Editorial

4 pages, 143 KiB

Open AccessEditorial

Optimization of Industrial Casting Processes

by Steve Cockcroft

Metals 2020, 10(3), 360; https://doi.org/10.3390/met10030360 - 10 Mar 2020

Cited by 1 | Viewed by 2071

Casting processes have seen continuous technological development for close to 5000 years, largely through a process of trial-and-error improvement [...] Full article

(This article belongs to the Special Issue Optimization of Industrial Casting Processes)

Research

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13 pages, 4862 KiB

Open AccessArticle

Influence of Subflux Turbulence Controller and Ladle Shroud Asymmetric Using on Hydrodynamic Conditions in One Strand Slab Tundish

by Adam Cwudziński

Metals 2019, 9(1), 68; https://doi.org/10.3390/met9010068 - 11 Jan 2019

Cited by 3 | Viewed by 2486

Abstract

The tundish plays a key role in the process of continuous steel casting (CSC), as it ensures a stable flow of steel to the mould. Therefore, particular attention is paid to the behavior of liquid steel in the tundish. A wedge-shape tundish with [...] Read more.

The tundish plays a key role in the process of continuous steel casting (CSC), as it ensures a stable flow of steel to the mould. Therefore, particular attention is paid to the behavior of liquid steel in the tundish. A wedge-shape tundish with a nominal capacity of 30 tons was tested. The present study has examined different variants of subflux turbulence controller (STC) and ladle shroud (LS) positions relative to one another. For the designed continuous casting variants with the modified tundish pouring zones, numerical simulations of liquid steel behavior were performed. From the computer simulations results, motion, velocity magnitude, and temperature of liquid steel were obtained. Moreover the shares of stagnant volume flow, dispersed plug flow, well-mixed volume flow and transient zone were calculated. It is possible to effectively modify the hydrodynamic conditions by appropriate selection the position of the STC and LS. Full article

(This article belongs to the Special Issue Optimization of Industrial Casting Processes)

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17 pages, 4864 KiB

Open AccessArticle

Numerical Simulation of Fluid Flow, Heat Transfer, Species Transfer, and Solidification in Billet Continuous Casting Mold with M-EMS

by Wenjie Zhang, Sen Luo, Yao Chen, Weiling Wang and Miaoyong Zhu

Metals 2019, 9(1), 66; https://doi.org/10.3390/met9010066 - 11 Jan 2019

Cited by 36 | Viewed by 5460

Abstract

Electromagnetic stirring in mold (M-EMS) has been widely used in continuous casting process to improve the solidification quality of the steel strand. In the present study, a 3D multi-physical-field mathematical model was developed to predict the macro transport phenomena in continuous casting mold [...] Read more.

Electromagnetic stirring in mold (M-EMS) has been widely used in continuous casting process to improve the solidification quality of the steel strand. In the present study, a 3D multi-physical-field mathematical model was developed to predict the macro transport phenomena in continuous casting mold with M-EMS using ANSYS commercial software, and was adopted to investigate the effect of current intensity (0, 150, 200, and 240 A) on the heat, momentum, and species transports in the billet continuous casting mold with a size of 160 mm × 160 mm. The results show that when the M-EMS is on, the horizontal swirling flow appears and shifts the high-temperature zone upward. With the increase of current intensity, two swirling flows form on the longitudinal section of continuous casting mold and become more intensive, and the flow velocity of the molten steel at the solidification front increases. Thus, the wash effects of the fluid flow on the initial solidified shell become intensive, resulting in a thinner shell thickness at the mold exit and a significant negative segregation of carbon at the billet subsurface. Full article

(This article belongs to the Special Issue Optimization of Industrial Casting Processes)

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8 pages, 5892 KiB

Open AccessArticle

Surface Wear in Hadfield Steel Castings DOPED with Nitrided Vanadium

by Konstantin Vdovin, Alexander Pesin, Nikolay Feoktistov and Dmitri Gorlenko

Metals 2018, 8(10), 845; https://doi.org/10.3390/met8100845 - 18 Oct 2018

Cited by 14 | Viewed by 3440

Abstract

This paper examines possible industrial applications of high manganese steel and the feasibility of its inoculation with a new ferroalloy, vanadium nitride. The abrasive and impact-abrasion surface wear experienced by castings has a classical pattern: microcutting—i.e., the deformation twinning of surface layers. Ferrovanadium [...] Read more.

