Study On Structural Optimization Of A Single-strand Continuous Casting Tundish

Tundish is not only the buffer vessel for keeping stable pressure, distributing liquid steel, and ensuring the steel continuous casting but also is key equipment for preventing steel slag into mould, removing non-metallic inclusion of liquid steel and making the temperature of liquid steel uniform. Reasonable state molten steel flow in tundish can promote quality of casting improved. Therefore, in order to further improve the efficiency of continuous casting and meet users’ demand for high quality products, metallurgical workers in recent years had adopted a series of measures to strengthen and expand the tundish metallurgy function. And one of the important measures is to install the appropriate flow control devices to obtain reasonable flow pattern. Based on slab continuous casting tundish saddle LingGang factory as the research object, according to the similarity principle, set up the physical model of tundish in laboratory, studies systematically the influence of flow field by the tundish weir dam position and shape. Ultimately determines the optimal flow control scheme and has industrial application with the optimal flow control one.According to geometric dimensions of the original tundish, a 1:2 scale model was made in the laboratory. Experiments were conducted under the condition of a constant Froude between the original tundish and the model. The liquid flow residence time curves was obtained in the experiments, and calculated some parameters from experiments, such as the the minimum residence time, the average residence time, the dead zone volume and so on. Thus, flow characteristic with different control devices was got. From the physical study, the original tundish had a lot of problems, the average residence time and the minimum residence time was too short, short circuit was existed, the dead zone volume is too large.The optimal combination for a dam weir was determined under the orthogonal experiment on dam weirs positions. The flow characteristic of fluid was improved.Compared with the original plan, the average residence time has been extended from 530.5 s to 559.9 s, stagnation time from 48.6 s to 70.0 s, decreased dead zone volume fraction from 13.68% to 8.91%. On the basis of the optimal combination of a weir dam, the top retaining wall would be replaced with the whole retaining wall with slag holes. Compared with the optimal combination of a weir dam, the average residence time had been extended from 559.9 s to 572.2 s, stagnation time from 70.0 s to 73.6 s, dead zone volume fraction had decreased from 8.91% to 6.91%. Fluid flow characteristics had been improved significantly. Thus, the optimal flow control scheme was determined.The industrial application results showed that by using the optimized tundish configuration, total oxygen content of slab had been decreased 12%,inclusion area of slab had been decreased 15%,strand center porosity and medial cracks had been reduced, quality of triangle zones had been improved, it could promote total quality of strand.