Design and construction for theory and method of magnetic-controlled negative pressure GTAW arc model based on multi-physics simulation

The two-dimensional GTAW arc model is insufficient to fully explain the effects of the external longitudinal magnetic field on the arc. Therefore, a three-dimensional GTAW arc model was established to elucidate the recirculation flow and negative pressure arc characteristic of magnetic-controlled arc. The external magnetic field controls the surface temperature, pressure, and current density distribution of the workpiece by controlling the flow of arc plasma. When the magnetic flux density is 0.04T, the surface temperature, pressure, and current density of the workpiece exhibit a bimodal distribution. Under the negative pressure of the GTAW arc, the arc plasma on both sides flowed counterclockwise around the center in the spiral upward direction and then counterclockwise downward from 0.9 mm below the tungsten electrode. By controlling the welding current and magnetic flux density, the occurrence of negative surface pressure on the workpiece can be effectively controlled.