Modelling of the Steel/Slag Interface in a Continuous Casting Tundish

Abstract

It is very important to understand the underlying physical phenomena at the steel/slag interface in a continuous casting tundish in order to control reoxidation and deoxidation phenomena that can occur. Aiming to investigate probable sources of exogenous inclusions originating from the covering slag, an existing mathematical model of the tundish was augmented to include key physical parameters needed for the prediction of the physical behaviour of steel/slag mixing phenomena. Results showed a recirculation flow in the inlet region to be responsible for both the entrainment of steel drops into the slag and slag fragments into the steel. The highest concentration of slag in the steel was found to be in the area behind the inlet where slag fragment sizes are smaller due to a high degree of turbulent energy dissipation. Likewise, higher concentrations of steel in the slag, consisting of smaller steel droplets, were only found in the inlet region and along the walls. The results indicate that only small slag fragments of approximately 10‐50 microns from the covering slag reach the outlet.

An in‐Depth Model‐Based Analysis of Decarburization in the AOD Process

“…The temperature‐dependent dynamic viscosity for steel, ν st , is calculated according to Kawai and Shiraishi 43. The temperature‐dependent dynamic viscosity for pure slag, ν sl , is calculated according to Seetharaman et al44 The slag/steel mixing properties and the dispersed slag phase droplet size are calculated according to Solhed et al45…”

A Mathematical Model for the Reduction Stage of the AOD Process. Part I: Derivation of the Model

“…However, much less attention has been paid to the reduction stage. Although numerous studies have been conducted on the emulsification of slag [31][32][33][34][35][36][37][38][39][40][41][42] and reduction of slag 18,[43][44][45][46] as separate research fields, a phenomena-based model capable of combining the present knowledge of both phenomena has not been previously discussed in the literature.…”

A Mathematical Model for the Reduction Stage of the AOD Process. Part II: Model Validation and Results

“…Simulated slag droplet diameters for tundish are typically smaller than 1 mm. 19) Many physical water-experiments have also been reported in the literature. 16,17,[20][21][22] Frohberg et al 20) reported mean diameters ranging from 2.3 to 2.8 mm, while Savolainen et al 22) observed average droplet sizes in the range of 2.0 to 8.5 mm.…”