Impurities and tramp elements in steel: Thermodynamic aspects and the application to solidification processes

Michael Christian Bernhard, Won-Bum Park, Youn-Bae Kang, Sergiu Ilie, Christian Bernhard

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The current status of developing a self-consistent thermodynamic database for tramp elements (Fe-C-Cu-Sn-S) and impurities (Fe-C-P) in steel is presented. The binary and ternary subsystems were modeled according to the CALPHAD-approach, enabling precise calculations of phase diagrams and thermodynamic properties of multicomponent steel. The Modified Quasichemical Model (MQM) was used to formulate the Gibbs energy of the liquid phase to consider the strong short-range ordering (SRO) tendency between metal M (M = Fe, Cu, Sn) and nonmetal (S and P) in melts. Ferrite (α-Fe, BCC) and austenite (γ-Fe, FCC) solid solutions and intermediate phases were treated by the Compound Energy Formalism (CEF). Numerous compounds, e.g. phosphides and higher-order sulfides, were modeled stoichiometrically. In the first part, the modeling of the selected quaternary Fe-C-Cu-Sn subsystem is presented and applications in calculating solid/liquid phase equilibria with respect to liquid metal embrittlement are shown. Based on the previously assessed Fe-C-P system, the approach of linking of thermodynamic databases to an in-house developed solidification model for continuous casting is introduced. It is demonstrated how to extract relevant data from computational thermodynamics for microsegregation modeling of steel. Finally, future requirements on experimental research and modeling work in the field of tramp element containing steel will be critically discussed.
Original languageEnglish
Title of host publicationProceedings of 6th ESTAD (European Steel Technology and Application Days) 2023
Publication statusPublished - 13 Jun 2023
Event6th ESTAD (European Steel Technology and Application Days) 2023 - CCD Congress Center Düsseldorf, Düsseldorf, Germany
Duration: 12 Jun 202316 Jun 2023
https://metec-estad2023.com/

Conference

Conference6th ESTAD (European Steel Technology and Application Days) 2023
Country/TerritoryGermany
CityDüsseldorf
Period12/06/2316/06/23
Internet address

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