Laser Cladding Performance and Process Parameter Optimization for Fe90 Alloy

Fe90 alloy has a high weld hardness, good toughness, and high oxidation resistance, and is often used as a cladding material to repair the surfaces of 42CrMo steel structures of large shearer picks. The influence of the laser cladding processing parameters on the microstructure, properties, and formation mechanism of Fe90 alloy layers on the surface of 42CrMo steel was studied. Simulations were conducted to investigate how these processing parameters affect the temperature field and internal stress of the cladding layer. A complex nonlinear relationship between variables and residual stresses in the laser cladding layers obtained by additive manufacturing was fitted. An optimization model for residual stress in the cladding layer was established and an improved genetic algorithm was used for optimization, which resulted in a 15.88% reduction in residual stress. The results show that optimizing the processing parameters increased the amount of Ni-Cr-Fe solid solution in the cladding layer, enhancing its strength and corrosion resistance. The amount of residual stresses rose with increases in laser power, but at higher powers, increasing the scanning speed and spot diameter reduced stresses. At lower powers, the amount of residual stresses initially increased and then decreased with the scanning speed, with more significant changes occurring with larger spot diameters. Analyzing temperature and residual stress changes allowed us to improve the cladding layer quality, providing a theoretical basis for laser cladding on 42CrMo.