Study on Microstructure and Performance of Interface between TiC Steel Bonded Carbide and Surfacing Transition Layer

The transition layer was deposited on TiC steel-bonded cemented carbide by using ERNiCrMo-3 welding wire.The microstructures and properties of interface between TiC steel bonded cemented carbide and ERNiCrMo-3 surfacing layer under different heat inputs were studied by using scanning electron microscopy, EDS spectrometer, microhardness tester and universal testing machine. The results show that there is a fusion zone with a thickness of 60-150 μm between TiC steel-bonded cemented carbide and ERNiCrMo-3 surfacing metal.With the increase of welding heat input, the thickness of the fusion zone gradually increases.When the heat input is 3.5 kJ/cm, the microstructure of the interface is uniform, without pores, cracks and abnormal grain growth phenomenon. There is element diffusion between the base metal and the surfacing weld, and the metallurgical bonding is realized. There is a buffer zone with gradually varying hardness change between the base metal and the surfacing weld. The highest shear strength of TiC steel bonded cemented carbide / ERNiCrMo-3 interface can reach 443 MPa, which meets the bonding performance requirement between wear-resistant parts and matrix under harsh conditions.