SM400A
JPApproximate matchJIS · JIS G3106:2020
Family of unalloyed carbon structural steels used in steel framing, locksmithing/metalwork and light boilermaking for applications without high-strength requirements. It's the most common and cheapest grade on the market, available in nearly every region of the world under closely related designations.
| Grade | Region | Standard | Re (MPa) | Rm (MPa) | Delta |
|---|---|---|---|---|---|
| SM400A | JP | JIS G3106:2020 | 245 | 400–510 | reference |
| SS400 | JP | JIS G3101:2020 | 245 | 400–510 | 0% |
| SS400 | KR | KS D3503:2018 | 245 | 400–510 | 0% |
| A36 | US | ASTM A36/A36M | 250 | 400–550 | +2% |
| S235JR | EU | EN 10025-2:2019 | 235 | 360–510 | -4% |
| E235 (ex-Fe360) | ISO | ISO 630-2:2021 (ancien ISO 630:1995, désignation historique Fe360) | 235 | 360–510 | -4% |
| Neighboring grades — different strength | |||||
| S275JR | EU | EN 10025-2:2019 | 275 | 410–560 | +12% |
| S355JR | EU | EN 10025-2:2019 | 355 | 470–630 | +45% |
| Grade | C | Mn | Si | P | S | Cu | N |
|---|---|---|---|---|---|---|---|
| SM400A | ≤0.23 | — | — | ≤0.035 | ≤0.035 | — | — |
| SS400 | ≤0.25 | ≤1.4 | — | ≤0.04 | ≤0.04 | — | — |
| SS400 | — | — | — | ≤0.05 | ≤0.05 | — | — |
| A36 | ≤0.26 | 0.6–0.9 | ≤0.4 | ≤0.04 | ≤0.05 | ≥0.2 | — |
| S235JR | ≤0.17 | ≤1.4 | ≤0.2 | ≤0.035 | ≤0.035 | — | — |
| E235 (ex-Fe360) | — | — | — | — | — | — | — |
| S275JR | ≤0.21 | ≤1.5 | ≤0.05 | ≤0.04 | ≤0.045 | — | — |
| S355JR | ≤0.24 | ≤1.6 | ≤0.55 | ≤0.04 | ≤0.04 | ≤0.55 | ≤0.012 |
Note: 'Weldable' variant of SS400, reserved for welded structures (bridges, buildings) with a slightly tighter composition (stricter P/S) to limit the risk of cold cracking. Mechanical properties nearly identical to SS400. The manganese ceiling is defined as a ratio to the actual carbon content rather than a fixed value.
Values compiled from public sources for guidance only — always verify against the official standard before use in design or fabrication.