Failure Analysis of Self-drilling and Self-tapping Screws SWRCH22A with Insufficient Torque
In order to solve the problem of premature breakage of self-drilling and self-tapping screws SWRCH22A with in-sufficient torque,unqualified samples were retrieved for chemical composition,macro analysis,metallography detection and electron microscope energy spectrum analysis.The results show that the causes of insufficient torque are hydrogen embrittle-ment,poor organization of heat treatment and cracks in the tooth base.The improvement measures such as strengthening heat treatment process control,hydrogen displacement after electroplating and improving machining precision are put forward.
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