铝合金激光+脉冲GMAW复合焊焊缝成形的预测

Prediction of Weld Shape and Size for Laser+GMAW-P Hybrid Welding of Aluminium Alloys

对铝合金激光+脉冲熔化极气体保护焊(Gas metal arc welding,GMAW)复合热源焊热过程进行数值模拟,将为优化焊接工艺参数和保证焊接质量提供理论依据,具有重要意义。根据铝合金大功率激光+脉冲GMAW复合热源焊接的特点,考虑光致等离子体和金属蒸汽羽的影响,对小孔内激光能量的吸收与小孔壁蒸发损失加以恰当处理,对原有小孔模型进行改进,提高了激光致小孔形状与尺寸的计算精度。利用计算出的小孔形状尺寸对激光体积热源分布参数进行标定,建立铝合金大功率激光+脉冲GMAW复合焊接的焊缝形状尺寸预测模型。对焊接温度场和焊缝成形进行数值模拟,获得多种工艺条件下高强铝合金复合热源焊接焊缝成形的数值分析数据。复合热源焊接工艺试验结果表明,铝合金复合焊焊缝形状尺寸的计算结果与试验结果总体吻合良好。

High power laser ＋ pulsed gas metal arc welding（GMAW）hybrid welding is an advanced welding process in manufacturing light weight structures. For aluminium alloys, its reflection rate is much higher than steels, thus, the previous keyhole model for steels has to be modified. With considering the characteristics of high power laser＋pulsed GMAW hybrid welding of aluminium alloys, the effect of metal steam plume and laser-induced plasma on the laser power absorption inside keyhole is dealt with, the previous model of keyhole profile is improved, and the calculation accuracy of laser-induced keyhole profile is enhanced. The distribution parameters of volumetric heat source for laser beam are calibrated by using the calculated keyhole profile. The predicting model of weld shape and size is established to determine the weld dimensions in hybrid welding of aluminium alloys. Through numerical analysis of temperature field and weld geometry, the data about the weld formation in hybrid welding of aluminium alloys are obtained under different conditions. High power laser ＋ pulsed gas metal arc hybrid welding experiments validate that the calculated results are in good agreement with experimentally measured ones.