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CIPRIANO, LUIZ CARLOS. "NUMERICAL SIMULATION OF THE CONTINUOUS CASTING PROCESS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1988. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33279@1.
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O processo de lingotamento contínua de metais é simulado numericamente. Placas ou tarugos metálicos são produzidos continuamente, mantendo-se o escoamento do material através do molde. A frente de solidificação depende da velocidade de retirada de material e da refrigeração imposta na superfície do lingote. A posição da interface líquido-sólido e o campo de temperaturas na região sólida são determinados, e consideram-se os efeitos da velocidade na curvatura da interface. É analisado um modelo retangular bi-dimensional e a equação da energia é resolvida utilizando-se o método numérica de diferenças finitas das volumes de controle. Os resultados são comparados com soluções analíticas simplificadas onde a termo de transporte não foi considerado e mostram que o calar transportado pelo movimento de lingote tem influência significativa na forma da interface e em sua localização dentro do molde durante o processo.<br>This work deals with a numerical simulation of the continuous casting process. This process is employed in the fabrication of metallic inguts. The position of the solid-liquid interface is determined together with the temperature field in the solid region. The research is facused on studying the effect of the withdrawal velocity on the interface position, aiming at accidental leakage preventien during the process. In this
analysis, the sensible heat is taken into acceunt, in contrast to previous marks reported in the open literature. The present work employed a two-dimensional model. The energy equation was integrated in the rectangular domain by means of the finite-volume method. The liquid regions was at the fusion temperatures, whereas one of the side boundaries was strogly cooled to promote solidification. An algorithm was developed to determine the interface pesition and the domain length. Comparisons of this results obtained with the available solutions obtained excluding sensible heat showed that, depending upon the value of the withdrawal velocity, the sensible heat may or may not be negleted. The simulations was performed with the aid of a microcomputer of the IBM-PC/XT type, employing the Fortran language.
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Miao, Xincheng. "Numerical study of a continuous casting process with electromagnetic brake." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-144798.
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This dissertation investigates the effect of electromagnetic braking and gas injection on the fluid flow in a continuous casting slab mold numerically and makes verifications on basis of a small Liquid Metal Model for Continuous Casting of steel (mini-LIMMCAST). Numerical calculations were performed by means of the software package CFX with an implemented RANS-SST turbulence model. The non-isotropic nature of the MHD turbulence was taken into account by specific modifications of the turbulence model. The numerical results were validated by flow measurements at the mini-LIMMCAST facility. Numerical simulations disclose the damping effect on the flow closely depending on the wall conductance ratio. In addition, specific modifications of the turbulence model play a crucial role in reconstructing the peculiar phenomenon of an excitation of nonsteady, nonisotropic, large-scale flow perturbations caused by the application of the DC magnetic field.
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Bradbury, Philip. "A mathematical model for the twin roll casting process." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296919.
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Bouhouche, Salah. "Contribution to quality and process optimisation in continuous casting using mathematical modelling." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2009. http://nbn-resolving.de/urn:nbn:de:swb:105-6900128.
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Mathematical modelling using advanced approach based on the neural networks has been applied to the control and the quality optimisation in the main processes of steelwork such as the ladle metallurgical treatment and continuous casting. Particular importance has been given to the improvement of breakout prediction system and the reduction in the rate of false alarm generated by the conventional breakout detection system. Prediction of the chemical composition and temperature of liquid steel in the ladle has been achieved by neural networks and linear model. This prediction can be considered as a soft sensor. Slab surface temperature stabilisation on the basis of the casting events has been controlled by a neural networks algorithm, that gives an improvement in the surface temperature fluctuation in comparison to the conventional control system which is based on the PID controller. Quality monitoring and classification is also achieved by a neural network which is related to the breakout detection system. This technique achieves a classification of different defects based on the different alarm signal given by the breakout prediction system. Fault detection and process monitoring is developed using neural networks modelling. All models are developed on basis of practical operating database obtained from the iron and steel industry.
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Bouhouche, Salah. "Contribution to quality and process optimisation in continuous casting using mathematical modelling." Doctoral thesis, [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966041208.
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Pimenta, Paulo Vicente de Cassia Lima. "Thermomechanical simulation of continuous casting process using element based finite-volume method." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13684.
