Mathematical Modelling Study of Dynamic Composition Change of Steel and Mold Flux in Continuous Casting of Steel

• Published in: ISIJ International 2019/11/15, Vol.59(11), pp.2024-2035
• Main Authors: Ni, Peiyuan, Tanaka, Toshihiro, Suzuki, Masanori, Nakamoto, Masashi, Ersson, Mikael, Jönsson, Pär Göran
• Format: Article
• Language: English
• Subjects: continuous casting; interfacial tension; mass transfer; mold flux; oxygen adsorption; steel-flux interfacial reaction
• ISSN: 0915-1559; 1347-5460; 1347-5460
• DOI: 10.2355/isijinternational.ISIJINT-2019-007

A kinetic model was developed to describe multicomponent reactions and mass transfer at the steel/molten flux interface under the effect of the interfacial tension. This model mainly describes the following interfacial physicochemical phenomena: i) Silica decomposition and oxygen adsorption at the interface, ii) Oxygen and titanium reactions at the interface, iii) Oxygen and aluminum reaction at the interface, iv) Silica mass transfer from the flux bulk to the interface, and v) Dissolution of the formed titanium dioxide and alumina into the flux and its transfer in flux. With this model, the dynamic changes of the mold flux composition, steel composition, interfacial oxygen content and interfacial tension for different mold flux compositions were predicted. Overall, the dynamic composition changes of the mold fluxes in a casting mold were reproduced. The basicity of the mold flux shows a large influence on the dynamic change of its composition. The initial composition change of the mold flux is fast when the flux with a high basicity was used, compared with the case of the mold flux with a low basicity. The interfacial oxygen content and the interfacial tension were found to reach a constant value after the steel/flux reaches a metastable state. In addition, the interfacial adsorption of oxygen due to the interfacial tension effect was found to significantly accelerate the dynamic change process of the steel/mold flux system.