Modeling of transport phenomena and magneto-hydrodynamics for improved steel quality in square billet molds
Bibliographic record
Abstract
In the continuous casting process, a large number of internal and surface defects, such as Oscillation Marks (OM), bubble and inclusion entrapments, Mold Powder Entrainment (MPE), internal and surface cracks and segregations, are encountered which are associated with the fluid flow inside the mold cavity. Appropriate fluid flow conditions in the mold region favorably affect the casting defects elimination and can generate the correct temperature distributions within the mold, which significantly decreases the possibility of breakouts and deep oscillation marks. The flow patterns can be directly influenced by the design of Submerged Entry Nozzle (SEN), mold geometry and dimensions, the operational casting conditions, and external flow modifiers. The present Ph.D. study took advantage of today's numerical techniques and developed a numerical model to simulate asymmetrical fluid flows generated within a curved, square billet mold in presence of different flow modifiers. The fluid flow and electromagnetic numerical models are developed using the commercial packages, ANSYS-Fluent and COMSOL. All simulations are run on an SGI 288 core, High Performance Computing Cluster (HPCC), at the McGill Metals Processing Centre (MMPC) Stinson Laboratories, in Montreal, Canada. Two of the most important parameters which significantly influence fluid flows within the continuously casting molds are; 1), SEN's designs and location within the mold and 2), the applications of electromagnetic fields. Therefore, in this study, the fluid flow within the curved, square billet mold was evaluated under the effect of a multiple-port SEN's angle of rotation and the impact of Rotary Electro-Magnetic Stirring (EMS). In this study different SEN's angles of rotation, along with different types of Rotary-EMS, was applied, in order to determine optimum fluid flows within the mold region. The direct impingement of liquid steel towards mold corners was found strongly affecting the level fluctuations of liquid steel at the upper meniscus and probably result in MPE. Additionally, the Rotary-EMS generates swirling flows within the mold region. In previous research, it was found that the swirling flows generated by EMS in the mid-section of billet, bloom, or slab continuous casting molds, results in higher quality surfaces and microstructures of continuously cast products. However, the numerical results achieved in this study demonstrated that, by having an incorrectly SEN angle of rotation, the rotational Lorentz forces induced by a Rotary-EMS can be detrimental on the fluid flows near the top region of the mold. Therefore, nozzle location and Rotary-EMS can be combined to either drastically improve, or deteriorate, the quality of fluid regimes within the mold region. The calculation domain and the operational conditions used in this study correspond to the square billet mold and operational conditions practiced at the Rio Tinto Fer et Titane (RTFT) plant, located at Sorel Tracy, Quebec, Canada. The observed fluid flows with the proposed alternative location of SEN together with the effect of Rotary-EMS, decreased the meniscus level fluctuation and stabilized the layer of liquefied mold powder over the liquid steel meniscus, compared to the results delivered by the current operations. Additionally, a set of experiments were carried out in order to study the solidified microstructure for two different Aluminum alloys including, A356 and AA2024 under the effect of a Rotary-EMS. The experimental results show that, the rotational Lorentz forces induced due to the Rotary-EMS, modified the dendritic structure and significantly enhanced the homogenization of alloying elements in the solidified samples.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".