| 摘要 |
A welding torch for gas metal arc welding has a torch body which conducts electricity, receives a cable for directing a welding wire, and defines a passage for directing a shielding gas. A conductor tube has an inner end portion secured to the torch body and a free outer end portion, and a contact tip is secured to the outer end portion of the conductor tube. The contact tip has a central bore which directs the welding wire through the tip, and a diffuser directs the shielding gas around the contact tip and conducts electrical power to the contact tip. A tubular welding nozzle body is formed of a porous polycrystalline graphite material and has a slightly tapered inner surface which surrounds the contact tip for collimating the gas while substantially reducing the accumulation of spatter on the nozzle body. The contact tip may also be covered with the same graphite material to impede spatter accumulation, and the porous graphite material is impregnated with petrolatum and wax to extend the service life of the body. The tubular nozzle body may be protected by a surrounding copper jacket, and an interfitting band of ceramic material retains the body within the jacket.
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