Numerical simulation and experimental study of laser cladding Ni-based powder on 45# steel surface

The cladding process is the key factor in determining the quality and efficiency of cladding, and in-depth study of process characteristics has practical importance for the application of this technology in industries. The temperature and stress fields under different process parameters were studied to determine the optimal process parameters. The optimal process parameters were chosen according to the morphology of the cladding layer. On this basis, the cooling rate, temperature gradient and solidification rate of the coating in different depth directions were calculated, and the formation mechanism of the cladding layer morphology was revealed. In addition, the microstructure and hardness of the coating were characterised and tested, respectively. Results show that the microstructure of the coating is mainly composed of γ(Ni), FeNi3, M (M = Fe, Ni, Cr)23C6, M7C3, and CrB. The hardness of the optimised coating is 600 HV0.2, and the hardness of 45# steel is improved. This work has a certain guiding significance for engineering applications to repair 45# steel parts through numerical simulation and experimental combinations.