Study Of Wear-resistant Of Different Hardfacing Alloys With Direct Current Longitudinal Magnetic Field

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.Some surface peening technology, including heat treating, chemical heat treating, surfacing overlaying, hot spraying, surfacing, can be used to improve the ability of wear resisting. So more and more attentions has been payed to improve the ability of wear resisting at the basis of current technology.This paper is about the effect of applied longitudinal magnetic field on plasma overlaying of Co-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 promote arc revolution, changing plasma jet of arc column and radial distribution of density &arc, affecting 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, flng 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, microstmctures, 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. (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 microstmctures show that the magnetic field can refine primary structure andsecondary structure; The magnetic stirring can effect nucleate ratio and refine structure effective.(4)The ability of wear resisting and hardness of surfacing alloy is different between differentmagnetic field current, so each alloy has its own best magnetic field current.