Flow Modelling in Continuous Casting of Round Bloom Strands with Electromagnetic Stirring

Abstract

For the majority of continuously cast semis for stringent applications such as wire rods, rails, seamless tubes, etc. an optimal cleanness, surface and sub-surface quality as well as a minimum of centre line segregation and central shrinkage porosity is almost mandatory. Inmould electromagnetic stirring (M-EMS) has a number of functions but its primary purpose is to help breaking down coarse columnar dendritic solidification structure to produce a finer dendritic structure and a larger proportion of equiaxed grains. The rotary effect of M-EMS has also an important impact on the cleanness of the steels, which can be explained by its action on exogenous and endogenous inclusions. The modelling of turbulent flow, steel temperature, solidification, exogenous inclusion transport and electromagnetic stirring with mathematical and -as far as possible -physical models are presented, including PIV-measurements on a 1:1 scale water-model of the strand.The transient aspect of turbulent flow in a continuous slab casting mould is studied and the transient flow patterns of the upper rolls are investigated through the application of Large Eddy Simulation (LES), employing a static Smagorinsky sub-grid scale (SGS) model. The unsteady and coherent features of the upper recirculation zones are found, and the mechanism causing vortices developing from the upper recirculation zones is described and analysed. Results show that the asymmetry of flow patterns of the upper rolls appears most of the time. The upper swirls may break into a series of relatively small scale vortices that are chaotically distributed, and large-scale vortex shedding occurs during the switching process between flow patterns.

Large Eddy Simulation of Electromagnetic Three‐Phase Flow in a Round Bloom Considering Solidified Shell

“…), the magnetic flux density along the axis shows a good agreement with each other. The tendency of numerical results is also in agreement with the work from Trindade et aland Barna et al This partially validates the magnetic model.…”

“…In previous works, many flow‐related characteristics with M‐EMS are performed without considering solidification process. The influence of solidified shell growth on the fluctuation of slag‐metal interface is still unclear.…”

Experimental Investigations of Rotary Electromagnetic Mould Stirring in Continuous Casting Using a Cold Liquid Metal Model

“…[11][12][13][14][15][16][17] Numerical calculations can provide a better understanding of the complex flow behaviour, but experimental data are indispensable with respect to validation of these CFD models. Experimental investigations in an electromagnetically stirred Woods metal model were performed by Partinen et al 12,18) The authors measured the deformation of the free surface of the melt and determined the surface velocity using alumina particles on the surface.…”

Simulation in Metallurgical Processing: Recent Developments and Future Perspectives

“…In recent years, more international research has been conducted by using numerical simulation and experimental studies. [35][36][37][38][39] Nevertheless, this research has focused mainly on the magnetohydrodymamic flow field, and even though it has investigated the temperature field distribution under electromagnetic stirring, it has not considered the interaction with solidification. At the present stage, most of the studies are performed experimentally, but large scientific efforts are still necessary to build a model able to couple MHD, CET, and formation of segregation during solidification.…”