On 2018-08-08 14:48:54
Technical characteristics of vacuum heat treatment furnace
Strict vacuum sealing
It is well known that the vacuum heat treatment of metal parts is carried out in an airtight vacuum furnace. Therefore, it is very important to obtain and maintain the original leakage rate of the furnace and ensure the working vacuum of the vacuum furnace. Therefore, a key problem of vacuum heat treatment furnace is to have a reliable vacuum sealing structure. In order to ensure the vacuum performance of vacuum furnace, a basic principle must be followed in the structural design of vacuum heat treatment furnace, that is, the furnace body should be air-tightly welded, at the same time, the furnace body should be as little or no holes, less or avoid the use of dynamic sealing structure, in order to minimize the chance of vacuum leakage. Sealing structure must also be designed for parts and accessories such as water-cooled electrodes and thermocouple outlets installed on the vacuum furnace body.
Most heating and insulation materials can only be used in vacuum
The heating and insulating linings of vacuum heat treatment furnace work in vacuum and high temperature, so the requirements of high temperature resistance, low steam pressure, good radiation effect and low thermal conductivity are put forward. The requirement of oxidation resistance is not high. Therefore, tantalum, tungsten, molybdenum and graphite are widely used as heating and heat insulation materials in vacuum heat treatment furnace. These materials are easily oxidized in the atmosphere. Therefore, these heating and insulation materials can not be used in conventional heat treatment furnaces.
Water cooling device
Vacuum heat treatment furnace shell, furnace cover, electrothermal components, respectively disposal (water-cooled electrode), intermediate vacuum heat insulation and other components, all work in vacuum, heating state. Under such extremely unfavorable conditions, it is necessary to ensure that the structure of each component is not deformed and damaged, and that the vacuum sealing ring is not overheated or burned. Therefore, water-cooled devices should be set up according to different conditions to ensure the normal operation of the vacuum heat treatment furnace and sufficient service life.
Low voltage and high current
In a vacuum vessel, when the vacuum degree is within a certain range, the glow discharge will occur in the electrified conductor of the vacuum vessel at a higher voltage. In vacuum heat treatment furnace, serious arc discharge will occur, burning down the electric heating elements, insulation layer and so on, causing major accidents and losses. Therefore, the working voltage of the electric heating element of the vacuum heat treatment furnace is generally not more than 80-100 volts. At the same time, effective measures should be taken to prevent glow discharge or arc discharge, such as avoiding cutting-edge components as far as possible, and the spacing between electrodes should not be too narrow.
High degree of automation
The higher degree of automation of vacuum heat treatment furnace is due to the heating and cooling of metal workpieces, which need dozens or even dozens of actions to complete. These movements are carried out inside the vacuum heat treatment furnace, and the operators are unable to access them. At the same time, some actions such as heating and heat preservation after the completion of the metal workpiece quenching process requires six actions and to complete within 15 seconds. In such a rapid condition to complete many movements, it is easy to cause operator tension and constitute a misoperation. Therefore, only higher automation can accurately and timely mobilize by procedure.