The mechanical properties at room and high temperature

chemical composition

microstructure of the zinc alloy（ZA27alloy）worm gear in elevator traction machine were analyzed by electron universal test machine

spectrum analyzer

metallurgical microscope and scanning electron microscope.The results show that inclusion

shrinkage porosity

pore and partial over-loading are responsible for failure of the zinc alloy worm gear.Some feasible ways were presented to eliminate casting defects

and the working accuracy was improved to reduce the possibility of partial over-loading

ensuring the safe and effective runing of the elevator.