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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior<br>The continuous casting technique in the last four decades has been large used for to production of semi-finished steel. The heat transfer is major mechanism and it occurs in various steps during the continuous casting. The quality of steel is directly related to the way the heat transfer occur because the thermal variations produce mechanical loads as well as contact forces which are generated through the rollers and shake of the mold. Such factors may cause defects such as fractures or cracks in the final product if the resulting stresses and strains exceed critical values. The technique must be improved in order to reduce the appearance of defects and the production time. For this a good understanding of physical phenomena involved during the solidification process is critical. The focus of this work is to apply the EbFVM (Element based Finite-Volume Method) approach to study the effects of linear tensions unidirectionally coupled with the temperature applied to continuous casting of the steel 1013D (0,3% of carbon)
In the simulations we adopted some simplifications such as the Plane Strain and isotropic material. We also neglected the body forces contact with the rollers the liquid pressure on the walls of the steel ingot (ferrostatic pressure) and the convective effect. However despite of the simplifications adopted this work provides quantitative informations on the linear tensions accumulation that point out to areas of possible of cracks formations<br>A tÃcnica de lingotamento contÃnuo nas Ãltimas quatro dÃcadas à cada vez mais utilizada na produÃÃo de aÃo semiacabado. A transferÃncia de calor à o principal mecanismo dominante e ocorre em todas as etapas do processo. A qualidade do aÃo no lingotamento està diretamente relacionada à forma que ocorrem as trocas de calor pois as variaÃÃes tÃrmicas produzem carregamentos mecÃnicos assim como as forÃas de contato as quais sÃo geradas por intermÃdio dos rolos e da oscilaÃÃo do molde. Tais fatores podem causar defeitos como fraturas ou trincas no produto final caso as tensÃes e deformaÃÃes resultantes excedam valores crÃticos. O aprimoramento da tÃcnica tem a finalidade de evitar o surgimento de defeitos e reduzir o tempo de produÃÃo. Para isso à fundamental uma boa compreensÃo dos fenÃmenos fÃsicos envolvidos ao longo do processo de solidificaÃÃo. O foco deste trabalho à aplicar a abordagem do EbFVM (Element based Finite-Volume Method) no estudo dos efeitos das tensÃes lineares acopladas unidirecionalmente com a temperatura aplicado ao lingotamento contÃnuo do aÃo 1013D (0,3% de carbono)
Nas simulaÃÃes adotou-se algumas simplificaÃÃes com o estado plano de tensÃes e isotropia do material. Descartando-se as forÃas de corpo o contato com os rolos a pressÃo do aÃo lÃquido nas paredes do lingote (pressÃo ferrostÃtica) e o efeito convectivo. Contudo apesar das simplificaÃÃes adotadas este trabalho traz informaÃÃes quantitativas quanto a formaÃÃo do acÃmulo das tensÃes lineares que apontam para regiÃes de possÃveis formaÃÃes de trincas
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Siyasiya, Charles Witness. "The transformation behaviour and hot strength of 3CR12 during the continuous casting process." Diss., Pretoria : [s.n.], 2004. http://upetd.up.ac.za/thesis/available/etd-06202005-134528.
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Miao, Xincheng [Verfasser], Rüdiger [Akademischer Betreuer] Schwarze, Rüdiger [Gutachter] Schwarze, and Egbert [Gutachter] Baake. "Numerical study of a continuous casting process with electromagnetic brake / Xincheng Miao ; Gutachter: Rüdiger Schwarze, Egbert Baake ; Betreuer: Rüdiger Schwarze." Freiberg : Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://d-nb.info/1220911887/34.
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Elsilä, U. (Ulla). "Knowledge discovery method for deriving conditional probabilities from large datasets." Doctoral thesis, University of Oulu, 2007. http://urn.fi/urn:isbn:9789514286698.
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Abstract
In today's world, enormous amounts of data are being collected everyday. Thus, the problems of storing, handling, and utilizing the data are faced constantly. As the human mind itself can no longer interpret the vast datasets, methods for extracting useful and novel information from the data are needed and developed. These methods are collectively called knowledge discovery methods.
In this thesis, a novel combination of feature selection and data modeling methods is presented in order to help with this task. This combination includes the methods of basic statistical analysis, linear correlation, self-organizing map, parallel coordinates, and k-means clustering. The presented method can be used, first, to select the most relevant features from even hundreds of them and, then, to model the complex inter-correlations within the selected ones. The capability to handle hundreds of features opens up the possibility to study more extensive processes instead of just looking at smaller parts of them. The results of k-nearest-neighbors study show that the presented feature selection procedure is valid and appropriate.
A second advantage of the presented method is the possibility to use thousands of samples. Whereas the current rules of selecting appropriate limits for utilizing the methods are theoretically proved only for small sample sizes, especially in the case of linear correlation, this thesis gives the guidelines for feature selection with thousands of samples. A third positive aspect is the nature of the results: given that the outcome of the method is a set of conditional probabilities, the derived model is highly unrestrictive and rather easy to interpret.
In order to test the presented method in practice, it was applied to study two different cases of steel manufacturing with hot strip rolling. In the first case, the conditional probabilities for different types of retentions were derived and, in the second case, the rolling conditions for the occurrence of wedge were revealed. The results of both of these studies show that steel manufacturing processes are indeed very complex and highly dependent on the various stages of the manufacturing. This was further confirmed by the fact that with studies of k-nearest-neighbors and C4.5, it was impossible to derive useful models concerning the datasets as a whole. It is believed that the reason for this lies in the nature of these two methods, meaning that they are unable to grasp such manifold inter-correlations in the data. On the contrary, the presented method of conditional probabilities allowed new knowledge to be gained of the studied processes, which will help to better understand these processes and to enhance them.
