LAUSR

Ni-based surfacing coating was fabricated on the Cr12MoV die steel utilizing the ENiCrFe-2 alloy. The defect-free surfacing coating was obtained with a good metallurgical bonding between the coating and the substrate. The microstructure, element distribution, and micro-hardness were analyzed. Results showed that the microstructure was composed of planar crystals at the bottom of coating, and it consisted of columnar crystals at the middle region. There existed a diffusion layer with a width of about 100 μm at the ENiCrFe-2–Cr12MoV interface. Three regions were formed in the heat-affected zone with various microstructure morphologies. The average micro-hardness of coating was 275 HV0.5, which was more than that of Cr12MoV. Micro-hardness was dramatically increased (765 HV0.5) in the middle of the heat-affected zone. This was caused by the combined effect of grain refinement, solid solution strengthening, second-phase strengthening, and primary carbide strengthening. Moreover, the formation mechanism of middle heat-affected zone was discussed in this paper in detail.