Morphology, Hardness and Wear Properties of Plasma Cladding NiCrCu Coating on M2 High-Speed Steel

Abstract

To improve the cutting performance, the red hardness and wear resistance of M2 high-speed steel, as well as expand the application field, in this work, a coating was fabricated via plasma cladding on M2 high-speed steel using Ni, Cr and Cu alloy elements as precursor materials. The distribution and composition of alloying elements, microhardness and wear resistance of the coating were studied. The results show that the NiCrCu cladding layer contains many types of carbides. The secondary hardening caused by the dispersion of carbides can significantly improve the hardness, red hardness and wear resistance of material. The hardness of cladding layer is above 950 HV, after holding at 600 °C for 4 h, the hardness is above 932 HV. The alloy elements are evenly distributed, but, due to the rapid solidification after the cladding, there are composition fluctuations in the longitudinal direction. The wear resistance of the cladding layer is excellent; the wear rate is reduced from 1.75 to 1.44 × 10−6 mm3 N−1 m−1 or less; and the wear mechanism is a combination of abrasive wear and adhesive wear.