1.2363 (A2) cold-work tool steel: properties, composition, equivalents
1.2363 (X100CrMoV5) is the 5 % Cr air-hardening cold-work tool steel, AISI A2: 58–62 HRC with roughly twice the toughness of D2. Composition, heat treatment and A2/SKD12 equivalents.
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What is 1.2363?
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.
1.2363 chemical composition
| Element | Mass % | Note |
|---|---|---|
| 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.
1.2363 mechanical properties
| Thickness / condition | Yield strength ReH / Rp0.2 MPa (ksi) | Tensile strength Rm MPa (ksi) | Elongation A % | Hardness |
|---|---|---|---|---|
| +A soft annealed (delivery) | — | ≈ 700–800 (typ.) (≈ 101.5–116.0 (typ.)) | — | ≤ 241 HB |
| Hardened 940–980 °C air/vacuum, as-quenched | — | — | — | 63–65 HRC |
| Tempered 180–200 °C (2×) | — | — | — | 60–62 HRC |
| Tempered 400 °C (2×) | — | — | — | 57–59 HRC |
| Tempered 500–520 °C (2×, secondary hardening) | — | — | — | 57–58 HRC |
| Compressive yield at 60 HRC (typical) | ≈ 2200 (≈ 319.1) | ≈ 3400 (bend strength) (≈ 493.1 (bend strength)) | — | — |
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.
1.2363 equivalent grades
| Grade | System | Match | Why / differences |
|---|---|---|---|
| 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. |
Identical = same composition and mechanical limits within rounding. Near = one limit differs (e.g. carbon max or impact temperature). Functional = interchangeable for most uses after an engineering check. Full cross-reference for 1.2363 →
Old and superseded designations
| Old name | Standard | Note |
|---|---|---|
| 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 and tolerance standards
Product forms: flat bar and round bar (annealed), ground flat stock (precision), blocks and plate, forgings.
Dimensional 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.
Key property values
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 and 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.
Typical 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
Frequently asked questions
Is 1.2363 the same as A2?
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.
1.2363 or 1.2379 — which one should I use?
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.
What hardness does 1.2363 reach?
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.
Does 1.2363 really harden in air?
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.
Is 1.2363 stainless?
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.
What is the maximum working temperature of 1.2363?
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.
Related grades
Verified against EN ISO 4957:2018; EN ISO 4957:2018 Table 4; ASTM A681-08 (A2 comparison); JIS G4404:2015 (SKD12 comparison). Last checked: October 2026.