Study on droplet transfer behavior during medium and low power laser assisted pulsed MAG hybrid welding

This paper comparatively investigates the arc plasma morphology and the droplet transfer behavior and Characteristic of electrical signal between the pulsed MAG welding and the medium and low power laser assisted pulsed MAG hybrid Welding. Compared with the pulsed MAG welding, the assisted laser acts on the substrate before the arc to generate a stable keyhole and mass metallic vapor is generated near the keyhole leading the expansion of arc plasma morphology. The arc plasma appears obvious compression phenomenon under the action of medium power assisted laser. In addition, the keyhole has an attractive effect on the discharge channel and the height of the discharge channel becomes shorter, which makes the arc initiation stage more stable. The contact area between the arc root and the workpiece is expanded, in addition the laser has a compression effect on the arc, making the arc energy density higher and the energy use more efficient. The acting of assisted laser increased the droplet transfer frequency with the power increases, which essentially changes the electromagnetic force acting on the droplet. Others, the range of welding voltage distribution and the probability of high voltage distribution are reduced, and the transition is more stable.