Computation of Phase Fractions in Austenite Transformation with the Dilation Curve for Various Cooling Regimens in Continuous Casting
2016 (English)In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 47, no 3, 1553-1564 p.Article in journal (Refereed) PublishedText
A concise model is applied to compute the microstructure evolution of austenite transformation by using the dilation curve of continuously cast steels. The model is verified by thermodynamic calculations and microstructure examinations. When applying the model, the phase fractions and the corresponding transforming rates during austenite transformation are investigated at various cooling rates and chemical compositions. In addition, ab initio calculations are performed for paramagnetic body-centered-cubic Fe to understand the thermal expansion behavior of steels at an atomic scale. Results indicate that by increasing the cooling rate, the final volume fraction of ferrite/pearlite will gradually increase/decrease with a greater transforming rate of ferrite. The ferrite fraction increases after austenite transformation with lowering of the carbon content and increasing of the substitutional alloying fractions. In the austenite transformation, the thermal expansion coefficient is sequentially determined by the forming rate of ferrite and pearlite. According to the ab initio theoretical calculations for the single phase of ferrite, thermal expansion emerges from magnetic evolution and lattice vibration, the latter playing the dominant role. The theoretical predictions for volume and thermal expansion coefficient are in good agreement with the experimental data.
Place, publisher, year, edition, pages
Springer, 2016. Vol. 47, no 3, 1553-1564 p.
Austenite, Calculations, Carbon, Continuous casting, Cooling, Expansion, Ferrite, Lattice vibrations, Microstructure, Pearlitic transformations, Phase transitions, Steel castings, Ab initio theoretical calculations, Austenite transformations, Micro-structure evolutions, Microstructure examination, Substitutional alloying, Thermal expansion behavior, Thermal expansion coefficients, Thermodynamic calculations, Thermal expansion
Metallurgy and Metallic Materials
IdentifiersURN: urn:nbn:se:kth:diva-186936DOI: 10.1007/s11663-015-0545-1ISI: 000375451200009ScopusID: 2-s2.0-84963727246OAI: oai:DiVA.org:kth-186936DiVA: diva2:929294
FunderSwedish Research CouncilSwedish Foundation for Strategic Research
QC 201605182016-05-182016-05-162016-05-30Bibliographically approved