2219中厚铝合金VPTIG深熔焊接熔池行为与组织性能

Molten Pool Behavior,Microstructure and Mechanical Property in VPTIG Full Penetration Welding of Medium-thick 2219 Aluminum Alloy

针对2219-T87铝合金双频复合脉冲变极性TIG(DP-VPTIG)深熔焊接过程,采用高速图像采集和多物理场数值仿真技术对熔池传热传质行为进行研究,解耦了双频脉冲电流和方波变极性电流的作用机制,并探究了DP-VPTIG电弧对接头组织性能的影响。结果表明:双频脉冲能有效激发熔池内小孔,方波变极性电流能保证焊接过程稳定,DP-VPTIG可实现中厚板铝合金的高效高质量深熔焊接。相比常规VPTIG接头,DP-VPTIG接头焊缝组织更加细小,接头抗拉强度、屈服强度和延伸率分别提高了8%、17%和22%。

Focusing on the double-pulsed variable polarity TIG(DP-VPTIG)full penetration welding process of 2219-T87 aluminum alloy,the heat and mass transfer behavior of the molten pool were investigated by using high-speed image acquisition and multi-physics numerical simulation technology.The impact mechanisms of double-pulsed current and square wave variable polarity current on molten pool were revealed.The influence of DP-VPTIG arc on joint microstructure and mechanical properties was also explored.Obtained results show that the double-pulsed current effectively stimulates the formation of keyhole in molten pool.Square wave variable polarity current can make a contribution to a stable welding process.Moreover,DP-VPTIG enables efficient,high-quality full penetration welding for medium-thick aluminum plates.In comparison to conventional VPTIG,DP-VPTIG joints exhibit more refined weld microstructures,with enhancements in tensile strength,yield strength,and elongation by 8%,17%,and 22%,respectively.