Tecnologia em Metalurgia, Materiais e Mineração
Tecnologia em Metalurgia, Materiais e Mineração
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Silva, André Luiz Vasconcellos da Costa e; Beneduce Neto, Flávio; Avillez, Roberto Ribeiro

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The iron-oxygen-aluminum equilibrium has been a subject of interest for many years due to its importance in the steel industry. A great percentage of all flat rolled steel is aluminum killed “AK” (deoxidized) low-carbon steel, not only because of the low soluble oxygen contents that can be achieved but also because of the importance of the residual aluminum in forming aluminum nitride that is one of the main tools used to achieve crystallographic texture adequate for forming. The behavior both of oxygen and of aluminum in liquid iron are relatively well understood and quantified, as is the free energy of formation of alumina. Nonetheless, the Fe-Al-O behavior at liquid iron temperatures is not fully understood and considerable controversy still prevails. Thus, the objectives of this work are (a) to critically review the experimental work and assessments performed mainly on the Al-Fe-O–Al2O3 equilibrium, (b) to evaluate the current models used to describe this equilibrium and (c) to present a recommendation about the data, based on its evaluated reliability and consistency.


Steel, Deoxidation, Thermodynamics, Al-Fe-O system, CALPHAD.


O sistema ferro-oxigênio alumino tem sido investigado há muitos anos em função de sua importância para a indústria do aço. Uma grande fração de todo o aço plano produzido é de aço de baixo carbono acalmado ao alumínio, não apenas pelo baixo conteúdo de oxigênio residual em solução que pode ser obtido, mas, também, pela importância do alumínio residual na formação de AlN, importante no controle de estrutura e textura obtidas. Tanto o comportamento do oxigênio como o do alumínio no ferro líquido são relativamente bem compreendidos e quantificados, assim como a propriedades termodinâmicas da alumina. Entretanto, há discrepâncias significativas na quantificação do comportamento do sistema Fe-Al-O na tempertura do aço líquido, havendo, ainda, bastante controvérsia com respeito a equilíbrios importantes neste sistema. Assim, o objetivo deste trabalho é (a) realizar uma revisão crítica dos experimentos e avaliações termodinâmicas principalmente do equilíbrio Al-Fe-O–Al2O3 (b) avaliar os métodos atualmente usados para descrever este equilíbrio e (c) apresentar recomendações sobre os dados, com base em sua confiabilidade e consistência.


Aço, Desoxidação, Termodinâmica, Sistema Al-Fe-O, CALPHAD.


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