Magnesia-carbon brick is a high-quality refractory material. Because this kind of carbon-containing refractory product has the advantages of high refractoriness, good slag corrosion resistance, strong thermal shock resistance and low high temperature creep, it is widely used in electric furnaces, converters and ladles.
The service life has been greatly improved. At the same time, magnesia carbon bricks do not need to be fired at high temperature, which saves energy, and the production process is simple, so they are quickly promoted and used. However, in recent years, as the performance requirements of steel have become higher and higher, the ladle has gone from the past. A simple tool for storing and transporting molten steel is transformed into a generating device that can perform vacuum processing, argon blowing, heating, and fine-tuning of composition in the ladle, which makes the ladle use conditions extremely harsh, especially at the slag line of the ladle. The slag line bricks frequently appear in the shape of steamed bread, that is, the edge erosion is faster than the middle position of the brick, which seriously affects the later contracting and causes the ladle to be frequently offline during use. This not only affects the production rhythm, but also creates hidden dangers to safety. Has become a restricted link in the development of variety steel. The research found that the main influencing factors of ladle slag line bricks appearing like steamed bread:
(1) The expansion coefficient of the magnesia aggregate and the matrix are not consistent, the relative expansion coefficient of the aggregate is greater than the matrix, and irreversible expansion occurs after heating;
(2) Because a large amount of flake graphite is introduced into the magnesia-carbon bricks. After the graphite is heated, it will be heated and stretched and hardened.
(3) After the magnesia-carbon bricks are heated, they will not expand freely due to the limitation of the steel shell, but excessive expansion will cause excessive High thermal stress, resulting in reduced thermal shock, and the corners may be crushed.
Here is Slag line brick using effect comparison LMM brick in Ukraine steep plant and other manufacturer’s brick in China steel plant.
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