Eutectoid Magnetite in Wüstite Under Conditions of Compressive Stress and Cooling

Zhou, Chang Ling; T., H.; Li, Y.; Wang, L.

doi:10.1007/s11085-012-9296-4

Cited by 14 publications

(7 citation statements)

References 21 publications

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“…[12][13][14][15] Therefore, the research of phase transformation behavior of FeO in oxide scale has become a hotspot in recent years. [16][17][18][19][20][21][22][23] Based on the previous studies, it is worth noting that the chemical composition of steel also affects the phase transformation of FeO besides start cooling temperature, isothermal time and cooling rate. Shizukawa and Yoneda 21,24) proposed the effect of Mn, Au addition to steel on eutectoid transformation of FeO in oxide scale.…”

Section: Introductionmentioning

confidence: 99%

Phase Transformation Behavior of Oxide Scale on Plain Carbon Steel Containing 0.4 wt.% Cr during Continuous Cooling

Cao

Lin

et al. 2018

ISIJ International

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Pre-oxidation in air at 750°C for 10 min, the plain carbon steels without Cr and containing 0.4 wt.% Cr tended to rapidly form oxide scale composed of outer Fe 3 O 4 layer and inner FeO layer. Moreover, a FeCr 2 O 4 layer was observed at the FeO/substrate interface on the steel containing Cr. A comparative study was carried out between the scales on the two steels in inert gas cooled from 350-600°C to room temperature at the cooling rate range of 1-40°C/min, to determine the effect of low concentration Cr addition on the phase transformation of FeO. Based on the cross-sectional morphologies of oxide scale during various cooling conditions, the relationship between cooling rate and start cooling temperature were constructed, and the area fraction of eutectoid structure was analyzed. The result shows that the transformation rate and area fraction of eutectoid structure in oxide scale on steel containing Cr were greater than that on steel without Cr, and then the nucleation, growth and 100% transformation region of eutectoid structure in oxide scale on steel without Cr were delayed. This study proposed two mechanisms to discuss the experimental results. Firstly, the formation of FeCr 2 O 4 layer reduced the consumption of O, and then prevented short-range uphill diffusion of Fe from FeO to substrate. Secondly, combined with the lamellar spacing in eutectoid structure and the Fe-Cr-O equilibrium phase diagram, the Cr addition increased the formation temperature of FeO in oxide scale, which provided sufficient driving force for eutectoid transformation during continuous cooling.

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Section: Introductionmentioning

confidence: 99%

Phase Transformation Behavior of Oxide Scale on Plain Carbon Steel Containing 0.4 wt.% Cr during Continuous Cooling

Cao

Lin

et al. 2018

ISIJ International

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“…The ferrite and magnetite morphologies do not indicate the formation of a lamellar eutectoid structure, where the ferrite grows epitaxially from the Fe 3 O 4 surface (Matsuno and Ohmori, 1988). Zhou et al (2012) mentioned that the wüstite eutectoid decomposition promotes the formation of the magnetite/ferrite eutectoid even at cooling rates of about 80ºC/s. They also noted that the wüstite decomposition might induce proeutectoid magnetite formation in the wüstite.…”

Section: Hammermentioning

confidence: 97%

Archaeometallurgy of ferrous artefacts of the Patriótica Iron Factory (XIX century, Ouro Preto, Brazil)

et al. 2021

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The article reviews the metallurgical processes used in the first industrial ironworks operated in Brazil, the Patriótica Iron Factory, from 1812 to 1831. It discusses its impact on the ironmaking plants that spread in Minas Gerais's state during the XIX century. The remnants of this Factory in Ouro Preto were the first industrial site listed by the Brazilian Historic Heritage Authority (SPHAN) in 1938. Vale SA, owner of the site, and the National Historic and Artistic Heritage Institute (IPHAN) authorised collecting samples from two ferrous artefacts found in the old Factory, a hammer and an eyebolt nailed to the remnants of one of the reduction furnaces. The eyebolt's microstructure suggests that this part was produced in the Patriótica Iron Factory, while the hammer's microstructure indicates that this component was not produced in the Patriótica Iron Factory.

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“…In the previous literatures [4][5][6][7][8][9], the wüstite used to examine the transformation behavior was generally prepared at the temperature in the range of 700˚C~900˚C in air. The transformation process of wüstite finished in about 10h at most even when the oxide thickness was thick [14].…”

Section: Mechanism Of Eutectoid Transformation Of Wüstitementioning

confidence: 99%

“…Wüstite is unstable at temperatures below 570˚C and is transformed into magnetite and iron. In previous studies, the reactions of the wüstite transformations have been mainly categorized into three kinds: precipitation and growth of magnetite, formation of the magnetite seam at the scale/steel interface, and the eutectoid reaction [4][5][6][7][8][9]. The rate and the proportion of these transformations depend on the transformation conditions, such as wüstite formation temperature, cooling rate, and the transformation temperature.…”

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confidence: 99%

<strong>Crucial Mechanism to the Eutectoid Transformation of Wüstite Scale on Low Carbon Steel</strong>

Lin

Huang

et al. 2017

Preprint

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It is important to realize the transformation behavior of wüstite because it greatly affects the final structure of the oxide layer and the surface quality of the steel products. In the present study, the transformation behaviors of the wüstite layer are examined under nearly-oxygen-free conditions, to simulate the cooling processes after the hot rolled strip is coiled. As the single phase wüstite was prepared at 950˚C, the 460˚C transformed oxide layer was composed of a mixture of iron and magnetite formed through eutectoid reactions. For the 750˚C-fabricated wüstite, only magnetite was observed after transformation, without iron precipitates and residual wüstite. It is speculated that the unusual transformation behavior of the low-temperature-made wüstite results from the pseudo-structural intermediate phase transformation between wüstite and magnetite. This pseudo-structure is a pre-transformed wüstite and of various concentration of ferrous ion, which is determined by the fabrication conditions. During the hot strip mill process, the so-called wet scale, wüstite, is produced continuously from finish mill to laminar flow sections and ended at 570˚C. Consequently, the final eutectoid transformation below 570˚C is dominantly controlled by the surface temperature ranged from 750˚C to 950˚C for low carbon steel.

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Eutectoid Magnetite in Wüstite Under Conditions of Compressive Stress and Cooling

Cited by 14 publications

References 21 publications

Phase Transformation Behavior of Oxide Scale on Plain Carbon Steel Containing 0.4 wt.% Cr during Continuous Cooling

Phase Transformation Behavior of Oxide Scale on Plain Carbon Steel Containing 0.4 wt.% Cr during Continuous Cooling

Archaeometallurgy of ferrous artefacts of the Patriótica Iron Factory (XIX century, Ouro Preto, Brazil)

<strong>Crucial Mechanism to the Eutectoid Transformation of Wüstite Scale on Low Carbon Steel</strong>

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Eutectoid Magnetite in Wüstite Under Conditions of Compressive Stress and Cooling

Cited by 14 publications

References 21 publications

Phase Transformation Behavior of Oxide Scale on Plain Carbon Steel Containing 0.4 wt.% Cr during Continuous Cooling

Phase Transformation Behavior of Oxide Scale on Plain Carbon Steel Containing 0.4 wt.% Cr during Continuous Cooling

Archaeometallurgy of ferrous artefacts of the Patriótica Iron Factory (XIX century, Ouro Preto, Brazil)

<strong>Crucial Mechanism to the Eutectoid Transformation of W&uuml;stite Scale on Low Carbon Steel</strong>

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<strong>Crucial Mechanism to the Eutectoid Transformation of Wüstite Scale on Low Carbon Steel</strong>