The principle and function of plug brick used to prevent molten steel leakage in iron and steel production are mainly embodied in the following aspects:

I. Structural design and sealing performance

The plug brick is located at the lower end of the plug rod and closely cooperates with the nozzle brick. Its design purpose is to completely block the nozzle when not pouring, so as to ensure that the molten steel will not leak. The plug brick has high dimensional accuracy and can form a good sealing contact with the nozzle brick, thus effectively preventing molten steel from seeping out of the gap in the non-pouring state.

II. Material characteristics

Plug bricks are usually made of high refractory materials, such as clay, unburned high alumina or tar impregnated unburned high alumina bricks. These materials have the following characteristics:

High fire resistance: able to withstand the long-term erosion of high-temperature molten steel.

Low porosity: reduce the possibility of molten steel infiltration.

High mechanical strength: prevent erosion by molten steel in high temperature and high pressure environment.

III. Control during pouring

In the pouring process, by lifting the stopper rod, a gap is generated between the stopper brick and the nozzle brick, and molten steel flows out of the nozzle. This design can not only accurately control the outflow of molten steel, but also quickly close the nozzle when it is necessary to stop pouring to prevent the molten steel from continuing to flow out.

IV. Preventing erosion and leakage

Plug bricks may be partially eroded by high temperature scouring during use. In order to prevent this, the plug brick and the rod core are usually fixed by threads or pins, and the gap is filled with refractory mud during assembly. This design can effectively prevent molten steel leakage caused by crevice erosion.

V. Process optimization

In practical application, the following points should be noted to further prevent molten steel leakage:

Installation accuracy: ensure the matching accuracy of plug brick and nozzle brick, and avoid cracks caused by improper installation.

Regular inspection and maintenance: replace the damaged or eroded plug bricks in time to ensure their sealing performance.

Optimize the use environment: by adjusting the temperature and flow of molten steel, reduce the erosion of plug bricks.

Through the above design and measures, the plug brick can effectively prevent the leakage of molten steel and ensure the smooth progress of steel production.