Enhancing wear resistance of railway wheel by laser surface cladding of martensitic stainless steel on high carbon rail steel

Railway wheels experience various types of wear that alter their shape and dimensions and reduce life, for which laser surface cladding (LSC) provides one of the viable solutions to enhance wear resistance, extend lifespan, and reduce replacement needs. This study explores the potential of extending the service life of railway wheels through the LSC of Rockit (R) 401 martensitic stainless steel (18.79 % Cr, 2.57 % Ni, 0.2 % C) on an AISI 1070 steel substrate. The process is carried out utilizing a 6-kW fiber-coupled diode laser and a co-axial powder delivery system. Key process parameters are evaluated to assess their impact on clad characteristics, and an optimal process window is identified. The microstructure, surface topography, micro-compositional distribution, phase evolution and aggregation, and hardness of the clad layers on the top surface and in cross-section are analyzed. Tribological tests are conducted to further assess sliding and abrasive wear performance. Efforts are also made to understand how the phases in the clad region affect sliding and abrasion wear performance, with detailed insights obtained from comprehensive wear track analysis. Optical and scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray diffraction analyses confirm the successful formation of martensitic steel clad with distinctive microstructural features. The micro-hardness of the clad is found to be more than 2.5 times greater than that of the substrate. The clad is shown to offer over twice the sliding wear resistance and nearly double the abrasive wear resistance than the substrate, with shallower scars, lower volume loss, minimal surface damage, and a reduced wear coefficient, making it ideal for railway wheels.