Modeling of Interfacial Tension and Inclusion Motion Behavior in Steelmaking Continuous Casting Mold

Abstract

The current work is an expansion of our previous numerical model in which we investigated the motion behavior of mold inclusions in the presence of interfacial tension effects. In this paper, we used computational fluid dynamic simulations to examine the influence of interfacial tension on inclusion motion behavior near to the solid–liquid interface (solidifying shell). We have used a multiphase model in which molten steel (SPFH590), sulfur, and alumina inclusions have been considered as different phases. In addition, we assume minimal to negligible velocity at the solid–liquid interface, and we restrict the numerical simulation to only include critical phenomena like heat transport and interfacial tension distribution in two-dimensional space. The two-phase simulation of molten steel mixed with sulfur and alumina was modeled on volume of fluid (VOF) method. Furthermore, the concentration of the surfactant (sulfur) in molten steel was defined using a species model. The surfactant concentration and temperature affect the Marangoni forces, and subsequently affects the interfacial tension applied on inclusion particles. It was found that the alteration in interfacial tension causes the inclusion particles to be pushed and swallowed near the solidifying boundaries. In addition, we have compared the computational results of interfacial tension, and it was found to be in good agreement with experimental correlations.

Physical Model of Inclusions Removal at Static Steel–Slag Interface

“…Inclusion removal is a crucial step in the steelmaking process, and the removal effect directly affects steel quality [1][2][3][4]. At present, the main methods of inclusion removal include gas stirring in ladles [5][6][7][8][9][10], Ruhrstahl-Heraeus treatment [11][12][13][14], slag washing [15][16][17], bubble flotation [18], removal in tundishes [19][20][21][22], and continuous casting mold [23][24][25][26], among others. These methods promote inclusions to float to the slag-steel interface so that the inclusions are more easily removed by refining slag absorption.…”

Advancements in the Understanding of Single‐Bubble Dynamics: Integrated Experimental and Simulation Studies

“…Ladle bottom argon blowing, [9] tundish with gas curtain, [10] and SEN argon blowing are typical applications in this field. However, argon blowing may bring the following problems: 1) large bubbles float near the SEN and push away the slag layer, forming slag eyes; and 2) small bubbles are captured by the solidified billet shell deep into the mold along with the molten steel, [11,12] leading to subcutaneous bubble defects in the casting billet; and 3) small bubbles with inclusions adhering to them flow with the molten steel flow strands and are then captured by the solidified billet shell, [13][14][15][16][17] leading to cracks in the final product. Therefore, an in-depth understanding of the size distribution and spatial distribution of bubbles will help to improve the surface and internal quality of steel.…”