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Kholmatov, Shavkat. "On some positive effects of swirling flow for the continuous cast mould billets." Licentiate thesis, Stockholm : Division of Applied Process Metallurgy, School of Industrial Engineering and Management, Royal Institute of Technology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4453.
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Persson, Mikael. "Densities and viscosities of slags : modeling and experimental investigations." Licentiate thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3926.
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Klimeš, Lubomír. "Algoritmy stochastického programování." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229034.
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Stochastické programování a optimalizace jsou mocnými nástroji pro řešení široké škály inženýrských problémů zahrnujících neurčitost. Algoritmus progressive hedging je efektivní dekompoziční metoda určená pro řešení scénářových stochastických úloh. Z důvodu vertikální dekompozice je možno tento algoritmus implementovat paralelně, čímž lze významně ušetřit výpočetní čas a ostatní prostředky. Teoretická část této diplomové práce se zabývá matematickým a zejména pak stochastickým programováním a detailně popisuje algoritmus progressive hedging. V praktické části je navržena a diskutována původní paralelní implementace algoritmu progressive hedging, která je pak otestována na jednoduchých úlohách. Dále je uvedená paralelní implementace použita pro řešení inženýrského problému plynulého odlévání ocelové bramy a na závěr jsou získané výsledky zhodnoceny.
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Nascimento, Renato Rosa do. "Controle não linear aplicado a processos de lingotamento contínuo de tiras." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-05062017-090446/.
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O presente trabalho tem como objetivo explorar o uso de técnicas de controle avançados na indústria siderúrgica. Propõe-se uma estratégia de controle do nível do aço da piscina formada entre os rolos de um sistema lingotamento contínuo de tiras (LCT) utilizando a tecnologia twin-roll (rolos duplos). O processo LCT rolos duplos tem por finalidade a produção de tiras solidificadas de espessura constante sob uma força de separação entre os rolos também constante. O nível de aço bem como a força de separação são as variáveis mais críticas para a produção de tiras de aço de alta qualidade. O nível pode ser controlado usando a entrada de aço ou a velocidade de laminação. Entretanto, a velocidade de laminação é usualmente utilizada para regular a força de separação entre os rolos. A estratégia de controle proposta inclui a incorporação de um tundish intermediário submerso na piscina. O controle do nível é então feito a partir da saída de aço do tundish intermediário. Consideramos as técnicas de controle linearizante por realimentação de estado e de controle fuzzy usando ambos os modelos Takagi-Sugeno (T-S) e Mamdani. Resultados de simulação são apresentados para uma planta instalada no Instituto de Pesquisa Tecnológica (IPT) de São Paulo, divisão de metalurgia (DIMET).<br>The aim of this work is to explore the use of advanced control techniques in the metallurgical industry. A control strategy to regulate the molten steellevel of a strip-casting process is proposed. The process produces a solidified strip of constant thickness given by the roll gap under a constant roll separation force. Along with the molten steel level the rool separation force are the most criticaI process variables. The molten steel level may be controlled using the tundish output flow or the casting speed. However, the casting speed is usually used to control the roll force separation. In the control strategy proposed it is incorporated an intermediary tundish submerse into the pool between the rotating rolls to improve the strip thickness uniformity. The molten steel level is thus controlled by the intermediary tundish output flow. Conventional PI, feedback linearizing plus a fuzzy control term and a fuzzy controller in a cascade configuration are considered. Simulation results are presented considering the real system parameters of a plant installed at the Instituto de Pesquisa Tecnológica (IPT) de São Paulo, Divisão de Metalurgia (DIMET).
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Bernard, William J. "The continuous rheoconversion process Scale-up and optimization." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-082305-102150/.
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Almeida, Leandro de. "Estudo comparativo da estampabilidade do latão UNS C22000 produzido inicialmente pelo processo de fundição contínua em comparação a fundição semicontínua." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-01092017-160621/.
