Reason for wear of elevator safety gear wedges

A certain model of elevator safety gear wedge was worn. The reason for wedge wear was analyzed by macroscopic observation, chemical composition analysis, hardness testing, metallographic examination, scanning electron microscopy and energy spectrum analysis. The results show that during the braking process of the safety caliper, severe friction occurred between the wedge and the guide rail, generated a large amount of heat, which increased the temperature in the middle of the wedge working face, resulted in an over tempering effect. The surface structure of the wedge changed from tempered martensite to tempered sorbite, and the hardness and wear resistance in the middle of the wedge working face decreased, ultimately led to severe adhesive wear and abrasive wear of the wedge.