| 摘要 |
PROBLEM TO BE SOLVED: To provide an improved type apparatus and method for reducing the corrosive effect of an arc to both of an electrode and a nozzle. SOLUTION: In the plasma arc torch and method related thereto, selective switching is performed for a working mode and a standby mode. An electric arc is generated by an electrode and a base metal, and the plasma arc torch is selectively operated in the working and standby modes. In the working mode, the arc and a working arc curren are generated by the electrode 14 and the base metal 100, and a plasma gas flows through a nozzle at a certain working flow rate. In the subsequent standby mode, the arc and arc electric current lower than the working arc current are generated by the electrode and the nozzle. The gas flow rate in the standby mode can be reduced to the one less than the working flow rate, and the plasma gas can be switched from an oxidizing gas to a non-oxidizing gas. COPYRIGHT: (C)2004,JPO
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