微量氮对5086铝合金MIG焊接性能的影响

MIG welding of aluminum alloy with trace nitrogen additive

摘要: 文中采用纯Ar，75% Ar+25% He，Ar+N₂三种保护气体对5086铝合金进行了MIG焊接，研究保护气体对5086铝合金焊缝熔深以及对接接头力学性能的影响，通过焊接过程高速摄像、XRD试验，探讨保护气体对5086铝合金焊缝熔深影响的机理.结果表明，纯氩气相比，氩气中加入微量氮气显著增加焊缝熔深进而提高铝合金MIG焊的焊接效率，同时其焊缝质量及力学性能未受影响.其原因为：氮化铝的出现将阴极斑点固定在氮化铝出现较多的焊缝区域，使电弧阴极区相对稳定集中，增加电弧能量密度；氮化铝可以抑制阴极区金属铝蒸汽所带走的阴极区能量损失.

Abstract: When using MIG Welding with micro-addition of nitrogen for the aluminum alloy of 5086, it was found that the welding penetration related with welding productivity was increased without a loss of soundness and the mechanical properties compared to the weld using pure argon.This phenomena can be ascribed to:1) the formation of aluminum nitride layer resulted in the reduction of the spot of cathode and the increase of arc energy density, 2) the aluminum nitride could suppress the cathode energy loss because of the metal vaporization.