Slit Oriented Typebreathable brickSlit directional type is the most commonly used structural form of breathable bricks. According to the on-site use conditions, including refining steel type, refining process, ladle capacity, temperature, molten steel static pressure, etc., the design of reasonable slits can make the ventilation bricks blow through. The effect is the best, the life in use is increased, and the safety performance is stable. When compared with the performance of foreign breathable bricks, the breathability and service life of the bricks are better than those of foreign advanced products, which meet the performance requirements of ladle refining production. .
Use performance:
1, Slag resistance
In order to improve the material's slag resistance and resistance to molten steel penetration, Cr2O3 or part of chromium corundum is usually added to the corundum spinel permeable brick. Cr2O3 and a-Al2O3 have the same crystal structure, Cr2O3 not only improves the material's performance The slag resistance increases the wetting angle between the material and the molten steel, and has a significant improvement in the blockage of the pores of the breathable brick due to the penetration of the molten steel.
The aluminum-chromium solid solution and the independent chromium-containing glass phase formed by Cr2O3 fine powder and Al2O3 at high temperature are used to form a liquid phase with a certain viscosity when it contacts with the slag in the molten steel smelting process, thereby hindering the molten steel slag. At the same time, it can absorb iron oxide and magnesium oxide in the slag, and form a dense spinel in the working layer of the breathable brick, which improves the slag resistance of the breathable brick.
However, when Cr2O3 is added to the material, after high temperature firing or use, Cr3 is oxidized to Cr6, and Cr6 is toxic and will pollute the environment. Therefore, in order to save energy and protect the environment, Cr2O3 should be avoided as much as possible, and by replacing raw materials, the The high temperature performance after adding Cr2O3 reaches the level of adding Cr2O3.
2, thermal shock resistance
The main damage method of the breathable brick is thermal shock damage. With the continuous increase of the tapping temperature, there is a large temperature difference between the working surface of the breathable brick and the intermittent, which requires the material to have extremely high thermal shock resistance. The introduction of spinel phase into the castable will improve the thermal shock resistance of the breathable brick.
The oxide or non-oxide added to the breathable brick forms a solid solution phase with the aggregate at high temperature, which increases the high temperature strength of the brick, improves the permeability of the brick, and resists the erosion of the slag in the ladle to the breathable brick. After the brick is heat treated at high temperature, its performance is improved to meet its use requirements.
