Abstract This study compared the arc shapes and microstructures obtained from gas tungsten arc welding of AZ91 magnesium alloy for different parameters of an external alternating cusp-shaped magnetic field which was applied during the welding process; the parameters included excitation currents of 1 A to 3 A and excitation frequencies of 0 Hz to 100 Hz. The experimental results showed that the tungsten inert gas (TIG) arc did not rotate under the external alternating cusp-shaped magnetic field, but its cross section was continuously elongated or flattened with the change in frequency. As the excitation current and frequency changed, the arc expanded or compressed, the weld shape and the microstructure changed. When the excitation current was 2 A and the excitation frequency 80 Hz, the arc was obviously compressed, the weld appeared smooth, the depth-to-width ratio was the largest, and the microstructure was fine-grained.

中文翻译：

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交变尖头磁场TIG焊弧形及显微组织分析

摘要 本研究比较了AZ91镁合金在焊接过程中施加不同参数的外部交变尖峰磁场时，钨极气体保护焊获得的电弧形状和显微组织；参数包括 1 A 至 3 A 的励磁电流和 0 Hz 至 100 Hz 的励磁频率。实验结果表明，钨极惰性气体（TIG）电弧在外部交变尖峰状磁场下不旋转，但其横截面随着频率的变化而不断拉长或变平。随着励磁电流和频率的变化，电弧膨胀或压缩，焊缝形状和显微组织发生变化。当励磁电流为2 A，励磁频率为80 Hz时，电弧明显被压缩，焊缝看起来光滑，