Three-Dimensional Characterization of Defects in Continuous Casting Blooms of Heavy Rail Steel Using X-ray Computed Tomography

Cui, Lingxiao; Lei, Xunhui; Zhang, Lifeng; Zhang, Yuexin; Yang, Wen; Gao, Yuan; Liu, Yubao; Liu, Nan

doi:10.1007/s11663-021-02172-z

Cited by 13 publications

(4 citation statements)

References 30 publications

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“…The gas pores are resulted from the air entrapment and exhibited the spherical shape, while during solidification the volume contraction leads to irregular shapes known as the shrinkage defects. [ 29 ] The defects with sphericity <0.5 represent the shrinkage defects with fractured branches, [ 16 ] and the more spherical pore shape is evident as the sphericity increases from 0.5 to 1. [ 30 ] Moreover, the shrinkage defects with sphericity <0.5 can be categorized into two types: 1) island shrinkage with volume <0.008 mm 3 is mainly formed by the compromise of one or two voids, which is small in size and less irregular; 2) net shrinkage with volume >0.008 mm 3 is formed by the of cluster of micro‐voids, which is larger and highly irregular in morphology.…”

Section: Resultsmentioning

confidence: 99%

“…It was assured that the sample was mounted as stiff as possible without any chance of bending before cutting process. Figure 5 a reveals the schematic division of different zones in solidified microstructure of ingot, which was modified from the work of Cui et al [ 16 ] Figure 5b is taken from the lower half part of ingot, which clearly reveals the dimensions of extracted specimens to characterize the microstructure and internal defects in as‐cast ingot. The sample was scanned with original position metal analyzer (OPA) from the center region to inspect the carbon macrosegregation.…”

Section: Methodsmentioning

confidence: 99%

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Spatial Characterization of Internal Defects in Medium Carbon Steel via X‐Ray Computed Tomography

Ali

Zhang

Sui

et al. 2022

steel research int.

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Herein, the 3D characterization of internal defects in medium carbon steel with different soft reduction (SR) parameters is investigated, as regards its spatial morphology and size distribution using X‐ray computed tomography. The size of defects and their shape complexity increase from the equiaxed toward the center of the ingot, and the total number of defects is larger at the equiaxed region, which exhibits the aggregation and growth of small spherical pores into the large defects from equiaxed toward the center region. The two types of shrinkage defects, including island and net shrinkage, are identified. With the minimum reduction amount of 2 and 4 mm, the number and size of defects along with the carbon macrosegregation in the equiaxed region and center of the ingot are less as compared to the high reduction amount of 6 mm and without SR technology. The size of gas pores with sphericity >0.6 is <70 um with different reduction amounts and exceeds up to 150 um without SR. Therefore, minimum reduction amounts can easily regulate the internal defects in medium carbon steel.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Spatial Characterization of Internal Defects in Medium Carbon Steel via X‐Ray Computed Tomography

Ali

Zhang

Sui

et al. 2022

steel research int.

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“…As a nondestructive 3D inspection method, XCT has been widely used to measure the 3D structure of materials such as refractory, steel, and coke. [12][13][14][15] The 3D structure of copper cooling stave slag crust was characterized by XCT, and the spatial structure and distribution of internal metallic iron and pores were obtained. Different models were used to study the effects of metallic iron and air bubbles on thermal conductivity.…”

Section: Doi: 101002/srin202200710mentioning

confidence: 99%

X‐ray Computed Tomography Characterization of Slag Crust and the Effect of Bubbles and Metallic Iron in Slag on Heat Transfer to Copper Stave

Wang

Liu

et al. 2023

steel research int.

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Understanding the heat transfer properties of the slag crust is critical to the safe operation of copper staves. The distribution of metallic iron and bubbles in the slag crust is detected by X‐ray computed tomography. The thermal conductivity of the slag crust is modified based on an effective thermal conductivity model and laser thermal conductivity measurements to predict the effect of metallic iron and bubbles on the heat transfer in the slag crust. The results show that the average volume fractions of metallic iron and air bubbles in the slag crust are 3% and 4.5%, respectively. The measured value is consistent with the trend of the effective thermal conductivity calculation model, and the calculation result of the Maxwell–Eucken effective thermal conductivity model is very accurate. Variations in the volume fraction of metallic iron in the slag crust have a greater effect on the thickness of the slag crust, while variations in the volume fraction of bubbles have a smaller effect on the thickness of the slag crust. It is recommended to keep it between 10 and 30 mm in blast furnace production to help improve the operational life of the copper stave.

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“…The internal quality of the bearing steel bloom has great influence on its reliability and service life due to the inheritance of the defects from the bloom, such as shrinkage porosity, center segregation, and V-shaped segregation to the subsequent rolling product. Generally, homogenization of the chemical composition by means of electromagnetic stirring (EMS), pulsed magneto-oscillation (PMO), low superheat casting, low secondary cooling intensity, etc., is the most well-known approach to minimize the center segregation [1][2][3][4][5][6]. This approach aims to produce large ratio of equiaxed grains during solidification and normally is an effective way to reduce center segregation.…”

Section: Introductionmentioning

confidence: 99%

Industrial Application of Mechanical Reduction on Continuous Casting of Bearing Steel Bloom

Chen¹,

Deng²,

Niu³

2021

Processes

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Industrial experiments of mechanical soft reduction in continuous casting were conducted in the present study aiming to improve the internal quality of the bearing steel blooms. Two methods were developed to verify the solidification model for a reliable crater end in the caster, which is provided by SMS CONCAST. The verified solidification model was applied to determine the solidification status of the bloom and provides theoretical reduction region. Several trials were conducted to study the optimization of the reduction rate regarding the V-shaped and centerline segregation of the bloom. The results show an obvious improvement of internal quality in the bearing steel bloom by applying appropriate reduction during casting.

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Three-Dimensional Characterization of Defects in Continuous Casting Blooms of Heavy Rail Steel Using X-ray Computed Tomography

Cited by 13 publications

References 30 publications

Spatial Characterization of Internal Defects in Medium Carbon Steel via X‐Ray Computed Tomography

Spatial Characterization of Internal Defects in Medium Carbon Steel via X‐Ray Computed Tomography

X‐ray Computed Tomography Characterization of Slag Crust and the Effect of Bubbles and Metallic Iron in Slag on Heat Transfer to Copper Stave

Industrial Application of Mechanical Reduction on Continuous Casting of Bearing Steel Bloom

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