Microstructure and tribological property of laser cladding Stellite 6 alloy by laser remelting and ultrasonic surface rolling

Stellite 6 alloy was deposited onto the surface of 27SiMn steel using the laser cladding (LC) technique, which was then followed by laser remelting (LR) and ultrasonic surface rolling (USR).The surface roughness, microstructure, microhardness, surface residual stress, and wear resistance of LC, LR, and LR-USR samples were studied using electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray stress analyzer, Vickers hardness tester, and material surface performance tester. The results showed that compared with LC, LR-USR significantly refined the surface dendrites of the cladding layer, with the average dendrite size decreasing from 16.37 μm to 6.92 μm. After USR, the samples converted from tensile residual stress (TRS) to compressive residual stress (CRS), and the high-density dislocations and strain generated in the grains near the surface of the cladding layer. The wear depth volume of the LR-USR samples was the smallest, showing typical abrasive wear.