Study On Structure Optimization Of Four-strand Bloom Casting Tundish

Tundish is an important vessel in the continuous casting process, and it has an important effect on continuous casting technology and product quality. The flowing condition of molten steel in tundish is considered to be very important to lengthen the residence time of molten steel in tundish, uniform the molten steel temperature, reduce the wrapped slag and improve the floating and excluding of inclusions in the molten steel, and thus influences the quality of casting products. In recent years, the domestic and international metallurgists took a serious action on strengthening and enlarging the tundish metallurgical function. And one of the important measures is to install the appropriate flow control devices to obtain reasonable flow pattern.With the development of a certain company, variety steels are expected to produce in the bloom continuous caster of the steelmaking plant that has are producing plain carbon steel. But it could not meet the need to produce variety steels, because there were no flow controlling devices in four-strand trapeze tundish. So the tundish structure needs further optimization.In present work, according to the 4-strand bloom casting tundish at a certain steelmaking plant, the mathematical and physical simulation methods were used to obtain the optimum flow control device. The mathematical model, describing the flow phenomena in the tundish, was established according to the continuity equation and momentum equation, meanwhile the FLUENT commercial software was used to calculate, and the better scheme had been determined. The water model,1/4 of the prototype and made of Plexiglas, was used, and the experiments were conducted based on the Froude similarity by similarity principle. Through these experimental and theoretical studies, the optimum scheme was obtained.The results showed that the unsuitable flowing patterns of the molten steel resulted that the inclusions in the molten steel hardly have time to float upward in the prototype tundish and thus the cleanliness of bloom was influenced, caused by the large dead volume and the significant difference in flowing characteristics among four strands, namely, there are short circuit flow in strand 2 and strand 3 near the outlet of the elongated nozzle. The optimum inner configuration of turbulence inhibitor+baffle+dam effectively improved the flow pattern in tundish, modified the molten steel distribution among the strands, prolonged the average residence time, increased plug flow volume and decreased dead volume, equalized temperature profile among strands, which contributes to obtain stable operation and improve the quality of the bloom.