Effect of NbC and WC Addition on Microstructure and Properties of Laser Cladding Stellite6 Alloy Coating

The process of laser cladding Stellite6 alloy coating on 2Cr13 stainless steel surface was optimized by orthogonal experimental design methods. The NbC/Stellite6 and WC/Stellite6 alloy composite coatings were prepared by the optimized process with addition amount (mass fraction) of NbC and WC of 1%, 3%, 5%, 7%, 10%. The effects of NbC or WC addition on the microstructure, microhardness and corrosion resistance of the composite coatings were studied. The results show that the optimal process parameters of laser cladding of Stellite6 alloy coating were listed as follows: laser power of 1 600 W, powder feeding capacity of 40 g·min⁻¹ and scanning speed of 17 mm·s⁻¹. The microstructure of the two composite coatings prepared by the optimal process was uniform and dense, and the coatings formed a good metallurgical bond with the substrate. The microstructure of the NbC/Stellite6 alloy composite coating was more uniform and fine. With the increase of the addition amount of NbC or WC, the average microhardness of the composite coatings increased, which was higher than that of the substrate and Stellite6 alloy coating without WC or NbC, and the corrosion rate decreased, which was lower than that of the substrate and Stellite6 alloy coating without WC or NbC. The average microhardness and corrosion rate of the composite coating prepared by adding NbC were higher than those of the composite coating prepared by adding WC, and the average microhardness was 10–40 HV higher.