Introduction To Tundish

Since the 1850s, with the emergence of Bessemer converters and furnaces, as well as the rise of large-scale steel manufacturing, the progress of human civilization has significantly accelerated. Especially since the 20th century, the vigorous development of the steel industry has become an important material foundation for the progress of global economy and social civilization. Within the foreseeable time frame, steel remains a very important material in the world, and its comprehensive excellent performance makes it an irreplaceable material in major basic industries and infrastructure. Steel, with its competitive cost and high reserves of raw materials, easy mining, processing, and good recyclability, will continue to be the main global basic raw material.
In the development process of the steel industry, there have been no fundamental changes in its basic principles, but the technological formation of each process in the steel production process and the composition and connotation of engineering have undergone significant changes, resulting in profound changes in the structural mode and manufacturing process of steel mills.
In the 1950s, as a symbol of the steel industry revolution, continuous casting technology developed, characterized by fast process speed, concentrated investment, and increasingly improved technology. In 1970, the global continuous casting ratio was only 5.6%, but by 1990, the global continuous casting ratio had reached 62.4%, and some industrialized countries had continuous casting ratios exceeding 95%. In recent years, many steelmaking plants in the world have replaced mold casting with full continuous casting production. By 1994, there were 24 countries that had achieved full continuous casting.
Compared to traditional mold casting, continuous casting has the advantages of improving metal yield and reducing energy consumption, while reducing the consumption of metal resources and energy is in line with the requirements of sustainable development. The implementation of full continuous casting simplifies the steelmaking production process, shortens the process, and significantly improves production efficiency. The tundish is an intermediate link in the steelmaking production process, and it is the transition point from intermittent operation to continuous operation. The tundish, as a metallurgical reactor, is an important link in improving steel production and quality. The role of the tundish cannot be ignored, whether for the smooth operation of continuous casting or for ensuring the quality of the molten steel meets the needs. It is generally believed that the tundish plays the following roles:
1. Diversion effect. For multi flow continuous casting machines, the steel liquid is divided by a multi nozzle tundish.
2. Continuous pouring effect. During multi furnace continuous casting, the steel liquid stored in the tundish plays a bridging role when replacing the steel drum.
3. Decompression effect. The height of the liquid level inside the steel barrel is 5-6m, with a large impact force and significant changes during the casting process. The height of the liquid level in the tundish is lower than that of the ladle, and the variation is much smaller. Therefore, it can be used to stabilize the steel casting process and reduce the erosion of steel flow on the solidified shell of the mold.
4. Protective effect. By covering the liquid surface of the tundish with a covering agent, a long nozzle, and other protective devices, the steel liquid in the tundish is reduced from external pollution.
5. Remove impurities. The tundish, as the last refractory material container that passes through before the solidification of molten steel, has an important impact on the quality of steel. It should be possible to exclude non-metallic inclusions from the steel when it is in a liquid state.
The roles that tundish metallurgy research should play include:
1. Improve the flow conditions of molten steel and remove non-metallic inclusions as much as possible in the steel; That is to prevent short circuit flow, reduce dead zones, improve flow direction, and increase the residence time of molten steel.
2. Control the temperature of the molten steel well, and if necessary, increase heating measures to maintain a stable degree of superheat in the molten steel.
3. Choosing appropriate lining refractory materials and molten pool covering agents not only reduces heat loss but also facilitates the absorption, separation, and upwelling of inclusions.
Computational fluid dynamics is a very effective method to study various flow fields. The characteristic of tundish metallurgy is to carry out various metallurgical processes in molten steel flow, so the tundish flow field can be solved by computational fluid dynamics method. Due to the complex structure of the tundish, except for the early use of two-dimensional flow field calculations, three-dimensional flow field calculations are mostly used. He Youduo conducted research on three-dimensional flow field calculation earlier and used his calculation program to calculate the flow characteristics and influencing factors of various molten steel in the tundish. Xiao Zeqiang et al. utilized their long-term research achievements on the flow of argon blown molten steel in the ladle, and also calculated various flow fields in the tundish. They also paid early attention to the study of non isothermal flow fields in the tundish, pointed out that the influence of natural convection cannot be ignored, and conducted experimental verification using a water model. Computational fluid dynamics method has become the main means of tundish metallurgical analysis. With the rapid progress of computer hardware and software, computational fluid dynamics will be more widely used in metallurgical science and technology.