为了研究铝合金表面状态和焊接工艺方法对焊接接头性能的影响, 采用Nd∶YAG脉冲激光器对Al-Mg系铝合金激光焊接方法进行了理论分析和实验验证, 得到了焊接接头性能实验结果。结果表明, 原始表面和碱蚀表面处理的试样焊接过程不稳定, 阳极氧化试样焊接中形成了稳定的小孔效应, 焊接过程较稳定;阳极氧化、两面焊、填粉焊都能有效提高焊缝熔深和深宽比;试样阳极氧化、双面焊、填粉焊可使焊缝抗拉强度提高1倍以上, 其中Al-0.05Si填粉焊提升效果最好;表面处理试样硬度都有所提高, 磷酸阳极氧化提高效果最好。双面焊工艺使焊缝和熔合区硬度提高, 填粉焊焊缝中心硬度很低但熔合区硬度提高明显, 双面焊、填粉焊热影响区硬度低于单面焊。阳极氧化表面处理、双面焊工艺可以有效地改善Al-Mg铝合金的激光焊接性。

In order to study effect of aluminum surface state and welding processing on the properties of welding joints, the process of laser welding Al-Mg series aluminum alloy with Nd∶YAG laser was analyzed in theory and verified in experiments. The experimental results of the characteristics of welding joints were obtained. The results show that welding process of untreated sample and alkali corrosion surface treatment sample are not stable while welding process of anodizing treatment sample is stable and hole effect is formed stably. Weld seam penetration and depth-to-width ratio are all improved effectively by the aid of anodizing, double welding and powder filling welding. The tensile strength of the weld seam of anodizing sample, double-sided welding sample and powder filling welding sample increases more than 1 times and powder filling welding sample of Al-0.05Si has the highest tensile strength. Hardness of all surface treatment samples is improved and the effect of phosphoric acid anodizing is the best. Hardness of weld seam and fusion zone is improved through double welding. Central hardness of powder filling weld is lower while hardness of fusion zone increases obviously. Hardness of heat affected zone of double welding and powder filling welding is lower than hardness of single side welding. The results show that anodic oxidation surface treatment and double-sided welding technology can improve the property of laser welding of Al-Mg series aluminum alloy effectively.