Matching Characteristics between Four Kinds of Wheel Steels and U71Mn Hot-Rolled Rail

In order to investigate the effect of wheel materials on the matching behaviors between wheel and rail, the MMS-2A wear test machine was used to simulate the friction and wear behavior of the wheel/rail systems made of U71Mn hot-rolled rail and four kinds of wheel materials. The wear loss was measured by an electronic analytical balance and the microstructure of wheel/rail samples were analyzed by a scanning electron microscope. The results indicate that with the carbon content of wheels increasing, the wheel hardness increases and the wheel wear loss decreases, but the wear loss of the rail samples matching with the wheels increases gradually. The attrition rate of the wheel/rail samples is related to the roughness of the wear scars: the more serious the wear is, the rougher the wear scars are. In addition, the wear mechanism is determined by the hardness ratio of wheel to rail materials. When the hardness ratio is low, the wear process is dominated by a mechanism of abrasive wear, and the wear loss is the largest. With the increase of the hardness ratio, the main wear mechanism turns into a fatigue wear and the wear loss becomes less. When the hardness ratio approaches 1.1, more serious oxidation occurs to the wheel/rail samples, and oxidative wear will dominate the wear mechanism.