Macrosegregation Improvement by Swirling Flow Nozzle for Bloom Continuous Castings

Sun, Haibo; Zhang, Jiaquan

doi:10.1007/s11663-013-9999-1

Cited by 50 publications

(35 citation statements)

References 22 publications

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“…In order to determine macrosegregation, the segregation coefficient k was employed, being defined as [6]: (1) where: c -actual content of the element at a given point in the cc ingot, c 0 -mean content of the element in a ladle sample Average analysis of steel from ladle sample for a test melt is presented in Table 1. In order to determine the size of zones of particular crystals at cc ingot's cross-section, macro-etching test was performed on the test case templates.…”

Section: Segregation Of Elements In Continuous Cast Carbon Steel Billmentioning

confidence: 99%

“…Electromagnetic stirring systems are commonly applied in metallurgical practice to mitigate adverse effects of continuous casting of melts at temperatures much higher than the liquidus temperature for a given chemical composition of steel [1][2]. The values of segregation coefficient such elements as carbon, sulphur and phosphorus can be used to determine of appropriate electromagnetic mould stirrer (EMS) setting ranges.…”

Section: Introductionmentioning

confidence: 99%

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Segregation of Elements in Continuous Cast Carbon Steel Billets Designated for Long Products

Hutny¹,

Warzecha²,

Derda³

et al. 2016

Archives of Metallurgy and Materials

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This article presents research results concerning designation of the scope of segregation of elements by analysing the ingot, designated for hot rolling of long products. The research tests were performed under industrial conditions, during continuous casting production cycle of high carbon steels. From cc ingots with square cross-section of 160 mm samples having the length of 400 mm were collected, out of which two samples were cut up, the so-called templates with the thickness of 20 mm. Segregation of elements was determined based on the quantitative analysis of results performed by using spark spectrometry pursuant to PN-H-04045. Changes in concentrations of elements were analysed along the line, which join the opposite sides of the sample in their half length and pass through the geometric centre of the square cross-section. In the further course of the research study, there was also determined the segregation along perpendicular line up to the surface connecting the core of the cross-section with lateral plane. Designations of element contents were performed at points distanced from each other by approx. 10 mm and situated on the lines. There was found segregation of carbon, sulphur and phosphorus.

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Section: Segregation Of Elements In Continuous Cast Carbon Steel Billmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Segregation of Elements in Continuous Cast Carbon Steel Billets Designated for Long Products

Hutny¹,

Warzecha²,

Derda³

et al. 2016

Archives of Metallurgy and Materials

View full text Add to dashboard Cite

show abstract

“…Two methods to realize a swirling flow or rotational flow during the steel casting have been intensively studied, namely, the swirling flow SEN method [26][27][28][29][30][31][32][33][34] and the mold-electromagnetic stirring (MEMS) method. [35][36][37][38] When using a swirling flow SEN, the penetration depth of the SEN outlet flow in mold was found to decrease. [28] The stability of the steel flow in the mold was enhanced and the defects on the slab surface were effectively reduced.…”

Section: Introductionmentioning

confidence: 98%

“…[36] Therefore, the use of a swirling flow or a rotational flow during metal castings is becoming an important way to produce high-quality steels. However, previous studies [26][27][28][29][30][31][32][33][34][35][36][37][38] of swirling flows during steel castings mainly focused only on the influence on the steel flow itself. Furthermore, previous studies focusing on the inclusion behavior in steel flows have mostly been carried out for conventional continuous casting processes, where no rotational steel flow phenomena exist in the horizontal cross sections of the SEN or the mold.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Nonmetallic Inclusion Motions in a Swirling Flow Submerged Entry Nozzle in a New Cylindrical Tundish Design

