Herein, we theoretically and experimentally examined the effects of current pulse frequency on arc characteristics, weld appearance, and weld microstructure of AISI444 ferritic stainless steel (FSS) welded by tungsten inert gas (TIG). The arc shape, pressure, and density distribution of TIG welding were measured using a high-speed camera and the sensor measurement and keyhole probe methods. Moreover, the arc characteristics, weld appearance, and weld microstructure under 0- to 500-Hz current pulse frequency were examined. The results show that the arc shape gradually compresses with increasing pulse frequency. When the pulse frequency is 500 Hz, the compression effect is the most obvious, the arc pressure and arc density are the largest, the weld penetration depth is the largest, and the melting width is the smallest. When the pulse frequency is 300 Hz, the finest equiaxed crystal microstructure is obtained. Furthermore, the mechanism of arc compression, arc pressure increase, weld morphology change, and grain refinement is analyzed.

在此，我们从理论上和实验上研究了电流脉冲频率对采用钨惰性气体 (TIG) 焊接的 AISI444 铁素体不锈钢 (FSS) 的电弧特性、焊缝外观和焊缝微观结构的影响。TIG 焊接的电弧形状、压力和密度分布是使用高速相机和传感器测量和小孔探针方法测量的。此外，还检查了 0 至 500 Hz 电流脉冲频率下的电弧特性、焊缝外观和焊缝微观结构。结果表明，随着脉冲频率的增加，弧形逐渐压缩。脉冲频率为500Hz时，压缩效果最明显，电弧​​压力和电弧密度最大，焊缝熔深最大，熔化宽度最小。当脉冲频率为300Hz时，得到最细的等轴晶显微组织。进一步分析了电弧压缩、电弧压力增加、焊缝形貌变化和晶粒细化的机理。