart.com/compare/p355gh-vs-s355j2/

The two grades are cousins with the same headline number and entirely different qualification. P355GH belongs to EN 10028-2, the standard for pressure-purpose plate: it carries guaranteed proof strength at elevated temperature, up to 400 °C or beyond, because a vessel wall gets hot. S355J2 belongs to EN 10025-2, structural steel: it carries a Charpy value at −20 °C, because a bridge gets cold.

One more thing worth saying plainly, because it is the single most common error in enquiries: there is no such grade as S355GH. The S prefix belongs to structural steel and the GH suffix to pressure steel; mixing them produces a designation no standard defines. What the enquiry almost always means is P355GH.

- Standard: P355GH = EN 10028-2:2017 (pressure purposes) | S355J2 = EN 10025-2:2019 (structural)
- Material number: P355GH = 1.0473 | S355J2 = 1.0577
- Purpose: P355GH = Boilers, pressure vessels, heat exchangers | S355J2 = Structures, frames, bridges, machinery
- Min. yield ReH, ≤ 16 mm: P355GH = 355 MPa | S355J2 = 355 MPa
- Yield at 200 °C: P355GH = 255 MPa (guaranteed) | S355J2 = Not guaranteed
- Yield at 300 °C: P355GH = 213 MPa (guaranteed) | S355J2 = Not guaranteed
- Yield at 400 °C: P355GH = 181 MPa (guaranteed) | S355J2 = Not guaranteed
- Tensile Rm: P355GH = 510–650 MPa | S355J2 = 470–630 MPa
- Impact test: P355GH = 27 J at 0 °C (longitudinal, standard) | S355J2 = 27 J at −20 °C
- Max C: P355GH = 0.20 % | S355J2 = 0.24 %
- Max Mn: P355GH = 1.10–1.70 % | S355J2 = 1.60 %
- Max P / S: P355GH = 0.025 / 0.015 % | S355J2 = 0.035 / 0.035 %
- Cleanliness: P355GH = Tighter — designed for welded pressure joints | S355J2 = Standard structural limits
- Delivery condition: P355GH = N (normalised) | S355J2 = As rolled, N or M
- Forms: P355GH = Plate only, 5–150 mm | S355J2 = Plate, sections, hollow sections, bar
- Design codes: P355GH = EN 13445, AD 2000-Merkblatt, PED 2014/68/EU | S355J2 = EN 1993 (Eurocode 3)
- ASTM counterpart: P355GH = A516 Gr 70 (closest, not identical) | S355J2 = A572 Gr 50
- Certificate: P355GH = EN 10204 3.1 with elevated-temperature data | S355J2 = EN 10204 3.1 with −20 °C Charpy
- Price difference: P355GH = 15–30 % over structural plate | S355J2 = Baseline
- Does S355GH exist?: P355GH = No — the designation is invalid | S355J2 = No

Verdict: P355GH whenever the steel is part of a pressure envelope or sees service temperature above about 100 °C — vessel shells, boiler drums, heat exchanger shells, steam pipework flanges. S355J2 for everything structural, especially where cold toughness matters. They are not substitutes in either direction: using S355J2 in a pressure vessel fails the code because there is no proof strength at temperature, and using P355GH in a cold outdoor frame pays 15–30 % more for a property the frame does not need while giving up the −20 °C impact guarantee.

Q: What is the difference between P355GH and S355J2?
A: P355GH is a pressure-vessel plate with guaranteed proof strength at elevated temperature and tighter phosphorus and sulphur; S355J2 is a structural steel with a guaranteed Charpy value at −20 °C. Room-temperature yield is 355 MPa for both.

Q: Is there a grade called S355GH?
A: No. The S prefix means structural (EN 10025) and GH means pressure purposes at elevated temperature (EN 10028). Enquiries asking for S355GH almost always mean P355GH.

Q: Can I use S355J2 instead of P355GH?
A: Not in pressure equipment. The design code requires proof strength at design temperature, which S355J2 does not guarantee, and the notified body will reject the material certificate.

Q: Can I use P355GH for a structure?
A: Technically it is strong enough, but it costs more, comes only as plate, and its standard impact test is at 0 °C rather than −20 °C. For a cold outdoor structure it is the wrong choice despite being the more expensive steel.

Q: What is the ASTM equivalent of P355GH?
A: A516 Grade 70 is the usual counterpart — both are normalised pressure-vessel plates in the same strength class — but the chemistry and the elevated-temperature tables differ, so it is functional equivalence rather than a substitution.

Q: Which is easier to weld?
A: Both weld with standard procedures. P355GH has tighter sulphur and phosphorus limits and is supplied normalised, which helps in thick pressure joints; S355J2 allows slightly more carbon, so above 30 mm preheat is checked from the actual CEV.

---

## S235JR vs P265GH
URL: https://steelstandart.com/compare/s235jr-vs-p265gh/

S235JR and P265GH (or its lower class P235GH) look alike on a certificate — both are low-carbon steels around 235–265 MPa yield — which is why S235 plate turns up, wrongly, in vessel and boiler drawings. The difference is not so much the steel as the guarantee package and the legal status. P265GH is made to EN 10028-2 for pressure equipment: yield strength tabulated from 50 to 400 °C, Charpy 27 J at −20 °C, sulphur ≤ 0.010 %, aluminium-killed and normalized, carbon equivalent capped, and tested and certified plate by plate under the Pressure Equipment Directive. S235JR is made to EN 10025-2 for buildings and machinery: room-temperature properties only, 27 J at +20 °C, P/S ≤ 0.035 %, tested per heat.

The result: P265GH can always do S235JR's job (and S275JR's), but S235JR can never be used for a PED-scope pressure part without a particular material appraisal. The table compares S235JR with P265GH; the P235GH row shows the lower pressure class that matches S235 on strength.

- Standard / purpose: S235JR = EN 10025-2 — hot-rolled structural steel | P265GH = EN 10028-2 — flat products for pressure purposes, elevated temperature
- Material number: S235JR = 1.0038 | P265GH = 1.0425 (P235GH: 1.0345)
- Old name: S235JR = St37-2 | P265GH = HII (P235GH: HI)
- Legal scope: S235JR = CPR (construction products), EN 1090 | P265GH = PED 2014/68/EU, EN 13445 / EN 12952 / AD 2000
- Yield ≤ 16 mm: S235JR = 235 MPa | P265GH = 265 MPa (P235GH: 235 MPa)
- Yield at 300 °C: S235JR = not guaranteed | P265GH = 173 MPa (P235GH: 152 MPa)
- Yield at 400 °C: S235JR = not guaranteed | P265GH = 145 MPa (P235GH: 128 MPa)
- Tensile: S235JR = 360–510 MPa | P265GH = 410–530 MPa (P235GH: 360–480 MPa)
- Elongation: S235JR = ≥ 26 % | P265GH = ≥ 23 % (P235GH: ≥ 25 %)
- Impact (transverse): S235JR = 27 J at +20 °C (longitudinal) | P265GH = 27 J at −20 °C, 31 J at 0 °C, 34 J at +20 °C (transverse)
- Carbon max: S235JR = 0.17 % | P265GH = 0.20 % (P235GH: 0.16 %)
- Mn: S235JR = ≤ 1.40 % | P265GH = 0.80–1.40 % (P235GH: 0.60–1.20 %)
- S max: S235JR = 0.035 % | P265GH = 0.010 %
- P max: S235JR = 0.035 % | P265GH = 0.025 %
- Al / N: S235JR = N ≤ 0.012 (Al optional) | P265GH = Al ≥ 0.020 total, N ≤ 0.012 — fully killed, fine grain
- Residuals (Cr, Cu, Mo, Ni, Nb, Ti, V): S235JR = Cu ≤ 0.55 only | P265GH = each limited; Cr+Cu+Mo+Ni ≤ 0.70
- CEV max: S235JR = 0.35 % (≤ 30 mm) | P265GH = 0.40 % (≤ 60 mm)
- Delivery condition: S235JR = +AR, +N or +M at mill's option | P265GH = +N mandatory > 16 mm (normalized or normalizing-rolled)
- Testing frequency: S235JR = per heat / per 40 t (option A) | P265GH = per plate (or per heat-treatment batch) — EN 10028-1
- Inspection document: S235JR = 2.2 or 3.1 | P265GH = 3.1 minimum, 3.2 common (PED category III/IV)
- Creep data: S235JR = none | P265GH = informative creep rupture to ~480 °C
- Price: S235JR = 1.00 | P265GH = ≈ 1.15–1.30
- Typical use: S235JR = frames, beams, tanks (non-pressure), general fabrication | P265GH = boilers, pressure vessels, heat exchangers, LPG tanks, steam equipment

Verdict: P265GH (or P235GH) for anything that holds pressure or runs hot: boilers, air receivers, heat-exchanger shells, LPG vessels, steam piping components, autoclaves — and for any equipment inside the Pressure Equipment Directive, where a P…GH grade with a 3.1/3.2 certificate is the only compliant route.

S235JR for structure and atmospheric equipment: frames, skids, saddles and supports of the same vessel, non-pressure tanks, hoppers, walkways. It is 15–30 % cheaper and easier to source in sections and coil.

If a shop has only P265GH in stock, using it for structural parts is fine (it exceeds S235JR/S275JR). The reverse — S235JR in a pressure shell — is a code violation regardless of the measured properties, because the elevated-temperature yield, the impact at −20 °C and the per-plate testing were never done.

Q: What is the difference between S235JR and P235GH?
A: Same room-temperature yield (235 MPa), but P235GH (EN 10028-2) is a pressure-vessel steel: guaranteed yield up to 400 °C, Charpy at −20 °C transverse, sulphur ≤ 0.010 %, killed and normalized, tested per plate for the Pressure Equipment Directive. S235JR (EN 10025-2) is a structural steel with room-temperature guarantees and +20 °C impact, tested per heat.

