C | Si | Mn | S | P | Cr | Ni | Cu | V | Mo | W | Co |
0.80~0.90 | 0.20~0.45 | 0.15~0.40 | ≤ 0.030 | ≤ 0.030 | 3.75~4.50 | ≤0, 30 | ≤0, 25 | 1.75~2.25 | 4.50~5.50 | 5.50~6.50 | 4.50~5.50 |