A new superimposed double-arc welding method with one arc submerged in the weld pool

This study presents a new double-gas tungsten arc welding heat source, with two arcs serially arranged on the same side of a workpiece. During welding, a tungsten tube and inert gas are additionally used to help the rear electric arcs burn at the bottom of the existing weld pool formed by the fore arc. Bead-on-plate welding experiments using this heat source are carried out to investigate the heating efficiency of the heat source and the influences of the arc current, the gas flow rate in the tube on the welding process. Results show that the heat source presents higher melting efficiency and stronger heat penetrability compared with normal double-gas tungsten arc welding. The interactions of the forces near the weld pool in the welding process are also analyzed. Observation of the arc behavior by a high-speed camera proves that the electromagnetic force between the two burning arcs stabilizes the burning arcs and thus the welding process.