Study on the weld bead formation on square-groove butt joint using plasma-MIG hybrid welding process

The welding with hybrid heat sources combined a plasma arc and a metal inert gas (MIG) arc was performed on the I-groove joint of 9 mm thick high-strength steel plates. The plasma torch is set up in the leading position, while the MIG torch is set up in the trailing position. As a result of observing hybrid welding with a high-speed camera, the plasma arc and the MIG arc are repelled each other. The influence of the root gap on the cross section and the bead formation was investigated. As a result, defect-free beads were formed at the root gap of 1.5 mm.