Effect of Grinding Rotation Speed on Material Removal Behaviors of U75V Steel Rail for Heavy Haul Railway

Grinding tests of U75V steel rail used for heavy haul railway were conducted by a self-designed rail grinding testing machine, and the material removal behavior and the evolution law of rail surface quality under different grinding rotation speeds (1,000, 2,000, 3,000 r · min⁻¹) were studied. The results show that as the grinding rotation speed increased, the grinding amount and friction coefficient of the steel rail first decreased and then increased, the grinding temperature at the interface between steel rail and millstone, the surface roughness and the degree of burning all increased, the number of grinding marks decreased and their depth and width increased significantly, the uniformity of grinding marks decreased significantly, and the plastic flow phenomenon of the material was intensified. There were transverse cracks on the surface of the rail at a grinding rotation speed of 3 000 r · min⁻¹. With increasing grinding rotation speed, the thickness of the hard and brittle white etching layer induced by thermo-mechanical coupling effects increased significantly, and the material removal mechanism of the steel rail transformed from pure grinding mode to combined grinding-spalling mode.