Talk about the knotting of crucible type medium frequency induction heating furnace lining

There are two knotting methods for crucible induction furnace lining: wet knotting and dry knotting. Both methods can be used for knotting acidic furnace linings, neutral furnace linings, and alkaline furnace linings.

Wet knotting refers to knotting by adding water, water glass, brine and other adhesives to the furnace lining knotting material. Since the knotted material contains a certain amount of moisture, there is less dust during construction and good formability. However, wet knotting also has a series of disadvantages: the knotted furnace lining material is not dense enough, and the refractoriness of the furnace lining is reduced; it takes a long time to dry the furnace lining; when the moisture in the furnace lining vaporizes, the insulation performance of the sensor is reduced decline. Improper treatment often leads to breakdown of inter-turn ignition and may also cause grounding short circuit. Therefore, wet knotting of furnace lining should be avoided for larger smelting furnaces.

The thousand-style furnace building method is currently widely used in the furnace building of crucible-type induction furnaces. The dry furnace building method without cement can maximize the refractory performance of the furnace lining material, thin the sintered layer of the furnace lining, thicken the powdery layer, reduce the heat dissipation loss of the furnace lining, reduce the tendency of furnace lining cracks, and improve the furnace lining. Safety and reliability.

When the crucible type medium frequency induction heating furnace is used to smelt general gray cast iron, malleable cast iron and alloy cast iron, since the cast iron contains more silicon, the returned iron often also contains more silica sand, and the slag produced during melting is acidic. It is more appropriate to use acidic furnace lining.

Low price. Gangue sand basically completes its expansion change at 600 to 800°C. Above this temperature, the volume change is small. It has good thermal stability and resistance to molten iron leakage, and can be adapted to intermittent smelting operations. In addition, the load softening temperature of silica sand is high, close to its refractoriness, and its high-temperature mechanical strength is high. Therefore, silica sand is widely used as a lining material for crucible induction furnaces.

The service life of furnace linings knotted with silica sand varies greatly. Taking smelting cast iron as an example, the service life of furnace linings ranges from dozens to hundreds of furnaces. The reasons for the above differences are not only the problems in use and management and the erosion of the furnace lining by the slag, but also the ability to master the material selection, batching, knotting, and sintering processes according to the characteristics of the silica sand, as well as whether there is a reasonable It is related to factors such as the furnace lining structure design.