Ferro boron (FeB18) for boron-treated steels and special alloys. Very small additions sharply increase hardenability; also used in amorphous / soft-magnetic alloys and NdFeB permanent-magnet production.
| B | 17-20% |
| C | ≤ 0.5% |
| Si | ≤ 2.0% |
| Al | ≤ 0.5% |
| S | ≤ 0.01% |
| P | ≤ 0.10% |
| Size | 10-50mm |
