A Contribution to Scale Growth during Hot Rolling of Steel

Schwerdtfeger, Klaus; Zhou, Shunxin

doi:10.1002/srin.200300231

Cited by 29 publications

(25 citation statements)

References 15 publications

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“…8) As a consequence, the analysis of the influence of temperature and time on oxidation rate, phase composition and morphology of the secondary and tertiary scales is of great interest in order to better understand work roll wear and strip surface defects in hot strip rolling.…”

Section: Introductionmentioning

confidence: 99%

Growth Rate and Phase Composition of Oxide Scales during Hot Rolling of Low Carbon Steel

Basabe

Szpunar

2004

ISIJ International

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The rate of scale growth on low carbon steel in air over the temperature range 600-1200°C and the phase composition changes that occur between 750-1 200°C were investigated. The low carbon steel was oxidized with the air velocity of 4.2 cm/s in order to approximate the formation of secondary and tertiary scales in hot rolling. In addition, some experiments were performed with a lower air velocity of 0.14 cm/s. Above 1 000°C, with the air velocity of 4.2 cm/s, a transition from a parabolic rate of oxidation to a linear rate of oxidation was observed as the temperature increased. This transition in oxidizing mechanisms was related to the porosity of the oxide scale. The phase composition of the oxide scales changed with temperature and time. For the initial 30 s of oxidation, wustite was the predominant phase in the temperature range 800-1 200°C and as oxidation proceeded, the percentages of magnetite and hematite increased. The homogeneity of the oxide decreased as the oxidation temperature increased. At 850°C, with the air velocity of 4.2 cm/s, the oxide was homogeneous, and for the first 120 s of oxidation, the oxide had a high percentage of wustite and a low percentage of hematite. This indicates that 850°C is the ideal temperature for the finishing strip mill in order to reduce work roll wear and surface defects.

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Section: Introductionmentioning

confidence: 99%

Growth Rate and Phase Composition of Oxide Scales during Hot Rolling of Low Carbon Steel

Basabe

Szpunar

2004

ISIJ International

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“…During the initial linear stage, the rate-controlling process for oxidation is oxygen diffusion through a gas phase boundary layer. 23,25) After the transition, the rate controlling step is diffusion of iron ions through the wüstite layer.…”

Section: Oxidation Behaviormentioning

confidence: 99%

Evolution and Distribution of the Copper-rich Phase during Oxidation of an Iron–0.3wt%Copper Alloy at 1150°C

Webler

Sridhar

2008

ISIJ Int.

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Residual copper contents in low carbon steels lead to a cracking phenomenon known as surface hot shortness. This phenomenon is caused by a copper-rich liquid layer that forms due to copper enrichment as iron oxidizes during casting, reheating and/or hot rolling. Evolution of the copper-rich liquid layer is dependent on the competing processes of enrichment due to iron oxidation and diffusion of copper back into the metal. This paper presents comparisons between experiments and calculations of a fixed grid finite difference model that predicts the evolution of the copper-rich region. Experiments involved oxidizing an iron-0.3wt%copper alloy in a gold-image furnace equipped with thermogravimetric balance. Samples were oxidized at 1 150°C in three atmospheres, dry air, wet air (15 vol% H 2 O), and argon-15vol%H 2 O. Model predictions agree with measured data for dry air oxidation at 1 150°C for 60, 300, 420, 600, 900, and 1 200 s. Agreement was also obtained for iron oxidized for 1 800 and 2 700 s in argon-15vol%water vapor. However, model predictions deviated for samples oxidized 3 600 s in dry air, 3 600 s in water vapor, and 600 s in wet air. The deviations arise due to grain boundary penetration and diffusion of copper. Results suggest a critical amount of separated copper is necessary for substantial grain boundary penetration to occur and the required amount decreases when the gas contains H 2 O. The model was also used to estimate the evolution behavior of the liquid copper phase under industrially relevant conditions.

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“…Before the cold rolling or the galvanizing process, the strip must be completely removed to ensure the surface quality of the finished product [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…π F Ec    (2) Here, γ is the fracture surface energy. Nagl and Evans [10] analyzed the relationship between the cracking behavior and the thickness of scales under tension and found that the cracking stress/strain decreases with increasing thickness.…”

Section: Introductionmentioning

confidence: 99%

Impact tensile cracking behavior of oxide scale in Q235 strip iron

Shang

Wang

et al. 2018

MATEC Web Conf.

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Abstract. Scanning electron microscopy (SEM) is used to observe the fracture surface morphology of Q235 steel. The cracking law/crack rule principle of strip surface under tension is studied via universal tensile testing machine. The results show that the thickness of the scale is relatively uniform, about 10 μm, and the structure is dense and well attached to the matrix. Tensile experiments show that as the strain increases, the cracks increase slowly in the initial stage, rapidly in the middle period, and slowly in the final period. When the strain exceeds 0.15%, the cracks are difficult to increase. In order to avoid direct erosion of the abrasive on the substrate, a reasonable range of tension setting should be 0.15%-0.18% in the pretreatment process without acid descaling.

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A Contribution to Scale Growth during Hot Rolling of Steel

Cited by 29 publications

References 15 publications

Growth Rate and Phase Composition of Oxide Scales during Hot Rolling of Low Carbon Steel

Growth Rate and Phase Composition of Oxide Scales during Hot Rolling of Low Carbon Steel

Evolution and Distribution of the Copper-rich Phase during Oxidation of an Iron–0.3wt%Copper Alloy at 1150°C

Impact tensile cracking behavior of oxide scale in Q235 strip iron

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