Welding Torch

welding torch [′weld·iŋ ‚tȯrch]

(engineering)

A gas-mixing and burning tool for the welding of metal.

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Welding Torch 

part of a welding apparatus. In electric welding, the torch conducts electric current to the electrode and carries the shielding gas to the arc zone of the welding arc. In gas welding, the torch serves to adjust the mixture of gases and to guide the welding flame. The torch may be moved along the edges being welded by hand (in manual or semiautomatic welding) or automatically (in automatic welding).

Welding torches used in electric welding with consumable electrodes have a head equipped with an interchangeable tip through which the electrode wire extends. The head conducts the current and guides the electrode. A stream of gas is fed through a guide nozzle; the gas shields the weld puddle and the electrode from the atmosphere. Torches used with nonconsumable electrodes have a head equipped with a current-carrying collet clamp.

Welding torches used in gas welding feed the fuel gases, such as acetylene and oxygen, to the weld site. The gases pass through two channels and regulating valves and then enter a mixing chamber, where a combustible mixture is prepared; the mixture then enters the head. Low-pressure torches are equipped with a built-in injector that provides suction of the fuel gases. In high-pressure torches, the fuel gas is fed under pressure from gas generators or from cylinders.

M. G. BEL’FOR