The use of breathable bricks

The ladle breathable brick is a key functional element in the secondary refining process, which can adjust the uniform distribution of the molten steel temperature in the ladle to complete the casting temperature of the existing process. The alloy and deoxidizer in the ladle can be uniformly distributed through air blowing and mixing.

The properties that the breathable brick should have:

In order to meet the above metallurgical functions, the breathable brick must have the following main properties:

(1) Outstanding breathability.

Air permeability is one of the important parameters to measure the quality of breathable bricks. Studies have shown that the mixing energy of molten steel is proportional to the flow rate of the blown gas; the mixing can directly affect the mixing rate of the molten steel, and as long as the mixing energy is satisfied, the molten steel can achieve good mixing results. .When the amount of argon blowing is kept on time, the more argon bubbles are blown out, the more favorable it is for the degassing and stirring of molten steel.

(2) High temperature corrosion resistance.

The refining ladle is strict in terms of temperature and time. The temperature often reaches more than 1750 degrees Celsius, and the refining time sometimes reaches tens of minutes. During the refining operation, the alkalinity of the slag has a great influence on the life of the breathable brick. Therefore, the breathable brick It will be corroded by alkaline slag with strong permeability at high temperature, and the damage speed is fast.

(3) High temperature wear resistance.

When argon is blown at the bottom of the refined ladle, due to the bottom blowing of argon, the molten steel moves very fast in the ladle, and the erosion and wear of the molten steel on the furnace lining material and the bottom permeable bricks and seat bricks increases. When the ladle is hot repaired, in order to remove the permeable bricks Residual steel and slag on the surface, to restore the ventilation function of the breathable brick, it is necessary to clean the surface of the breathable brick with oxygen blowing to melt the steel slag adhered to the surface of the breathable brick; at the same time, blow gas into the breathable brick to blow away the slag. In the process, the breathable brick is scoured by high-speed airflow, so the breathable brick is required to have excellent high temperature wear resistance.

(4) Good thermal shock resistance.

Due to the intermittent operation of the ladle, when the ladle is poured into molten steel, the part of the breathable brick is affected by the high temperature molten steel, and the temperature rises suddenly. When molten steel is injected into it, it will also produce a great temperature change, so the application conditions of the breathable brick are very strict, and it is easy to produce heat shedding and structural shedding.

(5) The installation is required to be simple and reliable.

The breathable brick is installed inside the base brick at the bottom of the ladle. The working conditions are severe. The life of the ladle breathable brick cannot be synchronized with the life of the entire ladle. Therefore, the breathable brick needs to be replaced. There are steel penetration and steel breakout events.