Steel sheet metal screws cloudy - Mechanical properties - ISO 2702
The depth of the hardened layer
| Dimensions in millimeters | ||
| Thread | The depth of the hardened layer | |
| min. | max. | |
| ST2, ST2,6 | 0,04 | 0,10 |
| ST2,9, ST3,3, ST3,5 | 0,05 | 0,18 |
| ST3.9, ST4,2, ST4.8, ST5,5 | 0,10 | 0,23 |
| ST6,3, ST8,ST9,5 | 0,15 | 0,28 |
Kernel Hardness:
Hardness after quenching cores must be
270 HV5 till 370 HV5 for threads ≤ ST3,9
270 HV10 till 370 HV10 for threads ≥ ST4.2