A three-dimensional CFD-model was developed to investigate Active-TIG welding of 304L-SS, involving heat transfer, fluid flow, solidification, plasma arc effect, Marangoni convections, magnetohydrodynamics and oxide particle trajectory. The aim was to understand how flux-induced particles are distributed in the weld line. The results, validated with available experimental data, showed that A-TIG forms a pool with an increased maximum temperature (2800 K) and depth-to-width ratio (0.7). The flow pattern, dominated by two vortices due to Marangoni convection, collects particles from the surface, submerges them into the pool and leads to entrapment of the most in the weld cross section. The motion path of 70% of particles ended at the deeper half of the cross section. Detailed numerical picture of A-TIG weld pool was presented and discussed in this study to be a step in understanding of the nature of Active-TIG welding and to assist in improving the process.

建立了三维CFD模型，以研究304L-SS的Active-TIG焊接，涉及热传递，流体流动，凝固，等离子弧效应，Marangoni对流，磁流体动力学和氧化物颗粒轨迹。目的是了解助熔剂诱导的颗粒如何在焊缝中分布。结果得到了可用的实验数据的验证，结果表明A-TIG形成了一个池，其最高温度（2800 K）和深宽比（0.7）增加。由于Marangoni对流，流场以两个涡旋为主，从表面收集颗粒，将其浸入池中，并导致大部分焊缝截留。70％的粒子的运动路径终止于横截面的较深一半。