Q: Can S235JR be used for a pressure vessel?
A: Not for equipment within the PED scope, except through a particular material appraisal by a notified body — which is rarely worthwhile when P235GH/P265GH exist. For non-PED items (e.g. sound engineering practice below 0.5 bar or small volumes) it may be acceptable; check EN 13445-2 and the national rules.

Q: Can P265GH replace S235JR or S275JR?
A: Yes — it meets or exceeds their strength and toughness, and its 3.1 certificate is acceptable for structural use under EN 1090 if the CE marking route allows it. It costs more, so it is done only to use up stock or simplify traceability.

Q: What is the difference between P235GH and P265GH?
A: Strength class: P235GH (1.0345, ex HI) has 235 MPa yield and 360–480 MPa tensile, common for tubes; P265GH (1.0425, ex HII) has 265 MPa and 410–530 MPa, the standard vessel plate. Chemistry differs slightly (C 0.16 vs 0.20 %, Mn ranges).

Q: What are HI and HII?
A: The DIN 17155 names of P235GH (HI) and P265GH (HII), withdrawn in 1992 but still used in German, Turkish and Middle-East boiler practice.

Q: What is the ASTM equivalent of P265GH?
A: ASTM/ASME A516 Grade 60 (near — yield 220 MPa) or Grade 65 (240 MPa); A285 Grade C for low-pressure equipment.

---

## S235JR vs S235J0
URL: https://steelstandart.com/compare/s235jr-vs-s235j0/

Same steel, different promise about cold. Both grades sit in EN 10025-2 with a 235 MPa minimum yield and the same tensile range; what changes is the Charpy V-notch test. JR is verified at room temperature, J0 at zero, J2 at minus twenty. The steel is not magically tougher — the mill simply commits to a result at a lower temperature, and to the cleaner chemistry needed to pass it consistently.

That is why the upgrade is cheap in thin material and expensive in thick. A 10 mm plate will pass at 0 °C almost regardless; a 60 mm plate needs controlled rolling, tighter phosphorus and sulphur and sometimes a normalising pass.

- Standard: S235JR = EN 10025-2:2019 | S235J0 = EN 10025-2:2019
- Material number: S235JR = 1.0038 | S235J0 = 1.0114
- Impact energy: S235JR = 27 J at +20 °C | S235J0 = 27 J at 0 °C
- Min. yield ReH, ≤ 16 mm: S235JR = 235 MPa | S235J0 = 235 MPa
- Tensile Rm, 3–100 mm: S235JR = 360–510 MPa | S235J0 = 360–510 MPa
- Elongation A, ≥ 3 mm: S235JR = 26 % | S235J0 = 26 %
- Max C, ≤ 16 mm: S235JR = 0.17 % | S235J0 = 0.17 %
- Max P: S235JR = 0.035 % | S235J0 = 0.030 %
- Max S: S235JR = 0.035 % | S235J0 = 0.030 %
- Max N: S235JR = 0.012 % | S235J0 = 0.012 %
- Deoxidation: S235JR = Optional (FN — rimming not permitted) | S235J0 = FN, fully killed practice in effect
- Typical thickness limit in stock: S235JR = All sections and plate | S235J0 = Plate and heavier sections
- Price difference: S235JR = Baseline | S235J0 = 0–3 % in thin, 3–8 % in heavy plate
- Where it is required: S235JR = Indoor, ambient, non-critical | S235J0 = Outdoor structures in temperate climates
- Old name: S235JR = St37-2 | S235J0 = St37-3 U
- Next step up: S235JR = S235J2 (27 J at −20 °C) | S235J0 = S235J2 (27 J at −20 °C)
- ASTM parallel: S235JR = A36 (no low-temperature requirement) | S235J0 = A36 with supplementary impact testing
- EN 1993-1-10 use: S235JR = Limited thickness in cold service | S235J0 = Greater permitted thickness at low temperature
- Certificate: S235JR = EN 10204 3.1 with room-temperature Charpy | S235J0 = EN 10204 3.1 with 0 °C Charpy
- Same weld procedure?: S235JR = Yes | S235J0 = Yes

Verdict: Specify J0 when the steel will be cold and loaded at the same time — outdoor frames in a temperate climate, plant that starts up in winter, thick welded joints where restraint adds to the risk. JR is enough indoors and for light thicknesses. If the structure is genuinely exposed to hard winters, do not stop at J0: EN 1993-1-10 usually pushes the answer to S235J2 or S355J2, and the cost gap between J0 and J2 is smaller than the gap from JR to J0.

Q: What does J0 mean in S235J0?
A: The impact quality: a Charpy V-notch test giving at least 27 joules at 0 °C. JR is the same energy at +20 °C, J2 at −20 °C.

Q: Is S235J0 stronger than S235JR?
A: No. Yield, tensile and elongation are identical. Only the guaranteed low-temperature toughness differs, along with slightly tighter phosphorus and sulphur limits.

Q: Can I use S235J0 where S235JR is specified?
A: Yes — it meets everything JR requires and adds a toughness guarantee. The reverse is not true and should never be accepted without the designer's approval.

Q: Does J0 cost more?
A: Slightly in thin material, more in heavy plate, where reaching 27 J at 0 °C requires controlled rolling and cleaner steel. In sections the difference is often lost in the rounding.

Q: Which impact class do I actually need?
A: EN 1993-1-10 answers it from the service temperature, the plate thickness and the stress level. As a rough guide: indoors JR, outdoors in a temperate climate J0, outdoors in a cold climate or in thick welded joints J2.

Q: Is S235J0 the same as St37-3?
A: It replaced St37-3 U from the withdrawn DIN 17100. The old name still appears on drawings in Germany, Türkiye and the Balkans.

---

## S235JR vs S355J2
URL: https://steelstandart.com/compare/s235jr-vs-s355j2/

S235 and S355 are the two ends of the everyday EN 10025-2 structural range — the same low-carbon steel family, the same delivery forms, the same mills, but a 50 % difference in yield strength that changes section sizes, weld procedures and price. S235JR is the base grade; S355J2 is the plate grade specified for cranes, bridges and machinery. This page puts the numbers side by side and says when each one is the right choice.

The short version: S355 costs only 5–10 % more per tonne but carries 50 % more load per kilogram, so any strength-governed member should be S355. S235 wins when deflection, buckling of slender elements, easy forming, or minimal welding control matter more than strength.

- Standard: S235JR = EN 10025-2:2019 | S355J2 = EN 10025-2:2019
- Material number: S235JR = 1.0038 | S355J2 = 1.0577
- Old names: S235JR = St37-2, Fe360B, 40B | S355J2 = St52-3 N, Fe510D, 50D
- Min. yield ReH, ≤ 16 mm: S235JR = 235 MPa (34 ksi) | S355J2 = 355 MPa (51 ksi)
- Min. yield, 40–63 mm: S235JR = 215 MPa | S355J2 = 335 MPa
- Tensile Rm, 3–100 mm: S235JR = 360–510 MPa | S355J2 = 470–630 MPa
- Elongation A, ≤ 40 mm: S235JR = ≥ 26 % | S355J2 = ≥ 22 %
- Impact (Charpy V): S235JR = 27 J at +20 °C | S355J2 = 27 J at −20 °C
- Carbon max: S235JR = 0.17 % (≤ 40 mm) | S355J2 = 0.22 %
- Mn max: S235JR = 1.40 % | S355J2 = 1.60 %
- P / S max: S235JR = 0.035 / 0.035 % | S355J2 = 0.025 / 0.025 %
- CEV max, ≤ 30 mm: S235JR = 0.35 % | S355J2 = 0.45 %
- Deoxidation: S235JR = optional (FN) | S355J2 = fully killed (FF)
- Preheat for welding: S235JR = none to ~40 mm | S355J2 = consider above 25 mm (EN 1011-2)
- Typical hardness: S235JR = 100–140 HB | S355J2 = 150–190 HB
- Min. bend radius, 8–16 mm (transverse): S235JR = 2.0 t | S355J2 = 3.0 t
- Design fy (EN 1993-1-1), t ≤ 40 mm: S235JR = 235 MPa | S355J2 = 355 MPa
- Relative price per tonne (2026, coil/plate): S235JR = 1.00 | S355J2 = ≈ 1.05–1.10
- Strength per € (yield/price): S235JR = 1.00 | S355J2 = ≈ 1.40
- Typical use: S235JR = secondary steelwork, frames, general fabrication | S355J2 = primary structure, cranes, bridges, machinery, heavy transport

Verdict: Choose S355J2 when strength governs: beams, columns, crane girders, lifting gear, trailers, anything designed to EN 1993 where a smaller section saves weight or the load is high. The 5–10 % price premium is repaid by 30–35 % lighter members. You also get −20 °C toughness and cleaner steel.

Choose S235JR when strength does not govern: deflection-limited beams (stiffness E is identical, so S355 does not help), slender elements that fail by buckling before yield, parts that will be cold-formed with tight radii, thin sheet, galvanized handrails and fences, and small shops without welding-procedure control. It is also the grade to order when a drawing says St37 or A36.

Do not mix them unmarked on one job: S355 in the wrong place is harmless, but S235 substituted where S355 was designed is a 34 % strength shortfall.

Q: What is the difference between S235 and S355?
A: Yield strength: 235 vs 355 MPa (up to 16 mm) — S355 is 51 % stronger. Tensile 360–510 vs 470–630 MPa. S355 allows more carbon and manganese (CEV 0.45 vs 0.35 %), so thick S355 needs welding care; S355J2 is also tested at −20 °C and is cleaner (P/S ≤ 0.025 %).

Q: Is S355 much more expensive than S235?
A: No — typically 5–10 % more per tonne for plate and coil, sometimes less for sections. Per unit of load capacity S355 is about 40 % cheaper, which is why primary structures use it.

Q: Is S355 harder to weld than S235?
A: Slightly. Both weld with standard E42/E46 consumables without preheat in thin sections; S355 above ~25 mm or in restrained joints should have preheat calculated per EN 1011-2 because its carbon equivalent can reach 0.45 %. Low-hydrogen consumables are standard for S355.

