| 摘要 |
There are provided a plasma arc torch and associated methods for selectively switching between a working mode and a standby mode. An electric arc is established between an electrode and a workpiece, and the torch is operated selectively in the working and standby modes. In the working mode, the arc extends between the electrode and the workpiece, the arc has a working arc current, and a plasma gas flows through a nozzle at a working flow rate. In the subsequent standby mode, the arc extends between the electrode arid the nozz le and has a current less than the working arc current. The gas flow rate in th e standby mode can be reduced to less than the working flow rate, and the plas ma gas can be switched from an oxidizing gas to a non-oxidizing gas.
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