Induction furnace is divided into core and coreless two kinds, the most common application is coreless induction furnace (i.e. medium frequency induction furnace).
About induction melting furnace
Induction melting furnaces are a kind of advanced melting equipment, which applies the principle of electromagnetic induction to generate heat inside the molten charge and make the charge melt. Therefore, the thermal efficiency is high and the burning loss of alloying elements is low. Due to the electromagnetic stirring effect, the molten metal composition is uniform, with no segregation phenomenon, the heat source does not need coke, and can produce a cupola furnace can not produce special high-quality cast iron. Induction furnace melting control is easy, has good operating conditions, environmental pollution, low noise, convenient and economical reuse of metal charge (small to iron filings, large to the size of the furnace chamber can accommodate the large material), so the induction furnace melting cast iron is widely used. The use of induction furnace smelting of cast iron tends to expand more and more.
At present, China’s various induction melting furnaces have professional manufacturer’s production, the variety is relatively complete, and can meet the production requirements.
According to the use of current frequency is divided into ①: industrial frequency coreless induction furnace -50Hz; ②: intermediate frequency coreless induction furnace > 50 ~ 10000Hz; ③: high-frequency coreless induction furnace > 10000Hz.
The heating principle of the medium frequency coreless induction furnace produced by Shenguang Electric Furnace Co:
About coreless induction furnace
A coreless induction furnace works according to the principle of electromagnetic induction. Crucible spiral induction circle is equivalent to the original winding of the transformer, and the metal charge in the crucible is equivalent to the secondary winding of the transformer, when the induction circle passes the alternating current, then due to the role of the alternating magnetic field to make the crucible short-circuit connection of the metal charge to produce a strong induction current, the current flow to overcome the resistance of the surface layer of the metal charge to produce heat and make the metal melt. This kind of furnace is characterized by the surface effect and the stirring effect of electromagnetic force. The former is determined by the frequency of the induction current, the higher the current frequency of the surface effect is more significant, the metal charge surface heat penetration depth is more shallow is also doomed to the metal charge diameter should not be too large, reducing the electrical efficiency, which is the high-frequency induction furnace is not a large-scale fundamental reasons. The latter is embodied in the metal charge melting to form a molten pool, the liquid metal by the role of electromagnetic force produces a strong perturbation, the formation of a stirring effect, and the direction of movement to form a hump.
The melting of this stirring effect is conducive to the rapid melting of metal so that the temperature and composition of the molten pool are more uniform, conducive to deoxidation, degassing, and removal of inclusions in operation.
Structure of coreless induction furnace: A coreless induction furnace consists of furnace body, furnace frame, tilting mechanism, water-cooling system and electrical equipment.
