The water cooling device, the furnace shell of vacuum heat treatment furnace, the conduction of the furnace cover, the conductance of the electric thermal element (the water-cooled electrode), the middle vacuum insulation, etc., all work under the vacuum and heating condition. In this extremely unfavorable condition work, must ensure the structure of each component is not deformed, do not damage, vacuum sealing ring is not too hot, do not burn. Therefore, the components should be equipped with water cooling devices according to different situations to ensure that the vacuum heat treatment furnace can operate normally and have sufficient service life.
With low voltage large current: in vacuum container, really a lxlo degrees with a few empty – 1 when the scope of the vacuum container under high voltage electric conductor, glow discharge is produced. In the vacuum heat treatment furnace, the serious will produce arc light discharge, burn the electric heating element, the insulation layer and so on, cause the major accident and the loss. Therefore, the working voltage of the vacuum heat treatment furnace is generally not more than 80 100 volts. In the electric heating element structure design at the same time to take effective measures, such as to avoid a sophisticated components, the spacing between the electrode cannot be too narrow, preventing the occurrence of glow discharge and arc discharge.
Most heating and insulation material can only be used in the vacuum state, vacuum heat treatment furnace heating and insulation lining is working under vacuum and high temperature, thus put forward to the material resistant to high temperature, low steam, radiation effect is good, small coefficient of thermal conductivity. The resistance to oxidation is not high. Therefore, the vacuum heat treatment furnace is widely used for heating and insulation materials such as tantalum, tungsten, molybdenum and graphite. These materials are easy to oxidize in the atmosphere and therefore, conventional heat treatment furnaces cannot use these heating and insulation materials.
Strict vacuum seal: all the known, vacuum heat treatment of metal parts are conducted in airtight vacuum furnace, therefore, obtain and maintain the gas leakage rate was due to the stove, ensure vacuum degree of vacuum furnace, and to ensure the quality of the parts of the vacuum heat treatment has very important significance. So a key problem of vacuum heat treatment furnace is to have a reliable vacuum seal structure. Vacuum performance, in order to ensure that the vacuum furnace in vacuum heat treatment furnace structure design must follow a basic principle, is the furnace should use airtight welding, at the same time as little as possible to open or not open hole in the furnace body, less use or avoid use dynamic seal structure, to minimize the vacuum leak. The parts and accessories such as water cooled electrodes and thermocouple export devices installed in the vacuum furnace must also design the sealing structure.
The degree of automation is high: the degree of automation of vacuum heat treatment furnace is high because of the operation of heating and cooling of metal workpiece, which requires a dozen or even dozens of actions to complete. These actions are carried out in a vacuum heat treatment furnace, which the operator can’t access. At the same time, some actions, such as heating and insulation, must be completed in 15 seconds. In such a rapid condition to complete many actions, it is very easy to cause the operator’s tension to constitute a misoperation. Therefore, only the higher order of the eye movement can be accurate and timely to coordinate with the program.