Computer Applications of Thermodynamic Databases to Inclusion Engineering

Abstract

Computerized thermodynamic databases for solid and liquid steel, slags and solid oxide solutions, for large numbers of components, have been developed over the last two decades by critical evaluation/optimization of all available phase equilibrium and thermodynamic data. The databases contain parameters of models specifically developed for molten slags; liquid and solid steel; and solid oxide solutions such as spinels. With user friendly software, which accesses these databases, complex equilibria involving slag, steel, inclusions, refractories and gases simultaneously, can be calculated for systems with many components, over wide ranges of temperature, oxygen potential and pressure. In the present article, several case studies will be presented, illustrating applications to complex steelmaking processes such as: Ca injection processes (Fe-Ca-Al-O inclusion diagram), corrosion of refractories, Mn/Si deoxidation, Ti/Al deoxidation (Fe-Al-Ti-O inclusion diagram), spinel formation (Fe-Mg-Al-O inclusion diagram), (Ti,N)(N,C) inclusion formation, oxide metallurgy.

Mechanism of Non-metallic Inclusion Formation and Modification and Their Deformation during Compact Strip Production (CSP) Process for Aluminum-Killed Steel

“…As shown in Table 6, in different calcium aluminates are calculated by FactSage. 10) As an approximate comparison, Fujisawa et al's 11) experimental results are also listed in Table 6, and a reasonable agreement can be found between them.…”

Mathematical Model for Prediction of Composition of Inclusions Formed during Solidification of Liquid Steel

“…[29][30][31][32] The software contains Equilib as one of the modules, which is based on the Gibbs free energy minimization technique for calculation of various multicomponent-multiphase reaction equilibria. In order to calculate steel-inclusions equilibria using equilib module, the various data bases have been used.…”

“…This data base is based on the associated solution model proposed by Pelton and coworkers. 31,32) For activity composition relationship of slag FACT-SLAGA data base was employed in addition to the solid stoichiometric compounds data bases. A sequential calculation procedure involving microsegregation model and Factsage was adopted for the prediction of inclusion formation during solidification.…”

Thermodynamic Model for Prediction of Slag-Steel-Inclusion Reactions of 304 Stainless Steels

“…43) Thus, the formation of inclusions at different temperatures and varying steel compositions in a multicomponent system can be apace and accurately predicted by means of thermodynamic software. Holappa et al 44) developed a thermodynamic model using ChemSage to calculate equilibrium oxide and sulfide inclusions in steel and predict the "liquid window" for the formation of liquid calcium aluminates.…”