WELDING TORCH FOR GAS-SHIELDED WELDING

The feeding of shielding gas to the torch in MIG, MAG and TIG welding takes place by means of a separate supply line, the control of the stream of shielding gas taking place by means of a solenoid valve. This solenoid valve is generally in the so-called wire feed box. Between the wire feed box and the nozzle assembly of the torch there is generally a gas supply line a few metres long, in which foreign matter such as air or moisture accumulates during breaks in work and impairs the welding result when materials that are particularly sensitive to gas are used, in particular aluminium or aluminium alloys. The invention proposes a novel welding torch for gas-shielded welding, in which a shielding gas line (19) with a built-in shut-off valve (20, 35) is arranged in the nozzle assembly (5, 30) or in the torch barrel (4). The shut-off valve is preferably a nonreturn valve or a pressure-maintaining valve, with which a predetermined positive pressure of shielding gas with respect to the surrounding atmosphere is ensured in the shielding gas supply line. The flow shut-off device directly ahead of the gas outlet on the nozzle assembly reliably avoids the concentration of foreign matter inside the shielding gas supply line.