Failure Analysis on Casting High Aluminum Zinc Based Alloy ZA27 Worm Gear in Elevator Traction Machine

By means of field investigation, combined with ICP-OEM, OM, SEM, EDS and finite element analysis, the mechanism and cause of fracture of the casting high aluminum zinc based alloy ZA27 worm gear tooth in elevator traction machine were analyzed. At the same time, the tooth surface pitting formation mechanism was explored. The results show that the tooth fracture of the worm gear was fatigue fracture. The tooth root was alternating load stress concentration point, and the casting defects here accelerated the formation of fatigue crack source. The formation of pits on the worm gear tooth surface was related to the casting defects of the second surface.