Effect of plasma welding current on heat source penetration ability of plasma-GMAW hybrid welding

In the plasma-gas metal arc welding (GMAW) hybrid welding of aluminum alloy, the weld penetration under different plasma welding currents was compared. When the plasma welding current was lower than 150 A, the hybrid welding penetration was greater than the sum of the single plasma welding and the single GMAW penetration. When the plasma welding current reached 130 A, with the increase of the plasma welding current, the advantage of the weld penetration of the hybrid welding was gradually weakened compared with that of the single welding. The above change mechanism is revealed from the perspectives of heat source energy distribution and molten pool stress. The results show that when the plasma welding current is lower than 110 A, the area of the high-temperature region in the arc zone of GMAW in the hybrid welding increases compared with that in the single GMAW. The trend of arc energy transfer to the penetration direction increases under the action of arc pressure, arc shear force, electromagnetic force, and droplet impact. With the increase of plasma welding current, the high-temperature area of the GMAW arc first increases and then decreases. When the plasma current reaches 130 A, the effect of arc pressure, arc shear force, electromagnetic force, and droplet impact on increasing the penetration begins to weaken.