Design of swirling flow submerged entry nozzles for optimal head consumption between tundish and mold

Abstract

A technology of swirling flow formation in a submerged entry nozzle is proposed as an effective measure for controlling the flow pattern in a continuous casting mold. As a result of a joint study between Nippon Institute of Technology, Osaka University, Kyushu Refractories, and Sumitomo Metal Industries, swirling flow submerged entry nozzles with a swirl blade for steel slab casting have been developed to improve the productivity of the process and the surface quality of slabs and coils. The swirl blade in the submerged entry nozzle forms the swirling flow expending the potential energy between the tundish and the mold. Thus, the swirl blade and the internal shape of the submerged entry nozzle, which determine the swirling flow rate, should be designed considering the flow rate in the nozzle and the head between the tundish and the mold of the applied casting machine. From full-scale water model experiments, we obtained an empirical equation to estimate the required head between the tundish and the mold from the flow rate, the internal shape of the nozzle, and the specification of the swirl blade. Then, we investigated energy efficiency to create the swirling flow, using an empirical equation from the results of a water model experiment and a numerical analysis of the swirling flow in the nozzle. The obtained empirical equation is valuable to design swirling flow submerged entry nozzles adopted for various casting conditions. © 2007 ISIJ.