Reduction of Tundish Skull and Yield Imp

New types of furniture, also termed as flow modifiers or baffles, were incorporated in industrial scale slab and bloom casting tundish systems with an aim to reduce residual metal loss (i.e., tundish skull) at the end of sequence casting. To this end, water model experiments were carried out in which slag vortexing phenomena during emptying of tundish was studied embodying different types of furniture into existing tundish designs. These in general indicate that a wedge shaped bottom together with an embedded pouring box applied in conjunction have the potential to reduce tundish skull and improve yield losses significantly. In addition, limited residence time distribution measurement experiments were made to investigate metallurgical performance of modified design tundish systems. These indicate that deployment of new furniture with minor design modifications, despite contributing to a reduction in tundish capacity (10–12%), do not influence metallurgical performance of steelmaking tundish systems to any significant extent. Accordingly, designs of currently employed slab and bloom casting tundish systems were modified in four different steel mills and plant trials conducted to assess the extent of yield improvement. Significant improvements in yield losses, to the extent of 50–60%, have been confirmed by the industry during sequence casting.