Q: Can I replace S235 with S355?
A: Yes, upward substitution is always safe for strength. Check only that welding procedures suit the higher CEV, and that the extra strength does not change the failure mode in fatigue-critical or ductility-governed details.

Q: Which is stiffer, S235 or S355?
A: Neither — Young's modulus is 210 GPa for both. A beam of the same section deflects identically; S355 only lets you use a smaller section if strength, not deflection, is the limit.

Q: What are S235JR and S355J2 called in ASTM and DIN?
A: S235JR ≈ ASTM A36 (250 MPa) and DIN St37-2; S355J2 ≈ ASTM A572 Grade 50 (345 MPa, add Charpy) and DIN St52-3 N.

---

## S235JR vs S355JR
URL: https://steelstandart.com/compare/s235jr-vs-s355jr/

This is the S235 against S355 question asked inside one impact class. JR means the Charpy test is carried out at room temperature, 27 joules, on both grades — so the choice here is purely strength and chemistry, with the toughness question parked.

It comes up in two situations. The first is a supplier offering S355JR where a drawing calls for S235JR: structurally an upgrade, commercially usually free, but still a change. The second is the opposite, an offer of S235JR against an S355 drawing, which is a downgrade and has to be refused unless the designer re-checks. Both cases hinge on the same table.

- Standard: S235JR = EN 10025-2:2019 | S355JR = EN 10025-2:2019
- Material number: S235JR = 1.0038 | S355JR = 1.0045
- Impact test: S235JR = 27 J at +20 °C | S355JR = 27 J at +20 °C
- Old names: S235JR = St37-2, Fe360B, 40B | S355JR = St52-3, Fe510B, 50B
- Min. yield ReH, ≤ 16 mm: S235JR = 235 MPa (34 ksi) | S355JR = 355 MPa (51 ksi)
- Min. yield, 16–40 mm: S235JR = 225 MPa | S355JR = 345 MPa
- Min. yield, 40–63 mm: S235JR = 215 MPa | S355JR = 335 MPa
- Tensile Rm, 3–100 mm: S235JR = 360–510 MPa | S355JR = 470–630 MPa
- Elongation A, ≥ 3 mm: S235JR = 26 % | S355JR = 22 %
- Max C, ≤ 30 mm: S235JR = 0.17 % | S355JR = 0.24 %
- Max Mn: S235JR = 1.40 % | S355JR = 1.60 %
- Max Si: S235JR = not specified | S355JR = 0.55 %
- Carbon equivalent CEV, ≤ 30 mm: S235JR = 0.35 % | S355JR = 0.45 %
- Cold forming: S235JR = Excellent — the lower carbon tolerates tight radii | S355JR = Good, but larger bend radii and more springback
- Weldability: S235JR = Excellent in all thicknesses | S355JR = Excellent to ~30 mm; check CEV above that
- Common forms: S235JR = Sections, hollow sections, sheet, bar, plate | S355JR = Sections, hollow sections, plate, heavy plate
- Where it dominates: S235JR = General fabrication, frames, handrails, brackets | S355JR = Load-bearing frames, machine bases, cranes
- ASTM closest: S235JR = A283 Gr C / A36 (with caveats) | S355JR = A572 Gr 50
- JIS closest: S235JR = SS400 / SM400A | S355JR = SM490A
- GB closest: S235JR = Q235B | S355JR = Q345B

Verdict: S355JR for anything structural, because the 51 per cent yield advantage translates directly into smaller sections and the price gap is small. S235JR where forming, not strength, is the job — brackets, trims, cold-bent parts and anything drawn or pressed, where the lower carbon and the 26 per cent elongation make the steel behave. Accepting S355JR against an S235JR drawing is normally safe; the reverse never is without a design check.

Q: Is S355JR stronger than S235JR?
A: Yes — 355 MPa minimum yield against 235 MPa up to 16 mm, and 470–630 MPa tensile against 360–510. Stiffness is identical: both have a 210 GPa modulus, so deflection does not improve.

Q: Can the supplier send S355JR instead of S235JR?
A: Usually acceptable, since every mechanical property is higher, but it is a substitution the designer should confirm. Cold-formed parts are the exception: S355 springs back more and needs larger radii.

Q: What does JR mean?
A: The impact quality: a Charpy V-notch test of 27 joules at +20 °C. J0 is the same energy at 0 °C, J2 at −20 °C. JR is the entry class and is not suitable for low-temperature service.

Q: Which galvanizes better?
A: S235JR, marginally. Coating appearance is driven by silicon and phosphorus; S355 permits up to 0.55 % silicon, which can push the coating into the Sandelin range and give a dull, thicker layer. Ask for the silicon content before galvanizing critical visible work.

Q: Do they cost the same?
A: Close. In Europe S355JR is usually within a few per cent of S235JR and sometimes identical, because mills roll more of it. In markets where S235 dominates stock, the order flips.

Q: Which one is St37 and which is St52?
A: S235JR replaced St37-2 and S355JR replaced St52-3 when DIN 17100 was withdrawn. The old names are still used commercially in Türkiye, Germany and much of the Balkans.

---

## S275JR vs S355JR
URL: https://steelstandart.com/compare/s275jr-vs-s355jr/

S275 and S355 are neighbours, not opposites. Both are hot-rolled non-alloy structural steels to EN 10025-2, both come as JR, J0 or J2, both weld with the same consumables and both arrive from the same mills. The whole difference is 80 MPa of yield strength and the chemistry needed to reach it.

That matters less than the S235 versus S355 question, because a 29 per cent strength gain is often eaten by deflection or buckling limits before it saves any steel. Where it does count is in plate work and in markets where S275 has quietly stopped being stocked — in much of Europe a mill will happily roll S355 and charge almost the same, which is why the grade is disappearing from service-centre lists.

- Standard: S275JR = EN 10025-2:2019 | S355JR = EN 10025-2:2019
- Material number: S275JR = 1.0044 | S355JR = 1.0045
- Old names: S275JR = St44-2, Fe430B, 43B | S355JR = St52-3, Fe510B, 50B
- Min. yield ReH, ≤ 16 mm: S275JR = 275 MPa (40 ksi) | S355JR = 355 MPa (51 ksi)
- Min. yield, 16–40 mm: S275JR = 265 MPa | S355JR = 345 MPa
- Min. yield, 40–63 mm: S275JR = 255 MPa | S355JR = 335 MPa
- Min. yield, 63–80 mm: S275JR = 245 MPa | S355JR = 325 MPa
- Tensile Rm, 3–100 mm: S275JR = 410–560 MPa | S355JR = 470–630 MPa
- Elongation A, ≥ 3 mm: S275JR = 23 % | S355JR = 22 %
- Impact energy, JR: S275JR = 27 J at +20 °C | S355JR = 27 J at +20 °C
- Max C, ≤ 30 mm: S275JR = 0.21 % | S355JR = 0.24 %
- Max Mn: S275JR = 1.50 % | S355JR = 1.60 %
- Max P / S: S275JR = 0.035 / 0.035 % | S355JR = 0.035 / 0.035 %
- Carbon equivalent CEV, ≤ 30 mm: S275JR = 0.40 % | S355JR = 0.45 %
- Density, E modulus: S275JR = 7.85 kg/dm³, 210 GPa | S355JR = 7.85 kg/dm³, 210 GPa
- Typical price difference: S275JR = baseline | S355JR = 0–4 % over S275 in Europe, sometimes zero
- Stock availability (2026): S275JR = Falling: many service centres only order it in | S355JR = Stocked in every form
- ASTM closest: S275JR = A572 Gr 42 / A283 Gr D | S355JR = A572 Gr 50
- JIS closest: S275JR = SM400B–SM490A | S355JR = SM490A / SS490
- GB closest: S275JR = Q275 | S355JR = Q345B

Verdict: Default to S355JR unless the drawing or the local stock says otherwise. The strength is 29 % higher, the price difference in Europe has narrowed to almost nothing, and the availability is better. S275JR still makes sense where an existing structure is built in it and connection details must match, where a design is deflection-governed and the extra yield buys nothing, or where a market genuinely prices it lower — which is still the case in parts of Asia and the Middle East.

Q: What is the difference between S275 and S355?
A: Minimum yield strength: 275 MPa against 355 MPa up to 16 mm thickness, and 410–560 against 470–630 MPa tensile. Everything else — standard, delivery condition, weldability, density, modulus — is effectively the same.

Q: Can I substitute S355 for S275?
A: Structurally almost always yes, since every strength property is higher. But it is still a design change: the engineer has to confirm that no detail relies on the lower yield, such as a ductile connection designed to yield before a weld fails.

Q: Is S275 cheaper than S355?
A: Rarely by much in Europe today. Mills roll far more S355, so the scale advantage has closed the gap; in some months S275 costs more because it has to be ordered specially.

Q: Do S275 and S355 weld the same way?
A: Broadly yes, with the same consumables. S355 allows a higher carbon equivalent (0.45 against 0.40 per cent), so above roughly 30 mm it is more likely to need preheat. Check the actual CEV on the mill certificate rather than the maximum in the standard.

Q: What is S275JR in ASTM?
A: The nearest common equivalents are A572 Grade 42 and A283 Grade D. None is identical: the chemistry limits and the impact testing regime differ, so a substitution needs the designer's approval.

Q: Which is better for a steel building frame?
A: S355 in most cases. Columns and beams sized on strength get lighter, and the material cost difference is small. Where the frame is governed by deflection or by the slenderness of long members, the extra yield does nothing and S275 is equally good.

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## SPHC vs DD11
URL: https://steelstandart.com/compare/sphc-vs-dd11/

Ask a mill for the European equivalent of SPHC and you will be offered DD11, and for most orders that answer is correct. Both are the cheapest hot-rolled sheet a mill makes with forming in mind, both sit in the same chemistry band, and both are bought by the tube makers, roll formers and pressing shops that have no structural calculation to satisfy.

