Structural steel grades: S235JR, S275JR, S355J2 and ASTM A36, A572 and A992 compared
Minimum yield and tensile strength, impact test temperatures and carbon equivalent of EN 10025-2 grades S235JR, S275JR and S355J2, the old St37 and St52 names, and how ASTM A36, A572 Grade 50 and A992 compare.
Updated October 17, 2026
Hot-rolled structural steel for beams, channels, angles, bars and plate is ordered by grade. In Europe the grades come from EN 10025-2; in the US from ASTM standards such as A36, A572 and A992. This guide lists the minimum values each grade guarantees, explains the old DIN names still used on many drawings, and shows how the European and American grades relate.
How to read an EN 10025 grade name
- S — structural steel.
- 235 / 275 / 355 — minimum yield strength in MPa for thicknesses up to 16 mm. It drops slightly for thicker material.
- JR / J0 / J2 / K2 — the impact test: 27 J at +20 °C (JR), 0 °C (J0) or −20 °C (J2), or 40 J at −20 °C (K2).
- +N, +AR — delivery condition (normalized or as rolled). Hollow sections add H, as in S355J2H — see hollow section grades.
EN 10025-2 grades: minimum mechanical properties
| Grade | ReH min, t ≤ 16 mm (MPa) | ReH min, 16 < t ≤ 40 mm (MPa) | Rm, 3 ≤ t ≤ 100 mm (MPa) | Elongation min (%) | CEV max, t ≤ 30 mm |
|---|---|---|---|---|---|
| S235JR | 235 | 225 | 360–510 | 26 | 0.35 |
| S275JR | 275 | 265 | 410–560 | 23 | 0.40 |
| S355J2 | 355 | 345 | 470–630 | 22 | 0.45 |
| Quality | Test temperature | Minimum energy |
|---|---|---|
| JR | +20 °C | 27 J |
| J0 | 0 °C | 27 J |
| J2 | −20 °C | 27 J |
| K2 | −20 °C | 40 J |
The carbon equivalent (CEV) is a measure of weldability: the lower it is, the less risk of cracking in the heat-affected zone. All three grades are readily weldable within these limits; thick S355 sections may need preheating according to the welding procedure.
Which EN 10025 grade to choose
- S235JR — general structural work, frames, brackets and secondary members designed for 235 MPa. The most widely stocked grade.
- S275JR / S275J0 — when the design calls for 275 MPa, common for plate and some sections in the UK and Ireland.
- S355J2 — primary members where higher strength saves weight: about 50% more yield strength than S235JR, with toughness tested at −20 °C for outdoor and dynamically loaded structures.
Old designations: St37, St44 and St52
| Old name (DIN 17100) | EN 10025-2 grade | Minimum yield, t ≤ 16 mm (MPa) |
|---|---|---|
| St 37-2 | S235JR | 235 |
| St 44-2 | S275JR | 275 |
| St 52-3 | S355J2 (formerly S355J2G3) | 355 |
DIN 17100 was withdrawn decades ago, but St37 and St52 are still common shorthand on drawings and in quotes. Treat them as the EN 10025-2 grades in the table, and order by the EN name so the mill certificate states a current standard.
ASTM A36, A572 Grade 50 and A992
| Grade | Yield min (MPa / ksi) | Tensile (MPa / ksi) | Typical use |
|---|---|---|---|
| ASTM A36 | 250 / 36 | 400–550 / 58–80 | Plate, bars, angles, channels and general shapes |
| ASTM A572 Grade 50 | 345 / 50 | min 450 / 65 | High-strength plate, bars and shapes |
| ASTM A992 | 345–450 / 50–65 | min 450 / 65 | Wide-flange (W) beams and columns in the US |
A36 sits between S235 and S275 in yield strength. A572 Grade 50 and A992 match S355 in yield strength. The grades are close, not identical: chemistry limits, thickness steps and impact requirements differ, and A36 has no mandatory impact test unless it is ordered as a supplementary requirement. Use an equivalent only when the design code and the engineer accept it.
Grades we supply
- Bars and angles — flat, round and square bars and equal angles in S235JR to S355J2, and in ASTM A36 and A572.
- Beams, channels and plate — HEA, HEB, IPE, UPN and hot-rolled sheet are listed in S235JR. State the grade you need with the request.
- Hollow sections — EN 10219 grades S235JRH to S355J2H; see hollow section grades.
Every delivery can come with an EN 10204 3.1 mill certificate showing the cast analysis and test results — see what a 3.1 certificate contains.
Frequently asked questions
What is the difference between S235 and S355?
S355 has a minimum yield strength of 355 MPa against 235 MPa for S235, about 50% more, so the same load can be carried with a lighter section. S355 is usually ordered as S355J2, impact tested at −20 °C; S235 is usually S235JR, tested at +20 °C.
Is ASTM A36 the same as S235JR?
No, but they are close. A36 requires at least 250 MPa yield and 400–550 MPa tensile strength; S235JR requires 235 MPa and 360–510 MPa for thin material, plus an impact test at +20 °C that A36 does not require by default.
What replaced St37 and St52?
St 37-2 corresponds to S235JR and St 52-3 to S355J2 under EN 10025-2. The old DIN 17100 names are still used informally, but certificates are issued to the EN grade.
What does J2 mean in S355J2?
J2 means the steel must absorb at least 27 J in a Charpy V-notch impact test at −20 °C. It shows the steel stays tough at low temperatures, which matters for outdoor structures and members under dynamic loads.
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