Bead-on-plate welding of 6-mm thick AA6061-T6 aluminum alloy is used to characterize the high-frequency (HF) pulse-modulated square wave AC TIG (HFPM AC TIG) welding. The modulation HF pulse reduces the reignition voltage of negative half-wave arc. However, its effectiveness on increasing weld penetration is not evident until the penetration rate (penetration-to-workpiece thickness ratio) exceeds 45%. Above this value, the weld penetration increases significantly with increasing peak current of the HF pulse, and first increased and then decreased with increasing pulse frequency from 10 to 40 kHz. Maximum penetration achieved at optimal welding condition increases by 120% compared with that of conventional AC TIG welding. The grain size and width of partially melted zone are visibly reduced. The average equiaxed grain size, pore number density, and average pore size in HFPM AC TIG weld metal decrease with increasing pulse frequency.

中文翻译：

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AA6061-T6铝合金的高频脉冲调制方波交流氩弧焊

使用厚度为6毫米的Aa6061-T6铝合金进行的珠焊来表征高频（HF）脉冲调制方波AC TIG（HFPM AC TIG）焊接。调制HF脉冲降低了负半波电弧的重新点火电压。但是，直到熔深率（熔深对工件的厚度比）超过45％时，其对提高焊缝熔深的有效性才变得明显。高于此值，焊缝熔深随着HF脉冲峰值电流的增加而显着增加，然后随着脉冲频率从10 kHz增至40 kHz而先增加然后减少。与传统的AC TIG焊接相比，在最佳焊接条件下获得的最大熔深增加了120％。明显减小了部分熔融区的晶粒尺寸和宽度。平均等轴晶粒度，孔数密度，