Microstructure evolution mechanisms and mechanical properties of 30CrMnSiA steel repaired by laser cladding

In this paper, 30CrMnSiA steel is repaired using the laser cladding method. The effect of laser process parameters on the microstructure evolution of repaired specimens is studied, and their mechanical properties are evaluated. The results indicated that the base material developed a microstructure after laser cladding, with a martensitic microstructure in the cladding zone, tempered sorbite microstructure in the heat-affected zone, and tempered troostite microstructure in the base material zone. This structure is the result of phase transformation caused by the rapid cooling and heating of the high-energy laser beam, and heat transfer. Adopting optimal process parameters results in an average hardness of the cladding zone of 574.8 HV0.3, representing a 12 % improvement. The tensile strength reached 1527 MPa, 91.9 % higher than the original specimen, and the yield strength reached 482 MPa, a 79 % improvement.