以Q345低合金高强钢对接接头为研究对象,建立热-冶金-力学耦合的三维有限元模型,在考虑相变情况下采用三维双椭球体热源模型对单道焊的焊接温度场进行数值模拟,再基于提取的热循环曲线(TCC)对该热源模型进行简化。分别采用三维双椭球体热源模型和基于TCC简化的热源模型对单道焊和多道焊对接接头的残余应力进行计算,并进行了试验验证。结果表明:根据温度场模拟得到的单焊道焊缝TCC与试验结果吻合良好,相对误差小于2.34%,验证了提取的TCC的准确性;采用三维双椭球体热源模型和基于TCC简化热源模型模拟得到的接头残余应力与试验结果吻合良好,其中单焊道接头纵向残余应力相对误差分别小于11.38%,4.34%,验证了2种模拟方法的准确性;与三维双椭球体热源模型相比,基于TCC简化热源模型的计算效率提高32%以上。

Taking Q345 low alloy high strength steel butt joint as research subject, the three-dimensional thermal-metallurgical-mechanical finite element model was established. The temperature field of single-pass welding was numerically simulated by three-dimensional double ellipsoid heat source model considering phase transformation. The heat source model was simplified based on the extracted thermal cycle curve (TCC). The residual stress distribution of single-pass and multi-pass welded butt joints was calculated by three-dimensional double ellipsoid heat source model and the heat source model simplied by TCC, respectively, and test verification was carried out. The results show that TCC of single pass weld obtained by temperature field simulation was in good agreement with the test results, and the relative error was less than 2.34%, verifying the accuracy of the extracted TCC. The residual stress simulation of the joint by the three-dimensional double ellipsoid heat source model and heat source model simplied by TCC were in good agreement with the test results, and the relative errors of longitudinal residual stress of single-pass welded joint were less than 11.38%, 4.34%, respectively, verifying the accuracy of the two simulation methods. Compared with that of the three-dimensional double ellipsoid heat source model, the calculation efficiency of heat source model simplied by TCC was improved by above 32%.