Numerical investigation of the free surface in a continuous steel casting mold model

Panaras, Giorgos; Theodorakakos, A.; Berggeles, G.

doi:10.1007/s11663-998-0081-3

Cited by 47 publications

(42 citation statements)

References 15 publications

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“…[1,2] This affects delivery of superheat to the solid/liquid interface of the growing shell. This agrees with the predications and measurements of Panaras et al [35] and might help to explain the mechanisms of different mechanisms of surface defects formation. As solidification starts, the dendrites begin to grow and the heat transfer mode changes [36].…”

Section: Simulated Results and Comparisonssupporting

confidence: 92%

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Mold Thermo-Mechanical Rigidity Criterion for Surface Quality of Continuous Casting of Steel

El-Bealy¹

2013

MSA

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A theoretical investigation of heat flow, solidification and solid shell resistance "I c " has been undertaken by using a mathematical model and previous plant trials. The ultimate purpose is to develop operating conditions and therefore to improve the surface quality for continuously cast steel slabs. A new simple criterion called mold thermo-mechanical rigidity "MTMR" has been proposed to evaluate and to improve these purposes. The parameters of MTMR and its non-dimensional number which use to control the surface defects are present in this investigation. Previous plant trails of slab surface defects formation have been investigated thermo-mechanically with this criterion. The predications show that this criterion is very sensitive of operating parameters and is a significant qualitative tool to evaluate the surface quality. From examination of the behavior of MTMR, the susceptibility and mechanism of surface defects formations with MTMR have been primarily discussed.

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Section: Simulated Results and Comparisonssupporting

confidence: 92%

“…onset of a steadily growing gap, the air gap increases very slowly [35,36] which results in a slight fluctuation of heat flux due to the effect of increasing in the ferrostatic head effect. This is associated with very slight decreasing in Q  until minimum value at mold exit 100 kW/m 2 .…”

Section: Simulated Results and Comparisonsmentioning

confidence: 99%

Mold Thermo-Mechanical Rigidity Criterion for Surface Quality of Continuous Casting of Steel

El-Bealy¹

2013

MSA

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“…150,151) The critical velocity also depends on the relative densities of the steel and flux phases and the mold geometry. 151,152) High velocity surface flows also may cause emulsification of the slag, where slag and steel intermix and even create a foam, if too much argon gas is present. 153) This allows easy capture of particles via vortexing or surface shearing flow.…”

Section: Entrainment Of Mold Slagmentioning

confidence: 99%

State of the Art in Evaluation and Control of Steel Cleanliness.

2003

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This paper first reviews the current "state-of-the-art" in the evaluation of steel cleanliness, discussing over 20 different methods. The demand for cleaner steels requires lowering non-metallic oxide inclusions and also controlling their morphology, composition and size distribution. Because no single method can measure all of these aspects accurately, it is best to combine several methods together to quantify steel cleanliness in a given operation. Owing to the cost, time requirements, and sampling difficulties, steel cleanliness is widely inferred using total oxygen, nitrogen pick-up, and other indirect methods. Recent cleanliness values using these indicators are summarized for LCAK at many steel plants around the world. Secondly, this paper reviews operating practices to improve steel cleanliness at the ladle, tundish and continuous caster, emphasizing findings quantified with plant measurements. Inclusions come from many sources, including deoxidation, reoxidation, slag entrapment, refractory wear, and chemical reactions. They generate many defects such as cracks and slivers in the steel product. Steel cleanliness is controlled by attention to a wide range of important operating conditions throughout the steelmaking and casting processes. For ladle operations, FeO and MnO in the slag, ladle treatments, and inclusion modification are discussed. For tundish operations, tundish depth and capacity, casting transitions, refractory lining, tundish flux; gas stirring, and flow controls are discussed. Important transfer operations from ladle to tundish and from tundish to mold, such as argon protection, sealing issues, and SEN clogging are summarized. Caster operations reviewed include the effect of casting speed, fluid flow pattern control, surface level control, and caster curvature.

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“…[1][2][3] Some researchers have studied the relationship between unsteady fluctuations in liquid steel level in the mold and the superficial defects mechanism using mathematical simulations. [4][5][6][7][8][9] For some authors, the Submerged Entry Nozzle (SEN) has determinant influence on the flow pattern at the upper section of the continuous casting mold and therefore, on the internal and superficial defects in the produced steel. [10][11][12] Several numerical experiments and water model experiments have been done to determine the SEN contribution to surface defects generation and mold powder trapping.…”

Section: Introductionmentioning

confidence: 99%

Transient Internal Flow Characterization of a Bifurcated Submerged Entry Nozzle

et al. 2006

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Many authors have pointed out that the steel superficial quality strongly depends on the operating conditions at the continuous caster mold. The analysis of the dynamic behavior of the fluid inside the mold Submerged Entry Nozzle (SEN) was done in this work by means of numerical simulations. In this work, the tundish sliding nozzle was not included. The results of two different turbulence models, the K-e and the Large Eddy Simulations (LES) models were compared. In simulations with both models, the velocity magnitude at 24 points inside the SEN was recorded every 0.001 s. The power spectrum of the results obtained with the LES turbulence model shows that the behavior inside the SEN is periodic. This behavior is compared with that obtained in physical simulations.KEY WORDS: continuous casting; fundamental frequencies; K-e turbulence model; LES turbulence model; submerged entry nozzle.ISIJ International, Vol. 46 (2006), No. 8, pp. 1183No. 8, pp. -1191 water model was employed. The mathematical model was solved using a commercial Computational Fluid Dynamics (CFD) software. Three different flow velocity conditions were simulated. To accomplish the dynamic analysis of the fluid inside the SEN, 24 monitoring points were defined. Several velocity magnitude time series were obtained for each monitoring point. Through a frequency analysis of the time series, it was found that jets at ports have periodic behavior which changes with SEN inlet flow velocity. Finally, it was found that the periodic frequencies obtained with mathematical simulations are similar to that measured in physical simulations. System DescriptionThe SEN geometry importance on the flow patterns inside the mold has been recognized long time ago. For instance, the SEN geometry in thin-slab continuous casting is very different to that used in the standard slab casting. 16,17) To compare the results of numerical simulations of this work with physical simulations reported in a previous work, 9) a pool-type SEN represented schematically in Fig. 1 was used. Additionally, the SEN dimensions correspond to a 1 : 1/3 scaled water model and are reported in Table 1. A bifurcated SEN with two exit ports was chosen, because this type is used commonly in actual casting and most of the numerical simulations of the fluid inside the SEN have been done using this geometry.In this work, the internal geometries of the bore and ports were assumed cylindrical. Nozzles with squared and cylindrical ports have been studied mathematically using the K-e turbulence model elsewhere. 10,12) These works have concluded that no significant differences between them were observed. The purpose of the port angle is to direct the molten steel jet into the mold cavity properly. The effect of the port angle on the flow pattern inside the mold has been widely studied. 10,12) In this work, downward ports were used. The port angle was 15 deg. This angle is commonly used at industry.Several configurations of the SEN bottom are used in actual casting. The most usual designs includes flat, pointed...

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Numerical investigation of the free surface in a continuous steel casting mold model

Cited by 47 publications

References 15 publications

Mold Thermo-Mechanical Rigidity Criterion for Surface Quality of Continuous Casting of Steel

Mold Thermo-Mechanical Rigidity Criterion for Surface Quality of Continuous Casting of Steel

State of the Art in Evaluation and Control of Steel Cleanliness.

Transient Internal Flow Characterization of a Bifurcated Submerged Entry Nozzle

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