Abstract: In order to improve the properties of surfacing layers,study the influence of surfacing current and magnetic field current on properties and microstructure of surfacing layer,DC transverse magnetic field was applied when Co-based alloy was welded on the surface of low-carbon steel by plasma arc surfacing.The hardness,wear resistance,microstructure and phase constitution of the surfacing layers were investigated via hardness and wear tests as well as SEM and XRD analysis.Furthermore,the influence of surfacing current and magnetic field current on the hardness and wear resistance of the surfacing layer were studied.The results showed that the properties of surfacing layers with introducing DC transverse magnetic field were better than that without magnetic field.When the surface current was 160 A and the magnetic field current was 3 A,the optimal effect of grain refining could be gained.The optimal hardness and wear extent have been obtained at the same time.Furthermore,the DC transverse magnetic field can suppress the"arc blow"and improve the stability of surface process.