Shield for Improving Wavy Meniscus in the Billet Continuous Casting Mold with Electromagnetic Stirring

Cho, Myung Jong; Park, Eun Byung; Kim, Sang Won

doi:10.2355/isijinternational.50.1180

Cited by 15 publications

(13 citation statements)

References 16 publications

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“…The Lorentz force can be calculated by first solving Maxwell's equations and then applying Ohm's law as is done by the previous works. [18][19][20][21][22] In this paper, instead of solving the complicated Maxwell's equations, a semi-empirical equation is proposed to calculate the Lorentz force in time-averaged scheme: ; x, y, z are coordinate points in the calculation domain and (0,0,z) is the central axis of the rotational electromagnetic field, m. a and b are the half sizes of the bloom/ billet, m; c0 and c1 are coefficients, c0, c1 < 1.…”

Section: Lorentz Force Modelmentioning

confidence: 99%

Magnetohydrodynamic Phenomena, Fluid Control and Computational Modeling in the Continuous Casting of Billet and Bloom

et al. 2014

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Magnetohydrodynamic flow phenomena with electromagnetic stirring were studied in billet casting. Solidification microstructure and oscillation marks were also investigated. EMS with 310 A current was proven to increase central equiaxed zone from 10-15% in unstirred billet to over 45% in stirred billet for steel grade 40CrMo4. Dendritic microstructures at the billet corners were found to deflect downwards due to the sustained upward flow along the mould corners. Rhomboidity was observed to relate to the unsteady flow in the mould during changes of casting speed and EMS intensities. Computational modeling was performed and validated with the results obtained from the casting experiments. Through modeling, a declining phenomenon of the injected stream from the SEN was observed towards the back wall under certain stirring intensities. This would influence thermal distribution of the strand shell and casting qualities, thus requiring correct matching of the vertical shear flow field with the horizontal rotation flow in order to obtain a favorable flow field. In addition, vortexes were found on the free surface around the SEN tube, which were influential to the cleanliness of steel melt. Modeling was also performed for a bloom caster with various SEN designs in the context of cleanliness. It was found that ported SENs showed obvious advantage on inclusion removal over the straight bore SEN. Reducing casting speed is actually an effective way to improve cleanliness. Casting trials with 65 bloom casting heats verified the modeling results and remarkable improvement in cleanliness was observed by using a 2-port SEN.

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Section: Lorentz Force Modelmentioning

confidence: 99%

Magnetohydrodynamic Phenomena, Fluid Control and Computational Modeling in the Continuous Casting of Billet and Bloom

et al. 2014

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“…However, this increment of meniscus turbulence may cause serious level fluctuation and increase the chances of mold powder entrapment, deteriorating the surface quality of the strand. [18,21] Figure 10 indicates the temperature field on the Y ¼ 0 plane at different stirring currents. When M-EMS is off, the molten steel from the SEN flows downward with slow superheat dissipation.…”

Section: Flow Field and Solidificationmentioning

confidence: 99%

“…They also set up a model to compute the flow field and inclusion distribution inside the whole strand by using the analytical expression for the electromagnetic force deduced by Spitzer [10] . Cho et al [18] installed an electromagnetic shield around the mold upper in the billet continuous casting with M-EMS. The designed shield was numerically investigated and applied to the actual billet caster.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Coupled Turbulent Flow and Macroscopic Solidification in a Round Bloom Continuous Casting Mold with Electromagnetic Stirring

Ren

Chen

Wang

et al. 2015

steel research int.

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In this article, a coupled three-dimensional mathematic model is established to describe electromagnetic field, fluid flow, heat transfer and solidification in a round bloom continuous casting mold with electromagnetic stirring (M-EMS). The interaction between the induced flow and the impinging jet from a straight-through submerged entry nozzle (SEN) of the caster is numerically analyzed. The results show that the electromagnetic force appears to be circinate at the cross section of the round bloom. Moreover, the flow of the melt is characterized by a dominant swirling movement along the azimuthal direction in the horizontal plane with M-EMS. However, the swirl flow velocity decreases remarkably when solidification is taken into account. With the increase of stirring intensity, the steady flow becomes unstable accompanying with the bias flow, and the temperature distribution is unsymmetrical in the mold. The significant swirl flow with M-EMS prevents the superheated jet moving downward and weakens the invasion depth of the jet, and thus the location of the hot zone in the mold moves up evidently.

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“…Thus, the dual M-EMS [17,18] was proposed to inhibit the disturbance near the meniscus by generating an opposite stirring mode in the mold cavity. The magnetic shield technology [19] was put forward in succession. However, the investment and maintenance cost of the equipment is quite high, which will increase the cost of productions.…”

Section: Introductionmentioning

confidence: 99%

Novel Opposite Stirring Mode in Bloom Continuous Casting Mould by Combining Swirling Flow Nozzle with EMS

Sun

Liu

2018

Metals

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The metallurgical performances in a mold cavity were investigated using a conventional bilateral-port nozzle or a swirling flow nozzle (SFN) plus with in-mold electromagnetic stirring (M-EMS) for bloom continuous casting (CC) process. To this end, a coupled model of electromagnetism, flow, and heat transfer was developed. Meanwhile, corresponding plant trials were conducted to evaluate the influence of a melt feeding mode on the internal quality of an as-cast bloom in Shaoguan Steel, China. Under the case of the SFN plus with M-EMS, a novel opposite stirring mode in the bloom CC mold cavity can be observed. A swirling flow in the anti-clockwise direction generated by the SFN, and the other swirling flow in the clockwise direction induced by the M-EMS were formed in regions with distances ranging from 0 m to 0.11 m and 0.218 m to 1.4 m from the meniscus, respectively. As compared to the case of the bilateral-port nozzle plus with M-EMS, the opposite stirring mode in the mold cavity can promote the melt superheat dissipation, improve the casting soundness and the componential homogeneity, inhibit the mold level fluctuation, and also be beneficial to prevent slag erosion for the nozzle external wall at the meniscus. Here, the fluctuation range of carbon segregation along the casting direction is reduced from 0.16 to 0.06, and the magnitude of mold level fluctuation is reduced from 5.6 mm to 2.3 mm under the adoption of SFN plus with M-EMS, respectively.

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Shield for Improving Wavy Meniscus in the Billet Continuous Casting Mold with Electromagnetic Stirring

Cited by 15 publications

References 16 publications

Magnetohydrodynamic Phenomena, Fluid Control and Computational Modeling in the Continuous Casting of Billet and Bloom

Magnetohydrodynamic Phenomena, Fluid Control and Computational Modeling in the Continuous Casting of Billet and Bloom

Numerical Analysis of Coupled Turbulent Flow and Macroscopic Solidification in a Round Bloom Continuous Casting Mold with Electromagnetic Stirring

Novel Opposite Stirring Mode in Bloom Continuous Casting Mould by Combining Swirling Flow Nozzle with EMS

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