不锈钢薄板大功率激光点焊温度与应力特性研究
The Analysis on Temperature and Stress Characteristics of Stainless Steel Sheet Under High Power Laser Spot Welding

以0.5 mm厚的304不锈钢薄板为研究对象,采用热-结构间接耦合法,获取其在3 000 W功率光纤激光器点焊加工过程中温度场和应力场的分布特点及变化特性.在温度场模拟过程中采用修正的锥形热源模型,并将模拟得到的焊点形状与实验得到的形状进行对比.结果显示:运用该修正热源模拟得到的温度场分布特点与实际加工过程相吻合; 模拟得到熔池的凝固速度均在4 000 K？s-1以上,属于远离平衡态的快速凝固; 在焊接过程中,计算域的最大等效应力均分布在夹具位置,且在熔池周围出现环状的高应力区.
The 304 stainless steel sheet with 0.5 mm thickness is set as the research object.Thermo-structural indirect coupling method is used to obtain its distribution and variation characteristics of temperature field and stress field during the spot welding process of 3 000 W power fiber laser.In the temperature field simulation process,the modified cone-shaped heat source model is adopted,and the simulated solder joint shape is compared with another that obtained by the experiment under the same conditions.The results show that the temperature field distribution obtained by using the modified heat source is consistent with the actual process.According to the result of simulation,the solidification rate of the molten pool is above 4 000 K？s-1,which belongs to rapid solidification that is far from equilibrium.During the whole welding process,the maximum Von Mises stress of the calculated domain is distributed in the clamp position,and around the molten pool,the high stress zone appears