Where they differ is what the certificate promises. JIS G3131 guarantees SPHC a *minimum tensile* of 270 MPa and an elongation, and says nothing about yield at all. EN 10111 guarantees DD11 a *yield band* of 170–360 MPa with a tensile *ceiling* of 440 MPa. One standard is worried that the sheet is too weak; the other is worried that it is too strong to form predictably.

For a press shop that difference is real. A DD11 certificate tells you the springback will fall inside a range; an SPHC certificate does not, and a batch at the top of the chemistry band can come in materially harder than the last one.

- Standard: SPHC = JIS G3131:2018 | DD11 = EN 10111:2008
- Designation meaning: SPHC = Steel Plate Hot Commercial | DD11 = Drawing quality, hot rolled (D = Draw)
- Material number: SPHC = — (JIS uses no number system) | DD11 = 1.0332
- Purpose: SPHC = General-purpose hot-rolled sheet and strip | DD11 = Hot-rolled sheet and strip for cold forming
- Yield ReH: SPHC = Not specified | DD11 = 170–360 MPa (a range, not a minimum)
- Tensile Rm: SPHC = 270 MPa minimum | DD11 = 440 MPa maximum
- Elongation: SPHC = 27–31 % by thickness | DD11 = 24 % min. A80 (t < 3 mm) / 28 % min. A
- Max C: SPHC = 0.15 % | DD11 = 0.12 %
- Max Mn: SPHC = 0.60 % | DD11 = 0.60 %
- Max P / S: SPHC = 0.050 / 0.050 % | DD11 = 0.045 / 0.045 %
- Impact test: SPHC = None | DD11 = None
- Grades above it: SPHC = SPHD (drawing), SPHE (deep drawing), SPHF | DD11 = DD12, DD13, DD14 (increasing formability)
- Typical thickness: SPHC = 1.2–14 mm | DD11 = 1.5–11 mm strip, wider on plate mills
- Surface options: SPHC = As-rolled or pickled and oiled (SPHC-P) | DD11 = As-rolled, or pickled and oiled (HRPO)
- Bend behaviour: SPHC = Good, but batch-to-batch spread is wider | DD11 = Consistent; the yield ceiling is the point of the grade
- Structural design use: SPHC = No — nothing to design against | DD11 = No — the yield is a range, not a minimum
- Closest ASTM: SPHC = A1011 CS Type B | DD11 = A1011 CS Type B
- Closest EN / JIS: SPHC = DD11 (this comparison) | DD11 = SPHC
- Where it is bought: SPHC = Asia-sourced coil, Japanese and Korean mills | DD11 = European and Turkish mills
- Typical price: SPHC = Identical class — origin and freight decide, not the grade | DD11 = Identical class — origin and freight decide, not the grade

Verdict: They are the same steel bought under two philosophies. For a tube mill or a roll former taking regular deliveries, DD11 is the safer specification because the yield ceiling limits how hard a batch can arrive, which keeps the tooling setup stable. SPHC is the grade to accept when the material is coming from an Asian mill and the alternative is paying a premium for a European certificate that the part does not need.

What neither one is, is structural. If a drawing calls for a minimum yield, the answer is S235JR, not either of these.

Q: Is SPHC the same as DD11?
A: They are the same class of steel and are normally accepted as equivalents, but the guarantees differ: SPHC is certified to a minimum tensile of 270 MPa with no yield requirement, while DD11 is certified to a yield range of 170–360 MPa and a tensile ceiling of 440 MPa.

Q: What is the European equivalent of SPHC?
A: DD11 to EN 10111, material number 1.0332. For the higher JIS forming grades the ladder continues: SPHD corresponds roughly to DD12 and SPHE to DD13, with deep-drawing performance rather than strength as the step between them.

Q: Can SPHC be used structurally?
A: No. JIS G3131 specifies no minimum yield for SPHC, so there is no number to design against. A structural member needs a grade with a guaranteed minimum yield such as S235JR to EN 10025-2 or A36 to ASTM.

Q: What does SPHC stand for?
A: Steel Plate Hot Commercial — commercial quality hot-rolled sheet in the JIS system. The letters that follow the S, P and H place it in the JIS family; the C marks it as the plain commercial grade below SPHD and SPHE.

Q: Is SPHC pickled?
A: Not unless it is ordered that way. SPHC-P is the pickled and oiled version, the JIS equivalent of what the European trade calls HRPO — hot-rolled pickled and oiled — and it is the form to order when the surface will be painted, coated or welded without descaling.

Q: Which is cheaper, SPHC or DD11?
A: Neither carries a grade premium: they are both the base commodity of their standard. The price difference on any given day comes from origin, parcel size and freight, not from the specification on the certificate.

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## St 37-2 vs S235JR
URL: https://steelstandart.com/compare/st37-vs-s235jr/

This is not really a comparison, it is a translation. St 37-2 was withdrawn when DIN 17100 was replaced by EN 10025 in 1994, and its successor is S235JR, material number 1.0038. A mill today cannot supply St 37-2 against a valid standard; what it supplies is S235JR with the old name written on the order for the customer's comfort.

The name survives because a generation of drawings, price lists and workshop habits use it — in Türkiye, Germany, Austria and across the Balkans, "St 37" is still what people say when they mean ordinary structural steel. The question worth answering is therefore not which is better, but what changes when the drawing says one and the certificate says the other.

- Standard: St 37-2 = DIN 17100 (withdrawn 1994) | S235JR = EN 10025-2:2019
- Material number: St 37-2 = 1.0037 (St 37-2) | S235JR = 1.0038 (S235JR)
- Status today: St 37-2 = Not a current standard — cannot be certified against | S235JR = Current, CE-markable under EN 1090
- Min. yield ReH, ≤ 16 mm: St 37-2 = 235 MPa | S235JR = 235 MPa
- Tensile Rm: St 37-2 = 340–470 MPa (DIN value) | S235JR = 360–510 MPa
- Elongation: St 37-2 = 25–26 % | S235JR = 26 %
- Impact test: St 37-2 = Not required for St 37-2 | S235JR = 27 J at +20 °C
- Max C, ≤ 16 mm: St 37-2 = 0.17 % | S235JR = 0.17 %
- Max P / S: St 37-2 = 0.045 / 0.045 % | S235JR = 0.035 / 0.035 %
- Deoxidation: St 37-2 = Rimming permitted in the -2 class | S235JR = Rimming not permitted (FN)
- Sub-grades: St 37-2 = St 37-2, USt 37-2, RSt 37-2, St 37-3 | S235JR = S235JR, S235J0, S235J2
- Closest one-to-one: St 37-2 = RSt 37-2 → S235JR | S235JR = S235JR → RSt 37-2
- CE marking: St 37-2 = Not possible | S235JR = Yes, with a DoP
- Typical use today: St 37-2 = Old drawings, workshop language, repairs | S235JR = Everything current
- ASTM parallel: St 37-2 = A283 Gr C / A36 with caveats | S235JR = A283 Gr C / A36 with caveats
- JIS parallel: St 37-2 = SS400 | S235JR = SS400
- GB parallel: St 37-2 = Q235B | S235JR = Q235B
- Certificate you will receive: St 37-2 = EN 10204 3.1 stating S235JR | S235JR = EN 10204 3.1 stating S235JR
- Price difference: St 37-2 = None — it is the same material | S235JR = None
- Where the old name still appears: St 37-2 = Türkiye, Germany, Austria, Balkans | S235JR = —

Verdict: Order S235JR. If the drawing says St 37-2, write "S235JR (ex St 37-2, 1.0037)" on the purchase order and the certificate will match the drawing without anyone having to interpret it later. The two real differences worth knowing: the old -2 class allowed rimming steel and looser phosphorus and sulphur, and St 37-2 carried no impact requirement, so if the application is cold or welded and thick, the modern grade to ask for is S235J0 or S235J2 rather than a plain JR.

Q: Is St 37 the same as S235JR?
A: In practice yes. St 37-2 from the withdrawn DIN 17100 was replaced by S235JR in EN 10025-2; the yield strength is identical at 235 MPa. EN 10025-2 tightens phosphorus and sulphur, forbids rimming steel and adds an impact test.

Q: Can I still buy St 37?
A: You can order it by that name and you will receive S235JR. No mill can issue a certificate against a withdrawn standard.

Q: What is St 37 in ASTM?
A: The closest common grades are A283 Grade C and A36, but neither is identical: A36 has a higher tensile range and different chemistry limits. Treat it as functional equivalence, not a substitution.

Q: What was RSt 37-2?
A: The killed-steel version of St 37-2 — R for beruhigt, meaning deoxidised. It is the sub-grade that maps most cleanly onto S235JR, because modern EN steel is never rimming.

Q: Is St 37 the same as St 37-2?
A: St 37 is the family; the suffix is the quality class. St 37-2 is the basic class, St 37-3 added impact testing and corresponds roughly to S235J0 or S235J2.

Q: What about St 52?
A: St 52-3 is the higher-strength member of the same withdrawn family and corresponds to S355JR or S355J2 depending on the impact class.

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## St37 vs St52
URL: https://steelstandart.com/compare/st37-vs-st52/

St37 and St52 are the two DIN 17100 names that never died. The standard was withdrawn in 1994, but 'St37' still means everyday structural steel and 'St52' the strong one across Germany, Turkey, Poland, Iran and the Gulf, on hydraulic-cylinder drawings, in tube catalogues and in countless purchase orders. The numbers are the old minimum tensile strengths in kp/mm²: 37 kp/mm² ≈ 360 MPa and 52 kp/mm² ≈ 510 MPa; the yield strengths are 235 and 355 MPa — exactly the S235 and S355 of EN 10025-2 today.

So the modern answer to 'St37 or St52?' is 'S235JR or S355J2?', and the trade-offs are the same: S355 carries 50 % more load per kilogram for 5–10 % more money but needs slightly more welding care in thick sections. This page gives the original DIN values, the EN successors, and the middle grade St44 (S275) that many buyers forget exists.

