Classification of induction melting furnaces
Induction melting furnaces used in industry include crucible furnace (coreless induction furnace) and melting trench furnace (cored induction furnace). The crucible is made of refractory or steel and has a capacity ranging from several kilograms to dozens of tons. Its melting characteristic is that they melt in the crucible is subjected to electric power, forcing the liquid level of the molten pool to bulge, and the melt flows from the center of the liquid level to the periphery, causing circular flow. This phenomenon is called the electric effect, which can make the melt composition uniform. The disadvantage is that the slag is biased towards the periphery and the coverage is poor. Compared with melt trench furnace, crucible furnace has a flexible operation, high melting temperature, low power factor, and high power consumption. The inductor of the melt trench furnace consists of an iron core, an induction ring, and a melt trench lining. The melt trench is one or two belt-shaped annular trenches filled with melt connected with the melt pool. In principle, the melting trench furnace can be regarded as an iron core transformer with only one turn of the coil in the secondary and short circuit. The induced current flows in the melt of the melt channel to realize electrothermal transformation.
In production, after each furnace of metal melting is completed, the molten pool cannot be emptied, otherwise it is easy to dry up, and a part of the melt must be retained as the starting melt for the next furnace. The temperature of the melt trench is higher than that of the melt pool, and it is also subject to the scouring of melt flow, so the lining of the melt trench is easy to damage. In order to facilitate maintenance, the sensors of modern furnaces are made into assembly parts that are easy to replace. The capacity of the melting ditch furnace ranges from several hundred kilograms to more than one hundred tons. The melting trench furnace supplies power frequency electricity. As the iron core made of silicon steel sheet is used as the magnetic path, the electrical efficiency and power factor are very high. Melting ditch furnace is mainly used for melting cast iron, copper, zinc, brass, etc. It can also be used as a mixing furnace to store and heat the melt.