铝合金薄板MIG焊焊接变形仿真预测的工程应用

铝合金薄板因其材料和结构的特殊性,其焊接变形很难控制,由此造成的焊接质量问题一直是轨道交通行业的焦点问题,文中以MIG焊制造铝合金车体薄板为研究对象,应用数值模拟技术开展焊接变形的仿真预测,基于成熟的移动热源法,以分段温度函数法的高效计算方法,模拟了2.2 mm厚度车体端墙顶板的焊接过程,得到了焊接仿真熔池和焊后变形数值,与实测变形值误差在20%以内.结果表明,仿真熔池形貌与焊接熔池形貌基本吻合,反变形及仿真结构与现场焊接趋势吻合,控制压臂力度、压头位置、焊接顺序、反变形量等参数优化了端墙顶板的焊接工艺.

Engineering applications of MIG welding deformation simulation of aluminum alloy sheet

It is a great challenge to control the welding deformation of aluminum alloy sheet because of its characteristics of both material and structure. This kind of deformation is a key problem of welding quality in the railway industry. In this paper, more attentions have paid to welding distortion of joints made of aluminum alloy sheet by MIG welding. Herein,numerical simulation was served as an effective tool for simulating welding deformation. Based on moving heat source model and sectional temperature function,the welding process of top slab of end wall with 2.2 mm thickness was simulated. Results showed that range of error between the deformation values of simulation and actual measurement was within 20%,the morphology of the welding pool simulated was basically in agreement with the experimentally measured results. Backward deformation and simulated structure coincide well with the results of actual welding process,welding process optimization of top slab of end wall was carried out by controlling arm pressure and position,welding sequence and backward deformation method.