Abstract:
Aiming at the problem of poor high-temperature wear resistance of safety clamp wedge used in ultra-high speed elevator, the experiments of laser cladding to prepare VC-Fe
3C/Fe-Ni composite coating were made. FeV powder, graphite powder and Ni powder were used as cladding material. The evolution rule of microstructure at different mass ratios and process parameters was analyzed. The properties of composite coating such as hardness, high temperature wear resistance and impact toughness were tested. The research results show that the composite coating is made up of VC, Fe-Ni solid solution and Fe
3C by in-situ reaction. The content of VC increases with the adding of graphite content. At low scanning speed, the morphology of VC is presented as ball-like and cellular-like. Most VC particles are equably distributed in Fe-Ni solid solution. At high scanning speed, the morphology of VC is presented as chrysanthemum-like, dendrite-like and bulk-like. Most VC particles are distributed along grain boundary. At the mass ratio of 8:3:8 for FeV powder, graphite powder and Ni powder, the overlapping zone has no crack. The average hardness of composite coating is 5.9 GPa. The high-temperature wear loss of VC-Fe
3C/Fe-Ni coating is 25% that of Ni60 laser cladding coating and 9.7% that of 45 steel. The impact toughness value of VC-Fe
3C/Fe-Ni coating increases 37.6% than that of Ni60 laser cladding coating. Using this technology to the surface strengthening of elevator parts such as safety clamp wedge, the wear resistance and service life can be greatly improved.