随焊冲击对6061铝合金焊接接头性能影响

Effect of welding with trailing impact on properties of aluminum alloy welding joint

6061-T6高强铝合金板进行TIG焊接时,焊接热影响区存在明显过时效软化现象。为抑制这种焊接缺欠,用随焊旋转冲击法对焊接接头过时效软化区进行加载。针对接头性能进行显微组织、硬度及耐蚀性测试。结果表明:焊接接头过时效软化区经旋转冲击后,硬度由初始58.5HV升至71.2HV;随电压增加,冲击作用增强,硬度提高更明显。这主要是由于随焊旋转冲击产生的局部挤压、剪切综合作用,促进了新相沿晶粒边界生成,使接头软化区硬度上升,同时,耐蚀性也得到了改善。

The over aging softening phenomenon occurs in the TIG welding heat affected zone of the 6061-T6 high strength aluminum alloy plate.In order to hinder such welding defect,a new technique called as welding with trailing rotational impact was utilized to exert a load on the softening zone.Microstructure,hardness and corrosion resistance were measured.The results show that the hardness of the softening zone changes from 58.5HV to 71.2HV after the rotational impact.With the increase of voltage,the rotational impact effect is enhanced and the hardness is increased obviously.This is attributed to formation of new precipitates at grain boundaries promoted by the combination effect of local extrusion and shear resulted from the trailing rotational impact.