Research on Microstructure and Properties of Laser Cladding Nickel-based Alloy on Die Steel Surface

The failure of the die is mostly generated on the surface, and the wear life of the die is prolonged by laser cladding the nickel-base superalloy coating on the surface of the H13 die steel.The effects of phase composition, element distribution and laser cladding parameters on the macroscopic morphology and microstructure of the nickel-based coating on the surface of the die steel were analyzed by XRD, OM, SEM and EDS.The results show that the surface of the cladding layer is smooth, and no macroscopic cracks, pores and unmelted phenomena appear.With the increase of scanning speed, the growth state of microstructure of the cladding layer changes, the chrysanthemum eutectic structure disappears, the interfacial structure changes from cell crystal to planar crystal, and the bottom of the cladding layer consists of a large number of columnar crystals, dendrites and a small number of cell crystals.The cladding layer is composed of matrix phase and strengthening phases, γ-(F, Ni)is the cladding layer matrix phase, and the strengthening phases are mainly Ni₃Si₂, Ni₆Si₂B₁, Cr₂₃C₆ and CrB.The hardness of the cladding layer is high, and the average hardness is 565 HV0.2, which is 2.1 times than that of the substrate.