Iron Disc
| RM No. | 58A Chill-Cast Iron D |
| Base | Fe Disc |
| Al | 0.004 |
| As | 0.005 |
| B | 0.0005 |
| Bi | 0.007 |
| C | 2.67 |
| Ca | 0.0001 |
| Ce | 0.0004 |
| Co | 0.017 |
| Cr | 0.91 |
| Cu | 0.11 |
| La | 0.0001 |
| Mg | 0.0004 |
| Mn | 0.39 |
| Mo | 1.33 |
| Ni | 1.94 |
| P | 0.1 |
| Pb | 0.0002 |
| S | 0.045 |
| Sb | 0.001 |
| Si | 3.57 |
| Sn | 0.005 |
| Te | 0.006 |
| Ti | 0.017 |
| V | 0.014 |
| W | 0.004 |
| Zr | 0.002 |



