| 摘要 |
A method for heat-treating metallic workpieces, in which a flow of cooling g as is generated in a vacuum furnace by a fan in order to quench the workpieces, wi th the fan being driven by a rotary current motor that is operated with a predetermined suppl y voltage above a minimum pressure in the vacuum furnace which is determined with regard to th e motor power of the rotary current motor. In order to additionally develop this method such that a simple and inexpensive improvement of the quenching effect is achieved, the fan is started at a pressure in the vacuum furnace which is lower than the minimum pressure, with the rotary current motor being operated with a second, lower supply voltage until the minimum pressur e in the vacuum furnace is reached.
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