Study Of Wear-resisting Mechanism And Plasma Arc Surfacing Of Ni-based Alloy Powder

With the rapid development of technology and continuous increase of the degree of mechanization and automation, people pay more attention to hazard of parts wearing. It has a great economic significance that decreasing grinding abrasion and increasing mechanical wearing.This paper is about the effect of applied transverse magnetic field on Ni-based plasma overlaying welding alloy. The properties of surfacing deposit have been improved by introducing magnetic field. Electromagnetic has been applied to welding as a new welding technology in recent years. Experience shows that the introduced magnetic field can give an effective intervention to the transition of droplet, flowing of molten bath metal , crystalline and nucleation of molten bath and the process of crystalline growth. The magnetic field promotes the refining degree of primary crystallization structure, decreases the chemistry non-homogeneity, improves plasticity and toughness of surfacing deposit and decreases the sensibility of crystal crack and gas cavity. So it can improve quality of surfacing deposit.During the test the effect of surfacing current and magnetic current on hardness , wearing, microstructures were studied, and the surfacing deposit of introducing magnetic field was compared with the surfacing deposit without magnetic field in the properties. Results show that:1, Magnetic parameter and weld criterion parameters were found that they must be matched properly, just that, the optimal effect of grain refining can be gained.2, The surfacing deposit of introducing magnetic field has better properties than the surfacing deposit without magnetic field.3, The tests of hardness, wearing and microstructures show that the magnetic field can refine primary structure and secondary structure;The magnetic stirring can effect nucleate ratioand refine structure effective. It also can increase the hardness of surfacing deposit and improve the ability of resisting grinding abrasion.4> The hard phase in the deposited metal is distributed randomly without magnetic field;The hard phase is fine and distributed vertically to wearing surface in optimum parameters, then hardness and wear extent of the deposited metal are higher.