- DIN 17100 grade: St37 = St37-2 (also USt37-2, RSt37-2, St37-3) | St52 = St52-3 (U or N)
- Material number (DIN → EN): St37 = 1.0037 → 1.0038 | St52 = 1.0570 → 1.0577
- EN 10025-2 successor: St37 = S235JR (St37-3 N → S235J2) | St52 = S355J2 (St52-3 U → S355JR)
- Meaning of the number: St37 = 37 kp/mm² ≈ 363 MPa min. tensile | St52 = 52 kp/mm² ≈ 510 MPa min. tensile
- Min. yield, < 16 mm: St37 = 235 MPa | St52 = 355 MPa
- Min. yield, 40–63 mm: St37 = 215 MPa | St52 = 335 MPa
- Tensile (DIN 17100): St37 = 340–470 MPa | St52 = 490–630 MPa
- Tensile (EN successor): St37 = 360–510 MPa | St52 = 470–630 MPa
- Elongation: St37 = ≥ 26 % | St52 = ≥ 22 %
- Impact (DIN): St37 = St37-2: none; St37-3 U: 27 J at +20 °C; St37-3 N: 27 J at −20 °C | St52 = St52-3 U: 27 J at +20 °C; St52-3 N: 27 J at −20 °C
- Carbon max: St37 = 0.17 % (0.20 % > 16 mm) | St52 = 0.20 % (product 0.22 %)
- Mn max: St37 = not limited (DIN); 1.40 % (EN) | St52 = 1.60 %
- CEV (EN successor): St37 = ≤ 0.35 % | St52 = ≤ 0.45 %
- Preheat: St37 = none | St52 = above ~25 mm (EN 1011-2)
- Typical hardness: St37 = 100–140 HB | St52 = 150–190 HB
- Middle grade: St37 = St44-2 → S275JR (275 MPa) | St52 = —
- Tube lineage: St37 = St37.0 → P235TR1 (EN 10216-1); St37-2 hollow → S235JRH | St52 = St52.0 → P355N; ST52 precision tube → E355 (EN 10305-1); S355J2H hollow sections
- Relative price: St37 = 1.00 | St52 = ≈ 1.05–1.10
- ASTM cross-reference: St37 = A36 (near) | St52 = A572 Grade 50 (near)
- Typical use: St37 = general fabrication, light structures, tanks | St52 = cranes, machinery, bridges, hydraulic cylinders, heavy transport

Verdict: St52 (order S355J2 or S355JR) for anything strength-governed: crane and lifting parts, machinery frames, heavy chassis, hydraulic cylinders (as E355 tube), bridges. It is only marginally more expensive and 50 % stronger.

St37 (order S235JR) for general fabrication, deflection-governed or slender members, cold-formed and galvanized light steelwork, and anywhere welding control is minimal.

St44 (order S275JR) is the forgotten middle: British-style section stock and a good choice when S235 is marginal but S355 welding precautions are unwelcome.

When translating an old drawing, check the suffix: St37-2 has no impact guarantee, St52-3 always did — so S355J2 (−20 °C) is the safe reading of a bare 'St52-3'.

Q: What is the difference between St37 and St52?
A: Strength class. St37-2 has 235 MPa yield and 340–470 MPa tensile; St52-3 has 355 MPa yield and 490–630 MPa tensile. St52 allows slightly more carbon and manganese and always carried an impact requirement. Today they are S235JR and S355J2 (EN 10025-2).

Q: What do the numbers 37 and 52 mean?
A: The minimum tensile strength in kilopond per square millimetre: 37 kp/mm² ≈ 363 MPa, 52 kp/mm² ≈ 510 MPa. EN designations use yield strength in MPa instead (S235, S355).

Q: Are St37 and St52 still available?
A: Not under DIN 17100, which was withdrawn in 1994. Mills supply S235JR and S355J2 (EN 10025-2), which meet and exceed the old requirements; certificates may mention the old names for reference.

Q: What is St44?
A: The middle DIN 17100 grade: St44-2 with 275 MPa yield and 410–540 MPa tensile, now S275JR (1.0044). It corresponds to the British 43A/43B section steels.

Q: Is ST52 tube the same as St52-3 plate?
A: No. Cold-drawn 'ST52' precision and hydraulic tube follows DIN 2391 / EN 10305-1 as E355 (1.0580); similar chemistry, but different delivery conditions (+C, +SR, +N) and much higher strength when cold-worked. Hollow structural sections are S355J2H.

Q: What is St37 and St52 in ASTM?
A: St37-2 ≈ ASTM A36 (250 MPa yield); St52-3 ≈ ASTM A572 Grade 50 (345 MPa yield, add Charpy supplement S5 to match St52-3 N).

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## St 52-3 vs S355JR
URL: https://steelstandart.com/compare/st52-vs-s355jr/

Everyone in a Turkish, German or Balkan workshop still says St 52 when they mean 355 MPa structural steel, and they are almost right. DIN 17100 was withdrawn in 1994 and EN 10025-2 took over; the yield strength carried across unchanged.

The detail that trips people up is the suffix. St 52-3 was already an impact-tested grade — the "-3" class required a Charpy test — so translating it to S355JR quietly drops a guarantee. Read that way, this page is less a comparison than a warning about which modern grade to write on the order.

- Standard: St 52-3 = DIN 17100 (withdrawn 1994) | S355JR = EN 10025-2:2019
- Material number: St 52-3 = 1.0570 (St 52-3) | S355JR = 1.0045 (S355JR)
- Status today: St 52-3 = Withdrawn — no valid certificate | S355JR = Current, CE-markable
- Min. yield ReH, ≤ 16 mm: St 52-3 = 355 MPa | S355JR = 355 MPa
- Tensile Rm: St 52-3 = 490–630 MPa | S355JR = 470–630 MPa
- Elongation A: St 52-3 = 22 % | S355JR = 22 %
- Impact requirement: St 52-3 = 27 J at −20 °C (St 52-3 N) or 0 °C (St 52-3 U) | S355JR = 27 J at +20 °C only
- True modern successor: St 52-3 = S355J2 (−20 °C) or S355J0 (0 °C) | S355JR = —
- Max C, ≤ 16 mm: St 52-3 = 0.20 % | S355JR = 0.24 %
- Max P / S: St 52-3 = 0.040 / 0.040 % | S355JR = 0.035 / 0.035 %
- Carbon equivalent: St 52-3 = ≈ 0.45 % | S355JR = 0.45 %
- Delivery condition: St 52-3 = N (normalised) or U (untreated) | S355JR = As rolled, M or N by agreement
- Common forms: St 52-3 = Plate, sections, tube | S355JR = Plate, sections, hollow sections, tube
- Price difference: St 52-3 = None — same material family | S355JR = None
- Where the name survives: St 52-3 = Türkiye, Germany, Austria, Balkans, Iran | S355JR = —
- ASTM parallel: St 52-3 = A572 Gr 50 | S355JR = A572 Gr 50
- JIS parallel: St 52-3 = SM490A / SM490B | S355JR = SM490A
- GB parallel: St 52-3 = Q345B | S355JR = Q345B
- Certificate you will receive: St 52-3 = S355JR, J0 or J2 depending on what you ordered | S355JR = S355JR
- Risk if translated carelessly: St 52-3 = Losing the impact guarantee that St 52-3 carried | S355JR = —

Verdict: Do not translate St 52-3 as S355JR. The suffix -3 carried a Charpy requirement, so the honest successor is S355J2 (27 J at −20 °C) for St 52-3 N and S355J0 (0 °C) for St 52-3 U. Writing "S355JR (ex St 52-3)" on an order downgrades the toughness without anyone noticing until a cold-weather failure investigation. If the drawing simply says St 52 with no suffix, ask the designer; if the answer is unavailable, S355J2 is the safe reading.

Q: Is St 52 the same as S355?
A: The strength is: both are 355 MPa minimum yield. The impact class is not. St 52-3 required a Charpy test at 0 °C or −20 °C, so its modern equivalents are S355J0 and S355J2 rather than S355JR.

Q: What is St 52-3 N?
A: The normalised version, tested at −20 °C — equivalent to S355J2+N. The U version was untreated and tested at 0 °C, corresponding to S355J0.

Q: Can I still order St 52?
A: By name, yes; what arrives is an S355 grade. Specify the impact class you need, because that is the part the old name no longer carries automatically.

Q: What is St 52 in ASTM?
A: A572 Grade 50 is the usual counterpart at 345 MPa yield. It is close but not identical: the chemistry limits and the impact regime differ, so check before substituting on a stamped drawing.

Q: Is St 52 stronger than St 37?
A: Yes — 355 MPa against 235 MPa minimum yield, a 51 per cent difference. In modern names that is S355 against S235.

Q: Which S355 sub-grade is stocked?
A: S355J2 in plate, S355JR and S355J2 in sections, S355J2H in hollow sections. J0 is the least commonly stocked of the three and is often supplied as J2 instead.

