Optimization on laser cladding parameters for preparing Ni60 coating along with its friction and wear properties

Ni60 coating was prepared on Q235 substrate by using laser cladding method, and the optimization of processing parameters was performed based on response surface methodology. Laser power, scanning speed and powder feeding rate were considered as input variables, while dilution ratio, ratio of width to height, and hardness were considered as output responses. Then, the influence of processing parameters on cladding quality was studied by single track cladding experiments, and the optimal parameters were obtained by regression analysis. Subsequently, Ni60 coating was successfully prepared and its friction and wear properties were investigated. Results show that the optimal parameters are: laser power 540 W, scanning speed 30 mm/s, powder feeding rate 0.2 r/min and overlapping step 0.4 mm. The microhardness of coating is 499.4 HV0.5, which is 5 times higher than that of the substrate. Correspondingly, the wear loss of the coating is 68.3% and 82.1% lower than that of Q235 substrate at room temperature and 400 °C respectively, indicating that the Ni60 coating can improve the wear resistance of Q235 steel significantly.