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Description
Producers of stainless steels such as high alloyed duplex steels have shown an increasing interest in alloying with nitrogen. Alloying with nitrogen can replace some of the Nickel used since it affects mechanical strength, corrosion resistance and stabilizes the austenitic phase. Nitrogen is mainly used as a process gas instead of the more expensive argon gas. Depending on the ratio of nitrogen gas to argon gas, nitrogen content can be affected. However, controlling the level of nitrogen in liquid steel and predicting the final content is a difficult task often leading to a need of flushing with argon gas in order to reach desired levels of nitrogen content. Such an approach is both time and resource consuming.
Therefore, this study has developed a CFD model of an industrial AOD-converter that is coupled to the thermodynamic software Thermo-Calc. This type of model provides one possible route to establish nitrogen control in the AOD-process, combining both a kinematic understanding via the CFD calculations as well as an understanding of the thermodynamic situation. This combination applies non-ideal solution calculations for the thermodynamics and a more dynamic approach to the kinematic situation in comparison with existing prediction models that applies calculations using dilute solutions and kinematic expressions.