Role of Tundish Argon Diffuser in Steelmaking Tundish to Improve Inclusion Flotation with CFD and Water Modelling Studies

Abstract

Investigation on inclusion removal by bubble flotation method in a two-strand tundish was carried out using computational fluid dynamics and through water model studies. Recently, a new technique of gas curtain made of small bubbles of argon called Tundish Argon Diffuser has been used to remove the finer inclusions from steel in order to produce clean steel. Aim of this work was to find out the effect Tundish Argon Diffuser on the efficiency of inclusions removal and on optimization of its location for plant conditions. Both Physical and Numerical simulations were carried out in a 1:4 scaled down model for tundish of 50T capacity of Bokaro Steel Plant, India. Numerical simulations were carried out using ANSYS FLUENT CFD software. For physical modeling study, water model was used for fluid flow, residence time distribution and inclusion flotation studies. Results from both studies suggested that the use of tundish argon diffuser enhances the surface directed flow which in turn improves inclusion flotation and also reduces metal loss due to better mixing and lesser dead zone. Fluid flow analysis showed lesser turbulence on the free surface which lead to lesser de-oxidation of liquid steel after using Tundish Argon Diffuser. Location of Tundish Argon Diffuser needs to be optimized in order to get maximum benefit. For Bokaro Steel Plant conditions, placement of Tundish Argon Diffuser at 2400mm at both sides from the center gives the best result compared to all other locations.