This paper examines possible industrial applications of high manganese steel and the feasibility of its inoculation with a new ferroalloy, vanadium nitride. The abrasive and impact-abrasion surface wear experienced by castings has a classical pattern: microcutting—i.e., the deformation twinning of surface layers. Ferrovanadium nitride enhances the surface resistance of castings both as a cast and as thermally treated. A fine grain structure is formed in the surface layers, specifically layers in direct contact with abrasive particles. The deformation twins that are present at the solid solution grain boundaries tend to change their orientation and characteristics. The impact-abrasion wear also leads to hardened layer formation at the working surface due to deformation twinning. The carbides (nitrides) present in the surface wear do not produce any significant impact on the process of deformation twinning. As the wear line extends deeper into the casting surface, the carbides and nitrides are ripped out and cavities occur in the wearing zone. The wear is controlled by the solidification rate. Thus, at lower rates a hardened layer is formed, which accommodates adjacent areas with differing twin characteristics, such as orientation and spacing. Full article

(This article belongs to the Special Issue Optimization of Industrial Casting Processes)

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12 pages, 2390 KiB

Open AccessArticle

Design Optimisation of the Feeding System of a Novel Counter-Gravity Casting Process

by Michail Papanikolaou, Emanuele Pagone, Konstantinos Georgarakis, Keith Rogers, Mark Jolly and Konstantinos Salonitis

Metals 2018, 8(10), 817; https://doi.org/10.3390/met8100817 - 11 Oct 2018

Cited by 10 | Viewed by 3896

Abstract

The appropriate design of feeders in a rigging system is critical for ensuring efficient compensation for solidification shrinkage, thus eliminating (shrinkage-related) porosity and contributing to the production of superior quality castings. In this study, a multi-objective optimisation framework combined with Computational Fluid Dynamics [...] Read more.

The appropriate design of feeders in a rigging system is critical for ensuring efficient compensation for solidification shrinkage, thus eliminating (shrinkage-related) porosity and contributing to the production of superior quality castings. In this study, a multi-objective optimisation framework combined with Computational Fluid Dynamics (CFD) simulations has been introduced to investigate the effect of the feeders’ geometry on shrinkage porosity aiming to optimise casting quality and yield for a novel counter-gravity casting process (CRIMSON). The weighted sum technique was employed to convert this multi-objective optimisation problem to a single objective one. Moreover, an evolutionary multi-objective optimisation algorithm (NSGA-II) has been applied to estimate the trade-off between the objective functions and support decision makers on selecting the optimum solution based on the desired properties of the final casting product and the process characteristics. This study is one of the first attempts to combine CFD simulations with multi-objective optimisation techniques in counter-gravity casting. The obtained results indicate the benefits of applying multi-objective optimisation techniques to casting processes. Full article

(This article belongs to the Special Issue Optimization of Industrial Casting Processes)

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14 pages, 6233 KiB

Open AccessArticle

Effect of an Electrically-Conducting Wall on Transient Magnetohydrodynamic Flow in a Continuous-Casting Mold with an Electromagnetic Brake

by Zhongqiu Liu, Alexander Vakhrushev, Menghuai Wu, Ebrahim Karimi-Sibaki, Abdellah Kharicha, Andreas Ludwig and Baokuan Li

Metals 2018, 8(8), 609; https://doi.org/10.3390/met8080609 - 04 Aug 2018

Cited by 27 | Viewed by 3412

Abstract

Large eddy simulation (LES) of transient magnetohydrodynamic (MHD) turbulent flow under a single-ruler electromagnetic brake (EMBr) in a laboratory-scale, continuous-casting mold is presented. The influence of different electrically-conductive boundary conditions on the MHD flow and electromagnetic field was studied, considering two different wall [...] Read more.

Large eddy simulation (LES) of transient magnetohydrodynamic (MHD) turbulent flow under a single-ruler electromagnetic brake (EMBr) in a laboratory-scale, continuous-casting mold is presented. The influence of different electrically-conductive boundary conditions on the MHD flow and electromagnetic field was studied, considering two different wall boundary conditions: insulating and conducting. Both the transient and time-averaged horizontal velocities predicted by the LES model agree well with the measurements of the ultrasound Doppler velocimetry (UDV) probes. Q-criterion was used to visualize the characteristics of the three-dimensional turbulent eddy structure in the mold. The turbulent flow can be suppressed by both configurations of the experiment’s wall (electrically-insulated and conducting walls). The shedding of small-scale vortices due to the Kelvin–Helmholtz instability from the shear at the jet boundary was observed. For the electrically-insulated walls, the flow was more unstable and changed with low-frequency oscillations. However, the time interval of the changeover was flexible. For the electrically-conducting walls, the low-frequency oscillations of the jets were well suppressed; a stable double-roll flow pattern was generated. Electrically-conducting walls can dramatically increase the induced current density and electromagnetic force; hence they contribute to stabilizing the MHD turbulent flow. Full article

(This article belongs to the Special Issue Optimization of Industrial Casting Processes)

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13 pages, 4692 KiB

Open AccessFeature PaperArticle

Examination and Simulation of Silicon Macrosegregation in A356 Wheel Casting

by Pan Fan, Steve Cockcroft, Daan Maijer, Lu Yao, Carl Reilly and Andre Phillion

Metals 2018, 8(7), 503; https://doi.org/10.3390/met8070503 - 29 Jun 2018

Cited by 11 | Viewed by 4330

Abstract

Macrosegregation is commonly seen and has been extensively studied in large ingots in a variety of alloy systems. In comparison, this defect is rarely investigated in small aluminum shape castings. To address this shortcoming, a numerical model was developed to investigate silicon macrosegregation [...] Read more.

