This study investigates the microstructure and wear behavior of the laser-clad Stellite 6 coatings deposited on AISI 5046 rail steel, a material used in GM locomotive crankshafts. Stellite 6 powder was deposited via fiber laser cladding in both single-track and multi-track configurations under an argon shielding atmosphere. Microstructural characterization, elemental composition analysis, and phase identification were performed using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD), respectively. Wear behavior was evaluated by hardness testing and pin-on-disk tribometry. Microstructural analysis confirmed the creation of a cladding layer free of voids and cracks, with a dilution of 7.7% and a strong metallurgical bond between the clad and the substrate. The laser-clad layer exhibited a hypoeutectic microstructure consisting of Co-rich γ-phase primary dendrites and a Cr-rich interdendritic γ + carbide eutectic. Compared with the AISI 5046 substrate, the Stellite 6 layer demonstrated significantly enhanced tribological performance, including a 34% reduction in friction coefficient (0.45 vs. 0.60) and a 55% decrease in wear rate. This improvement is primarily attributed to the higher hardness of the layer (479 HV30 vs. 262 HV30, representing an ~1.8x increase), refined microstructure, and the formation of oxide glaze layers, which reduce direct metal-metal contact. While the substrate experienced severe adhesive–abrasive and oxidative wear, the laser-clad Stellite 6 coating exhibited a more controlled adhesive wear mechanism accompanied by stable glaze formation. These results demonstrate the effectiveness of laser-clad Stellite 6 layers as a high-performance surface engineering solution for restoring and enhancing the wear resistance of high-value railway components, particularly locomotive crankshafts.
Sani et al. (Sun,) studied this question.