Study On Improvement Of WC-Ni Based Alloy Cladding On 45 Steel By Laser Cladding With Paste Ni-based Solder

Laser clad technology is a efficient method to improve the surface properties of metal.It can rapidly cladding coating with high wear resistance,high hardness and high corrosion resistance on the surface of the substrate.However,the main limiting factor in the application of laser cladding technology is defects such as cracks and pores in the laser cladding coating,so that it is important to study how to reduce the defects such as pores and cracks in the laser cladding coating.In this paper,the defects of pores and cracks in the laser cladding of Ni60A+WC alloy powder were reduced by adding the paste nickel-based solder(BNi-1a)to the WC alloy powder.The best-clad coating was obtained by laser processing of the pre-coated alloy cladding layer by controlling the parameters of the cladding process such as laser power,scanning speed and spot diameter.Then the laser cladding in the vacuum environment was studied to solve the defects such as pores and cracks in the cladding layer with high content of ceramic particles.The hardness and the structure of the coating under different process parameters were tested,the wear resistance of the coating under different process parameters was analyzed,the hardness of the cladding layer was evaluated by micro-hardness testing,the microstructure of the coating was evaluated by scanning electron microscopy and phase structure of cladding were analyzed by X-ray.And the friction coefficient and wear resistance of the cladding layer were evaluated by friction and wear tester and surface morphology meter.The results show that the paste nickel-based solder is added into the Ni60A+WC alloy powder in the atmospheric environment,it can optimize the composition of the Cr and C alloy phases of the original cladding layer,the defects such as cracks and pores of the cladding layer are obviously reduced.The friction coefficient of the solder cladding layer is also reduced,and improve the wear resistance of the cladding layer.But with the raise content of ceramic particles to 30%,the effect of paste nickel-based solder on cladding coating become less and less.The laser cladding of 30%WC in vacuum environment shows that the vacuum environment can significantly reduce the pores of cladding layer,optimize the structure of cladding layer and reduce the occurrence of cracks and pores.It can be an applied in the future.