Sheh kai Precision uses a two step heating technique where a carburized technique is used first to harden the outer
layer of the screw, and then an induction heat treatment used only for the drilling/tapping portion of the fastener.
Separate processes and separation of the techniques as well as the area allows Sheh Kai to manufacture a fastener
with the desired hardness for drilling / tapping the required materials while also leave the desired amount of ductility
to the load bearing area of the fastener. This would safeguard the fastener itself from the effects of hydrogen and
corrosion induced embrittlement, preventing delayed and unexpected failure, thus enhancing the performance of
the fastener.
Two Steps Heat - Treatment
1st step – Case hardening to provide the shank of the screw with adequate
strength,good ductility, and hydrogen embrittlement resistant characteristics.
2nd step –Selective through hardening to provide the drill point and lead
threads with good drilling and tapping performance.