| 等级 | 化学成分 | |||||
| C (Max) | Si (Max) | Mn (Max) | P (Max) | S (Max) | C+Mn/6 (Max) | |
| SR-235 | - | - | - | 0.050 | 0.050 | - |
| SR-295 A | - | - | - | 0.050 | 0.050 | - |
| SD-295 A | - | - | - | 0.050 | 0.050 | - |
| SD-295 B | 0.27 | 0.55 | 1.50 | 0.040 | 0.040 | - |
| SD-345 | 0.27 | 0.55 | 1.60 | 0.040 | 0.040 | 0.50 |
| SD-390 | 0.29 | 0.55 | 1.80 | 0.040 | 0.040 | 0.55 |
| SD-490 | 0.32 | 0.55 | 1.80 | 0.040 | 0.040 | 0.60 |
