Wang Xingxing1, Li Yang1, Wu Shengjin1, Du Quanbin2, Jia Lianhui3, Li Shuai1, Chen Xiaoming4(1.Henan International Joint Laboratory of High-efficiency Special Green Welding, North China University of Water Resources and Electric Power, Zhengzhou 450045, China)

Abstract:

Ni/WC composite coating with high wear resistance, corrosion resistance and high hardness characteristics, it is widely used in shield components, raerospace and other fields. In order to improve the service life of hydraulic machinery overflow components, the paper simulated the material of hydraulic turbine blades, WC particles and Ni-based powder brazing filler metals were used to prepare Ni/WC composite brazing coating on the surface of 201 stainless steel by vacuum brazing process. The interface microstructure and mechanical behavior of the brazing coating were resolved with scanning electron microscope, metallographic microscope and rockwell hardness tester. The results show that the diffusion behavior of elements between the coating and substrate are main dissolution of elements Fe, Cr and Mn from the stainless steel into the coating microstructure, and the interface appears segregation precipitation phenomenon. 25wt.% WC coating occurs a uniform hardness distribution, 4.6 times more than steel substrate. The wear resistance of coating increased with the increase of WC content. 15~35 wt.% WC addition can significantly improve the wear resistance of the steel surface. The wear resistance of the coating is 8.4~15.7times that of the steel, the surface of the coating don’t change significantly, and the crack opening is flat and brittle fracture.