Induction Furnace Lining

1. What Material Is Used for the Lining of Induction Furnace?

The furnace lining is made of refractory bricks. Due to the different working conditions of each part of the lining, the material and performance of the refractory bricks used are also different.

For example, wear resistance is mainly considered for the upper and middle lining of the furnace body, thermal shock damage and alkali metal erosion are mainly considered for the lower part of the furnace body and the furnace body, and the primary slag erosion with high FeO is mainly considered for the furnace body, and the anti-hot metal machinery is mainly considered for the hearth and furnace bottom. Differential thermal expansion of scour and refractory bricks.

The working frequency of the intermediate frequency induction furnace is between 50 and 10 Hz, and it is widely used in the smelting of non-ferrous and ferrous metals. Compared with other casting equipment, the induction melting furnace has the advantages of high thermal efficiency, short smelting time, less burning loss of alloy elements, wide smelting material, less environmental pollution, and can accurately control the temperature and composition of molten metal.

2. Function of Furnace Lining of Electric Induction Furnace

(1) Contain metal liquid.

(2) Protect the induction coil.

(3) Accept induction heating to melt metal.

3. How Much Can the Lining of the Three-ton Electrotherm Induction Furnace be turned on?

Any furnace with cracks in its lining can no longer be used. If it continues to be used, molten iron may penetrate into the furnace lining through cracks, further expand the cracks, and finally lead to furnace penetration accidents. The furnace explosion may also occur due to molten iron melting the induction coil.

4. How Does the New Lining of the Inductotherm Induction Furnace Have Electricity?

(1) The inductor of the crucible induction furnace, also known as the furnace head, is a spiral coil wound by a rectangular copper tube. It is professionally designed according to the length, diameter, heating temperature, and heating beat of the heating workpiece, which can ensure the heating temperature of the workpiece and the temperature difference between the core and the surface.

(2) In order to protect the induction coil, the inductor of the medium frequency induction furnace needs to be equipped with the furnace lining. At present, there are basically two types of furnace lining assembly, one is the bonded furnace lining, and the other is the fabricated furnace lining.

(3) When the inductor of the medium frequency induction furnace is in use, the oxide skin falling off due to heating the workpiece should be cleaned in time. If the furnace lining is damaged, or cracked, if it is not cleaned in time, it is easy to ignite, causing overcurrent protection of intermediate frequency power supply, and it is easy to puncture the inductor coil and cause an inter-turn short circuit of the inductor. In principle, the oxide scale in the inductor furnace shall be cleaned at least once every shift (8 hours).

(4) Regularly observe and maintain the furnace lining of the intermediate frequency induction furnace. If the furnace lining is knotted, the crack must be filled with knotted material in time when the crack is not more than 2mm. If the crack is more than 2mm, the furnace lining must be knotted again; If it is a fabricated lining, it must be replaced. In order to avoid the short circuit between turns caused by the oxide skin falling into the gap and burning the inductor.

(5) The inductor coil of the coreless induction furnace is cooled by water. There must be sufficient water flow and water pressure to ensure the normal cooling of the inductor copper tube. Therefore, the working pressure of cooling water should not be less than 0.2~0.3mpa, the inlet water temperature should be less than 35 ℃, and the outlet water temperature should be less than 55 ℃. If the water pressure is insufficient, the inductor coil will be vaporized and heated. If it is not found in time, the copper pipe will break and the water will overflow. When the inductor is working at a high temperature, it is likely to explode. Therefore, water cooling of the inductor of the induction furnace is extremely important.

(6) The new inductor just put into production in the electrotherm induction furnace must be baked with low power (generally about 30kW), and the heated workpiece must be placed in the induction furnace for about 2 hours. Remove the residual water in the furnace lining to ensure the service life of the furnace lining.

(7) Once the dry guide rail (without water) of the inductotherm induction furnace is worn and deformed, it must be replaced. It is forbidden to use the furnace lining as the guide rail for heating the workpiece.

(8) The water-cooled guide rail of the medium frequency induction furnace is worn during use. Generally, the wall thickness of the water-cooled guide rail is 2mm. Therefore, the use of water-cooled guide rail has a certain period of time. If there is too much wear, it must be replaced. Otherwise, once water leaks, it will cause rapid cooling of the furnace lining and directly affect the use effect of the furnace lining.

(10) The water-cooled guide rail in the inductor of the induction furnace is actually the moving track for heating the workpiece, which has been working under high temperatures. If the water supply is insufficient or the water pressure is insufficient, gasification, redness, and deformation will occur, and the heated workpiece cannot pass through the sensor. Therefore, the water cooling of the water-cooled guide rail is also extremely important.

To sum up, the induction furnace must also be observed and checked during use. If problems are found, they should be handled in time. Only in this way can the crucible induction furnace be used normally without affecting production.

6. To What Extent Does the Lining of the Induction Furnace Need to Be Rebuilt?

In order to be safe, the remaining one-third of the furnace needs to be reheated.

7. How to Improve the Lining Life of the Induction Furnace?

Tighten up, boric acid is better used, and all kinds of sand are better adjusted than usual. But it depends on what is casting you open.

8. What Materials Are Needed for Lining the Induction furnace?

Quartz sand is used for acid furnace lining and magnesia is used for alkaline furnace lining.

If you are interested in induction furnaces, please feel free to contact me.

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