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## API 5L — Specification for line pipe (harmonised with ISO 3183)
URL: https://steelstandart.com/standard/api-5l/
Edition: 46th edition (ISO 3183 harmonised) (American Petroleum Institute)
Specification for seamless and welded steel line pipe for the pipeline transport of petroleum, natural gas and water. Grades are named by specified minimum yield strength in two parallel systems — L245 / Grade B, L290 / X42, L320 / X46, L360 / X52, L390 / X56, L415 / X60, L450 / X65, L485 / X70, L555 / X80. Every grade is ordered at one of two product specification levels: PSL1 sets minima, chemistry ceilings and a hydrostatic test; PSL2 adds a maximum yield strength, a yield-to-tensile ratio cap, a carbon equivalent limit, mandatory Charpy impact testing, drop-weight tear testing on larger sizes and tighter sulphur. Annex H covers sour service (suffix S) and Annex J offshore service (suffix O). Delivery conditions N, Q and M and manufacturing routes S, HFW, SAWL and SAWH are part of the designation.
Supersedes: API 5LX (withdrawn — high strength line pipe); API 5LS (withdrawn — spiral welded line pipe); DIN 17172 (StE 360.7 and related German line pipe grades)

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## ASTM A106/A106M — Standard Specification for Seamless Carbon Steel Pipe for High-Temperature Service
URL: https://steelstandart.com/standard/astm-a106/
Edition: 2019a (ASTM International)
Seamless carbon steel pipe NPS 1/8 to 48 for high-temperature service, suitable for bending, flanging and welding: Grades A, B and C (205, 240, 275 MPa yield; 330, 415, 485 MPa tensile), killed steel with Si ≥ 0.10 %. Hot-finished or cold-drawn; hydrostatic and NDE tests; supplementary S1–S9. Adopted by ASME as SA-106; dimensions per ASME B36.10M.
Supersedes: 

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## ASTM A240/A240M — Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
URL: https://steelstandart.com/standard/astm-a240/
Edition: 2022 (ASTM International)
Flat-rolled stainless steel (plate, sheet, strip) of ferritic, martensitic, austenitic, duplex and PH grades identified by UNS number: 304/304L/304H, 316/316L/316Ti, 321, 347, 309S, 310S, 410, 430, 2205 (S31803/S32205), 2507, 904L, 254 SMO and about 100 others. Gives chemistry, mechanical property minimums, hardness limits, heat-treatment conditions and finishes (via A480). Adopted by ASME as SA-240.
Supersedes: ASTM A167 (withdrawn 2014; general-purpose Cr-Ni sheet); ASTM A176 (ferritic/martensitic sheet, merged)

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## ASTM A276/A276M — Standard Specification for Stainless Steel Bars and Shapes
URL: https://steelstandart.com/standard/astm-a276/
Edition: 2023 (ASTM International)
Hot-finished and cold-finished stainless bars (round, square, hex, flat), shapes and forgings stock in austenitic, ferritic, martensitic and duplex grades (303, 304, 316, 321, 410, 420, 430, 431, 440C, 2205, 17-4 by reference to A564…). Conditions A (annealed), H (hardened & tempered), T (tempered), S (strain-hardened). Companion A479 covers bars for boilers and pressure vessels; A484 the general requirements and tolerances.
Supersedes: 

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## ASTM A29/A29M — Standard Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought
URL: https://steelstandart.com/standard/astm-a29/
Edition: 2020 (ASTM International)
General requirements and the chemical composition tables for hot-wrought carbon and alloy steel bars designated by SAE/AISI number (10xx, 11xx, 12xx, 13xx, 15xx, 40xx, 41xx, 43xx, 46xx, 47xx, 48xx, 50xx, 51xx, 61xx, 81xx, 86xx, 87xx, 88xx, 92xx, 93xx, 94xx) and UNS number. It does not give mechanical properties — those come from the ordering condition, ASTM A108 (cold-finished), A434 (Q&T alloy bar), A322 (alloy bar) or the customer specification. Also defines H-band hardenability referencing SAE J1268.
Supersedes: 

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## ASTM A295/A295M — Standard Specification for High-Carbon Anti-Friction Bearing Steel
URL: https://steelstandart.com/standard/astm-a295/
Edition: 2021 (ASTM International)
High-carbon chromium bearing steels for balls, rollers and races: 52100 (and 51100, 50100, 5195, K19526, 1070M) as bar, rod, wire and tube. Specifies chemistry including oxygen ≤ 15 ppm, inclusion cleanliness (E45 method A/D limits), decarburization, macroetch, annealed hardness and microstructure; heat-treated properties are by agreement. Carburizing bearing steels are in A534.
Supersedes: 

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## ASTM A333/A333M — Seamless and welded steel pipe for low-temperature service and other applications with required notch toughness
URL: https://steelstandart.com/standard/astm-a333/
Edition: 2018 (A333/A333M-18) (ASTM International)
Specification for seamless and welded steel pipe where notch toughness at low temperature must be demonstrated. Nine grades spanning plain carbon steel (Grade 1, Grade 6), nickel steels (Grade 3 at 3.5 % Ni, Grade 7 at 2.5 % Ni, Grade 9 at 2 % Ni + Cu, Grade 8 at 9 % Ni) and alloy grades 4, 10 and 11. Every grade carries a mandatory Charpy V-notch requirement at a stated test temperature, from -45 C for Grade 6 to -195 C for Grade 8. Covers composition, tensile properties, impact testing, hydrostatic and non-destructive testing. This is the specification that A53 and A106 do not cover: neither of those requires any impact test.
Supersedes: ASTM A333:earlier editions (grade list extended)

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## ASTM A36/A36M — Standard Specification for Carbon Structural Steel
URL: https://steelstandart.com/standard/astm-a36/
Edition: 2019 (ASTM International)
Carbon structural steel shapes, plate and bar for riveted, bolted or welded construction of bridges and buildings and for general structural purposes: one grade with 250 MPa (36 ksi) minimum yield and 400–550 MPa tensile (220 MPa yield above 200 mm plate). Chemistry varies by product and thickness; supplementary requirements S5 (Charpy), S91/S92 (CE and fine grain). Adopted by ASME as SA-36 and AASHTO as M270 Grade 36 via A709.
Supersedes: ASTM A7 (withdrawn 1967)

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## ASTM A516/A516M — Standard Specification for Pressure Vessel Plates, Carbon Steel, for Moderate- and Lower-Temperature Service
URL: https://steelstandart.com/standard/astm-a516/
Edition: 2017 (ASTM International)
Killed, fine-grain carbon-manganese-silicon plate for welded pressure vessels where improved notch toughness is important: Grades 55, 60, 65 and 70 (tensile 380–620 MPa). Normalizing mandatory above 40 mm; chemistry by thickness; general requirements per A20 (testing, UT, Charpy S5, HIC options by agreement). Adopted by ASME as SA-516 — the most-used ASME carbon-steel vessel plate.
Supersedes: 

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## ASTM A53/A53M — Pipe, steel, black and hot-dipped, zinc-coated, welded and seamless
URL: https://steelstandart.com/standard/astm-a53/
Edition: 2020 (A53/A53M-20) (ASTM International)
Specification for black and hot-dip galvanized welded and seamless steel pipe in NPS 1/8 to 26, for coiling, bending, flanging, threading and general mechanical and pressure applications. Defines two grades, A (205 MPa yield) and B (240 MPa yield), and three manufacturing types: Type F continuous furnace butt welded (Grade A only, NPS 4 and under), Type E electric-resistance welded, Type S seamless. Covers chemical composition ceilings, tensile requirements, flattening, bend and hydrostatic tests, galvanized coating, and threaded or plain ends. It contains no impact-test requirement and publishes no elevated-temperature allowable stresses.
Supersedes: ASTM A120 (withdrawn — black and galvanized pipe for ordinary use); ASTM A53:earlier editions (type and grade restrictions changed)

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## ASTM A564/A564M — Standard Specification for Hot-Rolled and Cold-Finished Age-Hardening Stainless Steel Bars and Shapes
URL: https://steelstandart.com/standard/astm-a564/
Edition: 2019 (ASTM International)
Precipitation-hardening stainless bars and shapes: 17-4 PH (S17400, Type 630), 15-5 PH (S15500), 13-8 Mo (S13800), Custom 450/455, 17-7 PH (S17700), XM-12 etc. Defines Condition A and the aged conditions (H900–H1150, H1150M/D; RH950, TH1050) with minimum yield, tensile, elongation, reduction of area and hardness for each. Plate/sheet are in A693, forgings in A705.
Supersedes: 

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## ASTM A572/A572M — Standard Specification for High-Strength Low-Alloy Columbium-Vanadium Structural Steel
URL: https://steelstandart.com/standard/astm-a572/
Edition: 2021 (ASTM International)
HSLA structural shapes, plate, sheet piling and bar in Grades 42, 50, 55, 60 and 65 (290–450 MPa yield) micro-alloyed with niobium (columbium) and/or vanadium (Types 1–5). Thickness limits per grade; supplementary S5 (Charpy), S90/S91 (CE), S32 (fine grain). Adopted as SA-572 by ASME; A709 Grade 50 and A992 are the bridge and W-shape derivatives.
Supersedes: ASTM A441 (withdrawn 1989)

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## BS 970 — Wrought steels for mechanical and allied engineering purposes
URL: https://steelstandart.com/standard/bs-970/
Edition: 1991 (Part 1) (BSI (British Standards Institution))
The British engineering steel standard: carbon, carbon-manganese, alloy and stainless wrought steels supplied as bar, billet, forging stock and rod. Part 1 sets the six-character designation system (three digits for the steel group, a letter for the requirement type, two digits for nominal carbon), the delivery conditions R to W by tensile band, and the limiting ruling section principle by which mechanical properties are guaranteed. It replaced the numbered En series of BS 970:1955, which is still the name most engineers use.
Supersedes: BS 970:1955 (the En series: En8, En19, En24, En31…); BS 970:1970 / :1983 Parts 1–6

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## DIN 17100 — General structural steels; quality specifications (withdrawn)
URL: https://steelstandart.com/standard/din-17100/
Edition: 1980 (withdrawn 1994) (DIN)
The German standard for general structural steels St33, St37-2, USt37-2, RSt37-2, St37-3, St44-2, St44-3, St52-3 and the machinery grades St50-2, St60-2, St70-2. Withdrawn in 1994 when EN 10025 was adopted, but the St37/St52 names remain in daily use worldwide. This page maps every DIN 17100 grade to its EN 10025-2 successor.
Supersedes: DIN 17100:1966

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## EN 10025-2 — Hot rolled products of structural steels. Part 2: Non-alloy structural steels
URL: https://steelstandart.com/standard/en-10025-2/
Edition: 2019 (CEN)
Technical delivery conditions for flat and long products (plate, strip, sections, bar) of non-alloy structural steels S235, S275, S355 and S450 in qualities JR, J0, J2 and K2, plus the machinery grade E295/E335/E360. Covers chemical composition, mechanical properties by thickness, impact energy by quality, carbon equivalent, delivery conditions (+AR, +N, +M) and inspection documents. Hollow sections are in EN 10210/10219, plate for pressure in EN 10028.
Supersedes: EN 10025:1993 / :2004 (part 2); DIN 17100:1980 (St37, St44, St52); BS 4360:1990 (40, 43, 50 grades); NF A 35-501; UNI 7070

