St37-2 steel (1.0037): properties, composition, equivalents
St37-2 (DIN 17100) is the withdrawn German structural steel now called S235JR: 235 MPa yield, 340–470 MPa tensile. What St37 means, how it maps to S235JR/1.0038, A36, SS400 and Q235, and what changed.
What is St37-2?
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general structural steel with 37 kp/mm² — about 360 MPa — minimum tensile strength and 235 MPa yield; the standard was withdrawn in 1994 when EN 10025 replaced it with S235JR (1.0038).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.
St37-2 chemical composition
| Element | Mass % | Note |
|---|---|---|
| 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.
St37-2 mechanical properties
| Thickness / condition | Yield strength ReH / Rp0.2 MPa (ksi) | Tensile strength Rm MPa (ksi) | Elongation A % | Hardness |
|---|---|---|---|---|
| < 16 mm (DIN 17100) | 235 (34.1) | 340–470 (49.3–68.2) | 26 | ≈ 100–140 HB |
| 16–40 mm | 225 (32.6) | 340–470 (49.3–68.2) | 25 | — |
| 40–63 mm | 215 (31.2) | 340–470 (49.3–68.2) | 24 | — |
| 63–80 mm | 215 (31.2) | 340–470 (49.3–68.2) | 24 | — |
| 80–100 mm | 215 (31.2) | 340–470 (49.3–68.2) | 24 | — |
| S235JR today, ≤ 16 mm (for comparison) | 235 (34.1) | 360–510 (52.2–74.0) | 26 | — |
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 toughness
St37-2 requires a minimum Charpy V-notch energy of 27 J at 20 °C (St37-3 U only; St37-2 had no impact requirement). The variants: St37-2 (no impact), USt37-2 (rimmed), RSt37-2 (semi/fully killed), St37-3 U (27 J at +20 °C, ≈ S235J0 today... strictly S235J0 is 0 °C), St37-3 N (27 J at −20 °C ≈ S235J2).
St37-2 equivalent grades
| Grade | System | Match | Why / differences |
|---|---|---|---|
| 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). |
| Q235B | 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'. |
| IS 2062 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. |
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 St37-2 →
Old and superseded designations
| Old name | Standard | Note |
|---|---|---|
| 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 and tolerance standards
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.
Dimensional tolerances: current: EN 10029 (plate), EN 10051 (coil), EN 10034 (sections) — DIN 1543/1016 are withdrawn.
Key property values
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 and heat treatment
As for S235JR: easily machined, punched and bent (0.5–1 t radius). Not hardenable. Galvanizes well.
Typical 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
St37-2 compared with related grades
Frequently asked questions
What is St37 steel?
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).
Is St37 the same as S235JR?
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.
What is the difference between St37 and St52?
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.
What is St37 equivalent to in ASTM?
ASTM A36 (250 MPa yield, 400–550 MPa tensile) is the standard American substitute. It is slightly stronger and has no impact requirement.
What does the 37 in St37 mean?
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).
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 10027-2 (material numbers). Last checked: September 2026.