Method and apparatus for DC reverse polarity plasma-arc working of electrically conductive materials

Abstract

A method of DC reverse polarity plasma-arc machining of electrically conductive materials with the aid of a plasmatron the plasmatron having a nonconsumable electrode with an insert made from a high-melting point material, the method being in that the material being machined is heated by the heat of an electric arc burning between the positive nonconsumable electrode of the plasmatron and the material being machined, with the supply of the plasma-forming gas, the intensity of the working current of the arc being selected such that its ratio to the diameter of the nozzle channel is within 50 to 100 A/mm on condition that at least a portion of the near-the-electrode zone of the arc is maintained in electric contact with the high-melting point insert of the electrode. In an apparatus for plasma-arc machining of electrically conductive materials, the electrode of the plasmatron, with a nozzle arranged coaxially therewith, is coupled to the positive terminal of a power supply source, whose negative terminal is coupled to the material being worked, at least a portion of the end face surface of the electrode of the plasmatron being made from a high-melting point material, and the diameter of the electrode at least 1.1 times the diameter of the nozzle channel.

Dependencies are inferred from the claim text.