Study on Stress State of Laser Cladding Layer on 316L Stainless Steel

The laser cladding under different processing parameters was carried out on Q235 steel plate using 316L stainless steel powder. The effects of subsequent laser remelting and heat treatment on the cladding samples were studied. The stress distributions of the cladding layer and the substrate were tested by blind hole method. The results show that the residual stress of the laser cladding layer is about 230 MPa, which is mainly tensile stress. The residual tensile stress is smaller at the location far from the cladding layer. In a certain range, with the decrease of scanning speed and the increase of laser power and the number of cladding layers, the residual stress increases correspondingly. The processes of laser remelting and heat treatment can effectively reduce the residual stress of the cladding layer. The laser remelting can reduce the residual stress by up to 55.9%, while the heat treatment process can reduce the residual stress by more than 70%. The residual stress reduces by 83.8% by the heat treatment at 800 ℃ for 2 h.