Working principle and structure diagram of vacuum induction melting furnace
The world’s first vacuum induction furnace was born in Germany in 1917 to smelt the engines of aircraft and rocket engines. Vacuum induction melting furnace is one of the most widely used equipment in the field of vacuum metallurgy. Facts have proved that a considerable proportion of alloy and special steel required by aerospace, missile, rocket, atomic energy equipment and electronic industry are produced by vacuum induction melting furnace. For example, when nickel base, cobalt base and iron base superalloys are melted in vacuum induction furnace, their hot working performance and mechanical properties are obviously improved. For example, stainless steel, heat-resistant steel, ultra-high strength steel, tool steel, bearing steel, magnetic materials, elastic alloy and expansion alloy are almost melted in vacuum induction furnace to ensure the performance and quality of materials. In addition, the vacuum technology network. It is considered that with the development of secondary remelting process, another application of vacuum induction melting furnace is to provide high quality consumable electrode for vacuum consumable arc furnace or electroslag remelting furnace, and to produce master alloy for precision casting.
As we all know, the whole process of metal melting, refining and alloying in vacuum induction melting furnace process is carried out in vacuum state, so the pollution caused by the interaction of the same gas phase is avoided. Secondly, under vacuum condition, carbon has a strong ability of deoxidation, and its deoxidation Product Co is continuously pumped out of the system, which overcomes the pollution problem of deoxidization by metal deoxidizer. The chemical composition of the alloy can be accurately controlled by the process of vacuum induction melting furnace. The active elements such as Al, Ti, B, Zr with strong affinity to oxygen and nitrogen can be controlled in a small range. Low melting point volatile metal impurities such as Pb, Bi, Sn, sb can be removed by evaporation, which plays an important role in improving the properties of materials. Strong induction stirring can accelerate the reaction speed, which is very effective for the uniform temperature and chemical composition of the molten pool.
The rapid development of vacuum induction melting process is closely related to the superalloy materials required by aerospace industry, such as Superalloys for aerospace, missile, rocket, atomic energy and other equipment. The highest working temperature of superalloys produced by vacuum melting is only 750-810 ℃, while that of superalloys produced by vacuum melting can reach 980-1090 ℃. This is mainly due to the reduction of interstitial elements O2, N2 and H2 in nickel based, iron-based and cobalt based superalloys melted in vacuum induction furnace, which can completely remove non-metallic inclusions and remove harmful metal impurities with low melting point, such as Pb, Bi, Sb, Cu, Sn, Te, etc.
The equipment of vacuum induction melting furnace is mainly composed of furnace shell, inductor, crucible, furnace tilting mechanism, ingot mould mechanism, power supply device and water cooling system. The furnace shell is attached with observation, temperature measurement, feeding, sampling, ramming and other devices. The furnace is equipped with vacuum system, power supply system and control system. There are two kinds of vacuum induction melting furnace, intermittent and semi continuous, which can be established or horizontal.
The important problem to be considered in the structure design of vacuum induction melting furnace is to avoid vacuum discharge. Therefore, all charged bodies in the furnace shell should be insulated, and the inductor should be free of sharp corners, burrs and sharp edges in structure.
To sum up, the vacuum induction melting furnace has the following characteristics:
(1) Some titanium alloys can be melted in vacuum.
(2) In the vacuum state, it can prevent the melted metal and alloy from chemical reaction with non-metallic inclusions.
(3) In the vacuum state, it can remove harmful dissolved gases and pollutants in liquid molten metal.
From the perspective of product application, vacuum technology network（ http://www.chvacuum.com/ ）It is considered that the vacuum induction melting furnace is mainly used to produce superalloys, ultra-high strength steels, stainless steels and other special alloys for aerospace, missile, rocket, atomic energy and electronic industries.
