Examination of Oxide Scales Formed During Hot Rolling of Steels

2019 ◽  
Vol 56 (7) ◽  
pp. 449-456
Author(s):  
T. Höfler ◽  
H. Danninger ◽  
B. Linder
Keyword(s):  
Hot Rolling ◽  
Oxide Scales

Modelling the Spalling of Oxide Scales During Hot Rolling of Steel Strip

2008 ◽  
Vol 70 (3-4) ◽  
pp. 137-148 ◽  
Author(s):  
Maribel de la Garza ◽  
Alfredo Artigas ◽  
Alberto Monsalve ◽  
Rafael Colás
Keyword(s):  
Hot Rolling ◽  
Steel Strip ◽  
Oxide Scales

Effect of steel composition on failure of oxide scales in tension under hot rolling conditions

2001 ◽  
Vol 72 (7) ◽  
pp. 250-258 ◽  
Author(s):  
Kim Soong Tan ◽  
Michal Krzyzanowski ◽  
John H. Beynon
Keyword(s):  
Hot Rolling ◽  
Oxide Scales ◽  
Steel Composition ◽  
Hot Rolling Conditions

Texture of Oxide Scales during Hot Rolling of Low Carbon Steel

2005 ◽  
Vol 495-497 ◽  
pp. 339-344 ◽  
Author(s):  
Vladimir V. Basabe ◽  
Jerzy A. Szpunar
Keyword(s):  
Carbon Steel ◽  
Oxide Scale ◽  
Hot Rolling ◽  
Low Carbon Steel ◽  
Cube Texture ◽  
Experimental Results ◽  
Oxide Scales ◽  
Low Carbon ◽  
Air Velocity ◽  
Temperature Range

The textures of oxide scales grown on low carbon steel in air over the temperature range 850-950°C were investigated. The low carbon steel was oxidized with the air velocity of 4.2 cm/s for 10 s in order to approximate the formation of tertiary scales in hot rolling. At 850°C, the wüstite texture and magnetite texture are weak with no dominant components. For the temperatures of 900 and 950°C, the wüstite and magnetite phases have a cube texture {001}<100>. The experimental results indicate that during hot rolling in the g region, the texture of the oxide scale is cubic and when rolling in the a region, the texture of the oxide scale is weak with no dominant components.

Microstructure and Phase Identification of Tertiary Oxide Scale on Steel by EBSD

2009 ◽  
Vol 283-286 ◽  
pp. 419-424
Author(s):  
Lucia Suarez ◽  
Pablo Rodriguez-Calvillo ◽  
Rafael Colás ◽  
Yvan Houbaert
Keyword(s):  
Oxide Scale ◽  
Plane Strain ◽  
Oxide Layer ◽  
Hot Rolling ◽  
Protective Atmosphere ◽  
Phase Identification ◽  
Oxide Scales ◽  
Orientation Relationships ◽  
Complex Deformation ◽  
Ebsd Technique

Oxide scales growing during hot rolling of steel represent an industrial and environmental problem. Tertiary oxide, which starts to form before entering the finishing stands, remains on the steel surface until the end of the process, affecting the final surface quality and the response to downstream processing. Characterizing scale layers and the scale/steel interface in terms of phase morphology, texture, grain structure and chemical composition is fundamental for a better understanding of their behaviour and the effect of thermomechanical cycles on the material response to further processing. Thin tertiary scale layers have been grown on ULC steel under controlled conditions in a laboratory device adequately positioned in a compression-testing machine, immediately before plane strain deformation. After heating under a protective atmosphere (nitrogen), the samples have been oxidized in air at 1050°C for a short oxidation time. Immediately after this controlled oxidation, some of the samples were subjected to plane strain compression (PSC) inside the experimental device, in order to simulate the finishing hot rolling process. Direct observations of oxide scale layers are impossible. The EBSD technique has been identified as a powerful tool that can be used to reveal the microstructure within the oxide scale and to distinguish between its constitutive phases, based on their distinct crystal lattices. The texture of the deformed oxide scales, originally grown on ULC steel, was determined in a SEM using the EBSD technique. This will help to achieve a better understanding of their complex deformation behaviour. Because the substrate deformation affects the oxide layer, orientation relationships between scale layer and substrate were measured and the crystallographic orientation between undeformed and deformed areas was determined. Strongly textured wustite grains with a clearly pronounced columnar structure were observed after oxidation at 1050°C. The detailed EBSD study reveals that the oxide layer is able to accommodate a significant amount of deformation.

Surface Roughness and Friction in Hot Rolling of Stainless Steels

2014 ◽  
Vol 783-786 ◽  
pp. 795-800
Author(s):  
Zheng Yi Jiang ◽  
Dong Bin Wei ◽  
Xia Wei Cheng ◽  
X. Gao ◽  
J.W. Zhang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Experimental Method ◽  
Oxide Scale ◽  
Stainless Steels ◽  
Hot Rolling ◽  
Friction Condition ◽  
Average Thickness ◽  
Oxide Scales ◽  
Fem Model ◽  
Martensitic Stainless Steels

An experimental method was developed to examine oxidations of austenitic and martensitic stainless steels. The results show that the surface roughness along both rolling and transverse directions decreases with an increase of reduction. When the reheating time is increased, the average thickness of oxide scales of stainless steels increases, which results in relatively rough surface after hot rolling. The effects of oxide scale on the friction condition and surface roughness transfer in hot rolling depend on the oxide scale generated during reheating. The calculated surface roughness is close to the experimental results, which verifies the developed FEM model.

The Microstructure of Nickel Oxide Scales

1981 ◽  
Vol 39 ◽  
pp. 86-87
Author(s):  
M. T. Tinker ◽  
L. W. Hobbs
Keyword(s):  
Electron Microscopy ◽  
Nickel Oxide ◽  
Ion Beam ◽  
Oxide Scales ◽  
Nickel Substrate ◽  
Outward Diffusion ◽  
Transmission Electron ◽  
Nickel Substrates ◽  
Nickel Base ◽  
Technological Interest

There is considerable technological interest in oxidation of nickel because of the importance of nickel-base superalloys in high-temperature oxidizing environments. NiO scales on nickel grow classically, by outward diffusion of nickel through the scale, and are among the most studied of oxidation systems. We report here the first extensive characterization by transmission electron microscopy of nickel oxide scales formed on bulk nickel substrates and sectioned both parallel and transversely to the Ni/NiO interface.Electrochemically-polished nickel sheet of 99.995% purity was oxidized at 1273 K in 0.1 MPa oxygen partial pressure for times between 5 s and 25 h. Parallel sections were produced using a combination of electropolishing of the nickel substrate and ion-beam thinning of the scale to any desired depth in the scale. Transverse sections were prepared by encasing stacked strips of oxidized nickel sheet in epoxy resin, sectioning transversely and ion-beam thinning until thin area spanning one or more interfaces was obtained.

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