St37 vs St52: differences explained
St37 vs St52 (DIN 17100): yield 235 vs 355 MPa, tensile 340–470 vs 490–630 MPa. Both withdrawn — today S235JR and S355J2. Side-by-side table, the St44 middle grade, and what to order now.
Overview
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 The standard was withdrawn in 1994, but 'St37' still means everyday structural steel and 'St52' the strong one across Germany, Turkey, Poland, Iran and the Gulf, on hydraulic-cylinder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.
St37 vs St52 side by side
| Property | St37 | St52 |
|---|---|---|
| DIN 17100 grade | St37-2 (also USt37-2, RSt37-2, St37-3) | St52-3 (U or N) |
| Material number (DIN → EN) | 1.0037 → 1.0038 | 1.0570 → 1.0577 |
| EN 10025-2 successor | S235JR (St37-3 N → S235J2) | S355J2 (St52-3 U → S355JR) |
| Meaning of the number | 37 kp/mm² ≈ 363 MPa min. tensile | 52 kp/mm² ≈ 510 MPa min. tensile |
| Min. yield, < 16 mm | 235 MPa | 355 MPa |
| Min. yield, 40–63 mm | 215 MPa | 335 MPa |
| Tensile (DIN 17100) | 340–470 MPa | 490–630 MPa |
| Tensile (EN successor) | 360–510 MPa | 470–630 MPa |
| Elongation | ≥ 26 % | ≥ 22 % |
| Impact (DIN) | St37-2: none; St37-3 U: 27 J at +20 °C; St37-3 N: 27 J at −20 °C | St52-3 U: 27 J at +20 °C; St52-3 N: 27 J at −20 °C |
| Carbon max | 0.17 % (0.20 % > 16 mm) | 0.20 % (product 0.22 %) |
| Mn max | not limited (DIN); 1.40 % (EN) | 1.60 % |
| CEV (EN successor) | ≤ 0.35 % | ≤ 0.45 % |
| Preheat | none | above ~25 mm (EN 1011-2) |
| Typical hardness | 100–140 HB | 150–190 HB |
| Middle grade | St44-2 → S275JR (275 MPa) | — |
| Tube lineage | St37.0 → P235TR1 (EN 10216-1); St37-2 hollow → S235JRH | St52.0 → P355N; ST52 precision tube → E355 (EN 10305-1); S355J2H hollow sections |
| Relative price | 1.00 | ≈ 1.05–1.10 |
| ASTM cross-reference | A36 (near) | A572 Grade 50 (near) |
| Typical use | general fabrication, light structures, tanks | cranes, machinery, bridges, hydraulic cylinders, heavy transport |
Which should you choose?
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'.
- General fabrication, frames, guards, tanks
- Deflection- or buckling-governed members
- Cold-formed profiles, galvanized handrails and fences
- Thin sheet and light structures
- Shops without welding-procedure control
- Cranes, hoists, lifting equipment
- Machinery and press frames, heavy weldments
- Hydraulic cylinder tubes (as E355) and rods
- Bridges, wind towers, heavy transport chassis
- Any member where a smaller section saves weight
Frequently asked questions
What is the difference between St37 and St52?
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).
What do the numbers 37 and 52 mean?
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).
Are St37 and St52 still available?
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.
What is St44?
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.
Is ST52 tube the same as St52-3 plate?
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.
What is St37 and St52 in ASTM?
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).
Related comparisons
Verified against DIN 17100:1980 (withdrawn) and EN 10025-2:2019. Last checked: September 2026.