Selection and Technological Progress of Refractory Materials for Coreless Induction Furnaces

Induction furnace is a device that uses the principle of electromagnetic field induction to convert electrical energy into heat energy to heat and melt the metal charge. According to the structure, it is divided into two categories: core induction furnace and coreless induction furnace.

The coreless induction furnace has the advantages of high efficiency, energy saving, low pollution, easy adjustment of composition, easy control of atmosphere, strong heating capacity, and intermittent operation. The induction furnace is divided into: power frequency induction furnace (within 50Hz); medium frequency induction furnace (50Hz-10000Hz) and high frequency induction furnace (above 10000Hz). In recent years, with the development and reliability improvement of high-power thyristor variable frequency power supply, the intermediate frequency furnace has gradually replaced the power frequency furnace. Compared with the power frequency furnace, the intermediate frequency furnace has high thermal efficiency and electrical efficiency, short melting time, low power consumption, and easy implementation. advantages of automation. In addition, the induction furnace is developing in the direction of large capacity and high power, which has higher requirements for refractory materials.

Refractory lining is an important factor that determines the output of induction furnace, casting quality and safety and reliability of production and operation. To obtain a refractory lining with good quality and long service life, we must first understand the conditions of use: (1) The thickness of the refractory lining is relatively high. Thin, the temperature gradient of the lining is large; (2) The electromagnetic stirring of the molten metal in the furnace causes mechanical erosion of the refractory lining; (3) The refractory lining is repeatedly quenched and thermally impacted.

Therefore, the selected refractory materials must have: sufficiently high refractoriness and softening temperature under load; good thermal shock stability; no chemical reaction with metals and slag; a certain high temperature mechanical strength; good insulation and Insulation; good construction, high filling density, easy sintering, convenient maintenance; abundant resources of refractory raw materials, low prices, etc. The development of induction furnace is closely related to the technological progress of refractory materials. The design of large-scale power frequency crucible induction furnace often starts from the selection of refractory materials and the simulation test of furnace lining. In any case, the selection of furnace lining refractories is based on the utilization and economy of the furnace. For the purpose of tight coupling on electrical appliances, the thinner the lining thickness, the better it is without affecting the service life.

Post time: Apr-18-2022