Apparatus and method for TIG welding with two electrodes and superposed pulsed currents at opposing phase

摘要

A TIG welding apparatus comprises; a twin electrode type welding torch 1 having a first and a second welding electrode 1 a , 1 b arranged approximately parallel and either side of an insulation plate of a predetermined thickness, and a main unit 2 which supplies to the first welding electrode 1 a a first welding current varied at a first period F, and to the second welding electrode 1 b a second welding current varied at the first period F and at an opposite phase to the variation of the first welding current. The main unit 2 superimposes a variation of a second period fm being shorter than the first period F, onto the first and second welding currents. As a result, the arc current is increased without increasing the welding current.