Mathematical Modeling of Iron and Steel Making Processes. Optimum Magnetic Flux Density in Quality Control of Casts with Level DC Magnetic Field in Continuous Casting Mold.

Yamamura, Hideaki; Toh, Takehiko; Harada, Hiroshi; Takeuchi, Eiichi; Ishii, T.

doi:10.2355/isijinternational.41.1229

Cited by 24 publications

(18 citation statements)

References 3 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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“…Experimental and theoretical results showed the existence of optimum magnetic flux density to minimize inclusions defects in the cast. 14) Application of braking technology is becoming common in thin slab CC and in ordinary high throughput CC.…”

Section: Brakingmentioning

confidence: 99%

Recent Progress of EPM in Steelmaking, Casting, and Solidification Processing

et al. 2007

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Recently, twin torch plasma heating became common rather than single torch which demands anode in the tundish wall. Recent Progress of EPM in Steelmaking, Casting, and Solidification ProcessingHideyuki YASUDA, 1) Takehiko TOH, 2) Kazuhiko IWAI 3) and Kazuki MORITA 4) 1) Department of Adaptive Machine Systems, Osaka University, Suita, Osaka 565-0871 Japan.2) Technical Development Bureau, Nippon Steel Corporation, 20-1, Shintomi, Futtsu, Chiba 293-8511 Japan.3) Department of Materials, Physics and Energy Engineering, Nagoya University, Nagoya, Aichi 464-8603 Japan. 4) Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 Japan.(Received on February 13, 2007; accepted on February 22, 2007 ) This paper reviews recent trends of electromagnetic processing in steelmaking, casting and solidification processing. Electromagnetic vibration for controlling the solidified structure and application of microwave in materials processing are also presented. Aim of this paper is to prospect the recent trends in electromagnetic processing of materials.KEY WORDS: continuous casting; solidification; container-less process; electromagnetic vibration; microwave.ISIJ International, Vol. 47 (2007), No. 4, Review ment of steel cast is under trial. With AC field, the plasma arc is reciprocally moved and the fan shape plasma is obtained as a time-averaged figure. This technique may enable the loss free surface treatment of the steel semi-products. 9) BrakingThe in-mold electromagnetic braking technique started as a localized MHD application 10) to brake directly the molten steel stream discharged from the submerged entry nozzle. At that time, however, the technique had several problems concerning the stability of braking effect and the resultant metallurgical benefits. The new technique of stably controlling the molten steel flow in the mold was developed by applying a level DC magnetic field (LMF) across the mold width to discover a new function of suppressing mixing in addition to the conventional functions ensuring the slab quality. [11][12][13] The metallurgical effects of LMF are to minimize the penetration of oxide inclusions into the cast and to stabilize the steel flow in the mold so as to avoid the entrainment of liquid flux into the cast. The latter function enhanced the rapid introduction of this technique to the thin slab caster, which has high casting speed characteristics. Another application of this technology is to minimize the transition region at the ladle change by imposing a level magnetic field during the sequential casting.When an external DC magnetic field is applied to moving electrically conductive fluid, electric current is induced in the fluid. The electric current in the fluid makes a circuit to satisfy the law of conservation of electric current, according to the electrical boundary condition and generates electromagnetic braking forces on the fluid. The electric current path formed in this way contains components in the direction opposite to the one for th...

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“…Takatani et al 3) analysed the molten steel flow and the effects of argon gas injection and EMBR on the meniscus behaviour in the continuous casting mold using a 3-D and unsteady mathematical model. Ishii et al, 4) Yamamura et al, 5) Harada et al 6) and Kubo et al 7) performed the numerical simulations to examine the effects of different types of magnetic fields utilized in the EMBR technique on the electromagnetic braking efficiency and also analysed the changes of molten steel flow field and inclusion distribution in the mold when the magnetic field was imposed with the argon gas bubble injection. Li et al 1,8,9) developed a numerical estimation to analyse the motion of inclusion considering the effects of argon gas injection and magnetic field application in the slab continuous casting mold.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Effects of Electromagnetic Brake and Argon Gas Injection on the Three-dimensional Multiphase Flow and Heat Transfer in Slab Continuous Casting Mold

Zhu

2008

ISIJ Int.

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A 3-D mathematical model has been developed to study the multiphase phenomena of magnetic field, flow field and temperature distribution of molten steel and inclusion behaviour, considering the coupled effects of electromagnetic brake (EMBR) and argon gas injection in the slab continuous casting mold with high casting speed. The effects of EMBR and argon gas injection on the flow and temperature of molten steel and inclusion removal rate have been investigated. Simulation results indicate that EMBR can slow down the flow velocity of molten steel effectively, especially near the meniscus; the areas of upper and lower re-circulation zones are reduced and temperature distribution of molten steel is more uniform and the temperature gradient is reduced; but it has no helpful for the removal of small inclusions. The argon gas injection can increase the molten steel flow up tendency in the upper re-circulation area duo to the buoyancy effect of ascending argon gas bubbles near the submerged entry nozzle (SEN) and be in favour of the floating up of inclusion particles, and temperature in the upper re-circulation zone increases. The increasing of argon gas flow rate results in a stronger vortex flow zone near the free surface, especially near the SEN and easily forms a secondary eddy flow with EMBR, which impacts the fluctuation of free surface and the slag entrapment. The double action of EMBR and argon gas injection can further increase the temperature in the upper re-circulation zone, especially near the meniscus, and the floating up rate of inclusions are also improved and the inclusions to be trapped into solidified shell is reduced.

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Mathematical Modeling of Iron and Steel Making Processes. Optimum Magnetic Flux Density in Quality Control of Casts with Level DC Magnetic Field in Continuous Casting Mold.

Cited by 24 publications

References 3 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

Recent Progress of EPM in Steelmaking, Casting, and Solidification Processing

Numerical Simulation of the Effects of Electromagnetic Brake and Argon Gas Injection on the Three-dimensional Multiphase Flow and Heat Transfer in Slab Continuous Casting Mold

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