Computational thermodynamics applied to steel elaboration

Gaye, Henri; Faral, Manon; Lehmann, J.

doi:10.1051/metal:2003134

Cited by 6 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This tendency shows fair accordance to the thermodynamic equilibrium of the present slagmetal system, which has been discussed by one of the authors (HRG) and co-workers. [31,32] on the basis of thermodynamic model (IRSID slag model) and experimental data.…”

Section: A Thermodynamics Of Deoxidation and Inclusion Composition Imentioning

confidence: 99%

Thermodynamics of the Formation of MgO-Al2O3-TiO x Inclusions in Ti-Stabilized 11Cr Ferritic Stainless Steel

Park

Lee

Gaye

2008

Metall Mater Trans B

View full text Add to dashboard Cite

The equilibration between CaO-SiO 2 -MgO-Al 2 O 3 -CaF 2 (-TiO 2 ) slag and Fe-11 mass pct Cr ferritic stainless steel melts was investigated at 1873 K in order to clarify the effect of Al and Ti addition as well as that of slag composition on the formation of complex oxide inclusions. The activity of oxygen calculated from the classical Wagner formalism changes from about a O = 0.0002 to 0.001 and the values of a O from [Al]/(Al 2 O 3 ) and that from [Si]/(SiO 2 ) equilibria are in relatively good agreement with each other with some scatters. The phase stability diagram of the inclusions and the equilibrium iso- [O] lines in the Fe-11 mass pct Cr-0.5 mass pct Si-0.3 mass pct Mn-0.0005 mass pct Mg steel melts was constructed by using FACTSAGE 5.5 program as a function of Al and Ti contents. The computed iso-[O] lines were slightly larger than the values estimated from the slag-metal equilibria. The composition of the inclusions could be plotted on the computed MgO-Al 2 O 3 -TiO x phase diagram. The inclusions in the steel melts equilibrated with the basic slags are located in the ''spinel + liquid'' region, while those in equilibrium with the less basic slags are mostly in the ''liquid'' single phase. This is in good accordance to the observed morphology of the inclusions. However, in cases of high concentration of Ti and Al, the inclusions were found to be spinel + liquid, even though the less basic slags are equilibrated. When plotted on logarithmic scales, the mole ratio X MgO Â X Al 2 O 3 X Ti 2 O 3 À Á of the inclusions (spinel potential) was expressed as a linear function of a Mg Â a 2 Al Â a O a 2 Ti Ä Å of the steel melts with a slope of unity theoretically expected. Also, the spinel potential is very low and nearly constant when the activity of Al 2 O 3 is less than that of TiO 2 in the slag saturated by MgO, whereas it linearly increases by increasing the log a Al 2 O 3 =a TiO 2 ð Þat X Al 2 O 3 =X TiO 2 ð Þ >1.

show abstract

Section: A Thermodynamics Of Deoxidation and Inclusion Composition Imentioning

confidence: 99%

Thermodynamics of the Formation of MgO-Al2O3-TiO x Inclusions in Ti-Stabilized 11Cr Ferritic Stainless Steel

Park

Lee

Gaye

2008

Metall Mater Trans B

View full text Add to dashboard Cite

show abstract

“…Dentre os programas, os mais utilizados são o FactSage, GEMINI2, MPE, MTDATA e o Thermo-Calc, que apresentam aplicações nas áreas química, metalúrgica e de materiais [40].…”

Section: Capacidade Sulfeto E Partição De Enxofreunclassified

Utilização de resíduo de mármore e de óxido de boro em escórias sintéticas dessulfurantes para aços.

Coleti¹

View full text Add to dashboard Cite

Este exemplar foi revisado e corrigido em relação à versão original, sob responsabilidade única do autor e com a anuência de seu orientador. A Clara pela paciência, incentivo e amor.A Escola Politécnica pela estrutura disponibilizada. VI ABSTRACTThe present market requires from steel industry better quality of steel that was produced by processes that cause less impact to the environment. Thus, this study aims to recycle the marble waste generated from the industry of ornamental rocks, which has in its composition calcium oxide (CaO) and magnesium oxide (MgO). Using this waste in the steel production process, the amount of CaO is enough to replace the lime in the slag whereas the MgO contributes to reduce the wear of the refractory material. Furthermore, it was part of this study to test the replacement of the fluorite by boron oxide as desulfurizing flux into the composition of mixtures. The marble waste was characterized using the following techniques: chemical analysis (EDXFR), particle size analysis with a light scattering method, specific surface area by BET method, Xrays diffraction (XRD), scanning electron microscopy (SEM), analysis of micro-regions by energy dispersive spectroscopy (EDS) and thermogravimetry analysis (TG) with mass spectrometer coupled (MS). In order to verify the efficiency of desulfurization, mixtures were formulated using conventional lime or marble waste, and fluorite or boron oxide. The blends were prepared using the computational thermodynamics programs, Thermo-Calc and FactSage. These mixtures were added into the molten steel under an argon atmosphere and the metallic bath stirred by a rotor of alumina at the temperature of 1600ºC. Metal Samples were removed periodically in order to verify the variation of sulfur content during the experiments. The characterization of marble waste showed in its composition the amount of 40% CaO and 14% MgO in a CaCO3 and MgCO3 carbonates forms. It was also observed a mass loss of 42.1%, in the form of CO2 at a temperature of 780 ° C. The experiments showed that the tested mixtures desulfurization efficiency was above 60%, in most cases.

show abstract