铝合金激光-MIG复合焊接气孔缺陷研究
Study on Porosity Defects of Aluminium Alloy in Laser-MIG Hybrid Welding
1 华中科技大学材料科学与工程学院，湖北 武汉 430074
2 通用汽车中国科学研究院，上海 201206
摘要
使用光纤激光器进行了5754铝合金激光-MIG复合焊搭接工艺试验，研究了铝合金激光-MIG复合焊接焊缝内部氢气孔、工艺气孔及夹层气孔的形貌与分布特征，深入分析了3类气孔的形成机理，探讨了铝合金激光-MIG复合焊接气孔的产生倾向。结果表明，氢气孔的形成与熔池中的氢析出、聚集与合并有关，工艺气孔产生的根源是焊接过程小孔的瞬间失稳，而夹层气孔则与搭接处的难熔氧化膜密切相关。铝合金激光-MIG复合焊接氢气孔产生倾向较电弧焊大，工艺气孔产生倾向较单独激光焊小。清除工件表面氧化膜、增加小孔稳定性、促进气泡逸出有利于减少焊缝内部的气孔。
Abstract
In this study, we describe a lap process experiment of 5754 aluminium alloy in laser-MIG hybrid welding by means of fiber laser. Morphology and distribution characteristics of hydrogen porosity, process porosity and interlayer porosity were studied in the weld using laser-MIG hybrid welding, and their formation mechanism were also analyzed. In addition, it was also discussed that the tendency of porosities emerged in the weld during laser-MIG hybrid welding. The results showed that formation of hydrogen porosity were related to precipitation, aggregation and combination of hydrogen element in molten pool. The root of process porosity arising was as a result of causes of porosity is welding process holes to the instantaneous instability of the keyhole during the welding, while the interlayer porosity correlated with the refractory oxide film. Tendency of hydrogen porosity appearing using laser-MIG hybrid welding is larger than that of employing the arc. Porosities in the weld can be reduced by removing surface oxidation film, increasing hole the stability of keyhole and promoting bubbles to escaping from the molten pool.
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黎硕, 王军, 杨上陆, 王春明, 胡席远, 陈志春, 唐舵. 铝合金激光-MIG复合焊接气孔缺陷研究[J]. 应用激光, 2013, 33(6): 595. Li Shuo, Wang Jun, Yang Shanglu, Wang Chunming, Hu Xiyuan, Chen Zhichun, Tang Duo. Study on Porosity Defects of Aluminium Alloy in Laser-MIG Hybrid Welding[J]. APPLIED LASER, 2013, 33(6): 595.
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