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  3. ISO 10666 - Drilling screws with tapping screw thread -- Mechanical and functional properties

ISO 10666 - Drilling screws with tapping screw thread -- Mechanical and functional properties

Drilling screws with tappíng 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 °C.

Tempering temperature must be within the range 275 ° C to 315 ° C due to the minimization of the risk of martensitic fragility.


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