Abstract
The mechanism of stable weld bead formation in fiber laser-MAG arc hybrid welding at high speed was investigated by observation of welding phenomena. Arc shape and droplet transfer were observed for arc welding and laser arc hybrid welding at welding speeds of 3m/min and 6m/min. The interaction between arc column and laser irradiation point, which some previous reports mentioned, was not observed at both welding speeds of 3m/min and 6m/min. In arc welding at welding speed of 6m/min, droplets transferred to the unmelted base metal in front of the molten pool and scattered as spatter. On the other hand, in laser-arc hybrid welding at welding speed of 6m/min, droplets transferred to the molten pool caused by the laser beam and spatter generation was suppressed. The formation of a molten pool caused by the laser beam in front of the molten pool caused by arc welding is effective in reducing spatter and stabilizing beads.
