Vacuum metallurgy of metals and their alloys in a vacuum, covering a wide range, including vacuum distillation, vacuum separation of ores and their semi-finished products, vacuum reduction of metal compounds, vacuum degassing and refining of molten steel outside the furnace, metal vacuum melting, vacuum sintering, vacuum heat treatment, vacuum brazing and vacuum solid-state bonding and other process methods. Vacuum metallurgy has been developed since the 1950s. The reason why it has been widely used is that the vacuum environment has a series of characteristics in the metallurgical process.
First of all, the chemical interaction between substances and residual gas molecules in the vacuum environment is very weak, so it is very suitable for smelting and refining of ferrous metals, rare metals, ultra-pure metals, and their alloys, and semiconductor materials. Secondly, in the vacuum environment, the purpose of degassing and smelting molten steel and vacuum carbon deoxidation can be achieved by reducing the partial pressure of a single gas molecule. Another feature of the vacuum environment is that it has the ability to carry out certain reactions at lower temperatures. For example, at the same temperature, some reaction processes are difficult to carry out in the atmosphere but very easy at low pressures. This is the basic principle of vacuum compound decomposition and non-ferrous metal smelting. Due to the wide application of vacuum technology in the metallurgical industry, the demand for vacuum accessories has also developed rapidly.