Development of Swirling-flow Submerged Entry Nozzles for Slab Casting

Abstract

We began development of swirling-flow submerged entry nozzles in 1997 as a fundamental and effective measure for controlling the flow pattern in continuous casting molds. As a first step, we developed a swirling-flow submerged entry nozzle for round billet casting at the Wakayama works. We then began developing swirling-flow submerged entry nozzles for slab casting. The main purpose of the present work was to demonstrate that the formation of swirling flow in submerged entry nozzle improves productivity and the quality of products in continuous casting. We examined swirling-flow submerged entry nozzles with a swirl blade in these main bodies because such an arrangement is the easiest way to apply swirling flow to submerged entry nozzles in continuous casters without investment by facilities. We had only to change the submerged entry nozzle in the experiment. Swirling-flow submerged entry nozzles for slab casting were developed and their operation examined at the Wakayama and Kashima works. It was found that the proposed submerged entry nozzles increased the casting speed and improved the surface quality of slabs and steel sheets.

A Study on the Nonmetallic Inclusion Motions in a Swirling Flow Submerged Entry Nozzle in a New Cylindrical Tundish Design

“…[28] The stability of the steel flow in the mold was enhanced and the defects on the slab surface were effectively reduced. [31] Furthermore, the swirling flow in the SEN was found to effectively reduce the clogging tendency of the SEN port. [31] This is due to the fact that the nozzle port flow becomes homogenous and stable when a swirling flow exists in the SEN.…”

“…[31] Furthermore, the swirling flow in the SEN was found to effectively reduce the clogging tendency of the SEN port. [31] This is due to the fact that the nozzle port flow becomes homogenous and stable when a swirling flow exists in the SEN. In addition, a swirling flow produced by the rotary MEMS method in an industry application was found to effectively reduce the central cracks, central porosities, and shrinkages.…”

“…[36] Therefore, the use of a swirling flow or a rotational flow during metal castings is becoming an important way to produce high-quality steels. However, previous studies [26][27][28][29][30][31][32][33][34][35][36][37][38] of swirling flows during steel castings mainly focused only on the influence on the steel flow itself. Furthermore, previous studies focusing on the inclusion behavior in steel flows have mostly been carried out for conventional continuous casting processes, where no rotational steel flow phenomena exist in the horizontal cross sections of the SEN or the mold.…”

“…Two methods to realize a swirling flow or rotational flow during the steel casting have been intensively studied, namely, the swirling flow SEN method [26][27][28][29][30][31][32][33][34] and the mold-electromagnetic stirring (MEMS) method. [35][36][37][38] When using a swirling flow SEN, the penetration depth of the SEN outlet flow in mold was found to decrease.…”

Modeling of Initial Mold Filling with Utilization of Swirl Blades

“…11) In addition, Yokoya et al have studied the control of the flow pattern in the immersion nozzle using a swirl blade for continuous casting. [14][15][16][17][18] Hallgren et al 12) investigated the effect of nozzle type and swirl flow during the initial uphill teeming based on physical and mathematical modeling. It was found that a divergent nozzle resulted in a smaller hump and a lower axial velocity compared to a straight nozzle.…”