Method of making a multigrip fastener and fastener made thereby

摘要

This disclosure relates to swage type fasteners including a pin having a plurality of combination locking and breakneck grooves and a collar adapted to be swaged into the grooves with one of the grooves acting as a breakneck whereby the excess length of pin is severed generally at the end of the collar and also relates to a method of making the pin. The multigrip pin is formed generally into its final shape and then is subject to a heat treating process to provide a desirable microstructure whereby more consistent breaks at the selected groove occurs. In one form of the invention a desirable microstructure consists of predominantly pearlite colonies with a proeutectoid ferrite matrix interspersed at the boundaries of pearlite colonies.