316L不锈钢激光熔覆层的应力状态研究

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

使用316L不锈钢粉末在Q235钢板上进行了不同工艺参数的激光熔覆,并对熔覆试样进行了激光重熔和热处理,利用盲孔法对熔覆层表层及基体应力分布状态进行分析。结果表明,激光熔覆层的残余应力约为230 MPa,主要为拉应力,基体离熔覆层位置越远,残余拉应力越小。在一定范围内,随激光功率的增大,扫描速度的减小,熔覆层数的增加,熔覆层残余应力呈逐渐上升趋势。激光重熔和热处理工艺都能有效减小熔覆层的残余应力,激光重熔最多能使残余应力降低55.9%,热处理工艺能使残余应力降低70%以上;热处理温度800℃保温2 h时,可使残余应力降低83.8%。

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.