St52-3 steel (1.0570): properties, composition, equivalents
St52-3 (DIN 17100) is the withdrawn German 355 MPa structural steel, now S355J2 (1.0577) or S355JR: 355 MPa yield, 490–630 MPa tensile. Mapping to S355, A572-50, SM490, Q355 and what changed in EN 10025.
What is 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 DIN 17100 was withdrawn in 1994, but 'St52' remains the everyday name for S355 in Germany, Austria, Turkey, Poland and much of the Middle East, and 'ST52' appears in countless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.
St52-3 chemical composition
| Element | Mass % | Note |
|---|---|---|
| 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.
St52-3 mechanical properties
| Thickness / condition | Yield strength ReH / Rp0.2 MPa (ksi) | Tensile strength Rm MPa (ksi) | Elongation A % | Hardness |
|---|---|---|---|---|
| < 16 mm (DIN 17100) | 355 (51.5) | 490–630 (71.1–91.4) | 22 | ≈ 150–190 HB |
| 16–40 mm | 345 (50.0) | 490–630 (71.1–91.4) | 21 | — |
| 40–63 mm | 335 (48.6) | 490–630 (71.1–91.4) | 20 | — |
| 63–80 mm | 325 (47.1) | 490–630 (71.1–91.4) | 19 | — |
| 80–100 mm | 315 (45.7) | 490–630 (71.1–91.4) | 18 | — |
| S355J2 today, ≤ 16 mm (for comparison) | 355 (51.5) | 470–630 (68.2–91.4) | 22 | — |
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 toughness
St52-3 requires a minimum Charpy V-notch energy of 27 J at -20 °C (St52-3 N (normalized); St52-3 U: 27 J at +20 °C). St52-3 always carried an impact requirement — the '-3' quality group — unlike St37-2.
St52-3 equivalent grades
| Grade | System | Match | Why / differences |
|---|---|---|---|
| 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 Gr. 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. |
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 St52-3 →
Old and superseded designations
| Old name | Standard | Note |
|---|---|---|
| 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 and tolerance standards
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).
Dimensional tolerances: current: EN 10029 (plate), EN 10051 (coil), EN 10034 (sections).
Key property values
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 and heat treatment
As S355: machinability ≈ 60 %, carbide tooling above 20 mm; bend radius 1.5–3 t; normalize after hot forming.
Typical 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
St52-3 compared with related grades
Frequently asked questions
What is St52 steel?
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).
Is St52 the same as S355?
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.
What is St52 in ASTM?
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.
Is ST52 tube the same as St52-3 plate?
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).
What is the difference between St52 and St37?
Yield 355 vs 235 MPa and tensile 490–630 vs 340–470 MPa. St52-3 always had an impact requirement; St37-2 did not.
Related grades
Verified against DIN 17100:1980 (withdrawn) and EN 10025-2:2019; DIN 17100:1980 Tables 1 and 2; EN 10025-2:2019 Annex (superseded designations); EN 10305-1:2016 (E355). Last checked: September 2026.