What are the requirements for the refractory material of the intermediate frequency induction heating furnace crucible?

We all know that the crucible is indispensable when the medium frequency induction heating furnace is used to smelt and heat treat metal. The quality of the crucible directly affects the smelting quality of the metal. Therefore, we have very high quality requirements for the crucible. The working conditions of the crucible of the medium frequency induction heating furnace are very harsh, and the lining wall is thin. The inside is directly affected by the thermal shock of high-temperature metal and the erosion of the slag liquid. The stirring force formed under the action of the electromagnetic field causes the crucible to be strongly eroded by the metal. The outside of the crucible wall is in contact with the water-cooled induction coil, and the temperature difference between the inside and outside is very large. In order to increase the life of the crucible, there are strict requirements for the refractory materials used to make the crucible:

(1) High enough high temperature resistance. The refractory material used to make the crucible should withstand a high temperature greater than 1700°C, and the softening temperature should be greater than 1650°C.

(2) Good thermal stability. The temperature of the crucible wall fluctuates greatly during operation, and the temperature field is unevenly distributed, so the crucible wall will continue to expand and contract in volume, resulting in cracks, which directly affect the service life of the crucible.

(3) Stable chemical properties. The crucible material should not be hydrolyzed and pulverized at low temperature, it is not easy to be decomposed and reduced at high temperature, and it is not easy to be eroded by slag and molten metal.

(4) It has high mechanical properties. It can withstand the impact of the charge at normal temperature, and can withstand the static pressure of molten metal and strong electromagnetic induction stirring at high temperatures. The crucible wall is not easily washed, worn and eroded. High high-temperature flexural strength also means that the refractory material has strong resistance to slag erosion and thermal vibration, which is an important characteristic of refractory materials, especially alkaline refractory materials.

(5) Small thermal conductivity. To improve the thermal efficiency of the furnace.

(6) Good insulation performance. The crucible material must not conduct electricity at high temperature, otherwise it will cause leakage and short circuit, resulting in accidents. Magnetic separation should be used to remove conductor impurities mixed in refractory materials before use.

(7) The material has good construction performance and is easy to repair, that is, it has good sintering performance and is easy to tie and repair.

(8) Rich resources and low prices.

Today, we briefly talked about the requirements for refractory materials for crucibles. With the development of metallurgy and foundry industry, the capacity of induction furnace has been continuously expanded, the power has been increased, and there are various smelting varieties, which put forward higher and higher requirements for crucible materials and higher requirements for refractory materials.