| Mechanical Properties | Strength grade designation | |||
|---|---|---|---|---|
| 4.6 | 4.8 | |||
| Tensile strength Rm | min. | N/mm2 | 392 | |
| max. (see Note 1) |
N/mm2 | 539 | ||
| Brinell hardness HB | min. | HB | 110 | |
| max. (see Note 1) |
HB | 170 | ||
| Rockwell hardness | min. | HRB | 62 | |
| max. (see Note 1) |
HRB | 88 | ||
| Vicers hardness | min. | 110 | ||
| max. (see Note 1) |
170 | |||
| Yeild stress Re | min. | N/mm2 | 235 | 314 |
| Stress under proof load Sp (see Note 2) |
Sp/Re | 0.94 | 0.91 | |
| N/mm2 | 222 | 286 | ||
| Elongation A after fracture | min. | % | 25 | 14 |
| Strength under wedge loading | The values for full size bolts equal the minimum values for tensile strength shown above (see Note 3) | |||
| Head soundness | No fracture (see Note 4) | |||
Note 1. Only for full size bolts.
Note 2. The allowed permanent extension is 12.5 pm.
Note 3. The fracture should not take place immediately under the head of the bolt.
Note 4. Where screws are threaded up to the head this property will be regarded as established even if a crack should appear in the first thread, provided that the head does not snap off.