ISO 2702 - Heat-treated steel tapping screws -- Mechanical properties

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