Prediction and sensitivity analysis of the surface quality in Ni60/WC coatings

For laser cladding a large temperature gradient easily weakened the surface quality by generating cracks and irregular coating surfaces, which in turn affected the bearing capacity and corrosion resistance of coatings in the rapid heating and cooling process. The response surface methodology (RSM) was used to predict coating cracks by changing the powder ratio, energy density, and preheating temperature, which obtained the relevant mathematical model. After that, the sensitivity of the crack length to process parameters was analyzed based on the sensitivity analysis method. The effect of Ni60/WC composite powder process parameters on the surface quality was revealed in laser cladding. The crack length first decreased and then increased, and the Smooth decreased with the increased powder ratio. The crack length and Smooth increased with the increased energy density. The crack length decreased and Smooth increased with the increased preheating temperature. Sensitivity analysis showed that the crack length and Smooth were the most sensitive to the powder ratio. Therefore, the process parameters were reasonably selected to control the surface quality. The mathematical model and sensitivity analysis method in the work could improve the surface quality, which provided a theoretical basis for the prediction and control of laser cladding cracks.