Study On High Wear-Resistant Alloy Steel Flux Cored Wires For Arc Spraying And Its Application

In the paper, we designed and investigated several alloy steel composition of flux cored wires for arc spraying. Alloy steel coatings with high wear resistance were deposited on low carbon steel surface. Micro-hardness, abrasive wear resistance, porosity, and the bonding strength of the arc sprayed coating were tested. Through the microscope, environmental scanning electron microscope (ESEM), EDS analysis, the microstructure of arc sprayed coatings was studied, moreover, the effects of Al, Ni, B on the coating performance and structure were also analyzed and assessed.The results manifested that with the increase of Al content, the bonding strength was not improved. In the arc spray atomization stage, Al was burned and transformed into aluminum oxide to deposit on the surface of the coatings. As aluminum oxide could not easily integrate with the metal aerosol particles and became slag, then a large number of pores formed, as a result, the bonding strength of the coating and substrate would reduce. And the loss was more than that for the exothermic reaction. Therefore, as the Al contents increased, the porosity of coating increased, and the hardness and wear resistance decreased.Since B combined with Fe to form the mixed phases FeB and Fe2B, which could effectively bind with substrate, and B and Ni could form the Ni-Cr-B-Si self-fluxing alloy system with good infiltration, so B could promote the bonding strength of coating and substrate. In an addition, B with C or Cr could form B4C or CrB,Cr2B, these hard phases was able to enhance wear resistance of the coating. While Ni was mainly used to form the Ni-Cr-B-Si self-fluxing alloy system, it could promote the bonding strength of coating, but its role to the porosity, hardness and wear resistance of coating was not obvious.According to the analysis of the wear of the coating surface, it was determined that the wear mechanism was micro-cutting wear, for the abrasives produced indentation but not chips on the coating surface. And the porosity and slag were conducive to the formation of chip, which finally reduced the wear resistance of the coating.The cored wire with the best performance in this paper was utilized for arc spraying on the drop chute of mixer which effectively improved the service life, and achieved good results.