scholarly journals Effect of a grain-refined microalloyed steel substrate on the formation mechanism of a tight oxide scale

2014 ◽  
Vol 85 ◽  
pp. 115-125 ◽  
Author(s):  
Xianglong Yu ◽  
Zhengyi Jiang ◽  
Jingwei Zhao ◽  
Dongbin Wei ◽  
Cunlong Zhou ◽  
...  
Keyword(s):  
Oxide Scale ◽  
Formation Mechanism ◽  
Microalloyed Steel ◽  
Steel Substrate

scholarly journals Precipitation Behavior of Magnetite in Oxide Scale during Cooling of Microalloyed Low Carbon Steel

2012 ◽  
Vol 572 ◽  
pp. 249-254 ◽  
Author(s):  
Xiang Long Yu ◽  
Zheng Yi Jiang ◽  
Dai Jun Yang ◽  
Dong Bin Wei ◽  
Quan Yang
Keyword(s):  
Carbon Steel ◽  
Oxide Scale ◽  
Steel Substrate ◽  
Low Carbon Steel ◽  
Precipitation Process ◽  
Low Carbon ◽  
Precipitation Behavior ◽  
Magnetite Particles ◽  
And Migration ◽  
The Stability

Precipitation behavior of magnetite particles in the thermal grown oxide scale during isothermal cooling of microalloyed low carbon steel was studied using scanning electron microscopy (SEM) and thin film X-ray. The oxide scale was generated from Gleeble 3500 Thermal Mechanical Simulator connected with a humid air generator, to simulate 550 and 450C isothermal treatments. Several types of magnetite precipitates were observed during different cooling processes with respect to the possible mechanisms of precipitation have been discussed. It is found that magnetite particles is as a result of pro-eutectoid precipitation from oxygen-rich wustite, and also as a product of the partial decomposition of wustite during the cooling process due to change of oxygen concentration and migration of iron ions. Furthermore, microalloyed elements in steel reduce the stability of wustite thereby facilitate the precipitation process, whose products of multi-phase oxide finally determine the adhesive strength of oxide scale and steel substrate.

scholarly journals Application of the Micro-Tensile Testing to Investigate the Adhesion of Thermal Oxide Scales Grown on AISI 441 Stainless Steel Sheet Oxidised in Air and Water Vapour

2009 ◽  
Vol 410-411 ◽  
pp. 187-193 ◽  
Author(s):  
Somrerk Chandra-ambhorn ◽  
Thanasak Nilsonthi ◽  
Youcef Madi ◽  
Alain Galerie
Keyword(s):  
Stainless Steel ◽  
Oxide Scale ◽  
Water Vapour ◽  
Tensile Testing ◽  
Steel Sheet ◽  
Steel Substrate ◽  
Testing Machine ◽  
Stainless Steel Sheet ◽  
Tensile Testing Machine ◽  
Mechanical Adhesion

A micro-tensile testing has been developed to investigate the adhesion behaviour of the oxide scale thermally grown on AISI 441 stainless steel sheet oxidised at 800 °C in different atmospheres - synthetic air and water vapour. In the test, a sample was placed in a tensile testing machine sitting in the chamber of a scanning electron microscope at room temperature. Evolution of the failure of the oxide scale was monitored in function of the imposed strain. It was found that the scale formed on steel oxidised in synthetic air exhibited the drastically lower spallation ratio in function of strain comparing to the scale on steel oxidised in 20 %v/v H2O/N2. For the sample oxidised in water vapour, it was clearly observed that the scale was primarily failed by the crack perpendicular to the tensile loading direction, followed by the spallation due to the compressive stress generated by the Poisson effect. After the test, precipitates rich in Nb, Si, and possibly Ti were observed at the internal interface between scale and steel substrate. For the oxidised samples that the final polishing direction paralleled to the main sample axis, the strain provoking the first spallation of the samples oxidised in synthetic air and 20%H2O/N2 were 6.23 and 3.52 % respectively. The theoretical model was developed in our previous work to quantify the mechanical adhesion energy. These values were 357 and 68 J.m–2 for the steels oxidised in synthetic air and 20%H2O/N2 respectively.

