补焊对6082铝合金焊接接头组织和性能的影响

Influence of repair welding on mircrostructures and properties of welded joints of 6082 aluminum alloy

通过拉伸、弯曲、硬度及等试验及金相组织分析,对未补焊和补焊1次的6082铝合金MIG焊焊接接头组织和性能进行了研究。结果表明:未补焊和补焊1次试样的断裂位置均位于热影响区,补焊1次时抗拉强度明显下降,但仍满足试验标准的要求;二者都有良好的弯曲性能;补焊对焊缝和母材的硬度影响不大,补焊1次时软化现象更显著;未补焊和补焊1次时焊缝和熔合区的显微组织无显著变化。焊缝组织呈等轴枝晶分布,熔合区组织为晶粒粗大的柱状晶,基体的晶粒沿轧制方向延长呈纤维状,α(Al)固溶体基体上均匀分布大量的强化相Mg2Si。

Microstructures and properties of 6082 aluminum alloy welded joints of first time repair welding by MIG welding were studied respectively through tensile tests,bending tests,hardness tests and microstructure analysis in this paper.The results showed that during the tensile test,both specimens were broken at the heat,affected zone,the tensile strength decreased obviously after repair welding,but still satisfied the standard.Both had good bending performance.Repair welding had little effect on hardness of the weld and base material,while the joints after repair welding showed significant softening phenomenon.Microstructure in weld and fusion changed little before and after repair welding,welding center were equiaxed grains.The grains of fusion zone were bulky columnar dendrites,base material were fibrously extending along the rolling direction,a large number of strengthening phase Mg2Si distributed evenly in α(Al) solid solution matrix.