Comparison on the wear properties and rolling contact fatigue damage behaviors of rails by laser cladding and laser-induction hybrid cladding

In this paper, the wear properties and rolling contact fatigue (RCF) damage behaviors of the rails with Ni-based coatings deposited by laser cladding (LC) and laser-induction hybrid cladding (LIHC) are studied comparatively by roll-sliding contact tests. The results indicate that the RCF damage characteristics of the rail rollers by both LC and LIHC are almost same at the maximum contact stress sigma(max) <= 800 MPa, while the wear rate of rail roller by LC is slightly lower. However, when the maximum contact stress increases to sigma(max )>= 1230 MPa, the coatings and heating affected zone (HAZ) at the contact edge of the rail roller by LC spall and fracture severely, leading to much higher wear rate and much poorer smoothness than that by LIHC. Thus, compared with LC technology, LIHC technology can reduce the wear rate and contact fatigue damage extent of rails at higher contact stress, and thereby maintain the surface profile and smoothness better.