Wearing Mechanism Of Magnetic Controlling On Metal Surface Strengthen Layer

Following the rapid development of industry technology and continued increase of the degree of mechanization and automation, people pay more attention to hazard of parts wearing. It has a great economic significance that decrease grinding abrasion and increase mechanical wearing.This paper is about the effect of introducing longitudinal magnetic field on plasma overlaying of Fe-based and Ni-based welding alloy. Improve the properties of surfacing deposit by introducing magnetic field. Electromagnetic is applied to welding as a new welding technology in recent years. The introduced magnetic field often applies in longitudinal magnetic field which parallels with arc axial. The longitudinal magnetic field promotes arc revolution, changes plasma jet of arc column and radial distribution of density of arc, affects the heating and melting of base metal and formation of weld. Experience shows that the introduced magnetic field can give a 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, decreases the sensibility of crystal crack and gas cavity. So it can improve quality of surfacing deposit.During the test we study the effect of surfacing current and magnetic current on hardness, wearing, microstructures, and comprise the surfacing deposit of introducing magnetic field with the surfacing deposit without magnetic field in the properties. Results show that: (1) We found that the magnetic current and weld criterion parameters must be matched properly, just that, the optimal effect of grain refining can be gained. We have a systematic research about it. (2) The surfacing deposit of introducing magnetic field has better properties than the surfacingdeposit 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 ratio and refine structure effective.