Macrosegregation is commonly seen and has been extensively studied in large ingots in a variety of alloy systems. In comparison, this defect is rarely investigated in small aluminum shape castings. To address this shortcoming, a numerical model was developed to investigate silicon macrosegregation during the low-pressure die casting of aluminum alloy (A356) automotive wheels. The model results were compared with silicon distribution maps measured using an optical, phase area-based technique. The model of the wheel casting process was implemented within FLUENT, a commercial Computational Fluid Dynamics (CFD) software package. In the formulation adopted, liquid metal flow is driven solely by solidification shrinkage due to the variation in density between the liquid and solid phases. Buoyancy and die filling have been ignored. Additionally, the model includes Darcy flow in the two-phase mushy zone, the release of latent heat, and solute redistribution at the micro-scale using the Scheil approximation. The model was validated against temperature and segregation data taken from a commercially cast wheel and shown to be qualitatively correct in predicting trends in temperature histories and segregation. A closer inspection of the data reveals that the model is quantitatively accurate within 10–30%, depending on the location. Full article

(This article belongs to the Special Issue Optimization of Industrial Casting Processes)

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25 pages, 7548 KiB

Open AccessArticle

Hydrodynamic Modeling and Mathematical Simulation on Flow Field and Inclusion Removal in a Seven-Strand Continuous Casting Tundish with Channel Type Induction Heating

by Haiyan Tang, Luzhao Guo, Guanghui Wu, Hong Xiao, Haiying Yao and Jiaquan Zhang

Metals 2018, 8(6), 374; https://doi.org/10.3390/met8060374 - 23 May 2018

Cited by 33 | Viewed by 3588

Abstract

The tundish with heating instrumentation is attracting more and more attention in continuous casting processes for maintaining a pre-determined constant pouring temperature under a given casting speed, which is beneficial for an improved and consistent steel product quality. However, the fluid flow, temperature [...] Read more.

The tundish with heating instrumentation is attracting more and more attention in continuous casting processes for maintaining a pre-determined constant pouring temperature under a given casting speed, which is beneficial for an improved and consistent steel product quality. However, the fluid flow, temperature distribution and the removal behaviors of non-metallic inclusions in it will be much different from that in a conventional tundish, due to the implementation of the heating practice. In the present work, to reduce the non-metallic inclusion amounts in billets of the second and sixth strands in a seven-strand tundish with channel type induction heating, the flow field profiles and temperature profiles of molten steel in this tundish have been investigated using hydrodynamic modeling coupled with mathematical simulation under isothermal and non-isothermal situations, respectively. The results of the isothermal experiment indicate that the prototype tundish has severe “short-circuiting flow” in the second and sixth strands, which might have caused the increased inclusion amounts in the billets of the two strands. The flow field of the tundish can be greatly improved by changing the channel design and adding two high dams at each side of the tundish. Compared with the prototype structure A0, the average residence time of the optimized case C5 is prolonged by 55.49% (from 501 to 779 s); the dead zone volume fraction is reduced by 66.18% (from 45.57% to 15.41%); and the flow of each strand becomes more consistent with lower standard deviation. The non-isothermal experiments show that the fluid presents an obvious rising tendency when it flows out from the heating induction channel. The larger the temperature difference inside and outside the channel is, the more consistent the fluid flow between different strands and the more homogeneous the flow field in the whole tundish. For the prototype tundish structure, when the temperature difference is 5 °C, the dead zone is basically eliminated, and the minimum residence time is prolonged by 789% (from 38 to 338 s), compared with the 0 °C of temperature difference. A mathematic model has been proposed accordingly, which can explain well the hydraulic phenomena. The inclusion removal rates of different cases were compared by mathematical simulation, and their removal mechanism was studied, as well. Full article

(This article belongs to the Special Issue Optimization of Industrial Casting Processes)

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13 pages, 40369 KiB

Open AccessArticle

Optimizing the Gating System for Steel Castings

by Jan Jezierski, Rafał Dojka and Krzysztof Janerka

Metals 2018, 8(4), 266; https://doi.org/10.3390/met8040266 - 13 Apr 2018

Cited by 28 | Viewed by 9661

Abstract

The article presents the attempt to optimize a gating system to produce cast steel castings. It is based on John Campbell’s theory and presents the original results of computer modelling of typical and optimized gating systems for cast steel castings. The current state-of-the-art [...] Read more.

The article presents the attempt to optimize a gating system to produce cast steel castings. It is based on John Campbell’s theory and presents the original results of computer modelling of typical and optimized gating systems for cast steel castings. The current state-of-the-art in cast steel casting foundry was compared with several proposals of optimization. The aim was to find a compromise between the best, theoretically proven gating system version, and a version that would be affordable in industrial conditions. The results show that it is possible to achieve a uniform and slow pouring process even for heavy castings to preserve their internal quality. Full article

(This article belongs to the Special Issue Optimization of Industrial Casting Processes)

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