Arc Characteristic and Behaviour of Droplet Transfer in CO2 Laser-MAG Hybrid Welding of High Strength Steel

The variation of arc characteristic and behaviour of droplet transfer of CO2 laser-metal active gas (MAG) hybrid welding have been studied. The arc characteristic was studied by conduction zone size, current line distribution and arc length. The behaviour of droplet transfer was studied by droplet diameter and detachment velocity. When the welding current varied in the range of 140 to 160 A, the droplet transfer mode is short-circuiting transfer. This droplet transfer mode is not benefit for the stability of the hybrid welding process. However, when the current is beyond 180 A the droplet transfer mode is changed from projected transfer to repelled transfer. This droplet transfer mode is benefit for the stability of hybrid welding process. The arc power determines the droplet transfer mode and laser power affects the behaviour of droplet transfer in laser-MAG hybrid welding process.