Drilling screws with tapp铆ng screw thread - Mechanical and functional properties - ISO 10666
Material - Drilling screws must be made of case-hardened steel or other heat-treatable steels.
metallurgical properties
Surface hardness - the smallest self-drilling screws, surface hardness after heat treatment must be 530 HV 0,3
Kernel Hardness after heat treatment must be
320 HV 5 till 400 HV 5 for threads ? ST 4,2 a
320 HV 10 till 400 HV 10 for threads > ST 4,2
including the recommended minimum tempering temperature 330 掳C.
The depth of the hardened layer | ||
thread Size | The depth of the hardened layer mm smallest | The depth of the hardened layer mm largest |
ST 2,9 a ST 3,5 | 0,05 | 0,18 |
ST 4,2 a ST 5,5 | 0,10 | 0,23 |
ST 6,3 | 0,15 | 0,28 |