Comparison of Wear Surface Microstructure Evolution and Polygonal Wear Behavior of CL60 Alloy Steel and Non Alloy Steel Wheel after Service

The microstructure observation, tensile test, hardness test and friction wear test were carried on the CL60 alloy and non-alloy wheels of the same subway vehicle that had been overhauled and put into service for 20 000 kilometers. The microstructure and mechanical properties evolution of the two types of wheel material were compared. The polygonal wear behavior was analyzed. The results show that two types of wheel steel belonged to ferrite-austenite steel, composed of austenite and a small amount of pre-equilibrium ferrite. The layer spacing of austenite in alloy steel was smaller than that in non-alloy steel, the content of pre-equilibrium ferrite in two types of steel was similar, the hardness, yield strength and tensile strength of the alloy steel were greater.The average grain size of the tread of alloy steel wheel after service was larger, the strain hardening degree was smaller, and the residual compressive stress was smaller. The polygonal wear resistance of the alloy steel wheel was better than this of the non alloy steel wheel.