Plasma arc welding method and apparatus

Claim 1

In a plasma arc welding torch of the type comprising a handle, a torch head secured to the handle, a pair of electrodes including a cathode and a tip serving as an anode disposed within the head for initiating an arc, means for supplying arc gas through the tip to the electric arc for creating an arc plasma and means for introducing shielding gas to the torch to be directed at the arc, the improvement which comprises; a nozzle containing a central passage, the nozzle secured to the torch head and surrounding at least the lower portion of the torch tip, the tip having a rounded configuration at the gas discharge end, the central passage in the nozzle being spaced apart from the tip and defining a conduit for shielding gas to flow around the tip, means on the surface of the central passage to constrict and direct the shielding gas across the end of the tip toward the plasma arc at an angle greater than parallel to but less than normal to the plasma arc.