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As curvas limite de conformação (CLC) são utilizadas há mais de 50 anos. Propostas inicialmente para o desenvolvimento de produtos provenientes da indústria automobilista em função das necessidades apresentadas pela área, são atualmente aplicadas de maneira geral para a indústria da estampagem na produção de inúmeros tipos de peças, oferecendo previsões de possíveis falhas e/ou defeitos durante as etapas do processo de estampagem. As CLC´s permitem prever o afinamento excessivo, enrugamento, estiramento e é claro, a fratura da peça. As diferenças metalúrgicas existentes entre os dois processos iniciais - fundição contínua (F.C.) e fundição semicontínua (F.S.C.) - resultam em diferenças nas propriedades finais obtidas para uma mesma rota de laminação a frio e recozimentos intermediários do material especificado. Desta forma, torna-se indispensável um estudo sobre a influência dos processos de fabricação iniciais F.C. e F.S.C. com relação à estampabilidade da liga, sendo esta avaliação efetuada através das CLC´s obtidas por ensaios de tração uniaxiais, propostos pelo IRSID (\"Institut de Recherches de La Sidérurgie\"), (lado esquerdo da curva ?2 < 0) e ensaio Erichsen (lado direito da curva ?2 > 0) e do ensaio de Nakazima reduzido em 60%, ou seja, todo o ferramental e os corpos de prova utilizados nos ensaios foram reduzidos em 60% das dimensões mencionadas pela norma ISSO 12004-2. A diferença microestrutural apresentada entre as etapas de fabricação dos dois processos avaliada através de ensaios de determinação do tamanho de grão, limites de resistência à tração, escoamento (0,2%), alongamento (em 50,80 mm), coeficientes de encruamento n, resistência K, ensaios de \"orelha\", levantamento da CLC0, Erichsen e textura, auxiliaram nas conclusões finais do levantamento das CLC´s para os dois processos do material acabado e metodologias. O processo de fundição semicontínua nas condições processadas apresentou melhores combinações entre as propriedades, exceto na formação de \"orelha\" apresentada na etapa intermediaria de processamento do material. Principalmente o parâmetro CLC0 no plano da chapa, resultou em uma deformação ?1 19% (?2 = 0), superior à apresentada pelo processo F.C., deformação muito importante para a fabricação de peças estampadas. Evidenciou-se também uma diferença de aproximadamente 37% entre as metodologias IRSID x Nakazima reduzido na obtenção da deformação plana para o processo F.C. e 31% para o processo de F.S.C.. Nas condições de deformação; estiramento biaxial, tração uniaxial e embutimento profundo, a chapa produzida pelo processo de fundição contínua apresenta melhor desempenho.<br>Forming limits curves (FLC) are used for more than 50 years. Initially proposed for the development of products from the automobile industry in terms of the needs of the area. It is currently being applied in general to the metal forming industry in the production of numerous types of parts, providing predictions of possible faults and / or defects during the stages of the stamping process. The FLC\'s can predict excessive thinning, wrinkling, stretching and of course, the fracture of the part. The existing metallurgical differences between the two initial processes - continuous casting (C.C.) and semi-continuous casting (S.C.C.) - result in differences in the final properties obtained for the same route of cold rolling and intermediate annealing of the specified material. Thus, it is essential to study the influence of the initial manufacturing processes CC and SCC with respect to the formability of the sheets. This investigation is based on the, assessment of the FLC\'s obtained by uniaxial tensile tests proposed by IRSID (\"Institut de Recherches de Sidérurgie\"), (?2 < 0, left side of the curve) and Erichsen test (right side of curve. ?2> 0) and the Nakazima test reduced by 60%. The difference between the sheets obtained in both processing routes was evaluated by the following parameters: grain size, tensile strength limits, yield strength (0.2%), elongation (at 50.80 mm), strain hardening coefficient n, resistance K, \"earing\" test, lifting of the CLC0, Erichsen test and texture where discussed in view of the obtained FLC\'s for both the two processes of the finished material. The semi-continuous casting process in processed conditions showed better combinations of properties except the formation of \"earing\" presented at the intermediate stage of processing of the material. Particularly the evaluation of the FLC0 parameter resulted in a strain in the plate plane ?1 19% (?2 = 0) superior to the sheet obtained by the continuous casting process. A difference of approximately 37% between the IRSID x Nakazima methodologies was also reduced in obtaining the flat deformation for the F.C. process and 31% for the F.S.C. process. However, for other deformation paths; biaxial stretching, uniaxial traction and deep drawing of the results for the continuous casting sheet were superior.
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Bernard, III William J. "The Continuous Rheoconversion Process: Scale-up and Optimization." Digital WPI, 2005. https://digitalcommons.wpi.edu/etd-theses/957.
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"Semi-solid metal (SSM) processing has emerged as a preferred manufacturing method due to the superior quality associated with semi-solid castings. In recent years, the driving force to reduce process cost has led to the development of a few rheocasting (also termed slurry-on-demand) processes. These include UBE’s New Rheocasting (NRC) process [1], Idra Prince’s Semi-Solid Rheocasting (SSR) process [2], and THT’s Sub-Liquidus Casting (SLC®) process [3]. A novel slurry-making SSM process developed at ACRC/MPI, termed the “Continuous Rheoconversion Process†(CRP), is a passive liquid mixing technique in which the nucleation and growth of the primary phase are controlled using a specially designed “reactorâ€. The reactor provides heat extraction, copious nucleation and forced convection during the initial stage of solidification, leading to the formation of thixotropic structures. In these studies, the critical issues/challenges to optimize the CRP for industrial applications have been addressed through validation experiments and pre-industrial trials."
