中文摘要：

为了揭示超声钨极氩弧（Tungsten inert gas,TIG）复合焊接电弧特性,采用小孔法获得的稳定电弧压力分布形式,分析超声能量作用下电弧压力分布形式与普通电弧压力分布形式之间区别。研究焊接电流、电弧长度及保护气喷嘴高度对压力分布的影响。试验中发现,电弧长度由2mm增加到6.2mm时,与普通电弧压力一直减小不同,复合电弧的压力分布呈现出周期性变化,并且在弧长为4.4 mm时,电弧压力达到最大值。普通TIG焊接中不作为工艺参数的保护气喷嘴高度,在复合焊接中对压力分布有很大影响,喷嘴高度由2mm升高到5mm,电弧压力峰值从170.8Pa减小到60.5Pa。试验结果表明：超声钨极氩弧复合焊接方法能获得较高的电弧力,并且压力分布接近于高斯分布,有利于增加焊接熔深,提高焊接生产效率。

英文摘要：

In order to further reveal the characteristic of U-TIG arc,a hole drilling method is used to determine the difference of arc distribution between Ultrasonic-TIG（U-TIG） and conventional TIG arc,and the influence of welding current,arc length and nozzles height on distribution characteristic is also discussed.It shows that the arc distribution of U-TIG welding periodically changes with arc length increasing from 2 mm to 6.2 mm,and arc pressure reaches maximum with arc length being 4.4 mm.This is different from conventional TIG welding whose arc pressure decreases continuously.Besides,nozzle height is not a process parameter in conventional TIG welding,however,it greatly influences the distribution of arc pressure in U-TIG welding：the peak pressure decreases from 170.8 Pa to 60.5 Pa with nozzle height rising from 2 mm to 5 mm.The experiments indicate that the U-TIG welding can obtain higher arc pressure,and the pressure distribution is close to Gaussian distribution,beneficial to welding penetration and productivity.