EXPERIMENTAL STUDY AND SIMULATION OF THE INTERMIXING IN CONTINUOUS CASTING STEEL MAKING TUNDISH OF DIFFERENT SHAPE

Abstract

Continuous casting is the most up-to-date technology available for producing high-quality steel at low cost, and good understanding of what goes on in the tundish is critical because it affects the purity and chemistry of the output steel. The tundish holds the white-hot liquid and feeds it out the bottom into a continuous casting mold, where it forms a moving strand of steel that eventually cools from white to red hot and gets cut into slabs for further processing. We need to know how the chemistry of the mix feeding out the bottom of the tundish varies as new ladle pours steel in the top of the tundish. Continuous casting, also called strand casting, is the process whereby molten metal is solidified into a "semi finished" billet, bloom, or slab for subsequent rolling in the finishing mills. A continuous casting setup essentially consists of three equipments: the ladle, the tundish and the continuous casting mold. The molten steel is transferred by the ladle into the caster machine, which continuously adds the liquid steel into the tundish. Tundish acts primarily as a distributor of molten steel between ladle and mold to maintain a stable liquid steel flow. When the new ladle is open and the steel from the new ladle is pour into the tundish, the some amount of the intermixing take place between the new grade steel and the old grade steel already available in the tundish. The final casting containing the intermixing amount is of inferior type and has low value and downgrade or re circulated for re melting. The intermixing amount is depends on the flow pattern in the continuous casting tundish and the flow control devices such as dam and turbo stopper in the tundish. The flow of molten steel is simulated by water modelling. The flow field in the tundish is computed by solving the mass and momentum conservation equations in a boundary fitted coordinate system along with a set of realistic boundary conditions. Due to opacity and high temperature of molten steel, it is difficult to make direct observations and measurements of various flow parameters within molten steel flows. Therefore, in addition to mathematical modeling, researchers have used water modeling to simulate the flow of molten steel in the tundish. An extensive study has been carried out with the help of water model and mathematical model to study the intermixing phenomenon and the fluid flow behaviour in various shapes of continuous casting tundishes.The experiments have been performed on rectangular tundish, T-shape tundish and delta tundish and the intermixing phenomenon analyzed in all these continuous casting tundishes. The simulation work also carried out for these shapes of the tundishes with the help of CFD software Fluent 6.3 & Gambit.