Ersson

Jonsson

et al. 2017

Metall Mater Trans B

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PEIYUAN NI, MIKAEL ERSSON, LAGE TORD INGEMAR JONSSON, and PÄ R GÖ RAN JÖ NSSONDifferent sizes and shapes of nonmetallic inclusions in a swirling flow submerged entry nozzle (SEN) placed in a new tundish design were investigated by using a Lagrangian particle tracking scheme. The results show that inclusions in the current cylindrical tundish have difficulties remaining in the top tundish region, since a strong rotational steel flow exists in this region. This high rotational flow of 0.7 m/s provides the required momentum for the formation of a strong swirling flow inside the SEN. The results show that inclusions larger than 40 lm were found to deposit to a smaller extent on the SEN wall compared to smaller inclusions. The reason is that these large inclusions have Separation number values larger than 1. Thus, the swirling flow causes these large size inclusions to move toward the SEN center. For the nonspherical inclusions, large size inclusions were found to be deposited on the SEN wall to a larger extent, compared to spherical inclusions. More specifically, the difference of the deposited inclusion number is around 27 pct. Overall, it was found that the swirling flow contains three regions, namely, the isotropic core region, the anisotropic turbulence region and the near-wall region. Therefore, anisotropic turbulent fluctuations should be taken into account when the inclusion motion was tracked in this complex flow. In addition, many inclusions were found to deposit at the SEN inlet region. The plotted velocity distribution shows that the inlet flow is very chaotic. A high turbulent kinetic energy value of around 0.08 m 2 /s 2 exists in this region, and a recirculating flow was also found here. These flow characteristics are harmful since they increase the inclusion transport toward the wall. Therefore, a new design of the SEN inlet should be developed in the future, with the aim to modify the inlet flow so that the inclusion deposition is reduced.

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“…Lei et al [17] and KwanGu et al [18] preliminarily investigated the flow, solidification, and solute transport in CC slab mold with an electromagnetic brake, but without detailed explanation of the effect of the electromagnetic field on the solidification process and solute transport, while the verification of the solute transport model was neglected. Sun et al [19] studied the effect of a swirling flow nozzle (SFN) on the flow, solidification, and macrosegregation behavior of casting blooms, and concluded that the formation of positive and negative segregation in the initial solidified shell can contribute to the flotation of solute-richer molten steel and the "solute washing effect" [20], which could offer the reader useful enlightenment for analyzing the swirling flow induced macrosegregation in the CC mold. However, the effects of M-EMS parameters on the macro-transport phenomena in CC bloom mold, especially the solute transport behavior, need detailed investigation.…”

Section: Introductionmentioning

confidence: 99%

Effects of EMS Induced Flow on Solidification and Solute Transport in Bloom Mold

Fang

Wang

et al. 2017

Metals

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Abstract:The flow, temperature, solidification, and solute concentration field in a continuous casting bloom mold were solved simultaneously by a multiphysics numerical model by considering the effect of in-mold electromagnetic stirring (M-EMS). The mold metallurgical differences between cases with and without EMS are discussed first, and then the solute transport model verified. Moreover, the effects of EMS current intensity on the metallurgical behavior in the bloom mold were also investigated. The simulated solute distributions were basically consistent with the test results. The simulations showed that M-EMS can apparently homogenize the initial solidified shell, liquid steel temperature, and solute element in the EMS effective zone. Meanwhile, the impingement effect of jet flow and molten steel superheat can be reduced, and the degree of negative segregation in the solidified shell at the mold corner alleviated from 0.74 to 0.78. However, the level fluctuation and segregation degree in the shell around the center of the wide and narrow sides were aggravated from 4.5 mm to 6.2 mm and from 0.84 to 0.738, respectively. With the rise of current intensity the bloom surface temperature, level fluctuation, stirring intensity, uniformity of molten steel temperature, and solute distribution also increased, while the growth velocity of the solidifying shell in the EMS effective zone declined and the solute mass fraction at the center of the computational outlet (z = 1.5 m) decreased. M-EMS with a current intensity of 600 A is more suitable for big bloom castings.

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Macrosegregation Improvement by Swirling Flow Nozzle for Bloom Continuous Castings

Cited by 50 publications

References 22 publications

Segregation of Elements in Continuous Cast Carbon Steel Billets Designated for Long Products

Segregation of Elements in Continuous Cast Carbon Steel Billets Designated for Long Products

A Study on the Nonmetallic Inclusion Motions in a Swirling Flow Submerged Entry Nozzle in a New Cylindrical Tundish Design

Effects of EMS Induced Flow on Solidification and Solute Transport in Bloom Mold

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