Abstract: A plasma torch 1 used in plasma-arc welding is provided with a rod-shaped electrode 10, a first cylindrical nozzle 11 which is provided to surround the electrode 10 and which injects a plasma gas and a second cylindrical nozzle 12 which is provided to surround the first nozzle 11 and which injects a shielding gas. A second injection opening 121 of the second nozzle 12 directs in a substantially parallel direction with respect to an axial direction of the electrode 10 or in a direction being away from the electrode 10, and a plurality of groove portions inclining with respect to the axial direction of the electrode 10 are formed in an outer circumferential surface of the first nozzle 11 or an inner circumferential surface of the second nozzle 12.

Abstract: A plasma torch 1 used in plasma-arc welding is provided with a rod-shaped electrode 10, a first cylindrical nozzle 11 which is provided to surround the electrode 10 and which injects a plasma gas and a second cylindrical nozzle 12 which is provided to surround the first nozzle 11 and which injects a shielding gas. A second injection opening 121 of the second nozzle 12 directs in a substantially parallel direction with respect to an axial direction of the electrode 10 or in a direction being away from the electrode 10, and a plurality of groove portions inclining with respect to the axial direction of the electrode 10 are formed in an outer circumferential surface of the first nozzle 11 or an inner circumferential surface of the second nozzle 12.

Abstract: An element such as Cr is caused to dissolve sufficiently in a base-material metal (Cu) in a solid solution state at a high temperature and a material in a supersaturated condition is obtained by performing quenching. After that, a strain is applied to this material and this material is subjected to aging treatment at a low temperature simultaneously with or after the application of this strain. As a result of this, it is possible to obtain a copper alloy having properties desirable as an electrode material, for example, a hardness of not less than 30 HRB, an electrical conductivity of not less than 85 IACS %, and a thermal conductivity of not less than 350 W/(m·K).

Abstract: An element such as Cr is caused to dissolve sufficiently in a base-material metal (Cu) in a solid solution state at a high temperature and a material in a supersaturated condition is obtained by performing quenching. After that, a strain is applied to this material and this material is subjected to aging treatment at a low temperature simultaneously with or after the application of this strain. As a result of this, it is possible to obtain a copper alloy having properties desirable as an electrode material, for example, a hardness of not less than 30 HRB, an electrical conductivity of not less than 85 IACS %, and a thermal conductivity of not less than 350 W/(m·K).

Abstract: An element such as Cr is caused to dissolve sufficiently in a base-material metal (Cu) in a solid solution state at a high temperature and a material in a supersaturated condition is obtained by performing quenching. After that, a strain is applied to this material and this material is subjected to aging treatment at a low temperature simultaneously with or after the application of this strain. As a result of this, it is possible to obtain a copper alloy having properties desirable as an electrode material, for example, a hardness of not less than 30 HRB, an electrical conductivity of not less than 85 IACS %, and a thermal conductivity of not less than 350 W/(m·K).