从宏观的焊接热过程出发，根据激光+GMAW复合热源焊接的特点，提出了适用于复合热源焊接的“双椭球体＋峰值递增圆柱体”组合式体积热源分布模式；建立了激光+GMAW复合热源焊接过程的有限元模型，数值计算了焊接温度场和焊缝横截面的形状尺寸，计算结果与试验结果吻合良好，证明了组合式体积热源模型的合理性和适用性. 采用焊接温度场的计算结果，进一步对复合热源焊接和GMAW的焊接变形和残余应力进行了数值模拟和对比分析. 结果表明，在焊缝熔深基本相同的情况下，复合热源焊接的焊接热输入、焊缝熔宽、焊接变形和高应力区域范围等均比GMAW小. 研究结果印证了激光+GMAW复合热源焊接工艺的优越性，并为焊接工艺参数的优化提供了基础理论数据.
From the viewpoint of macroscopic phenomena in heat transfer, a combined “double-ellipsoid + linearly-increased peak value cylinder” volumetric heat source distribution mode was proposed according to the characteristics of laser + GMAW hybrid heat source welding process. A finite element model of laser + GMAW hybrid heat source welding process was established. The temperature distribution, and the size of the weld cross-section were numerically calculated. It can be observed that the calculated results were in good agreement with the experimental results, which proves the rationality and applicability of the combined volumetric heat source model. And then, the calculated temperature field was utilized for the numerical modeling and comparison of the welding deformation and residual stress between GMAW and laser + GMAW hybrid welding process. The results shown that the heat input, weld width, welding deformation and high residual stress region of laser + GMAW hybrid welding were all much smaller than that of GMAW with the identical weld pool depth. The research confirmed the advantages of laser + GMAW hybrid welding, and provided basic theoretical data for the optimization of process parameters.
[1] Steen W M, Eboo M. Arc augmented laser welding[J]. Metal Construction, 1979, 11(7): 332-335.
[2] Steen W M. Arc augmented laser processing of materials[J]. Applied Physics, 1980, 51(11): 5636-5641.
[3] Dilthey U, Wieschemann A, Lueder F. Technical and economical advantages by synergies in laser arc hybrid welding[J]. Welding in the World, 1999, 43(4): 141-152.
[4] Shida T, Hirokawa M, Sato S. CO2 laser welding of aluminum alloys-welding of aluminum alloys using CO2 laser beam in combination with MIG arc[J]. Welding Research Abroad, 1997, 43(5): 36-41.
[5] Steen W M. Arc augmented laser welding-process variables, structure and properties[C]//The Joining of Metals, Spring Residential Conference, Coventry, 1981.
[6] Rejc J, Troyanova K, Iorio L, et al. Residual stresses prediction on clad pipeline girth welds through numerical simulation[J]. Procedia Manufacturing, 2019, 37: 605-612.
[7] Lu Y, Zhu S, Zhao Z, et al. Numerical simulation of residual stresses in aluminum alloy welded joints[J]. Journal of Manufacturing Processes, 2020, 50: 380-393.
[8] 逯世杰, 郑乔, 张超华, 等. 不同有限元软件对Q390钢厚板T型接头焊接残余应力和变形预测精度与计算效率的比较[J]. 机械工程学报, 2019, 55(6): 11-12
Lu Shijie, Zheng Qiao, Zhang Chaohua, et al. A comparative study on computational accuracy and efficiency of welding residual stresses and deformation in a Q390 steel thick plate T joint among three kinds of different FEM software[J]. Journal of Mechanical Engineering, 2019, 55(6): 11-12
[9] Kong F, Ma J, Kovacevic R. Numerical and experimental study of thermally induced residual stress in the hybrid laser-GMA welding process[J]. Journal of Materials Processing Technology, 2011, 211(6): 1102-1111.