A Review of Microstructure and Microtexture of Tertiary Oxide Scale in a Hot Strip Mill

2016 ◽  
Vol 716 ◽  
pp. 843-855 ◽  
Author(s):  
Xiang Long Yu ◽  
Zheng Yi Jiang ◽  
Jing Wei Zhao ◽  
Dong Bin Wei ◽  
Ji Zhou
Keyword(s):  
Oxide Scale ◽  
Hot Rolling ◽  
Steel Substrate ◽  
Steel Strip ◽  
Oxidation Mechanism ◽  
Research Field ◽  
Experimental Investigations ◽  
Hot Strip Mill ◽  
Phase Identification ◽  
Microstructure And Microtexture

In hot rolling, metal oxides formed on steel surface can generally be classified as primary, secondary and tertiary oxide scales, corresponding to the reheating stages, the roughing stages and the finishing passes of continuous mills, respectively. The tertiary oxide scale grows into the final products on the hot-rolled steel strip during the finishing rolling and the subsequent cooling down to ambient temperature. We provide here a systematic overview of the oxidation mechanism, microstructure and microtexture development of the tertiary oxide scale. Mechanism of oxidation and Fe3O4 precipitation in tertiary oxide has been given as the fundamental theory. Three main sections has been divided in this review. The first section includes experimental investigations on microstructure evolution from the formation of oxide scale during hot rolling, then through continuous cooling, to Fe3O4 precipitation behaviour in storage cooling of hot-coiled strip. By using electron backscatter diffraction (EBSD) to characterise both the steel substrate and the oxide scale concurrently, the second section has further dealed with the texture-based analysis of oxide scale: phase identification, orientation analysis and coincident site lattice (CSL) boundaries. The third section has provided the general type of crystallographic texture and its evolutions in deformed Fe3O4 and steel substrate. Finally, the upcoming challenges have been addressed in this intriguing and promising research field.

The formation mechanism of complex carbides in Nb-V microalloyed steel

2021 ◽  
pp. 131544
Author(s):  
Xiaolin Li ◽  
Haozhe Li ◽  
Linxi Liu ◽  
Xiangtao Deng ◽  
Zhaodong Wang
Keyword(s):  
Formation Mechanism ◽  
Microalloyed Steel ◽  
Complex Carbides

Characterisation and Pickling Behaviour of Thermal Oxide Scale on Low Carbon Steel Produced from a Thin Slab

2011 ◽  
Vol 696 ◽  
pp. 156-161 ◽  
Author(s):  
Somrerk Chandra-ambhorn ◽  
Tanongsak Somphakdee ◽  
Walairat Chandra-Ambhorn
Keyword(s):  
Oxide Scale ◽  
Steel Substrate ◽  
Steel Strip ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Thin Slab ◽  
Pickling Solution ◽  
Mechanical Adhesion ◽  
The One ◽  
Hot Rolled

Thin slab interested in this work was the one with the thickness of ca. 50 mm and mainly made from recycled steel. Chemical composition of the studied steel strip produced from such slab was Fe with 0.077 wt% C, 0.233 wt% Mn, 0.191 wt% Si, 0.159 wt% Cu and 0.052 wt% Ni. Scale retained on that steel after hot rolling was studied. The hot-rolled sample was pickled in 10%v/v HCl aqueous solution at 80 °C. Weight loss and relative XRD peaks of hematite-per-iron and magnetite-per-iron were measured at different pickling periods of time. It was observed that the as-received scale was crack-free. Hematite-and-iron ratio approached zero at the pickling time of 3 seconds. Magnetite-per-iron ratio gradually decreased with increased pickling time and approached zero later. These results indicated that pickling solution attacked the outermost hematite layer resulting in removing of this layer first. Sublayers of scale consisting of magnetite were completely pickled later. Pickling behaviour was not merely volumetric since scale was crack-free. Mechanical adhesion of scale on steel substrate was additionally investigated by tensile test to help characterise the oxide scale.

scholarly journals Formation Mechanism of Sliver-type Surface Defect with Oxide Scale on Sheet and Coil

2001 ◽  
Vol 87 (2) ◽  
pp. 85-92 ◽  
Author(s):  
Masafumi ZEZE ◽  
Arata TANAKA ◽  
Ryoji TSUJINO
Keyword(s):  
Oxide Scale ◽  
Formation Mechanism ◽  
Surface Defect

Study on Formation of Bottom Dross in Hot-Dip Zn-0.1%Ni Alloy

2014 ◽  
Vol 881-883 ◽  
pp. 1572-1575 ◽  
Author(s):  
Gong Luo ◽  
You Bin Wang ◽  
Jian Min Zeng ◽  
Huan He ◽  
Jia Lin Yan ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Steel Substrate ◽  
Molten Zinc ◽  
Ni Alloy

The composition, microstructure and formation mechanism of the bottom dross in hot-dipping Zn-0.1%Ni alloy bath have been investigated through XRF, XRD and SEM. It is found that the bottom dross is an aggregation consisting of FeZn13(ζ), FeZn15and a small amount of Ni3Zn22. The formation mechanism of bottom dross can be described that loose ζ phase formed on the steel substrate and then flakes off from substrate; ferroalloy is formed and precipitated from the melt with diffusion of Fe into molten zinc if the dissolved Fe surpass its solubility in the molten zinc. It also indicated that there exists a trace of Ni in the bottom dross in hot-dipping Zn-0.1%Ni alloy bath.