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Björn, Linnéa. "Investigation of Hot Ductility Gradients in Duplex Stainless Steel in the Beginning of the Continuous Casting Proces." Thesis, KTH, Materialvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160892.
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The steel quality is deteriorated at a continuous casting start. Therefore, material from the first cast slab is cut off and re-melted in the melt shop. If too little is discarded, the inferior quality in the retained length can cause defects like edge cracks during subsequent hot rolling. This means that manufacturing resources are wasted on processing inferior material which has to be re-melted anyways at a later stage. On the other hand, if an excessive length of the first slab is re-melted, good material is wasted. In either case, optimizing the length of the start-scrap material is both economically and environmentally beneficial. Edge cracks are more common in the beginning of the first slab, even though a part is cut off. It is likely that the edge cracks arise due to reduced hot ductility in the first cast material. The purpose of this project is to optimize where the cut should be made in order to achieve the best yield. The hot ductility was investigated by performing hot tensile- and bending tests. The hot tensile tests indicate high hot ductility for the investigated specimens. The area reduction, which is correlated to the hot ductility, is above 70 % for all the investigated specimens. When considering the average area reduction while neglecting possible differences between the heats, the specimens from one meter tend to have a lower hot ductility compared to the other specimens. However, the differences are small. No difference can be seen between edge and middle specimens when only looking at the tensile tests. The bending tests did not crack without notches, even though the maximum load and a test temperature of 750 °C was used. That strongly indicates high hot ductility as well. By using notches, the bending tests cracked and it was shown that edge specimens and specimens from one meter cracked the most. No edge cracks were found, after hot rolling, on the first cast slabs from the investigated heats.<br>Vid en stränggjutstart är kvalitén på första slaben sämre. På grund av detta så skärs en bit, av det först gjutna slabet av och smälts om i stålverket. Om för lite material kapas av kan det leda till defekter, såsom kantbrakor, under den efterföljande varmvalsningen. Detta innebär att resurser används i onödan för att tillverka material av otillräcklig kvalitet som sedan ändå måste smältas om i ett senare steg. Skärs istället för mycket material bort så smälts prima material om i onödan. Att optimera startskrotlängden är följaktligen positivt både för miljön och rent ekonomiskt. Under varmvalsningen kan defekten kantbrakor, det vill säga sprickor vid kanterna, uppstå. Trots att en bit av det första gjutna slabet skärs av, så är det första slabet fortfarande mest utsatt för kantbrakor. Detta tros bero på nedsatt varmduktilitet i det första gjutna materialet. Syftet med detta projekt är att optimera längden på startskrotet för att spara så mycket användbart material som möjligt. Varmduktiliteten undersöktes genom drag- och bockprovning. Dragproven indikerar hög varmduktilitet för de undersökta proven. Areakontraktionen, som är ett mått på varmduktiliteten, är över 70 % för alla undersökta prov. Medelareakontraktionen, när man bortser från eventuella skillnader mellan chargerna, visar att prov från en meter generellt har något lägre varmduktilitet än de övriga proven. Det är endast små skillnader som uppfattas. Ingen skillnad kan ses mellan kant- och mittenprov när man enbart tittar på dragprovsresultaten. Bockproven sprack inte trots att maximal last användes och att testtemperaturen var 750 °C. Detta tyder också på hög varmduktilitet. Genom att skapa anvisningar kunde man få bockproven att spricka och det visade sig att kantprov och prov från en meter sprack mest. Inga kantbrakor hade uppstått på de första gjutna slabsen under varmvalsningen av försökschargerna.
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Luz, Simone Milioli da. "Método de Monte Carlo aplicado ao processo de lingotamento contínuo." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/36328.
