Microstructure and properties of high-speed laser cladding Ni60 coating on surface of high manganese steel

High-speed laser system was used to prepare Ni60 wear-resistant cladding layer on surface of high manganese steel that was commonly used in crusher hammer. The optimum process parameters were obtained by orthogonal test range analysis. The macroscopic morphology, hardness, microstructure, phase, friction coefficient and wear amount of cladding layer were observed and tested by penetration testing, microhardness tester, OM, XRD, BSE and friction and wear test. The results showed that when laser power was 1 200 W, scanning speed was 4 mm/s, and powder feeding speed was 7.5 g/min, surface forming quality of cladding layer was good, surface hardness was 811.41 HV, which was about 2.8 times of substrate. Friction coefficient decreased by 37.7% compared with substrate and wear resistance was increased by 1.6 times. Cladding layer was mainly composed of γ-Ni dendrites, in which hard phases CrB, Cr₇C₆ and Cr₂₃C₃ significantly improved wear resistance of cladding.