Hardness for the different property classes of metric nuts
The hardness of metric nuts, like other fasteners, is an important mechanical property that indicates the material’s resistance to deformation or indentation. It is typically measured on the Rockwell hardness scale (HRC), Vickers hardness scale (HV), or Brinell hardness scale (HB), depending on the material and the standards used. The hardness value for different property classes of metric nuts can vary based on the material and the manufacturing specifications. Here’s a general explanation:
| Thread D | Property class | 6 | 8 | 10 | 12 |
|---|---|---|---|---|---|
| 5 | 6 | 8 | 10 | 12 | |
| Vickers hardness, HV | |||||
| M5 ≤ D ≤ M16 | 130-302 | 150-302 | 200-302 | 272-353 | 295-353 |
| M16 < D ≤ M39 | 146-302 | 170-302 | 233-353 | 272-353 | |
| Brinell hardness, HB | |||||
| M5 ≤ D ≤ M16 | 124-287 | 143-287 | 190-287 | 259-336 | 280-336 |
| M16 < D ≤ M39 | 139-287 | 162-287 | 221-336 | 259-336 | |
| Rockwell hardness, HRC | |||||
| M5 ≤ D ≤ M16 | 30(max) | 30(max) | 30(max) | 26-36 | 29-36 |
| M16 < D ≤ M39 | 36(max) | 26-36 | |||