Vacuum metallurgy is widely used in the smelting of rare metals, steel and special alloys. Vacuum metallurgy refers to the metallurgical operation carried out under the condition of lower than standard atmospheric pressure. It can remove the gas and impurities in the metal, enhance the deoxidation ability of carbon in metal, and improve the quality of metal and alloy. It is mainly used in vacuum separation, vacuum reduction, vacuum refining, vacuum casting and hot Treatment, vacuum coating, etc.
With the improvement of material requirements, vacuum metallurgy develops gradually. Vacuum metallurgy has begun to be used in the reduction of non-ferrous metals, refining and casting of non-ferrous metals and their alloys, and separation of some metallurgical intermediate products. All aspects of metallurgy are involved. Roots vacuum pump technology is more and more used in metallurgical industry, its benefits are more and more important. This paper introduces the application of Roots vacuum pump in vacuum metallurgy.
This paper introduces the selection of vacuum metallurgical equipment for vacuum pump in metallurgical industry. The gas sources for cold furnace pre pumping and hot smelting are as follows:
① The atmosphere in the extracted space (related to the volume to be pumped);
② Gases released during the process (including generated and introduced gases, which are related to time, temperature, pressure and production process);
③ The outgassing of the surface exposed in vacuum (related to the type of material, surface area, time, temperature and pressure, etc.);
④ Gas leakage and penetration (related to leakage rate of system components, welding quality of dynamic and static sealing components of equipment, and structural material);
⑤ Volatile gases (temperature and pressure dependent) caused by the vapor pressure of the material.
The gas produced in vacuum metallurgy operation may contain different substances, such as dust, fine metal particles, water vapor, volatile organic compounds, harmful gases, etc. appropriate measures should be taken in the pump or pipeline system to ensure smooth pumping, good operation and long service life of the pump and no impact on the environment.
In order to meet the needs of metallurgical process, the design of vacuum system is to select appropriate vacuum components such as pumps and valves according to the above-mentioned gas flow, and put forward reasonable layout scheme according to the pumping process, so as to remove the gas in the space to be pumped, overcome the outgassing and leakage, and keep the required vacuum degree in the vacuum chamber all the time.
In the steelmaking process, if the molten steel is vacuum treated at about 20 Torr, the quality of steel will be greatly improved. For example, in converter steelmaking, vacuum treatment of molten steel can improve its quality. After vacuum treatment, molten steel can enhance the melting process in steelmaking furnace and save ferroalloy consumption.
What oil does roots vacuum pump add? What type of vacuum pump oil can have excellent performance in vacuum metallurgy environment?
(1) After deep processing and cutting, the high-speed vacuum pump oil has less aromatics and gum components, which can avoid the pyrolysis of the oil due to thermal deterioration. The excellent high-temperature resistance makes the vacuum pump cleaner under long-term high-temperature use,
(2) High speed vacuum pump oil has low saturated vapor pressure, which does not affect the vacuum limit pressure due to the rise of pump body and oil temperature.
(3) it has good water separation and anti foam properties, avoiding oil emulsification and large amount of bubbles generated on the surface of oil products, resulting in the overflow of oil in the pump outlet and the pollution of the environment.
(4) High speed vacuum pump oil has good oxidation stability, which can avoid the deterioration of vacuum caused by oil oxidation. In the relatively harsh environment of vacuum metallurgy, it can effectively ensure the stable operation of the equipment, effectively extend the oil change cycle of the equipment, and save the oil cost of enterprises.