Iron Disc
| RM No. | 58A Fe-Ni2Si2W2Cr |
| Base | Iron Disc |
| Al | 0.029 |
| Al(S) | 0.028 |
| As | 0.028 |
| B | 0.0047 |
| B(S) | 0.0047 |
| Bi | 0.013 |
| C | 0.503 |
| Ca | 0.002 |
| Co | 0.22 |
| Cr | 0.955 |
| Cu | 0.322 |
| Mn | 0.79 |
| Mo | 0.878 |
| Nb | 0.113 |
| Ni | 1.93 |
| P | 0.031 |
| Pb | 0.008 |
| S | 0.021 |
| Sb | 0.0089 |
| Si | 2.03 |
| Sn | 0.017 |
| Ti | 0.052 |
| Ti(S) | 0.049 |
| V | 0.455 |
| W | 1.66 |
| Zr | 0.018 |



