Vacuum Induction Furnace Selection of Refractories for Cored
Cored vacuum induction furnace is a kind of equipment which converts electric energy into heat energy by using electromagnetic field induction principle, and makes the metal burden heated and melted.
The structure and working principle of the cored vacuum induction furnace are similar to that of a transformer. The primary winding is a multi-turn coil on the iron core, and the secondary winding is a closed metal molten groove. When the induction coil turns on alternating current, its alternating flux leads to the induction current in the molten channel, which makes the molten channel become hot and melt. Because the induction furnace can operate normally only when the groove is closed, the core induction furnace is suitable for continuous operation.
Selection of Refractory Material by Characteristics of Copper
The melting temperature of cored induction copper melting furnace generally ranges from 1200 to 1350 degrees C (copper melting point 960 degrees C), and the temperature of inductor melting channel reaches 1350 to 1450 degrees C. Because of the low melting point of copper, the viscosity of copper liquid is small (close to 0.1Pas viscosity of water), the density of copper melting furnace is high, and the permeated copper is easy to oxidize, accompanied by volume expansion. As a result, the lining structure is loose, cracks and spalling occur, thus reducing the service life of the lining. The following suitable refractories shall be used.
Induction furnace throat: corundum-mullite castable: adding appropriate amount of steel fibers to improve density and toughness, and enhance anti-spalling ability.
The position of inductor molten ditch: Special corundum material is selected, and mullite and corundum are the main mineral phases to form a stable network skeleton. Considering the permeability of copper, SiC is added to improve the wettability of the material.
In addition: the use conditions of furnaces of different manufacturers are different, so the use cycle is also different. The average time is about 6 months to 1.5 years. Of course, through exploration and continuous improvement, will achieve a very ideal use effect.