| Standard | Steel Grade | Chemical Composition (%) | ||||
| C | Si | Mn | P | S | ||
| JIS G3445 | STKM11A | ≤0.12 | ≤0.35 | ≤0.60 | ≤0.040 | ≤0.040 |
| STKM12A | ≤0.20 | ≤0.35 | ≤0.60 | ≤0.040 | ≤0.040 | |
| STKM12B | ||||||
| STKM12C | ||||||
| STKM13A | ≤0.25 | ≤0.35 | 0.30-0.90 | ≤0.040 | ≤0.040 | |
| STKM13B | ||||||
| STKM13C | ||||||
| STKM14A | ≤0.30 | ≤0.35 | 0.30-1.00 | ≤0.040 | ≤0.040 | |
| STKM14B | ||||||
| STKM14C | ||||||
|
Mechanical Properties
|
||||||
| Standard | Steel Grade | Mechanical Properties | ||||
| (MPa) Tensile Strength |
(MPa) Yield Strength |
(%) Elongation |
||||
| JIS G3445 | STKM11A | ≥295 | / | ≥35 | ||
| STKM12A | ≥345 | ≥175 | ≥35 | |||
| STKM12B | ≥390 | ≥275 | ≥25 | |||
| STKM12C | ≥470 | ≥355 | ≥20 | |||
| STKM13A | ≥375 | ≥215 | ≥30 | |||
| STKM13B | ≥440 | ≥305 | ≥20 | |||
| STKM13C | ≥510 | ≥380 | ≥15 | |||
| STKM14A | ≥410 | ≥245 | ≥25 | |||
| STKM14B | ≥500 | ≥355 | ≥15 | |||
| STKM14C | ≥550 | ≥410 | ≥15 | |||