Study on microstructure and sliding wear behavior of similar and dissimilar welded joints produced by laser-arc hybrid welding of wear-resistant steels

Welded joints of wear-resistant steel often experience wear problems due to a lack of strengthening particles. This study investigates the wear behavior of welded joints produced by laser-arc hybrid welding (LAHW) on wear-resistant steel with low strength (WRL) and high strength (WRH). The microstructure, wear rate, wear track morphology, and profile were analyzed. The experimental results indicate that the microstructures of the fusion zone (FZ), coarse-grain heat-affected zone (CGHAZ), fine-grain heat-affected zone (FGHAZ), and intercritical heat-affected zone (ICHAZ) in both similar and dissimilar welded joints consist of martensite, coarsening martensite, martensite + ferrite, and martensite + ferrite + bainite, respectively, regardless of WRL and WRH. The wear resistance of the FZ was weaker than those of both WRL and WRH. The wear direction, namely parallel or perpendicular to the welded seams, affects the wear behavior. The cross-sectional areas of the wear tracks in both similar and dissimilar welded joints showed minimal changes in the HAZ and FZ. The wear mechanisms in the different HAZs varied due to microstructural differences.