The service life of electric furnace crucible is mainly affected by furnace lining refractory materials, baking process and use process, and the following manufacturers are introduced respectively.

1, furnace lining refractory material

The quality and performance of furnace lining refractories play a fundamental role in the service life of the furnace.

(1) Furnace refractories should have a fairly high refractoriness, resist high temperature heat load, do not soften, do not melt. At the same time, it also has high volume stability, resistance to high temperature heat load, volume does not shrink and uniform expansion.

(2) Composition of refractory materials. Impurities in refractories can form compounds with low melting point at high temperatures, thereby reducing the refractoriness of refractories. Therefore, the quartz content in the furnace lining sand should be maximum, and the impurity composition should be strictly controlled. The composition of the furnace lining sand is controlled as follows: ω (SiO2) ≥98.0%; ω (Al2O3) ≤0.5%; ω (Fe2O3) ≤0.5%; ω (TiO2) ≤0.05%; ω (H2O) ≤0.5%.

(3) Refractory particle size ratio. Reasonable particle size ratio of refractory materials can easily form a high density refractory layer in the furnace building process, and it is not easy to have defects in the use process. The following is a group of more reasonable proportions: 3.35mm ~ 5mm, 0.85mm ~ 1.70mm, 0.1mm ~ 0.85mm, 0.1mm below the proportion of 17%, 33%, 20%, 30%.

2, oven technology

Oven is a process to obtain the sintering layer, the quality of the sintering layer directly affects the service life of the furnace, oven is an important link.

After the furnace cavity is built, the oven should be oven immediately; Before the oven, check whether the electrical equipment and cooling water system are normal; The oven should be strictly carried out according to the oven process. Oven process is the key factor in the oven process, the specific points: ① to control the heating speed, especially in the early stage of the oven, if the heating speed is too fast, the water in the lining is too fast, it is easy to form cracks, so that the life of the furnace is greatly shortened. When the furnace lining is heated to 573℃, the quartz phase transition process will expand too fast, which will easily cause cracks or even spalling, so the heating speed should be slowed down when it is heated to 600℃ at 400℃, and it should be insulated for 1h to 2h at 870℃, so that it can slowly and completely phase change. After the stage for sintering insulation, sintering temperature according to the specific refractory material, generally hope to get a thickness of 30% of the furnace lining thickness of the sintering layer, therefore, the general sintering temperature is higher than the iron temperature 50 ~ 100℃.

3, with the furnace process

The various processes of the furnace use process are also very important to the service life of the furnace, and various improper operations may reduce the service life of the furnace. Therefore, the following points should be noted during use.

(1) Because the sintering layer of the new furnace is thin, the use of the new furnace process is very important. The first furnace of the new furnace should be fed 50% of the water and melted, so as to avoid cracks and other defects caused by sudden cooling of the furnace lining after feeding all the water. The new furnace should be continuously melted as far as possible to avoid cracks caused by intermittent melting and hot and cold, and should generally be continuously melted for 1 week.

(2) Try to avoid high temperature melting in the melting process. In the high temperature state, the furnace lining will be crucible reaction with the liquid iron, as follows: SiO2+2C→Si+2CO, the higher the temperature, the higher the C, the lower the Si, the corrosion of the furnace lining will be intensified, especially in the new furnace is more obvious, so the melting in the first water temperature as far as possible to avoid high temperature.

(3) Avoid overheating of the lining. Because the heating rate of the intermediate frequency furnace is quite fast, when the smelting worker does not pay attention, the "bridging" phenomenon of the charge will cause the local high temperature of the furnace lining or even exceed the refractoriness of the furnace lining, which may melt the furnace lining and corrosion.

(4) In the process of use, when the furnace needs to be shut down for a long time due to failure and other reasons, the iron liquid in the furnace should be emptied to avoid the lining of the furnace when the hot metal condenses and causes damage to the lining.

(5) In the process of use, especially in the new furnace, try to use clean charge.

(6) In the furnace cooling, in order to avoid sudden cooling of the furnace lining, the empty furnace cooling should be carried out, and in order to avoid the furnace lining in the cooling process, the temperature difference between the upper and lower cracks should be covered, so that the furnace lining is uniform during cooling, so as to maximize the service life of the furnace.

(7) Because of the inevitable vertical cracks when the furnace is cold, the cold furnace should be started at low temperature, and then melted, so that the cracks can be bridged first, and the cracks can be further expanded when the hot metal is melted.

(8) During the use of the furnace, pay attention to observing the furnace condition, observing the furnace condition is a kind of protection for the furnace, measuring the bottom of the furnace every 3 days, and observing the furnace wall every day for each furnace, so as to ensure the safety of the furnace lining.

(9) Maintenance and maintenance of the electric furnace equipment, such as often purging the coil, cleaning the debris on the coil to prevent coil breakdown, thus avoiding the disassembly caused by equipment failure, and effectively improving the service life of the crucible.

The above information is provided by the furnace material manufacturer! The company is located in Xiangyang City, a charming city in China known as "the south ship and the north horse, the thoroughfare of seven provinces", and the transportation is very convenient. The company has two production bases, covering an area of nearly 50,000 square meters. At present, the production capacity of each refractory production line can reach 80,000 tons/year. Welcome to telephone consultation!