Numerical and physical simulation on enhancing steel cleanliness by increasing height of two-strand slab tundish
XIE Xuqi1, FANG Qing1,2, WANG Jiahui1, ZHANG Lichao1, LI Mijia1, ZHANG Hua1
1. Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China; 2. Hunan Valin Xiangtan Iron and Steel Co., Ltd., Xiangtan 411101, Hunan, China
Abstract：With the development of continuous casting process towards the direction of large cross section and high casting speed, the capacity of tundish has become key factor restricting production efficiency and billet quality. The flow field, residence time distribution (RTD) curves and inclusion removal rate in two-strand slab tundish of a steelmaking plant with different height additions were numerically and physically investigated. The results show that with the increase of tundish height, the capacity of tundish increases and the average residence time of molten steel increases correspondingly, and the ability of tundish to enhance the cleanliness of molten steel is also improved. When the baffle is raised by 200 mm with the tundish, the average residence time of molten steel in the tundish is extended by 12.1-153.6 s, the volume fraction of dead zone is reduced by 0.31-2.53 percentage points, the average free surface velocity in the impact zone is reduced by 6.7%-15.6%, and the extra temperature drop in the tundish is not obvious. The total removal rate of large size inclusions is increased by 1.63 percentage points, compared with the original tundish and other height expansion schemes. Moreover, when the tundish is heightened by 200 mm, the average residence time of molten steel is reduced from 743.7 s to 677.9 s by increasing the casting speed from 1.35 m/min to 1.50 m/min, but it is still 88.0 s longer than that of the prototype tundish at low casting speed, and volume fraction of dead zone is reduced by 2.18 percentage points, which reflects the advantages of the heightened tundish in continuous casting process with high casting speed. The present study can provide theoretical guidance for steelmaking plants to implement the industrial plan of heightening the tundish height and increasing the casting speed.
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2023, Vol. 33 
