Plasma welding torch having a nozzle with first and second orifices, and welding method using plasma welding torch having a nozzle with first and second orifices

摘要

A plasma welding torch that can be reduced in size more than in conventional cases. When an inert gas G such as argon gas is supplied to an outer circumferential space around a non-consumable electrode 13, a portion of the inert gas G is used as plasma gas GP that forms a plasma arc PA between the non-consumable electrode 13 and a base material 2 via a plasma orifice 51. A plasma welding torch 1 moves, maintaining this state, in the direction of the arrow shown in FIG. 4. Meanwhile, a portion of the inert gas G supplied to a gas flowing part 21 is not used as the plasma gas GP but is used as shielding gas GS and is ejected onto the base material 2 ahead in the welding direction via a shielding orifice 52. The welding on the base material 2 is performed in a state where the plasma arc PA and the base material 2 are shielded from the air by this shielding gas.