Two most common methods of lining the medium frequency furnace

The construction of medium frequency electric furnace crucible is commonly known as furnace lining.

The quality of furnace lining directly affects the smelting efficiency and use cost. Generally, furnace lining work in small and medium-sized foundries is completed by furnace workers. However, many furnace workers know little about refractory materials and furnace lining technology, and often make common sense mistakes during the furnace lining process. As a result, the furnace lining is not durable. It is recommended that furnace workers should learn more about refractory materials and furnace lining technology.

The lining material of medium frequency furnace is also called medium frequency furnace beating material, medium frequency furnace dry vibration material, medium frequency furnace dry beating material, medium frequency furnace ramming material, etc. It is divided into acidic, neutral and alkaline lining materials. The acidic lining material is made of high-purity quartz and fused quartz as the main raw materials, and composite additives as sintering agents; the neutral lining material is made of alumina and high-alumina materials as the main raw materials, and composite additives as sintering agents; the alkaline lining material is made of high-purity fused corundum, high-purity fused magnesia and high-purity spinel as the main raw materials, and composite additives as sintering agents.

Basic lining: Mainly used for melting various high alloy steels, carbon steel, high manganese steel, high chromium steel, tool steel, stainless steel and other alloy steels.

Acidic lining: Mainly used for the working lining of coreless induction furnaces for melting and heat preservation of cast iron.

Acidic, neutral and alkaline linings are widely used in coreless medium frequency furnaces and cored induction furnaces. As medium frequency furnace lining materials, they are used to melt gray cast iron, ductile iron and cast iron alloys, melt carbon steel, alloy steel, high manganese steel, tool steel, heat-resistant steel, stainless steel, melt aluminum and its alloys, melt copper, brass, nickel silver and bronze and other copper alloys.

There are two methods for knotting the lining of medium frequency hot induction furnaces: wet knotting and dry knotting. Both methods can be used for knotting acid medium frequency linings, neutral linings and alkaline linings.

Wet knotting of medium frequency furnace refers to the knotting by adding water, water glass, brine and other adhesives to the knotting materials of the furnace lining. Since the knotting materials contain a certain amount of water, there is less dust during construction and good formability. However, wet knotting also has a series of disadvantages: the knotted lining materials of the medium frequency furnace are not dense enough, and the refractoriness of the lining is reduced; the drying time of the furnace lining is long; the insulation performance of the sensor is reduced when the moisture in the lining is vaporized. If it is not handled properly, it often leads to the breakdown of the inter-turn fire and may also cause a ground short circuit. Therefore, for large melting medium frequency furnaces, wet knotting of the lining should be avoided as much as possible.

The dry furnace building method is currently the most widely used in the construction of crucible induction furnaces. The dry medium frequency furnace building method without binder can maximize the refractory performance of the furnace lining material, thin the sintering layer of the furnace lining, thicken the powder layer, reduce the heat dissipation loss of the furnace lining, reduce the tendency of the furnace lining cracks, and improve the safety and reliability of the furnace lining.