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A aplicação de modelos matemáticos baseados em técnicas numéricas aumentou com o avanço da informática através da criação de microprocessadores mais velozes e periféricos de armazenamento de dados com grande capacidade. Buscando uma maior produtividade e a melhoria da qualidade final do produto solidificado, propõe-se neste trabalho, desenvolver um modelo computacional de origem físico para o crescimento de grão no Lingotamento Contínuo. O modelo é simulado utilizando o Método de Monte Carlo juntamente com o Método das Diferenças Finitas, com o objetivo de obter e caracterizar a transição colunar-equiaxial através desse método. As simulações foram realizadas utilizando a programação Fortran 90/95 no ambiente Linux através do software Developer Studio e aplicados nos aços SAE 1015 e 1020. A seguir, foram realizadas comparações entre as macroestruturas simuladas e as macroestruturas das amostras dos aços obtidas pelo Laboratório de Fundição (LAFUN) da UFRGS. Destas simulações observou-se que o modelo oferece a possibilidade da simulação de diferentes condições operacionais para prever a evolução macroestrutural de lingotes.<br>The application of mathematical models based on numerical techniques increased with the advancement of information technology by creating faster microprocessors and peripherals with high data storage capacity. Seeking for a major productivity and the improvement of the final quality of the solidified product. In this assignment, the development of a computational model with a physical origen for the growth of the continuous casting, is proposed. The model is simulated by using the Monte Carlo Method with the Finite Differences Method, the goal is to obtain and characterize the columnar-equiaxed transition through this method. The simulations were performed using the Fortran 90/95 programming in Linux environment using the Developer Studio software and applied to the steel SAE 1015 and 1020. Following it, comparisons were made between the macro and simulated macrostructures of the samples obtained by the Laboratory of Steel Casting - Laboratório de Fundição (LAFUN) at UFRGS. From these simulations, it was observed that the modified model offers the possibility of simulating different operating conditions to predict the evolution of macrostructural ingots.
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Gschwenter, Viviane Lopes da Silva. "Correlação entre parâmetros de solidificação e formação estrutural de aços especiais produzidos pelo processo de lingotamento contínuo." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/17300.
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O presente estudo teve como objetivo a obtenção de equações empíricas permitindo a correlação da morfologia estrutural de aços com os parâmetros de solidificação: variação dos espaçamentos dendríticos secundários com a posição (l2xP) e variação dos espaçamentos dendríticos secundários com as taxas de resfriamento (l2x •T), como também o desenvolvimento de uma metodologia para determinação do início de transição colunarequiaxial e sua relação com a seção e composição química do aço. Para isso foram utilizadas técnicas de metalografia e um sistema de aquisição de imagens para a análise de macro e microestrutura (transição colunar-equiaxial, espaçamentos dendríticos secundários), de aços especiais obtidos por lingotamento contínuo. Foram selecionadas amostras retiradas de lingotes com três diferentes seções: 150x150mm, 180x180mm e 240x240 mm, englobando aços com diferentes valores de carbono equivalente, totalizando nove qualidades analisadas. Simulações foram geradas empregando um software do lingotamento contínuo (InALC), obtendo-se resultados das condições de solidificação em relação a taxas de resfriamento ( •T), para os parâmetros operacionais (composição química, velocidades e temperaturas de lingotamento). As equações dos parâmetros microestruturais obtidas experimentalmente foram implementadas no software InALC+, permitindo simulações também com previsão estrutural para os aços analisados. Pode-se concluir que o aumento da seção proporcionou maiores zonas colunares, independente da composição química dos aços, e que para um teor de carbono equivalente de 0,11%Ceq observou-se uma relação direta e linear entre os valores de início de TCE, tamanho da seção e taxa de resfriamento. As equações para EDS em função da distância para aços com valores de Ceq iguais apresentaram maiores valores na seção de 240 mm e 180 mm, seguidos pela seção de 150 mm. Nas equações de EDS em função da taxa de resfriamento simulada para aços com valores de Ceq iguais a 0,11%Ceq, os maiores valores de EDS ocorrem na seção 150mm, seguido pela seção 240mm e 180mm. Na comparação dos aços com valores de carbono equivalente em torno de 0,40%Ceq, o valor de EDS apresentou um aumento em função do aumento das seções. Em comparação a aços de mesma seção, as equações apresentaram um aumento do valor de EDS em função do aumento do Ceq.<br>The objective of this study was to obtain empirical equations permitting the relationships between as-cast structural morphology and solidification conditions: variation of the secondary dendrite arm spacings with positions (l2xP), variation of the secondary dendrite arm spacings with cooling rates (l2x • T ), as well as to develop a methodology to determine the start of the colunar-equiaxed transition and its correlation with mold section and chemical composition of the steel. Metallographic techniques and image acquisition system were used to analyze both macrostructures and microstructures (colunar-equiaxed transition and secondary dendrite arm spacings) of special steels produced by continuous casting. Transversal specimens were cut from the solidified ingots with different sections: 150x150mm, 180x180mm e 240x240mm, and with different equivalent carbon, totalizing nine steel types. Based on a heat transfer and solidification mathematical model of the continuous casting process (InALC+), results have been developed correlating the cooling rates as a function of operational parameters (chemical composition, casting speed and casting temperature). The correlation of these expressions with experimental equations relating dendrite spacings and colunar-equiaxed transition were implemented into the InALC+ software, providing an insight into the preview of structural characteristics for special steels. It can be concluded that the increasing of the section lead to bigger columnar zones, independent of the chemical compositions of the steels, and for 0.11%Ceq it was observed a direct and linear relation between the initial of the columnar-equiaxed transition, strand section and cooling rate. The expressions for SDAS in function of the distance for steels with equals Ceq presented bigger values for 240 and 180 mm, followed by 150 mm. In the expressions for SDAS in function of the simulated cooling rate for steels with 0.11%Ceq the bigger values were observed to 150 mm followed by 240 and 180 mm. In the comparison between the steels with 0.40% Ceq the SDAS values presented an increase in function of the increase of the section. For the same section the expression presented an increase in the SDAS value in function of the increase of the Ceq.