Tribological properties of magnetite precipitate from oxide scale in hot-rolled microalloyed steel

Wear ◽  
2013 ◽  
Vol 302 (1-2) ◽  
pp. 1286-1294 ◽  
Author(s):  
Xianglong Yu ◽  
Zhengyi Jiang ◽  
Dongbin Wei ◽  
Cunlong Zhou ◽  
Qingxue Huang ◽  
...  
Keyword(s):  
Oxide Scale ◽  
Tribological Properties ◽  
Microalloyed Steel ◽  
Hot Rolled

scholarly journals Microtexture and Rolling Deformation Behavior Analysis of the Formation Mechanism Fe3O4 at the Interface Formed on Hot-Rolled High-Strength Steel

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 312
Author(s):  
Chao Wang ◽  
Huibin Wu ◽  
Zhichao Li ◽  
Pengcheng Zhang ◽  
Leilei Li
Keyword(s):  
Oxide Scale ◽  
Oxide Layer ◽  
Formation Mechanism ◽  
High Strength Steel ◽  
Reduction Rate ◽  
High Strength ◽  
Fiber Texture ◽  
Steel Matrix ◽  
Two Phase ◽  
Spherical Grains

In order to better understand the formation mechanism of tertiary oxide scale in high-strength steel during hot rolling, the microtexture of the oxide layer has been characterized and analyzed by the electron backscatter diffraction (EBSD) method. The results show that the Fe3O4 phase in the oxide layer has a two-phase heterogeneous morphology, Fe3O4 in the oxide layer comprises columnar grains, and Fe3O4 near the substrate comprises spherical grains. As the reduction rate increases, the Fe2O3 layer is gradually wedged into the surface of the Fe3O4 layer. Fe3O4 forms a <110> fiber texture at a reduction rate of 10%. The inner layer of the oxide scale comprises spherical grains, and Fe3O4 is preferentially nucleated and precipitated in the direction of Fe surface grains <110> texture. With the increase in the reduction rate, the {112}<−1−21> directional slip system shows the lowest Schmidt factor value, so the grains with a low Schmidt factor exhibit higher stored strain energy. The formation of the spherical Fe3O4 seam layer close to the steel matrix is the result of the combined effect of the stress state at the matrix and ion diffusion.

Modelling of the Development of Initial Crack under Hot Rolling Condition

2006 ◽  
Vol 505-507 ◽  
pp. 1291-1296 ◽  
Author(s):  
Jian Ning Tang ◽  
A. Kiet Tieu ◽  
Zheng Yi Jiang
Keyword(s):  
Oxide Scale ◽  
Hot Rolling ◽  
Crack Width ◽  
Steel Substrate ◽  
Rolling Process ◽  
Initial Crack ◽  
Strip Surface ◽  
Hot Rolling Process ◽  
Scale Layer ◽  
Materials Flow

An oxide scale layer is formed on the steel strip surface due to the high temperature (850-1100 °C) of the strip in hot rolling. The oxide scale layer may not be continuous because of the defects such as void existing in the layer before the strip enters the roll bite. The non-zero cracks may therefore be formed on the oxide scale layer, especially, when the oxide scale layer is relatively thick. These cracks may become narrower (even become closed) or wider (even form steel substrate extrusion) after hot rolling deformation. The development of the crack depends on the materials flow in the hot rolling process. The shape of the profile of the oxide scale layer has a significant effect on the materials flow in hot rolling process so it is important to investigate the effect of the oxide scale profile on the propagation of the crack. In this paper, the authors used the FEM method to simulate the crack propagation in oxide scale under hot rolling conditions for different profile parameters of the oxide scale layer. Simulation results indicate that the larger is the initial profiles surface roughness, the larger the crack width remained after rolling. With a rough profile and large initial crack width, the steel substrate extrusion may be formed.

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