An Electron Diffraction Study of Oxide Films Formed on High Temperature Oxidation Resistant Alloys

Hickman, Jared; Gulbransen, Earl A.

doi:10.1149/1.3071794

Cited by 10 publications

(10 citation statements)

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“…Chromium, by forming stable carbides, also slows down the decarburisation reaction [56]. However, this slowing down was not noticed in all the alloys [57].…”

Section: 221carbonmentioning

confidence: 99%

Surface composition modification of high-carbon low-alloy steels oxidized at high temperature in air

Genève

Rouxel

Pigeat

et al. 2008

Applied Surface Science

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“…Chromium, by forming stable carbides, also slows down the decarburisation reaction [56]. However, this slowing down was not noticed in all the alloys [57].…”

Section: 221carbonmentioning

confidence: 99%

Surface composition modification of high-carbon low-alloy steels oxidized at high temperature in air

Genève

Rouxel

Pigeat

et al. 2008

Applied Surface Science

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“…16) However, the diagram only represents equilibrium conditions while, in hot working, conditions can be affected by kinetics. Iron oxidation consists mainly of the outward diffusion of iron ions and the inward diffusion of oxygen.…”

Section: High Temperature Oxidation Of Steelmentioning

confidence: 99%

Modelling the Behaviour of Oxide Scale in Hot Rolling

Krzyżanowski

Beynon

2006

ISIJ International

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In the hot strip mill, the slab is brought to temperature in the reheating furnace and discharged for rolling. To break the primary scale, the slab is passed through a slab descaler before the reversing roughing mill. A secondary oxide scale is inevitably formed between successive rolling passes during hot rolling, which is further removed by high pressure water jets before the subsequent passes during reversing rolling or before the strip enters the tandem finishing mill. Whether the oxide scale is deformed or fractures, it will inevitably affect the interaction between tool and workpiece for several reasons: the thermal conductivity of the oxide scale is significantly less than that of the steel 1); fractured scale can enable direct contact of hot metal with the cold tool 2,3) ; because of the possibility of sliding of the fractured scale raft due to weakness of the scale/metal interface at high temperatures 4) ; and because the location of the plane of sliding is determined by the cohesive strength at the different interfaces within the multilayer oxide/metal system and by the stress distribution when delamination within the scale takes place. 5)The oxide scale on the surface of the hot metal is important for the control of friction and heat transfer when in contact with the roll, as well as influencing the rate of heat loss between rolling deformations under air or water sprays. During multi-pass hot rolling of long products, the magnitude of the coefficient of friction within the roll bite is variable due to the complex pressure-slip variations. A new Coulomb-Norton type friction model for long products and bar sections has been developed recently at Swinden Technology Centre (Corus RD&T UK).6) Among other assumptions, the model takes into consideration some complex interactions at the stock-roll interface due to the presence of secondary oxide scale, as mentioned above. Hence, the different modes of scale failure, such as the through-thickness cracking and the sliding mode, depending on the temperature and steel composition, have been implemented into the mathematical model. The friction force occurs either between the roll surface and oxide scale or between the roll surface, the oxide scale fragments and eventually fresh steel extruded through the scale gaps depending on the relative magnitude of the shear stresses inside the scale layer and at the oxide scale/stock interface. An additional point of consideration is the demand for increasingly small final thicknesses of the hot rolled steel strip, approximately 1.2 mm during conventional rolling and 0.8-1.0 mm for ultra-thin hot rolled strips produced on mini-mills using endless rolling technology.7) The scale related imperfections formed on upper and lower surfaces of the thin strip affect deformation of subsurface layers of the material during rolling which become relatively more pronounced during rolling of the very thin strips.Perhaps of greater and growing importance is the role played by the oxide scale in determining the quality of the surface of t...

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“…This is might be due to the introduction of water vapor that increases the volatilization activity. Hickman and Gulbransen [16] in their study has concluded that the presence of water vapor increase the volatilization of metal oxide by 30 % as compared to dry environment.…”

Section: Ir Transmission Spectramentioning

confidence: 97%

Effects of water vapor on protectiveness of Cr₂O₃ scale at 1073 K

Arifin

Hamid

Berahim

et al. 2018

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. Fe-Cr alloy is commonly being used as boiler tube's material. It is subjected to prolonged exposure to water vapor oxidation. The ability to withstand high temperature corrosion can normally be attributed to the formation of a dense and slow growing Cr-richoxide scale known as chromia, Cr 2 O 3 scale. However, oxidation may limit the alloy's service lifetime due to decreasing of its protectiveness capability. This paper is to presents an experimental study of thermo gravimetric and Fourier transform infrared analysis of Cr 2 O 3 at 1073 K in dry and humid environment. Samples were used from commercially available Cr 2 O 3 powder. It was cold-pressed into pellet shape of 12 mm diameter and 3 mm thick with hydraulic press for 40 min at 48 MPa. It then sintered at 1173 K in inert gas environment for 8 h. The samples are cooled and placed in 5 mm diameter platinum pan. It is subjected to reaction in dry and wet environment at 1073 K by applying 100%-Ar and Ar-5%H 2 gas. Each reaction period is 48 h utilizing Thermo Gravimetric Analyzer, TGA to quantify the mass changes. After the reaction, the samples then characterized with Fourier Transform Infrared Spectroscopy, FT-IR and Field Emission Electron Scanning Microscopy, FE-SEM. The TGA result shows mass decreasing ratio of Cr 2 O 3 in wet (P H 2 O =9.5x10 5 Pa) and dry environment is at a factor of 1.2 while parabolic rate at 1.4. FT-IR results confirmed that water vapor significantly broaden the peaks, thus promotes the volatilization of Cr 2 O 3 in wet sample. FESEM shows mostly packed and intact in dry while in wet sample, slightly porous particle arrangement compare to dry. It is concluded that water vapor species decreased Cr 2 O 3 protectiveness capability.

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An Electron Diffraction Study of Oxide Films Formed on High Temperature Oxidation Resistant Alloys

Cited by 10 publications

References 0 publications

Surface composition modification of high-carbon low-alloy steels oxidized at high temperature in air

Surface composition modification of high-carbon low-alloy steels oxidized at high temperature in air

Modelling the Behaviour of Oxide Scale in Hot Rolling

Effects of water vapor on protectiveness of Cr₂O₃ scale at 1073 K

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An Electron Diffraction Study of Oxide Films Formed on High Temperature Oxidation Resistant Alloys

Cited by 10 publications

References 0 publications

Surface composition modification of high-carbon low-alloy steels oxidized at high temperature in air

Surface composition modification of high-carbon low-alloy steels oxidized at high temperature in air

Modelling the Behaviour of Oxide Scale in Hot Rolling

Effects of water vapor on protectiveness of Cr2O3 scale at 1073 K

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Product

Resources

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Effects of water vapor on protectiveness of Cr₂O₃ scale at 1073 K