The Mechanism of Phase Transformation in Thermally-Grown FeO Scale Formed on Pure-Fe in Air

Hayashi, Shigenari; Mizumoto, Kouhei; Yoneda, Suzue; Kondo, Yasumitsu; Tanei, Hiroshi; Ukai, Shigeharu

doi:10.1007/s11085-013-9442-7

Cited by 39 publications

(16 citation statements)

References 15 publications

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“…20,21,24,38) When the similar TRs of 10%, there are much more LAGBs occurred at the low CR of 10°C/s in Fig. 3(a).…”

Section: Grain Boundary Characters Of Fe3o4/ α-Fe2o3mentioning

confidence: 92%

“…22) Various explanations for this phase evolution have been proposed, based on an investigation on the isothermal decomposition of the thermally grown Fe1-xO. 20,21,24) Substantial studies on the texture in oxide phases and © 2015 ISIJ their orientation relationship (OR) is now being investigated via electron backscatter diffraction (EBSD). [17][18][19][25][26][27][28][29] Cubic Fe3O4 and Fe1-xO share a strong <100> texture and a cubecube OR in undeformed oxide scale whatever the steel substrate.…”

Section: Introductionmentioning

confidence: 99%

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Crystallographic Texture Based Analysis of Fe3O4/α-Fe2O3 Scale Formed on a Hot-rolled Microalloyed Steel

Jiang

Zhao

et al. 2015

ISIJ Int.

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Oxide scale formed on the strip surface during hot rolling has posed a serious obstacle to ensure a defect-free surface of steel products in an ecologically friendly way. Recently, an influential idea is that the tertiary oxide scale with a tailored texture can be expected to enhance surface quality and tribolgoical properties during particular lubrication. In this study, texture evolutions of magnetite (Fe3O4) and hematite (α-Fe2O3) in deformed oxide layers formed on a hot-rolled microalloyed steel were investigated by electron back-scattering diffraction (EBSD). Fe3O4 develops a strong θ fibre parallel to the oxide growth, and α-Fe2O3 has a dominant {0001}<1010> texture component. This could be explained by surface energy minimisation during oxides growth and transformation between two oxides, which can also be affected by propagation of cracks along high angle grain boundaries in Fe3O4. Our data further demonstrate that a high thickness reduction (>28%) can reduce α-Fe2O3 wedging through Fe3O4 cracks, and tailoring Fe3O4 texture to {111} components can prevent the α-Fe2O3 growth titling 54.76° from the <001> crystal direction of Fe3O4. As such, these means can dramatically alleviate disturbance from 'red scale' (α-Fe2O3) during high-temperature steel processing.

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“…20,21,24,38) When the similar TRs of 10%, there are much more LAGBs occurred at the low CR of 10°C/s in Fig. 3(a).…”

Section: Grain Boundary Characters Of Fe3o4/ α-Fe2o3mentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Crystallographic Texture Based Analysis of Fe3O4/α-Fe2O3 Scale Formed on a Hot-rolled Microalloyed Steel

Jiang

Zhao

et al. 2015

ISIJ Int.

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“…4 suggest the existence of the granular precipitates to a certain extent during the cooling. The phase transformation can be due either to disproportionation or superficial oxidation of wustite in magnetite or both [11][12][13]. In addition, the grains shift along the rolling direction of the steel sample when the grain size is larger than 15 μm (Fig.…”

Section: Characterising Grain Sizesmentioning

confidence: 99%

“…Hence, the distribution of these oxide phases depends largely on the heat treatment and atmospheric conditions during hot rolling and the alloying elements contained in the steel compositions [8,10]. In particular, phase distributions within oxide scales will be elusive when considering wustite decomposition below 570 °C and re-oxidation of magnetite in open-air storage of hot-coiled steel [11][12][13]. In addition, it is still unknown how to characterise the crystallographic texture evolution in tertiary oxide layers.…”

Section: Introductionmentioning

confidence: 99%

Dependence of texture development on the grain size of tertiary oxide scales formed on a microalloyed steel

Jiang

Zhao

et al. 2015

Surface and Coatings Technology

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Q. (2015). Dependence of texture development on the grain size of tertiary oxide scales formed on a microalloyed steel. Surface and Coatings Technology, Dependence of texture development on the grain size of tertiary oxide scales formed on a microalloyed steel AbstractBoth orientational and geometrical characteristics of grains in tertiary oxide scales have been quantitatively investigated using the electron backscatter diffraction (EBSD) technique. Phase and orientation mappings demonstrate that the {001} planes of magnetite and the {0001} planes of hematite are parallel to the direction of oxide growth. Pole figures (PFs) as scattering plots clearly display the direct correlation between the orientations and microstructure sites of magnetite grains. Magnetite grains develop a strong rotated cube texture component that shifts to the {100} component, whereas those with the grain size of 1-5. μm develop the {001} cube texture component. The refined magnetite grains surrounding the abnormal ones can be a combined process, including magnetite pro-eutectoid during hot rolling and cooling and re-oxidation during air-cooling. Our findings offer insights toward further understanding of the link between the geometrical and orientation parameters of grains with respect to the deformation behaviour of oxide scales formed at elevated temperatures.

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“…Among them, the FeO transforms to a mixture of Fe 3 O 4 and Fe below 570°C, and the phase transformation behavior and the microstructure have been reported. [1][2][3][4][5][6][7][8][9] Because the phase transformation of FeO goes through the precipitation of Fe 3 O 4 in FeO matrix and eutectoid transformation, considerable stress and strain can occur in the scale, which has a possibility to affect the mechanical properties or adhesiveness of the scale. Especially, since the low scale adhesiveness results in the scale defects and deteriorates the surface quality of the hot-rolled steel-sheet products, understanding the stress or strain development in the scale during the phase transformation is industrially important.…”

Section: Introductionmentioning

confidence: 99%

Strain Development in Oxide Scale during Phase Transformation of FeO

Tanei

Kondo

2017

ISIJ Int.

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Development of a strain in oxide scale during phase transformation of FeO was investigated by a flexure method. A pure iron foil was oxidized on only one side, and the formed FeO was transformed at 400 or 500°C. In-situ observation of the bending behavior of the foil-formed specimen during the phase transformation of FeO was performed. Compressive strain develops in the scale in the early stage of the phase transformation, following which a significantly large expansion strain develops. Such a strain development corresponds to the two-step phase transformation of FeO and can be explained by the volume change of the scale considering the non-stoichiometry of FeO.

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The Mechanism of Phase Transformation in Thermally-Grown FeO Scale Formed on Pure-Fe in Air

Cited by 39 publications

References 15 publications

Crystallographic Texture Based Analysis of Fe<sub>3</sub>O<sub>4</sub>/<i>α</i>-Fe<sub>2</sub>O<sub>3</sub> Scale Formed on a Hot-rolled Microalloyed Steel

Crystallographic Texture Based Analysis of Fe<sub>3</sub>O<sub>4</sub>/<i>α</i>-Fe<sub>2</sub>O<sub>3</sub> Scale Formed on a Hot-rolled Microalloyed Steel

Dependence of texture development on the grain size of tertiary oxide scales formed on a microalloyed steel

Strain Development in Oxide Scale during Phase Transformation of FeO

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