Application of an Equiaxed Grain Growth and Transport Model to Study Macrosegregation in a DC Casting Experiment

Pakanati, Akash; Tveito, Knut Omdal; M’Hamdi, M.; Combeau, Hervé; Založnik, Miha

doi:10.1007/s11661-019-05133-z

Cited by 13 publications

(8 citation statements)

References 35 publications

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“…As shown in Figure 17a, not only under low superheat, but also under high superheat, both of the velocity magnitudes in the inner curve sides had a greater value than those in the outer curve sides. Meanwhile, as to the standard deviation calculated by Equation (16) in Figure 17b, the values in the inner curve side also had a greater value than those in the outer curve side. These phenomena indicated that there was more active interdendritic fluid flow in the inner curve side by comparison with the outer curve side, which corresponded with the gravity features of the curved segment of the continuous casting machine in Figure 1.…”

Section: Magnitude Of Interdendritic Fluid Flow Velocitymentioning

confidence: 83%

“…Then, the corresponding velocity can be calculated. Finally, the difference between V δ Va and V δ Vao is the magnitude of interdendritic fluid flow velocity V i f f , as shown in Equation (16). The corresponding flowchart is also shown in Figure 12.…”

Section: Model Descriptionmentioning

confidence: 99%

“…However, because the structures are somewhat conceptual and the pressure gradients are assumed or approximate, the calculated velocities always deviate from the real. At the same time, flow velocity in the pure liquid zone is always simulated by many researchers, but it is still very difficult to correctly simulate the flow velocity in the mushy zone, especially for complex fluid flow or large-size casting or with different actual dendritic grains of complex morphology [2,6,7,15,16]. Additionally, if based on the actual result (like the segregation content ratio) and local solute redistribution equation [5,6], the velocity magnitude can be calculated by at least two contents, but it is only a relative value with respect to a reference content that may not be available to compare (e.g., original liquid content that ignores element diffusion or liquid transfer) and is always a cubic average value with a large scale (e.g., centimeter) for the shortcomings of content measuring methods.…”

Section: Introductionmentioning

confidence: 99%

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A New Approach to Calculate the Velocity of Interdendritic Fluid Flow during Solidification Using Etched Surface Height of Actual Metal Ingot

Hou

Peng

Liu

et al. 2021

Metals

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Macrosegregation remains one of main defects affecting metal materials properties, which is mainly caused by interdendritic fluid flow during solidifying. However, as for controlling actual specific segregation, it is still difficult to effectively measure or simulate this kind flow instead of pure fluid flow, especially in complex casting processes of high-grade materials. Herein, a new method for obtaining velocity magnitude and direction of interdendritic fluid flow during metal solidifying is proposed from boundary layer and standard deviation obtained by measuring etched surface heights of the actual ingot and using statistical principles. Taking continuous casting bloom of GCr15 bearing steel as an example, it is indicated that the calculated velocity magnitudes under different sides and superheats can be explained by process features and, hence, solidification mechanism. The velocity magnitude and fluctuation are higher on the inner curve side and under low superheat. Meanwhile, it is found that the fluctuation extent of secondary arm spacing is more relevant with interdendritic fluid flow, although its magnitude is mainly determined by the cooling rate. Moreover, on the basis of the calculated velocity directions and magnitudes, there is a positive correlation between segregation area ratio and the effective ratio between interdendritic flow velocity and growth velocity especially in the equiaxed grain zone, which corresponds with classic macrosegregation formation theory. The above findings and comparison with other results demonstrate the validity of the new approach, which can obtain the magnitude and the direction of interdendritic fluid velocity for two or three-dimensional multiscale velocity distribution by tailoring measuring length and numbers.

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Section: Magnitude Of Interdendritic Fluid Flow Velocitymentioning

confidence: 83%

Section: Model Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A New Approach to Calculate the Velocity of Interdendritic Fluid Flow during Solidification Using Etched Surface Height of Actual Metal Ingot

Hou

Peng

Liu

et al. 2021

Metals

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“…Based on volume averaged method, simulations for ingot solidification have been carried out to investigate the mechanism of macrosegregation formation [24][25] and the effect of electromagnetic stirring [26] . Recently, such class of models were introduced to the computer simulation of continuous casting processes [27][28][29] .…”

Section: Introductionmentioning

confidence: 99%

Effect of vertical electromagnetic stirring on solute distribution in billet continuous casting process

Wang

Delannoy

et al. 2021

J. Iron Steel Res. Int.

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A volume averaged columnar solidification model, which couples the flow, temperature and solute concentration fields, is applied to simulate experimental casting cases with and without vertical electromagnetic stirring (V-EMS). The calculated distribution of electromagnetic intensity and final macrosegregation maps are consistent with the experimental results. Calculation results reveal that the V-EMS promotes longitudinal melt flow, accelerates heat dissipation, shortens the solidification end and reduces the central segregation of carbon.However, when V-EMS is applied, the solute distribution becomes asymmetric because the melt flow shows opposite directions between the near and far sides from stirrer. An obvious positive segregation band is observed at about 1/4 width of the billet near the stirrer in both calculated and experimental results. The position and degree of such positive segregation could be affected by installation height of stirrer, as demonstrated by additional simulation cases.

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“…This three-phase model is based on the volume average method. It allows to describe the influence of grain morphology on macrosegregation [15,16].…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling of copper macro-segregation in the binary alloy Al-4Cu

et al. 2021

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In this paper, the modeling of the solidification of Al-4Cu alloy was studied. The calculation code is developed to model the equiaxed globular solidification of the Al-4Cu alloy in a square mold. The mold walls are subjected to constant temperatures and the velocity components are equal to 0, the exchange coefficient ’H’ between the interface of the melt and the mold is estimated at 500 W/( m2 K) and the initial melt temperature ’T0’ is equal to 900 K. The resolution method used is finite differences, the upwind scheme for convective terms, and the space-centered scheme for diffusive terms. The calculated profiles are temperature, solid fraction, concentration and macro-segregation of copper. At the beginning of cooling, the solidification of the Al-4Cu alloy started in the four corners of the plate. The grains formed at the walls could not move in the studied surface. With cooling time, the solidification of the casting developed rapidly in the lower part; because, the grains formed away from the walls sedimented and accumulated in this part of the plate. On other hand, the liquid was located mainly in the upper part. The segregation of copper in the two-phase mixture is due to its continuous rejection from the solid to the liquid.

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Application of an Equiaxed Grain Growth and Transport Model to Study Macrosegregation in a DC Casting Experiment

Cited by 13 publications

References 35 publications

A New Approach to Calculate the Velocity of Interdendritic Fluid Flow during Solidification Using Etched Surface Height of Actual Metal Ingot

A New Approach to Calculate the Velocity of Interdendritic Fluid Flow during Solidification Using Etched Surface Height of Actual Metal Ingot

Effect of vertical electromagnetic stirring on solute distribution in billet continuous casting process

Numerical modeling of copper macro-segregation in the binary alloy Al-4Cu

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