不锈钢激光焊温度场的建模与仿真

Modeling and simulating of temperature field of laser welding for stainless steel

利用有限元软件ANSYS对304不锈钢激光焊温度场的分布进行了动态模拟。分析了材料热物理参数的温度相关性、熔化潜热、对流及辐射对激光焊接温度场的影响,建立了激光焊接组合体移动热源模型。针对激光焊接过程中高度非线性、光斑面积非常小的特点,采用了过渡单元建模及逐步加载和求解的措施。为了保证节点选取的精确程度,在加载过程中采用了余量控制法。仿真结果表明,模拟得到的焊缝形状与实际焊缝形状基本吻合;等温线呈椭圆形,在移动热源的前方等温线密集,温度梯度较大,热源后方的等温线较稀疏,温度梯度小;激光焊接时熔池表面附近的金属蒸气最高温度可达13 332℃。

Temperature field of laser welding stainless steel 304 was dynamically simulated with finite element analysis software-ANSYS.Effects of temperature correlation of the physical parameters of material,latent hear of fusion,convection and radiation on the temperature field of laser welding were analyzed.In view of the characters of laser welding,a heat source combined the body loads were designed.Considering the high non-linear of the solution and the small focal diameter,a serial of measures were adopted,such as modeling with pyramid,stepped loading and solution.In the load history,an over-measure control method was taken to ensure the precision of nodal selection.It was shown that the simulation results of weld shape were in accordance with the experimental results,the isotherms looked like ellipse and were dense at the head of the moving heat source.And the temperature gradient was high at the head of the heat source.But at the end of the moving heat source the isotherms were sparse and the temperature gradient was low.Temperature near the surface of the weld pool was the highest,and up to about 13332℃.