Vacuum refers to the lower than the local atmospheric pressure of the gas state;
Features: to protect the workpiece is not oxidative decarburization; to protect the oxidation of the heating element; reduce the workpiece within the gas; smelting metal can be added more easily oxidized elements.
Vacuum resistance furnace: external vacuum furnace, internal vacuum furnace. 2, carbon tube furnace, 3, vacuum induction furnace.
The characteristics of the vacuum furnace
(1) strict vacuum seal;
(2) most of the heating and insulation materials can only be in a vacuum.