Customers often ask about the service life of the lining of the medium frequency melting furnace. The lining of a conventional medium frequency melting furnace can be used for hundreds of furnaces, while some lining materials are damaged after dozens of furnaces. The difference in the service life of the lining of the medium frequency furnace is particularly large. The reason for the large difference may be the problem of the lining material, the problem of knotting and furnace building, or even the maintenance of the lining during the use of the medium frequency melting furnace. Various improper operations of the medium frequency furnace may reduce the service life of the furnace. The following are the maintenance points of the lining of the medium frequency melting furnace.
1. When the medium frequency melting furnace is stopped for cooling, in order to avoid sudden cooling of the lining, the empty furnace should be cooled. At the same time, in order to avoid cracks caused by excessive temperature difference between the upper and lower linings during the cooling process, the furnace cover should be covered to make the lining evenly cooled up and down during cooling, thereby ensuring the service life of the furnace.
2. During the use of the medium frequency melting furnace, if it needs to be stopped for a long time due to failure or other reasons, the molten iron in the furnace should be emptied to avoid the lining being damaged by the condensation of the molten iron; when the molten iron cannot be emptied and the molten iron has condensed, and it is impossible to determine whether the lining is intact, the furnace should be dismantled for safety reasons.
3. Perform maintenance and care on the medium frequency melting furnace equipment, such as frequently blowing the coil and cleaning the debris on the coil to prevent the coil from breaking, thereby avoiding the dismantling of the furnace due to equipment failure, which can effectively increase the service life of the crucible.
4. The medium frequency melting furnace should avoid overheating of the furnace lining. Since the medium frequency melting furnace heats up very quickly, when the furnace workers are not careful, the furnace charge will “bridge” and the furnace lining will be locally high temperature or even exceed the refractoriness of the furnace lining, which may cause the furnace lining to melt and corrode; or when the furnace workers are not careful, the melting temperature is too high and the furnace lining may also melt and corrode; this will greatly reduce the service life of the furnace lining. Therefore, during the melting process, you must pay attention at all times, such as the melting worker should frequently poke the charge, and the furnace workers should keep track of the molten iron temperature according to the color of the molten iron to ensure the safety of the furnace lining.
5. Since the sintering layer of the new medium frequency melting furnace is thinner, the use process of the new furnace is very important. The first batch of molten iron from a new furnace should be melted after 50% of the molten iron is discharged, so as to avoid defects such as cracks caused by sudden cooling of the furnace lining after all the molten iron is discharged; the new furnace should be melted continuously as much as possible to avoid cracks caused by intermittent melting and hot and cold melting, and generally should be melted continuously for 1 week; when a new furnace is used, try to avoid strong impact on the furnace bottom and furnace wall when unloading materials to avoid lining peeling and cracks under strong impact. Therefore, in order to obtain a high furnace life, the furnace process should be done well in the early use of the furnace.
6. Since vertical cracks are inevitable when the medium frequency melting furnace is cold, when the cold furnace is started, the furnace should be baked at low temperature first, and then melted, so that the cracks can be healed first, and the cracks can be prevented from being further expanded by the penetration of molten iron into the cracks when the molten iron is melted.
7. Try to avoid high-temperature melting during the melting process of the medium frequency melting furnace. Under high temperature, the furnace lining will react with the molten iron in a crucible, as shown in the following formula: SiO2+2C→Si+2CO. The higher the temperature, the higher the C, and the lower the Si, the more severe the corrosion of the furnace lining will be, especially when the furnace is new. Therefore, when melting, try to avoid high temperature while ensuring the outlet temperature. The outlet temperature is 1490-1540℃, but it is generally controlled at 1490-1520℃ during the smelting process. It is worth mentioning that after the outlet is discharged, the power is turned off to keep it at a lower temperature. When the outlet is ready, the temperature is raised according to the temperature of the previous package of molten iron. This can reduce the erosion of the furnace lining by the high-temperature molten iron, extend the service life of the furnace lining, and reduce power consumption. It is a good way to increase the furnace life and reduce power consumption.
8. During the use of the medium frequency melting furnace, pay attention to the furnace condition. Observing the furnace condition is a kind of protection for the furnace. Measure the furnace bottom every 3 days, and observe the furnace wall every day for each furnace, thereby ensuring the safety of the furnace lining.