In modern iron and steel industry, the use of refractory materials is very important, and sleeve brick, as one of the important products, plays an indispensable role. This paper will introduce the characteristics, uses, production process and its importance in steel production in detail.

I. Definition and structure of sleeve brick

Sleeve brick is a hollow refractory tubular material, which is usually used to protect metal mandrel from direct corrosion by high temperature metal and slag. It is designed to be sleeved outside the metal mandrel to maintain the rigidity of the metal mandrel and control the pouring flow. The structural design of sleeve brick enables it to withstand complex working conditions in high temperature environment, while ensuring the stability and durability of metal mandrel.

Structurally, sleeve bricks are usually made of high-quality refractory materials, which have good corrosion resistance and thermal shock resistance. The hollow design inside allows the metal mandrel to pass through, while the outside is closely matched with the surrounding refractory and metal structure to form a complete pouring system.

II. Use of sleeve brick

Sleeve bricks are mainly used in the continuous casting process of iron and steel industry. In the process of continuous casting, molten steel needs to flow into the crystallizer through an accurately controlled gating system to form billet. The function of sleeve brick is to protect the metal mandrel and ensure that molten steel can flow into the crystallizer stably and evenly, thus ensuring the quality and dimensional accuracy of billet.

Specifically, the functions of sleeve brick in continuous casting system include:

Protecting metal mandrel: In high temperature environment, molten steel and slag corrode metal mandrel very seriously. Through the protection of refractory materials, sleeve brick prolongs the service life of metal mandrel and reduces the production cost.

Control of pouring flow: the internal structure and size design of sleeve brick can accurately control the flow of molten steel and ensure the stability and uniformity of pouring process. This is very important for producing high quality billet.

Improve production efficiency: By optimizing the design and performance of sleeve bricks, the downtime and maintenance cost during pouring can be reduced, thus improving the production efficiency of the whole continuous casting system.

III. Production process of sleeve brick

The production process of sleeve brick includes the selection of raw materials, molding, sintering and other links. The following are the main steps of sleeve brick production:

(1) Selection of raw materials

The main component of sleeve brick is alumina (Al₂O₃), and its content is usually between 40% and 75%. In addition, other refractories and additives will be added to improve the performance of sleeve bricks. The selection and proportion of raw materials have a decisive influence on the quality and performance of sleeve bricks.

(2) forming

Forming is one of the key links in sleeve brick production. Usually, the mixed raw materials are made into the required shape and size by pressing or grouting. The formed sleeve brick needs to be dried to remove excess water and ensure the smooth progress of the subsequent sintering process.

(3) sintering

Sintering is the most important step in the process of sleeve brick production. In the high-temperature sintering furnace, the sleeve brick is sintered at high temperature, which makes its structure more compact and its performance more stable. The control of sintering temperature and time is very important to the final performance of sleeve brick.

(4) Quality inspection

After the production is completed, the sleeve bricks need to undergo strict quality inspection. Test items include chemical composition analysis, physical performance test, appearance inspection, etc. Only the sleeve bricks that pass all the testing items can be recognized as qualified products and used in actual production.

IV. Features of sleeve brick

Sleeve brick has the following remarkable characteristics:

High fire resistance: able to withstand high temperature environment without softening or melting at high temperature.

Good thermal shock resistance: under the condition of rapid temperature change, the sleeve brick can maintain the structural integrity without cracks or damage.

Good wear resistance and crack resistance: it can be used for a long time under complex working conditions, reducing wear and cracks.

Good corrosion resistance: it can resist the chemical corrosion of molten steel and slag and prolong the service life.

No pollution to molten steel: the material and production process of sleeve brick ensure that it will not pollute molten steel during use and ensure the quality of billet.

Accurate size and smooth runner: the size and shape of sleeve brick are strictly controlled, and the runner is smooth, which can effectively control the flow of molten steel.

V. Market and application of sleeve brick

With the continuous development of steel industry, the demand for sleeve bricks is increasing. The major steel producing countries and regions in the world, such as China, Japan, South Korea, Germany and the United States, are the main consumer markets of sleeve bricks. In China, with the transformation and upgrading of the steel industry, the demand for high quality and high performance sleeve bricks is particularly urgent.

The application scope of sleeve brick is not limited to the steel industry, but also widely used in other high-temperature industrial fields, such as glass, ceramics, cement and other industries. In these industries, sleeve bricks also play an important role in protecting equipment from high temperature erosion and improving production efficiency and product quality.

VI. Conclusion

As an important refractory, sleeve brick plays an irreplaceable role in the continuous casting process of iron and steel industry. Its excellent performance and wide application make it an indispensable part of modern industrial production. With the continuous progress of science and technology and the continuous improvement of production technology, the performance of sleeve bricks will be continuously improved and the application scope will be further expanded. In the future, sleeve bricks will continue to provide strong support for the high-quality development of the steel industry.