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Santos, Newton Silva. "Simulação fisica e numerica do processo de lingotamento continuo rotativo." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264712.
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Orientador: Amauri Garcia<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica<br>Made available in DSpace on 2018-08-04T22:38:42Z (GMT). No. of bitstreams: 1
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Previous issue date: 2005<br>Resumo: O presente trabalho descreve o desenvolvimento de um simulador físico estático do processo de lingotamento contínuo rotativo, como parte de uma metodologia experimental auxiliada por um modelo matemático para a determinação de coeficientes transitórios globais de transferência de calor metal/molde ao longo da solidificação. Através desta metodologia, investigou-se a influência da formação do gap de ar entre as paredes do molde e o metal, na cinética total do processo. O simulador fisico foi construído na mesma escala do processo industrial e constitui-se de um trecho de um equipamento de lingotamento contínuo rotativo Properzi. O simulador é equipado com um sistema de refrigeração à água por bicos pulverizadores, canal de vazamento e termopares acoplados a um sistema de aquisição de dados, onde foram realizados experimentos com ligas utilizadas na indústria de condutores elétricos de alumínio. Para a determinação dos coeficientes transitórios de transferência de calor, após o mapeamento experimental das temperaturas, empregou-se o método de comparação teórico-experimental de perfis térmicos (método IHCP) através de um modelo numérico baseado na técnica de diferenças finitas, aplicada em um volume de controle do sistema experimental. Os resultados obtidos demonstraram consistência da metodologia, permitindo a caracterização destes coeficientes e com isso a possibilidade de se prever a evolução da solidificação em processos industriais<br>Abstract: The present study describes the development of a static experimental set-up representing the solidification system of a Rotary Continuous Caster, as part of a metholology, which connected to a numerical model permits to determine transient global metal/mold heat transfer coefficients along solidification. By using this methodology the influence of air gap formation between mold walls and metal surface on process kinetics has been investigated . The static simulator has the same escale of an industrial caster and is constituted of a Properzi copper wheel sector, equipped with a spray cooling system, a pouring system and a thermocouple arrangement connected to a data aquisition system. Experiments were performed using aluminum alloys of the electrical conductors industry. The heat transfer coefficients were obtained by using a method base don com pari sons of numerically calculated and experimental thermal profiles (lHCP method). The used numerical model is based on a finite difference technique and applied on a control volume from the experimental system. The results have shown that the used methodology is consistent, permitting the characterization of metal/mold heat transfer coefficients and as a consequence, to predict the solidification evolution in industrial processes<br>Mestrado<br>Materiais e Processos de Fabricação<br>Mestre em Engenharia Mecânica
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Barcellos, Vinicius Karlinski de. "Desenvolvimento de software de simulação da solidificação de aços no processo de lingotamento contínuo de tarugos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/34743.
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O objetivo deste trabalho consiste no desenvolvimento e aplicação de um software de simulação para o processo de lingotamento contínuo que seja capaz de simular com precisão e confiabilidade a solidificação de tarugos de aço, possibilitando a otimização do processo de fabricação dos produtos siderúrgicos. Para a validação do software, utilizou-se de resultados obtidos experimentalmente de medições de temperaturas em planta e de amostras de aços lingotados. As medidas de temperatura foram realizadas com a inserção de termopares ao longo da parede de moldes e com uso de pirômetro óptico posicionado em diferentes regiões da máquina de LC. O modelo desenvolvido mostrou-se bastante coerente e preciso quando seus resultados foram comparados com os dados experimentais do processo. Foram analisados lingotes de seção quadrada de 240 mm, 180 mm e 150 mm. Com a simulação de uma seqüência de corridas monitoradas foi possível obter resultados para ajuste de parâmetros térmicos como os coeficientes de transferência de calor nas interfaces metal/molde e metal/ambiente. Posteriormente, aferições foram realizadas com dados reais de processo e com outros programas numéricos da literatura aplicados ao processo de LC. Com o programa de simulação devidamente aferido, correlações numéricas e experimentais foram realizadas para verificar a influência de parâmetros térmicos (ρ, c, k, TL, TS), parâmetros de processo (TV, VL, CQ) e parâmetros estruturais (λ1, λ2, TCE) na evolução da casca solidificada e perfil térmico dos tarugos. Dessa forma, equações empíricas que correlacionam esses parâmetros foram analisadas e posteriormente adotadas no programa numérico.<br>The development and application of simulation software for the continuous casting process is proposed in this work. The heat transfer and solidification models were validated with experimental results of temperature measurements in an industrial plant as well as with steel billets samples. Thermocouples embedded in the mold walls were used to measure temperatures along the mold length and non-contact pyrometers positioned at different locations along the machine were used to monitored the strand surface temperatures. The model seemed to predict quite accurately the continuous casting simulation when calculated results were compared with experimental measurements. In this study, steel billet with square section of 240 mm, 180 mm and 150 mm were analyzed. Some of the monitored heats were used to adjust thermal parameters as the heat transfer coefficients. After, the model results were compared with results from a heat transfer model of literature. With the simulation software properly calibrated, numerical and experimental correlations were performed to analyze the influence of thermal parameters (ρ, c, k, TL, TS), process parameters (TV, VL, CQ) and structural parameters (λ1, λ2, TCE) in the evolution of solidified shell and thermal profile of the billets. Therefore, empirical equations that correlate these parameters were analyzed and subsequently adopted in the numerical model.
