Numerical Simulation of V-shaped Segregation in Continuous Casting Blooms Based on a Microsegregation Model

Guan, Rui; Ji, Cheng; Zhu, Miaoyong; Deng, Shijie

doi:10.1007/s11663-018-1352-2

Cited by 28 publications

(12 citation statements)

References 39 publications

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“…Such trend was maintained until the completion of solidification, as seen in the rest figures of Figure 1. The predicted smaller extent of segregation at lower superheat is in agreement with the findings reported by Mäkinen and Uoti [17], Sun et al [18], as well as Choudhary and Ganguly [19].…”

Section: Macrosegregation Patterns and Verificationsupporting

confidence: 92%

“…Sun et al reported that a lower melt superheat and a higher nucleation density decreased the severity of macrosegregation by weakening the flotation of grains [18]. Guan et al demonstrated that V-shaped segregation decreased with decreasing superheat in continuous casting blooms [19]. Choudhary and Ganguly observed that low superheat favored the surviving of equiaxed crystals, which ejected solutes uniformly within the mushy zone, resulting in a reduction in segregation [20].…”

Section: Introductionmentioning

confidence: 99%

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Simulation and experimental validation of the effect of superheat on macrosegregation in large-size steel ingots

Zhang

Jahazi

Tremblay

2020

Int J Adv Manuf Technol

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A 3D model was employed to study the effect of melt initial superheat on the macrosegregation formation using FE modeling and experimentation methods. The casting process of three ingots with the initial melt superheats of 75°C, 65°C and 55°C were simulated. The three cases represented three variables encountered in industry during casting of large size ingots. For the above three studied cases, all other casting conditions were kept the same. Results showed that the variation of initial melt superheat gave rise to changes in temperature pattern, liquid flow field, solidification speed, and thermomechanical contraction. Under the combined actions of all these changes, lower superheat tended to alleviate the segregation intensity in the upper part of the ingot body, in the hot-top, and in the solute-rich bands between the ingot centerline and periphery. The beneficial effect of lower superheat on alleviation of segregation severity was confirmed by experimental chemical measurement results. The results were analyzed in terms of heat and mass transfer theories and allow for a better understanding of the underlying mechanisms responsible for the occurrence of macrosegregation in ingot casting process. The findings should be helpful for the casting process design of a given ingot of high value-added steels or other alloys.

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Section: Macrosegregation Patterns and Verificationsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Simulation and experimental validation of the effect of superheat on macrosegregation in large-size steel ingots

Zhang

Jahazi

Tremblay

2020

Int J Adv Manuf Technol

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“…However, the predictive reliability of the solute transport model significantly depends on the accuracy of the prescribed thermophysical properties. The latter is closely associated with dendritic microsegregation models [4,5]. It is the microsegregation of elements on the dendritic scale that leads to the enrichment and paucity of the liquid and macroscale segregation of chemical species, through thermo-solutal convection currents in the course of ingot solidification.…”

Section: Introductionmentioning

confidence: 99%

“…It is the microsegregation of elements on the dendritic scale that leads to the enrichment and paucity of the liquid and macroscale segregation of chemical species, through thermo-solutal convection currents in the course of ingot solidification. Therefore, the selection of microsegregation model is of utmost significance for the accuracy of any macrosegregation predictions [4].…”

Section: Introductionmentioning

confidence: 99%

On the Impact of Microsegregation Model on the Thermophysical and Solidification Behaviors of a Large Size Steel Ingot

Zhang

Jahazi

Gallego

2020

Metals

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The impact of microsegregation models on thermophysical properties and solidification behaviors of a high strength steel was investigated. The examined microsegregation models include the classical equilibrium Lever rule, the extreme non-equilibrium Scheil-Gulliver, as well as other treatments in the intermediate regime proposed by Brody and Flemings, Clyne and Kurz, Kobayashi and Ohnaka. Based on the comparative analyses performed on three representative regions with varied secondary dendrite arm spacing sizes, the classical equilibrium Lever rule and non-equilibrium Scheil scheme were employed to determine the thermophysical features of the studied steel, using the experimentally verified models from literature. The evaluated thermophysical properties include effective thermal conductivity, specific heat capacity and density. The calculated thermophysical data were used for three-dimensional simulation of the casting and solidification process of a 40 metric ton steel ingot, using FEM code Thercast®. The simulations captured the full filling, the thermo-mechanical phenomena and macro-scale solute transport in the cast ingot. The results demonstrated that Lever rule turned out to be the most reasonable depiction of the physical behavior of steel in study in large-size cast ingot and appropriate for the relevant macrosegregation simulation study. The determination of the model was validated using the experimentally measured top cavity dimension, the thermal profiles on the mold outside surface by means of thermocouples, and the carbon distribution patterns via mass spectrometer analysis.

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“…V-segregation V-segregation is the name given to the eponymously-shaped channels that are formed in the centre of the equiaxed zone of continuously cast steel slabs, blooms and billets, in which the macrosegregation level of interstitial elements such as carbon and sulphur, and of substitutional elements such as molybdenum and chromium, can be quite extensive. Even today, the mechanism behind the development of V-shaped segregate channels or lines is still not well understood [106]. The appearance of the V-segregates differs between different cast sizes, width of the equiaxed zone and casting speed.…”

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confidence: 99%

Applied Mathematical Modelling of Continuous Casting Processes: A Review

Vynnycky

2018

Metals

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With readily available and ever-increasing computational resources, the modelling of continuous casting processes-mainly for steel, but also for copper and aluminium alloys-has predominantly focused on large-scale numerical simulation. Whilst there is certainly a need for this type of modelling, this paper highlights an alternative approach more grounded in applied mathematics, which lies between overly simplified analytical models and multi-dimensional simulations. In this approach, the governing equations are nondimensionalized and systematically simplified to obtain a formulation which is numerically much cheaper to compute, yet does not sacrifice any of the physics that was present in the original problem; in addition, the results should agree also quantitatively with those of the original model. This approach is well-suited to the modelling of continuous casting processes, which often involve the interaction of complex multiphysics. Recent examples involving mould taper, oscillation-mark formation, solidification shrinkage-induced macrosegregation and electromagnetic stirring are considered, as are the possibilities for the modelling of exudation, columnar-to-equiaxed transition, V-segregation, centreline porosity and mechanical soft reduction.

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Numerical Simulation of V-shaped Segregation in Continuous Casting Blooms Based on a Microsegregation Model

Cited by 28 publications

References 39 publications

Simulation and experimental validation of the effect of superheat on macrosegregation in large-size steel ingots

Simulation and experimental validation of the effect of superheat on macrosegregation in large-size steel ingots

On the Impact of Microsegregation Model on the Thermophysical and Solidification Behaviors of a Large Size Steel Ingot

Applied Mathematical Modelling of Continuous Casting Processes: A Review

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