对奥氏体不锈钢薄板的激光焊接过程进行数值模拟分析, 得到不同焊接工艺条件下的瞬态温度场分布和接头残余应力分布。结果表明, 激光焊接温度场具有准稳态特征, 等温线呈椭圆形, 在移动热源的前方等温线密集, 后方等温线稀疏。随着脉冲能量的增大, 焊接热循环曲线的峰值温度升高。接头残余应力场模拟计算结果表明, 沿垂直于焊缝方向的横向残余应力值大于纵向残余应力值。对焊接热循环曲线与接头微观组织之间的关系进行分析, 结果显示, 峰值温度的高低与冷却速率的大小对焊缝微观组织具有较大影响。接头区域的显微硬度测试表明, 熔合线附近的硬度高于焊缝金属与母材本身的硬度。

Numerical simulation analysis is carried out to the laser welding process of austenitic stainless steel sheet, and the distribution of transient temperature field and joint residual stress distribution are obtained under different welding conditions. The results show that the laser welding temperature field has quasi-steady state characteristics, and the shape of isotherm presents ellipse. The isotherm is dense in the front of moving heat source, while it is sparse in the rear. With the increase of pulse energy, the peak temperature of the welding thermal cycle increases. The simulation results of residual stress field show that along the direction perpendicular to the weld, the transverse residual stress is larger than the longitudinal residual stress. The relationship between the welding thermal cycle curve and the microstructure of the joint is investigated. The results show that the peak temperature and cooling rate have great effect on the microstructure of weld. The microhardness test of the joint area shows that the hardness near the weld line is higher than the weld metal and the base material itself.