Abstract: Friction and wear performance of 75 kg/m pearlitic heavy-duty heat-treated rail steel was investigated by means of the ring-block butt-abrasion test at different test forces and cycle times, and compared with that of rail steel with RE, Nb and Ni elements adding. At the same time, the surface morphology, profile damage, microstructure evolution in the plastic deformation zone and elemental content changes of the specimens after wear were analyzed by using a combination of scanning electron microscope, transmission electron microscope and electron microprobe techniques. The results show that with the increase of test force, the wear loss increases, the wear form transitions from oxidizing wear to adhesive wear and fatigue wear, and the thickness of the white layer in the deformation zone increases. With the increase of friction wear cycle times, the grain size of the deformation zone is finer, and the thickness of the plastic deformation layer becomes larger. However, under the larger test force, the crack extension in the white layer intersects and causes the material to break, and the wear loss increases. The pearlitic lamellar spacing of the rail steel with adding RE, Nb and Ni elements is refined by 21.8% compared with that of the original state rail steel, and the smaller the pearlite lamellar spacing is, the smaller the thickness of the white layer is formed and is less prone to breaking, and thus it has better wear resistance.

Key words: heat treated rail steel, pearlitic rail steel, friction and wear, wear mechanism