中厚板多道焊接温度场和残余应力场的三维数值分析

Numerical Simulation on Temperature Field and Residual Stress Field of Cut Deal by Multi-pass Welding

运用有限元分析软件ANSYS,对两块6 mm厚316L不锈钢平板对接焊的三维瞬态温度场和应力场进行了数值分析。考虑了材料物理性能随温度的变化和周边热对流和热辐射的影响,采用移动的表面高斯分布热源来模拟焊接过程中的热量输入,利用"生死单元"技术模拟焊缝金属的填充、熔化和凝固过程。模拟结果表明,焊件热影响区狭窄,温度场呈移动的纺锤形分布。在垂直于焊缝方向的路径上,残余应力呈典型的W形分布,焊缝区纵向残余应力为拉应力,最大值达到材料的屈服应力,残余应力分布与中厚板焊接理论吻合良好。

The finite element analysis of temperature field and residual stress field in butt-welding of two 6mm thickness stainless steel plates was accomplished using ANSYS codes. A 3-demisional finite element model was set up during the calculation. The enthalpy and temperature dependence of material property were taken into consideration. The moving Gaussian heat source was used to simulate the welding heat cycle. The course of stuffing, melting, solidifying of metal in welding was successfully simulated with the birth-death element method. The thermal analysis shows the heat-affected zone is narrow and the temperature field is spindle-shaped distribution. The residual stress results show that, on a path perpendicular to the welding direction, the residual stress is typical W-shape distribution. The maximum of residual stress is longitudinal tensile stress, which almost reach the yield stress. The distribution of residual stress from the simulation agrees with the results from the welding theory.