Reasons for the Lining of the Intermediate Frequency Furnace to Fall Off

The lining of the intermediate frequency furnace is usually bundled with refractory materials of various particle sizes (commonly used refractory materials mainly include magnesium, quartz, aluminum, and composite materials). Cracking and spalling of intermediate frequency furnace linings are common problems, which can lead to premature failure of the furnace lining and shorten its service life. What is the reason for the falling off of the intermediate frequency furnace lining?

The initial damage of the intermediate frequency lining is due to the corrosion of the front end caused by the dissolution of the refractory sintered layer in the slag, and the appearance of cracks caused by temperature cycles. Another factor that causes cracks to propagate throughout the liner is the stress created by heating to too high a temperature resulting in a difference in the coefficient of expansion between the “three bands”.

The transverse cracks in the lining of the intermediate frequency furnace are due to the lack of degassing forks between the front and rear materials when the lining is knotted, resulting in delamination between the materials; secondly, the cooling speed of the backing of the upper mouth of the furnace is too fast. When the temperature difference with the lower furnace lining is too large, the furnace lining will shrink inconsistently during the quenching process, and the furnace lining is prone to tensile damage and transverse cracks. Another reason is that the furnace structure is loose due to physical reasons, which causes the mica backing to loosen, resulting in the failure of the furnace lining.

Due to the non-standard cold start smelting of intermediate frequency furnace lining, transverse cracks often appear, resulting in unreasonable rapid cold and heat cycle effects. The lining will have multiple longitudinal cracks.

There are irregular cracks in the lining of the intermediate frequency furnace, which may be caused by the large size of the charge hitting the cold lining during the feeding process. However, the steel structure of the furnace is unreliable, and the coil displacement occurs when the furnace is tilted, causing the lining to be pulled, resulting in cracks in the lining; The temperature difference between the upper and lower parts is too large, resulting in random cracks during cooling.