Investigation on the Rolling Contact Fatigue Behaviors of Different Laser Cladding Materials on the Damaged Rail

Abstract

Surface damages on rail became severe with the increase in the axle load and speed. Laser cladding was used to repair the local damages on rail surfaces to ensure the service performance and prolong the life of rails. In the present study, five types of cladding materials (304, 314, 2Cr13, 316L, and 434L) were clad at a small part (trapezoidal shape) of the rail disc to simulate the defected rail in the field. Vickers hardness tester, optical microscopy (OM), scanning electron microscopy (SEM), and electron-dispersive X-ray spectroscopy (EDS) were employed to investigate the service properties of the repaired rail discs. Results indicated that all these five clad rail discs had lower wear-rates than the unclad rail disc. The wear-rates decreased with the increase in the initial hardness of the clad layer. Cracks with large angles mainly propagated along the boundary at the front edge, while at the rear edge, the crack morphology was closely related to the hardness of clad layer. 434L would induce the minimum wear loss and the modest rolling contact fatigue (RCF) of the repaired rail disc, which could be the potential cladding material for repairing the damaged rail.