20120223058 | NON-CONSUMABLE ELECTRODE TYPE ARC WELDING APPARATUS - A non-consumable electrode type arc welding apparatus includes a torch having an electrode portion and a nozzle, a gas supply that supplies, to the torch, a shielding gas flowing through a gap formed between the electrode portion and the nozzle, a first power source that applies a voltage between the electrode portion and the nozzle to generate a pilot arc, a second power source that applies a voltage between the electrode portion and a work to generate a main arc, and a controller that controls the first power source and the second power source. The electrode portion has an electrode and an electrode holding portion holding a base portion of the electrode, the electrode holding portion has a protrusion protruding toward the nozzle from the side facing the nozzle, and the protrusion and the nozzle are caused contact and separate from each other. | 09-06-2012 |