Fretting wear characteristics evolution mechanism of 60Si2MnA steel for high-speed railway fastener clips

The fastener clips of the high-speed railway may fracture due to accumulated fretting damage, posing a hazard to train operation safety. To investigate the evolution mechanism of fretting wear characteristics of high-speed railway fastener clips, this paper conducted fretting wear tests on 60Si2MnA steel used for clips and analyzed the fretting wear characteristics under different number of fretting cycles (N). The results indicate that as N increases, the friction coefficient rises initially, then falls, slightly rises again, and eventually stabilizes. Furthermore, the surface wear volume and depth of 60Si2MnA steel material increase continuously, and its fretting wear mechanism undergoes a transformation. Specifically, at 20,000 cycles, surface plastic deformation primarily causes material damage. While at 40,000 cycles, an oxide plastic deformation layer appears on the material surface, where adhesive wear and oxidation wear become the primary wear mechanisms. When N increases to 80,000, plastic strain accumulates continually on the material surface, causing the oxide plastic deformation layer in the outer contact area to break and detach gradually. Adhesive wear transforms into abrasive wear, cracks occur inside the material, and fatigue wear becomes a significant wear mechanism. This study fills the research gap in the fretting wear evolution mechanism of 60Si2MnA steel.