Effect of Wheel Material Characteristics on Wear and Fatigue Property of Wheel-Rail

The wear and fatigue damage characteristics between wheels of different materials and hot-rolled U75V rail steels were investigated by using a MMS-2A wheel/rail rolling wear testing apparatus. The results indicate that with the increasing carbon content of wheel materials, the proportions of pearlite in the microstructure increased and the interlamellar spacing of cementite decreased, resulting in the increasing of the surface hardness. With the increasing hardness ratio of wheel/ rail steels, the thickness of plastic deformation layer on wheel samples decreased significantly, however, for the rail samples, the thickness increased firstly and then decreased. Also, with the increasing hardness ratio of wheel/ rail steels, the wear of wheel samples transformed from small flakes to large flakes. The wear mechanism of wheel samples transformed from mild delamination to deep delamination. The higher hardness of wheel samples, the shorter the length of fatigue crack. Additional effect of high hardness was the angle of the tip of crack propagation of rails increased, thus leading to the fatigue cracks propagating to the heart of rail steels.