What is the main performance of magnesia carbon brick?

The experience of using magnesia-carbon brick in converters, electric furnaces, and ladle shows that: due to its superior high temperature resistance, slag erosion resistance, and good thermal shock stability, it is very suitable for steel smelting. Using carbon materials that are difficult to be wetted by furnace slag, molten steel, and the high refractory properties of magnesia, high slag resistance and solubility, low high-temperature creep etc, the magnesia-carbon brick is used in severely corroded slag lines and Steel mouth and other parts. 

The characteristics of magnesia carbon brick are mainly reflected in the following aspects:

1.Microstructure compactness of magnesia carbon brick

The compactness of magnesia-carbon bricks depends on the types and amounts of binders and antioxidants, the types of magnesia, and the particle size and amount of graphite. In addition, molding equipment, brick pressing technology and heat treatment conditions have a certain influence. In order to achieve a significant porosity below 3.0%, ensure that the molding pressure is 2t/cm2, and strengthen the bulk density of the matrix part to improve its corrosion resistance, magnesia-carbon bricks with a particle size of less than 1mm are used in wind eye bricks and steel outlet bricks..

Different binders also have a certain influence on the compactness of magnesia-carbon bricks. The binder with high residual carbon rate will have a higher bulk density. The effect of adding different antioxidants on the compactness of magnesia-carbon bricks is significantly different. Below 800 degrees, the apparent porosity increases with the oxidation of antioxidants, and above 800 degrees, magnesia-carbon bricks without metal show pores. The apparent porosity of the metal-containing magnesia carbon bricks does not change, and the apparent porosity of the metal-containing magnesia-carbon bricks is significantly reduced. At 1450 degrees, it is only half of that of 800 degrees.

2.High temperature performance of magnesia carbon brick

2.1High-temperature mechanical properties: Different additives have different effects on improving the high-temperature strength of magnesia-carbon bricks. Studies have shown that for high-temperature flexural strength above 1200°C, no additives <calcium boride<aluminum<aluminummagnesium<aluminum+boride Calcium<Aluminum Magnesium + Calcium Boride, where Aluminum Magnesium + Boron Carbide is between Aluminum Magnesium and Aluminum Magnesium + Calcium Boride

2.2 Thermal expansion performance: The participating expansion value of magnesia-carbon brick without added metal is much lower than the expansion value of adding metal, and the participating expansion value increases with the increase of the amount of metal added.

2.3 The thermal expansion and high temperature flexural strength of magnesia-carbon bricks in different directions of anisotropy are different, mainly due to the orientation of flake graphite，determine the principles and methods of working lining brick masonry. The magnesia carbon brick in the vertical direction has higher high temperature strength and lower thermal expansion.