Patent ID: 8513564

Claim:
A plasma welding torch, comprising: a non-consumable electrode that forms a plasma arc between a base material and the non-consumable electrode; and a nozzle, through which inert gas flows, the nozzle including: a first orifice having the non-consumable electrode accommodated therein, and being open to the outside; and a second orifice extending along a direction at a predetermined angle with respect to the non-consumable electrode from a part of the first orifice, and being open to the outside; wherein the inert gas flows through the first orifice when the plasma welding torch moves in a predetermined direction with respect to the base material, a portion of the inert gas, as plasma gas, causes the plasma arc to be formed between the base material and the non-consumable electrode through the first orifice, a portion of the rest of the inert gas is ejected, as shield gas, onto at least the base material in the predetermined direction through the second orifice, and an opening area ratio between an opening area of the first orifice and an opening area of a second orifice is set such that, for a predetermined inert gas flow rate and a predetermined plasma torch moving speed in the predetermined direction, a sufficient proportion of the inert gas flows through the first orifice for the plasma arc to melt and penetrate the base material and a sufficient proportion of the inert gas flows through the second orifice for the shield gas to shield the plasma arc and the base material from air.