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针对铝锂合金激光焊接产生的成形不良和气孔缺陷,探究不同焊接位置对焊缝成形及气孔的影响,并对比分析不同焊接位置熔池受力状态、熔融金属流动和小孔动态行为,解释缺陷形成及其抑制机理。研究发现:不同焊接位置熔池受力状态和熔融金属流动决定焊缝成形。平焊时焊缝成形差、下榻严重;横焊时背面焊缝不连续,有飞溅;立向上焊时背面焊缝内凹严重;立向下焊可得到最优焊缝成形和最优的气孔缺陷。焊缝气孔受小孔动态行为影响,不同焊接位置气孔随热输入的变化规律一致,气孔先增后减,在仅熔池透状态下有气孔最大值。立上焊时小孔不稳定,焊缝气孔多且分布杂乱;立向下焊时小孔稳定性高,气孔最少,主要分布在焊缝中心线上。
In allusion to the forming defects and porosity defects of Al-Li alloy laser welding, the influence of different welding positions on the formation of weld and pores was investigated. The stress state, flow of molten metal and dynamic behavior of molten metal in different welding positions were analyzed and compared to explain the defects Formation and inhibition mechanism. It is found that the state of molten pool and the flow of molten metal in different welding positions determine the weld formation. Weld formation when flat welding poor, serious grave; horizontal weld when the back of the weld is not continuous, splashing; upside welding on the back of the weld serious concave; vertical weld can be the best weld formation and the optimal porosity defect. The weld porosity is affected by the dynamic behavior of the pinhole. The stomatal change at different welding positions is consistent with the change of heat input. The pinhole first increases and then decreases, and the maximum stomatal aperture exists in the pass state only. Vertical welding hole instability, weld stomata and distribution of clutter; vertical weld hole stability, porosity at least, mainly in the weld centerline.