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## EN 10025-5 — Hot rolled products of structural steels. Part 5: Structural steels with improved atmospheric corrosion resistance
URL: https://steelstandart.com/standard/en-10025-5/
Edition: 2019 (CEN)
Weathering (Cu-Cr-Ni-P) structural steels that form a protective rust patina: S235J0W, S235J2W, S355J0W, S355J2W, S355K2W and the phosphorus variants S355J0WP/J2WP, as plate, strip, sections and bar. Chemistry (Cu 0.25–0.55, Cr 0.40–0.80), mechanical properties by thickness, impact by quality, delivery conditions; the European home of the material sold as Corten A/B.
Supersedes: EN 10155:1993 (S355J2G1W, S355J2G2W …); DIN 17100 WT St 37-3 / WT St 52-3

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## EN 10028-2 — Flat products made of steels for pressure purposes. Part 2: Non-alloy and alloy steels with specified elevated temperature properties
URL: https://steelstandart.com/standard/en-10028-2/
Edition: 2017 (CEN)
Plate, sheet and strip for boilers and pressure vessels: non-alloy P235GH, P265GH, P295GH, P355GH and alloy 16Mo3, 13CrMo4-5, 10CrMo9-10, 11CrMo9-10, 12CrMo9-10, X12CrMo5, 13CrMoSi5-5, X10CrMoVNb9-1, X20CrMoV11-1. Chemistry, room- and elevated-temperature yield to 500–600 °C, impact at −20/0/+20 °C, creep data (informative), delivery conditions (+N, +NT, +QT).
Supersedes: DIN 17155:1983 (HI, HII, 17Mn4, 19Mn6, 15Mo3, 13CrMo44, 10CrMo910); BS 1501-1/-2; EN 10028-2:1992 / 2003 / 2009

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## EN 10028-3 — Flat products made of steels for pressure purposes. Part 3: Weldable fine grain steels, normalized
URL: https://steelstandart.com/standard/en-10028-3/
Edition: 2017 (CEN)
Normalized fine-grain pressure-vessel plate in strength classes 275, 355, 400 and 460 MPa: P275N/NH/NL1/NL2, P355N/NH/NL1/NL2, P460N/NH/NL1/NL2 (and P275NH etc.). Al-killed with Nb/V/Ti grain refinement; impact guaranteed at −20 °C (N/NH), −40 °C (NL1) and −50 °C (NL2); NH grades have elevated-temperature yield to 400 °C.
Supersedes: DIN 17102:1983 (StE, WStE, TStE, EStE 255–500); BS 1501-224/225; EN 10028-3:1992 / 2003 / 2009

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## EN 10083-2 — Steels for quenching and tempering. Part 2: Technical delivery conditions for non alloy steels
URL: https://steelstandart.com/standard/en-10083-2/
Edition: 2006 (CEN)
Non-alloy steels for quenching and tempering: C22 to C60 and their E (P ≤ 0.030) and R (controlled S) variants, plus 28Mn6. Specifies chemistry, hardenability, and mechanical properties in the +N and +QT conditions by ruling section. Part 1 covers general delivery conditions; Part 3 the alloy grades (42CrMo4 etc.).
Supersedes: DIN 17200:1987 (C45, Ck45, Cm45); EN 10083-2:1991

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## EN 10083-3 — Steels for quenching and tempering. Part 3: Technical delivery conditions for alloy steels
URL: https://steelstandart.com/standard/en-10083-3/
Edition: 2006 (CEN)
Alloy steels for quenching and tempering: Mn, Cr, CrMo, CrNiMo, MnCr, MnB grades such as 42CrMo4, 34CrNiMo6, 25CrMo4, 41Cr4, 30MnB5, 51CrV4, 36NiCrMo16. Gives chemistry, hardenability bands (+H, +HH, +HL), mechanical properties in +QT by ruling section, and impact values.
Supersedes: DIN 17200:1987 (alloy grades); EN 10083-1:1991 (alloy grades)

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## EN 10084 — Case hardening steels. Technical delivery conditions
URL: https://steelstandart.com/standard/en-10084/
Edition: 2008 (CEN)
Case-hardening steels supplied as bar, rod, wire, forgings and hot-rolled flat products: C10E to C16E, 17Cr3, 16MnCr5, 20MnCr5, 18CrMo4, 20NiCrMo2-2, 18CrNiMo7-6, 20MoCr4 and others, with their +H hardenability bands and R (controlled S) variants. Specifies chemistry, Jominy bands, delivery hardness (+A, +FP, +S, +TH) and informative core properties.
Supersedes: DIN 17210:1986 (Ck15, 16MnCr5, 20MnCr5); EN 10084:1998

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## EN 10088-2 — Stainless steels. Part 2: Technical delivery conditions for sheet/plate and strip of corrosion resisting steels for general purposes
URL: https://steelstandart.com/standard/en-10088-2/
Edition: 2014 (CEN)
Flat products (hot- and cold-rolled sheet, plate, strip) of ferritic, martensitic, precipitation-hardening, austenitic and duplex stainless steels: 1.4016, 1.4301, 1.4307, 1.4401, 1.4404, 1.4571, 1.4462, 1.4542 and about 80 others. Gives chemistry, mechanical properties by product form and thickness, work-hardened conditions (+C), surface finishes (1D, 2B, 2R, 2G…) and corrosion-test requirements. Part 1 lists all grades; Part 3 covers bar, rod, wire and sections; EN 10028-7 covers pressure purposes.
Supersedes: DIN 17440:1996; BS 1449-2; NF A 35-573; EN 10088-2:2005

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## EN 10088-3 — Stainless steels. Part 3: Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products
URL: https://steelstandart.com/standard/en-10088-3/
Edition: 2014 (CEN)
Long products of stainless steel: bar, rod, wire, sections and bright (cold-drawn, peeled, ground) products in the same grade families as Part 2, including free-machining 1.4305 and 1.4570, precipitation-hardening 1.4542/1.4545 with +P conditions, and martensitic 1.4006/1.4021/1.4057 with +QT classes.
Supersedes: DIN 17440 (long products); BS 970 Part 1 (stainless); EN 10088-3:2005

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## EN 10089 — Hot rolled steels for quenched and tempered springs. Technical delivery conditions
URL: https://steelstandart.com/standard/en-10089/
Edition: 2002 (CEN)
Technical delivery conditions for hot-rolled bars, flats and coils in spring steels intended to be quenched and tempered after forming: the silicon grades (38Si7, 46Si7, 56Si7), the chromium grades (55Cr3, 60Cr3), the chromium-vanadium and chromium-molybdenum grades (51CrV4, 52CrMoV4, 51CrMoV4) and the silicon-chromium grades (54SiCr6, 56SiCr7, 61SiCr7, 60SiCr7, 45SiCrMo6, 60SiCrV7). Fixes chemical composition, delivery conditions (+AR, +A, +QT), hardenability where agreed, surface decarburisation limits, surface quality and inspection documents. It does not specify the mechanical properties of the finished spring — those are produced by the spring maker after forming.
Supersedes: DIN 17221:1988 (hot rolled spring steels); BS 970 Part 2 spring grades (735A50, 527A60, 250A58); NF A 35-571; UNI 3545

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## EN 10111 — Continuously hot rolled low carbon steel sheet and strip for cold forming. Technical delivery conditions
URL: https://steelstandart.com/standard/en-10111/
Edition: 2008 (CEN)
Hot-rolled sheet and strip for cold forming in grades DD11 (bending), DD12 (drawing), DD13 (deep drawing) and DD14 (extra deep drawing), width ≥ 600 mm, thickness typically 1.5–11 mm; as-rolled or pickled (+P). Chemistry, mechanical properties by thickness, ageing clause and tolerances (EN 10051).
Supersedes: DIN 1614-1 (StW22, StW23, StW24); EN 10111:1991 (FeP11–FeP14)

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## EN 10130 — Cold rolled low carbon steel flat products for cold forming. Technical delivery conditions
URL: https://steelstandart.com/standard/en-10130/
Edition: 2006 (CEN)
Cold-rolled uncoated sheet and strip 0.35–3.0 mm in grades DC01 to DC06 (bending to super-deep-drawing), with surface qualities A/B, finishes b/g/m/r and optional +ZE electro-galvanizing (EN 10152). Specifies chemistry, yield/tensile/elongation, r and n values (DC04+), ageing limits and tolerances (EN 10131).
Supersedes: DIN 1623-1 (St12, St13, St14); EN 10130:1991 (FeP01–FeP06); BS 1449-1 CR grades

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## EN 10149-2 — Hot rolled flat products made of high yield strength steels for cold forming. Part 2: Thermomechanically rolled steels
URL: https://steelstandart.com/standard/en-10149-2/
Edition: 2013 (CEN)
Thermomechanically rolled (TM) high-strength low-alloy strip, sheet and plate for cold forming: S315MC, S355MC, S420MC, S460MC, S500MC, S550MC, S600MC, S650MC, S700MC, S900MC, S960MC, thickness 1.5–20 mm. Micro-alloyed with Nb, V, Ti; specifies chemistry, yield/tensile/elongation, minimum bend radii and impact (option). Part 3 covers the normalized grades (S260NC–S420NC).
Supersedes: SEW 092 (QStE 340TM … QStE 690TM); EN 10149-2:1995

