Abstract: The wear and damage behaviors of U75V rail under different slip ratio conditions are explored using a MJP-30A rolling wear testing machine. The wear rate change of rail material is investigated with the slip ratio increasing. The results indicate that the wear rate of U75V rail material shows a rising trend of "step" style with the slip ratio increasing. According to the Tγ/A-wear rate mapping, three wear regions including mild wear area, severe wear area and catastrophic wear area can be divided. Under different slip ratio conditions, the wear and damage mechanism of rail material is obviously different. When the slip ratio is below 3%, main wear damage of rail material is oxidative wear and mild fatigue wear. As the slip ratio rises to 6% and 12%, main wear damage is light abrasive wear. While, at the slip ratio of 18% and 25%, main wear damage is serious abrasive wear. With an increase of slip ratio, the thickness of rail material plastic deformation layer, propagation depth and angle of fatigue cracks both present a trend of first increasing and then decreasing. When the range of slip rate is 12%~18%, the thickness of rail material plastic deformation layer, the propagation depth and angle of fatigue crack reach the maximum.

Key words: Tγ/A-wear rate, damage, rail material, slip ratio, wear