Study On The Complex Coating Of Ni60 And WC-Ni60 On The 45 Steel Surface By Induction Cladding

In this paper, the sample of cylindric 45 steel coated with Ni60 alloy was prepared by high frequency induction cladding. Moreover. WC-Ni60 alloy coating with different contents of WC panicles was prepared on plane 45 steel substrate.The microstructure, composition, interface structure, worn surface and phase structure of the coating were characterized by metallographic microscope, electron probe X-ray microanalysis (EPMA), X-ray diffraction (XRD), respectively. HK micro-hardness of the cross-section was tested by DMH-2LS micro-hardness tester. HV hardness of WC-Ni60 coating surface was measured by HV-50A durometer. Friction coefficient of WC-Ni60 coating was examined with UMT-2 tribometer, and the measurements of corrosion resistance was carried out.The experiment results showed that:(1) For the substrate of cylindric 45 steel, the best cladding result was obtained when binder was sodium silicate, with induction current 650A and time for cladding 20-25s. The coating was consisted of Ni-base sosoloid and Ni4B3 Fe3Ni2,Cr7C3,Cr3C2 hard phases, which matched well with the 45 steel substrate, and there was a diffusion laver in the interface. The surface hardness and corrosion resistance were improved for the reason of the Ni60 coating by induction cladding. (2) For the substrate of plane 45 steel, the wear-resistant coating was consisted of WC hard particles and hard phases (including Cr3C2,Cr23C6,Ni4B3) which distributed in the intergranular. The WC particles were centered on the surface and middle of the coating, and the structure of cladding interface was compact. There was a trend of hole addition with the increasing of WC content. The micro-hardness of WC-Ni60 coating was much higher than 45 steel and also higher than the Ni60 coating. The hardness in the middle and the surface of the WC-Ni60 coating was higher than that in the interface. The hardness and wear resistance of coating were enhanced with the increasing of WC content, and WC-Ni60 coating obtained the best wear resistance with the content of 50% WC, the hardness of the coating got the highest when the content of WC was 60%, but the wear resistance decreased. The wear mechanisms of coating were adhesion and abrasive wear. The corrosion resistance of WC-Ni60 coating was better than Ni60 coating.