Tungsten Inert Gas Welding Of WC-Co-Ni Cemented Carbide To 45 Steel

WC-Co cemented carbide is the largest yield and most widely used of cemented carbide currently.Using Ni instead of Co to made WC-Co-Ni cemented carbide, can save the scarce resources Co, reduce the cost of materials.Connect with steel is one of the most commonly used preparation methods of cemented carbide products currently, the WC-Co-Ni cemented carbide and steel arc connection are seldom reported, the feasibility of arc welding has important research value.This article uses Ni instead of Co to made WC-Co-Ni cemented carbide. Then using TIG arc cold welding experiment to weld the WC-Co-Ni cemented carbide and 45 steel by different composition of filler material.Scanning electron microscope, energy spectrum analysis, X-ray diffraction, bend strength test to different filling materials of joint, analyzed the welding joints’ organization, element diffusion, mechanical properties. Results show that the total amount of carbon in raw material control in 6.05 ~ 6.15% can help prevent ? phase or graphite phase generated in sintering, ball milling 10 h can make the powder mixed well.In sintering process, heating for 30 min and 15 min in 450 and 850℃ respectively of the removing glue stage, heating for 2 hours in 1270℃ of the solid phase sintering stage, heating for an hour in 1380 o℃ f the liquid phase sintering stage, can sintered hard alloy that no pores, cracks and surface deformation.Welded joint of commercial wire that H08Mn2 SiA, ER308 and ERNiCrMo-3 formed ? phase and eutectic carbides at the interface between welded metal/ hard alloy, welded joint of ERNiCrMo-3 wire crack along the ? phase after welding directly, bending fracture occurs at the interface of welded joint of H08Mn2 SiA and ER308, and brittle fracture get along chunk ? phase aggregate distribution of interface,the average bending strength do not exceed 0.56 GPa highest, these welding wire are not suitable for WC-Co-Ni hard alloy welding. Welded metal/hard alloy interface area of Fe-35Ni-C and Fe-55Ni-C alloy wire without ? phase generated, joint bending strength was improved, but the welding joint of Fe-35Ni-C wire generate small amount of eutectic carbides that affects the bending performance near interface. Welded joint of WC-10Co-20Ni’s bending strength are better than the WC-15Co-15 Ni, WC-20Co-10 Ni by same welding wire, show that increase Ni content of the hard alloy can improve ability of alloy welding. Using Fe-Ni-C welding wire, no preheating before welding, no slow cooling after welding, joint was not found crack, the WC-Co-Ni hard alloy can be arc cold welding with steel.