Micro-structure and properties of mining bit brazing joint employed by the high strength and ductility CuZnNiMn button materials

Cu-Zn-Ni-Mn button brazing filler metal was prepared in this paper for mining bit of coal mining and tunneling machines. The welding of the actual product was accomplished by high frequency induction method using the button type brazing filler metal. The macroscopic morphology, shear performance, shear fracture morphology, microstructure and composition of brazing interface were analyzed after brazing. The experimental results show that the filler material can wet the steel matrix and hard alloy well, and the brazing rate reached 100%. The shear strength of the brazed joint reached 270 MPa and the shear morphology shown as typical dimple ductile fracture. At the interface of steel-base solder and cemented carbide, Fe atoms and Co atoms appeared long-term diffusion. The solid solution of Fe base and single phase solid solution of Fe-Co-Ni were formed, which ensures the good strength and toughness of the brazing interface.