7xxx高强铝合金熔化焊研究进展

Research progress of fusion welding of 7xxx high strength aluminum alloys

  • 摘要: 针对7xxx高强铝合金的焊接研究现状,主要从TIG,MIG,激光焊及激光−电弧复合焊4类熔化焊工艺进行了介绍;从焊接缺陷、焊缝成形、接头软化、疲劳性能及耐蚀性等方面详述了7xxx高强铝合金熔化焊过程中存在的问题。对于7xxx高强铝合金的TIG,MIG,激光焊及激光−电弧复合焊,焊接缺陷、焊缝成形质量差及接头中强化相熔解等因素都会导致接头发生软化、耐蚀性变差及疲劳寿命降低;通过优化焊接工艺参数,减少焊接缺陷,改善焊缝成形质量,有利于改善接头的软化、耐蚀性差及疲劳寿命低等问题。选用合适的焊丝(含Ti,Zr元素及Er,Sc稀土元素)使焊缝产生沉淀强化、细晶强化及固溶强化,可改善接头软化的问题;采用适当的焊后热处理,改善强化相的尺寸、形态及分布状态,也可改善接头软化的问题;而采用适当的焊后热处理,还可以改善接头的耐蚀性。

     

    Abstract: According to research status of 7xxx high strength aluminum alloy welding, it was mainly introduced from four kinds of fusion welding process including TIG, MIG, laser welding and laser-arc hybrid welding. The problems existed in fusion welding process of 7xxx high strength aluminum alloy were described in detail from aspects of welding defects, formation of weld, softening of welded joints, fatigue property and corrosion resistance. For TIG, MIG, laser welding and laser-arc hybrid welding of 7xxx high strength aluminum alloy, welding defects and low formation quality of weld and strengthened phase dissolved in welded joints could lead to softening, poor corrosion resistance and low fatigue life of welded joints. Optimizing welding parameters, reducing welding defects and improving formation quality of weld were beneficial to improve softening, corrosion resistance and fatigue life of welded joints. Selecting appropriate welding wire (containing Ti, Zr elements and Er, Sc rare earth elements) could make weld produce precipitation strengthening, fine grain strengthening and solid solution strengthening, which could improve softening problem of welded joints. Selecting appropriate post-welding heat treatment could improve size, shape and distribution of strengthening phase, and also improve softening problem of welded joints, while it could also improve corrosion resistance of welded joints.

     

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