Thermodynamic Analysis of Selective Oxidation Behavior of Si and Mn-added Steel during Recrystallization Annealing

Suzuki, Yosuke; Yamashita, Takako; Sugimoto, Yoshiharu; Fujita, Sakae; Yamaguchi, Shu

doi:10.2355/isijinternational.49.564

Cited by 85 publications

(42 citation statements)

References 16 publications

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“…Both Fe2SiO4 and (Fe,Mn)2SiO4 formulas have an identical crystal structure, and a part of Fe atoms can be substituted with Mn atoms in the fayalite. 11,24) The atomic configuration of the fayalite could be determined by HRTEM study, as described in the Fig. 4 where the "A region" marked in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…It has been reported that whether the fayalite was formed on the surrounding of the silica particle, or not depends upon such thermodynamical conditions as furnace temperature, oxidation potential, or annealing time during decarburization. 19,24) It is well-known that Si is more oxidized than Fe. Therefore, after the formation of thermodynamically stable silica particles, the fayalite was formed in the surrounding of the spherical silica particles with a reaction of Fe, Mn, and the already-formed silica with the additionally supplied oxygen.…”

Section: 26)mentioning

confidence: 99%

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A TEM Study of Oxide Layers Formed during Decarburization Annealing of Electrical Steel

et al. 2011

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It is very important to know the morphology and chemical properties of subscales of oxide layers on surface for controlling and understanding high temperature oxidation in electrical steel. In present work, the oxide layers were investigated by various methods of transmission electron microscopy (TEM) such as scanning transmission electron microscopy (STEM), nanobeam electron diffraction (NBD), energy dispersive X-ray spectrometry (EDS), and electron energy loss spectrometry (EELS). The high-angle annular dark field (HAADF) of STEM could be a useful analysis technique to study the morphology of the oxide layers. The main oxides formed in the subscales during the decarburization annealing were fayalite, iron oxides, and silica, which were identified by EDS, NBD and EELS. The crystalline fayalites were found both in the surface region within several tens nanometers and in the region within a micrometer surrounding silica, and the atomic configuration in the unit cell of the fayalite was presented. Amorphous silica was formed both in the upper region of the subscales with a spherical shape and in the interface between the spherical silica and the iron matrix with a lamellar shape. TEM could be useful technique to characterize morphologies, microstructures and elemental compositions of oxides, and to understand the oxidation mechanism for the manufacture of the high quality electrical steel.

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Section: Resultsmentioning

confidence: 99%

Section: 26)mentioning

confidence: 99%

A TEM Study of Oxide Layers Formed during Decarburization Annealing of Electrical Steel

et al. 2011

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“…This is because weights of high strength steel sheets have increased, and as well, elements such as aluminum, silicon and manganese are typically contained in high strength steel which form oxides on the steel surface and thus tend to disturb the wetting of the molten zinc in the process. [1][2][3][4][5][6] Because of this situation, various industrial process techniques have been suggested and developed to improve the wettability of high strength steel. At the same time, the importance of a fundamental investigation of wetting behavior has increased in order that new ideas can be developed.…”

Section: Introductionmentioning

confidence: 99%

Tailoring Model Surface and Wetting Experiment for a Fundamental Understanding of Hot-dip Galvanizing

Kawano

Renner

2011

ISIJ Int.

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The wettability of molten zinc-aluminum on a steel substrate is an important issue in the hot-dip galvanizing process for automotive applications. Especially, the effects of surface oxides have been current topics during recent years. However wetting behavior under the effects of oxide has not been well illustrated due to the complexity of the surface of actually used steel. In this work, wetting experiments using molten zinc-aluminum were applied to tailored model surfaces of iron to investigate its fundamental behavior. Well-defined aluminum oxide islands were successfully patterned on iron surfaces by physical vapor deposition with masks for this purpose. The sessile drop method with zinc-aluminum was conducted in a laboratory-made apparatus. This apparatus included a unique spin-off technique that allowed us to make an interface analysis at the early stage of wetting. The initial contact angles of the patterned samples were revealed to have followed the Cassie equation. This indicates that the wetting of zinc-aluminum on an oxide-iron system can be treated as if it is a static wetting in its initial stage, even though this system is originally considered as a reactive wetting. The molten zinc-aluminum on a patterned sample diffused into the interface between the oxide islands and the substrate in the stage after initial wetting. It is suggested that this manner of zinc-aluminum diffusion plays a key role in the reaction and formation of the interface during the hot-dip galvanizing process.

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“…[5][6][7][8][9]). However, only a few studies have been reported on the oxidation of Cr-alloyed Fe-Mn-based steels [10,11].…”

Section: Introductionmentioning

confidence: 99%

Prediction of Oxide Phases Formed upon Internal Oxidation of Advanced High-Strength Steels

2017

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The effect of Cr on the oxidation of Fe-Mn-based steels during isothermal annealing at different dew points was investigated. The Fe-Mn-Cr-(Si) phase diagrams for oxidizing environments were computed to predict the oxide phases. Various Fe-Mn steels with different concentrations of Cr and Si were annealed at 950°C in a gas mixture of Ar or N 2 with 5 vol% H 2 and dew points ranging from -45 to 10°C. The identified oxide species after annealing match with those predicted based on the phase diagrams. (Mn,Fe)O is the only oxide phase formed during annealing of Fe-Mn binary steel alloys. Adding Cr leads to the formation of (Mn,Cr,Fe) 3 O 4 spinel. The dissociation oxygen partial pressure of (Mn,Cr,Fe) 3 O 4 in the Fe-Mn-Cr steels is lower than that of (Mn,Fe)O. The Si in the steels results in the formation (Mn,Fe) 2 SiO 4 , and increasing the Si concentration suppresses the formation of (Mn,Cr,Fe) 3 O 4 and (Mn,Fe)O during annealing.

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Thermodynamic Analysis of Selective Oxidation Behavior of Si and Mn-added Steel during Recrystallization Annealing

Cited by 85 publications

References 16 publications

A TEM Study of Oxide Layers Formed during Decarburization Annealing of Electrical Steel

A TEM Study of Oxide Layers Formed during Decarburization Annealing of Electrical Steel

Tailoring Model Surface and Wetting Experiment for a Fundamental Understanding of Hot-dip Galvanizing

Prediction of Oxide Phases Formed upon Internal Oxidation of Advanced High-Strength Steels

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