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## EN 10217-1 — Welded steel tubes for pressure purposes. Part 1: Non-alloy steel tubes with specified room temperature properties
URL: https://steelstandart.com/standard/en-10217-1/
Edition: 2019 (CEN)
Technical delivery conditions for electric-welded and submerged-arc-welded non-alloy steel tubes for pressure purposes with specified properties at room temperature: grades P195TR1, P195TR2, P235TR1, P235TR2, P265TR1 and P265TR2. The TR1 qualities carry no impact requirement; the TR2 qualities add a Charpy requirement at 0 C and tighter composition, and are the ones permitted for welded pressure equipment under most national rules. Covers composition, mechanical properties, tightness and non-destructive testing, dimensions and tolerances (with EN 10217-1 Annex and EN 10220 for the size tables). Seamless equivalents are in EN 10216-1; tubes for elevated-temperature service are in Parts 2 of each.
Supersedes: DIN 1626 (welded tubes for pressure, St 33, St 37.0, St 44.0); BS 3601; NF A 49-141

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## EN 10219 — Cold formed welded steel structural hollow sections
URL: https://steelstandart.com/standard/en-10219/
Edition: 2019 (CEN)
Cold-formed welded circular, square and rectangular hollow sections for structures: Part 1 technical delivery conditions (S235JRH, S275J0H/J2H, S355J0H/J2H/K2H, S420MH, S460MH, fine-grain and weathering variants), Part 2 tolerances, dimensions and sectional properties. Distinguished from EN 10210 (hot-finished) by lower corner radii tolerance class and cold-forming-related ductility limits.
Supersedes: EN 10219:1997 / 2006; DIN 59411 (cold-formed hollow sections); BS 6363

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## EN 10255 — Non-alloy steel tubes suitable for welding and threading. Technical delivery conditions
URL: https://steelstandart.com/standard/en-10255/
Edition: 2004 + A1:2007 (CEN)
Welded and seamless non-alloy steel tubes in grade S195T (1.0026), sizes DN 6 to DN 150 (½" to 6"), suitable for screwing (EN 10226-1 threads) and welding: light series L/L1/L2, medium series M and heavy series H, plus the derived series L1/L2. Used for water, gas, compressed air, sprinkler and structural applications; galvanizing per EN 10240. The successor of BS 1387 (Class A/B/C) and DIN 2440/2441/2442.
Supersedes: BS 1387:1985 (Class A, B, C); DIN 2440 / 2441 / 2442 (mittelschwer, schwer, leicht); NF A 49-145; UNI 8863

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## EN 10305-1 — Steel tubes for precision applications. Part 1: Seamless cold drawn tubes
URL: https://steelstandart.com/standard/en-10305-1/
Edition: 2016 (CEN)
Technical delivery conditions for seamless cold drawn precision steel tubes: grades E215, E235, E275, E355 and E470, in the delivery conditions +C (as drawn), +LC (lightly annealed), +SR (stress relieved annealed), +A (annealed) and +N (normalised). Specifies composition, mechanical properties by delivery condition, close dimensional and wall tolerances, straightness, surface finish and inside and outside roughness. The grade designation E followed by a number is the minimum yield strength in MPa in the normalised (+N) condition — E355+N is ReH 355 min, Rm 490-630, the same levels as S355. In the cold-finished conditions the tensile strength is far higher (E355+C is Rm 640 min) and the standard does not always state a yield value for them, which is the point most often misread. Welded precision tubes are in Parts 2 and 3, hydraulic cylinder tubes in Part 4, and tubes for mechanical and general engineering in EN 10297-1.
Supersedes: DIN 2391-1 / DIN 2391-2 (St 30 Si, St 35, St 45, St 52); BS 6323 Part 4; NF A 49-310

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## EN 10346 — Continuously hot-dip coated steel flat products for cold forming. Technical delivery conditions
URL: https://steelstandart.com/standard/en-10346/
Edition: 2015 (CEN)
Hot-dip zinc (+Z), zinc-iron (+ZF), zinc-aluminium (+ZA), aluminium-zinc (+AZ), aluminium-silicon (+AS) and zinc-magnesium (+ZM) coated sheet and strip: forming grades DX51D–DX57D, structural grades S220GD–S550GD, HSLA HX grades, and multiphase steels. Specifies base chemistry, mechanical properties, coating masses (Z100–Z600, ZM70–ZM310…), surface qualities A/B/C, finishes and tests (T-bend, adhesion).
Supersedes: EN 10142 (zinc); EN 10147 (structural zinc); EN 10214 (ZA); EN 10215 (AZ); EN 10292 (HSLA); EN 10327/10326 (2004); DIN 17162 (St02Z…)

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## GB/T 1591 — High strength low alloy structural steels
URL: https://steelstandart.com/standard/gb-t-1591/
Edition: 2018 (SAC (Standardization Administration of China))
Chinese low-alloy structural steel: plate, strip, sections and bar in the Q355 to Q690 ladder, in quality classes B, C, D, E and F separated by the impact test temperature. Specifies chemical composition, carbon equivalent, yield and tensile by thickness, elongation and Charpy energy. The 2018 revision is the edition that replaced Q345 with Q355 and introduced the delivery-condition suffixes N and M alongside the as-rolled grades.
Supersedes: GB/T 1591-2008 (Q345, Q390, Q420, Q460); GB/T 1591-1994; GB/T 1591-1988

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## GOST 19281 — Rolled steel with increased strength. General specifications
URL: https://steelstandart.com/standard/gost-19281/
Edition: 2014 (Rosstandart / EASC (interstate standard))
Low-alloy structural rolled steel of increased strength: plate, sections, bar and strip in grades from 09G2S and 10KhSND to 17G1S, classified by strength class from 265 to 590 MPa. Specifies chemistry, yield and tensile by thickness, elongation, impact energy at room temperature, −40 °C, −60 °C or −70 °C depending on the grade and category, and impact after mechanical ageing. This is the standard behind Russian and CIS cold-climate structural steel.
Supersedes: GOST 19281-89; GOST 19282-73 (merged)

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## GOST 380 — Carbon steel of ordinary quality. Grades
URL: https://steelstandart.com/standard/gost-380/
Edition: 2005 (Rosstandart / EASC (interstate standard))
Grades and chemical composition of ordinary-quality carbon steel: St0 to St6, each in rimmed (kp), semi-killed (ps) and killed (sp) deoxidation practice. The standard fixes chemistry only. Mechanical properties come from the product standards that call it up — GOST 535 for sections, bars and shapes, GOST 14637 for heavy plate and GOST 16523 for thin sheet — which is why a St3sp certificate always names two standards.
Supersedes: GOST 380-94; GOST 380-88; GOST 380-71

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## IS 2062 — Hot rolled medium and high tensile structural steel
URL: https://steelstandart.com/standard/is-2062/
Edition: 2011 (BIS (Bureau of Indian Standards))
Indian structural steel for plate, strip, sections, flats and bars in grades E250, E275, E300, E350, E410, E450 and E550, each with quality sub-grades A, BR, B0 and C set by the impact requirement. Specifies chemical composition, carbon equivalent, yield stress by thickness, tensile strength, elongation and Charpy energy. This is the standard called up by IS 800, the Indian structural steel design code, and it is the specification on most Indian project drawings.
Supersedes: IS 2062:2006; IS 2062:1999 (Fe 410 designations); IS 226 (withdrawn)

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## IS 3431 — Steel for the manufacture of volute, helical and laminated springs for automotive suspension
URL: https://steelstandart.com/standard/is-3431/
Edition: 1982 (3 amendments, reviewed 2022) (BIS)
Indian Standard for hot-rolled steel bars and flats used to make volute, helical and laminated springs for automotive suspension. Covers five grades — 55Si7, 60Si7, 65Si7, 50Cr4V2 and 60Cr4V2 — with chemical composition, hardenability, mechanical properties, freedom from surface defects, straightness, dimensions and tolerances. Steel may be made by the open-hearth, electric or combined processes, and a minimum reduction ratio of 16:1 from ingot to product is required. General delivery conditions follow IS 8910. It is a steel specification: the finished spring is covered by IS 7906 (helical compression springs and automobile leaf-spring assemblies).
Supersedes: IS 3431:1965 (first edition)

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## EN ISO 4957 — Tool steels
URL: https://steelstandart.com/standard/iso-4957/
Edition: 2018 (ISO / CEN)
Non-alloy and alloy cold-work, hot-work and high-speed tool steels supplied as bar, rod, wire, forgings, plate and strip: C45U–C120U, 1.2842 (90MnCrV8), 1.2379 (X153CrMoV12), 1.2363 (X100CrMoV5), 1.2344 (X40CrMoV5-1), 1.2343, 1.2767, HS6-5-2 and others. Specifies chemistry, annealed hardness, hardening temperatures and hardness after hardening as reference values.
Supersedes: DIN 17350:1980; EN ISO 4957:1999

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## JIS G3101 — Rolled steels for general structure
URL: https://steelstandart.com/standard/jis-g3101/
Edition: 2020 (JISC)
Technical delivery conditions for hot-rolled plate, sheet, strip, sections, bar and flat bar in the general structural grades SS330, SS400, SS490, SS540 and SS590. The standard specifies tensile strength, yield point by thickness and elongation; chemical composition is limited only for phosphorus and sulphur on the lower grades. There is no impact requirement and no carbon equivalent — weldable structural grades with guaranteed toughness are in JIS G3106 (SM400, SM490, SM520, SM570).
Supersedes: JIS G3101:1995 (SS41, SS50 designations in kgf/mm²); JIS G3101:2004; JIS G3101:2015

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## JIS G3131 — Hot-rolled mild steel plates, sheets and strip
URL: https://steelstandart.com/standard/jis-g3131/
Edition: 2018 (JISC)
Technical delivery conditions for hot-rolled mild steel sheet, plate and strip in three forming grades: SPHC (commercial), SPHD (drawing) and SPHE (deep drawing), in thicknesses from 1.2 to 14 mm. Specifies chemical composition, tensile strength, elongation by thickness and the pickled variant (suffix P). No yield strength, impact energy or carbon equivalent is guaranteed — structural grades are in JIS G3101 and G3106.
Supersedes: JIS G3131:1996; JIS G3131:2005

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