对于高速轨道客车铝车身的生产制造,气孔是焊接中最常见的缺陷.采用X射线法研究了不同温度和湿度下铝合金6082和5083熔化极氩弧焊(MIG)焊缝的气孔情况.结果表明,在焊接过程中环境的绝对湿度(是温度和湿度的综合体现)对焊缝的气孔率有重要影响,铝合金6082焊缝的气孔敏感性要比铝合金5083高.在拉伸试验中铝合金6082接头的断裂位置一般在焊接热影响区(HAZ),随着绝对湿度的增加,接头的抗拉强度和断后伸长率几乎保持不变,但接头的正弯和背弯角度分别减小了74.4％和64.4％.铝合金5083接头的断裂位置一般出现在熔合区,随着绝对湿度的增加,接头的抗拉强度和断后伸长率分别减小了4.0％和15.7％,但是弯曲性能变化不大.%Generally speaking,porosity defect is one of the inevitable challenges encountered in the joints of aluminum alloy structures during fabrication of high speed railway vehicles.X-ray inspection was used to investigate the porosity rate of aluminum alloy 6082 joints and 5083 joints welded by metal inert gas arc welding (MIG) under different temperatures and humidity.The results demonstrated that the susceptibility of aluminum alloy 6082 welded joints to porosity was higher than that of 5083 welded joints.The porosity rate in aluminum alloy joints was almost determined by the absolute humidity in the welding environment.During the tensile strength test,the fractures of the welded aluminum alloy 6082 joints were mainly located in the heat affected zone (HAZ).With the increase of the absolute humidity,the tensile strength and elongation of the 6082 joints remained almost stable.However,the front and back bending angles of the joints were reduced by 74.4％ and 64.4％,respectively.The fractures of the welded aluminum alloy 5083 joints were mainly located in the fusion zone.With the increase of the absolute humidity,the tensile strength and elongation of the 5083 joints decreased by 4.0 ％ and 15.7 ％,respectively.Whereas,the bending capacity of the 5083 joints was hardly affected by the humidity variation in the welding environment.
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