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Gomes, Noraldo Hipolito Guimarães. "Estudo comparativo de tubos submersos anti-clogging no processo de lingotamento contínuo." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/97/97134/tde-20082013-162244/.
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O processo de lingotamento contínuo de produtos planos de aço tem sido alvo de incessantes estudos devido a sua importância na produção de bobinas laminadas a partir de placas, para um grupo muito diversificado de clientes, dentre os quais, destacam-se as indústrias automobilística e de eletrodomésticos (\"linha branca\"), que têm se mostrado muito exigentes. No entanto, por tratar-se de aços desoxidados ao alumínio, é comum a ocorrência de formação de um depósito de óxido de alumínio (alumina), no interior do tubo submerso do processo de lingotamento contínuo, o que diminui seu diâmetro interno, levando à restrição de passagem do aço líquido pelo seu interior, provocando a perda de produtividade devido à necessidade de se reduzir a velocidade de lingotamento e até mesmo a contaminação do aço com inclusões de alumina, principalmente naqueles seqüenciais com um elevado tempo de lingotamento, próximo de dez horas. Para tanto, desenvolveu-se um tubo com um material interno anti-clogging que na literatura é chamado de C-less, para minimizar e/ou evitar a deposição de alumina e com uma linha de escória reforçada com uma camada de zircônia (ZrO2) mais espessa e mais nobre, para resistir ao ataque da escória. O objetivo desta dissertação foi comparar tubos de diferentes fornecedores, avaliando as principais variáveis que têm influência direta na sua performance: perfil de aquecimento, taxa de erosão na linha de escória, índice de obstrução e parâmetros físico-químicos através da correlação dos materiais antes e após uso (post-mortem). Os resultados encontrados mostraram uma melhor performance dos tubos do fornecedor \"M\", que apresentaram menores taxas de desgaste e, conseqüentemente, maior potencial de vida (maior tempo de lingotamento) após análise da linha de escória, que pode ser atribuída a uma melhor distribuição dos grãos de zircônia na matriz (maior homogeneidade), além de apresentarem grãos mais finos e desta forma, reduzindo os espaços \"vazios\" na matriz, propícios ao ataque da escória por meio de um desequilíbrio químico entre esta escória líquida e o refratário. Além disto, seu material anti-clogging e projeto de distribuição do mesmo na peça, propiciaram um melhor resultado em relação à obstrução pela deposição de alumina ao longo do corpo do tubo submerso.<br>The continuous casting process of steel plane products has been objective of incessant studies due to its importance in the production of laminated coils starting from slabs, for a very diversified group of customers, among all the automobile industries and of appliances (\"home appliances\"), that have been showing very demanding. However, for being low carbon aluminum killed steels, is common the occurrence of aluminum oxide (alumina) deposit formation, inside of submerged nozzle in continuous casting process, what decreases its internal diameter, taking to the restriction of passage of the liquid steel for its interior, provoking the productivity loss due to the need of being reduced the casting speed and even the contamination of the steel with alumina inclusions, mainly in those sequential with a high casting time, close of ten hours. For so much, a submerged nozzle was developed with a internal anti-clogging material that it is called C-less in the literature, to minimize and/or to avoid the alumina building up and with a slag reinforced line with a zirconium layer (ZrO2) thicker and more noble, slag attack resist to. The dissertation objective was compare submerged nozzles from different suppliers, evaluating the main variables that have direct influence in its performance: heating profile, slag line erosion rate, clogging index and physical-chemical parameters through the materials correlation before and after use (post-mortem). The results showed submerged nozzle\'s better performance from supplier \"M\", that presented smaller waste rates and, consequently, last longer live (larger time of casting) after analysis of the slag line, that can be attributed to a better distribution of the zirconium grains in the head office (larger homogeneity), besides they present finer grains and this way, reducing the empty \" spaces \" in the head office, favorable to slag attack by means of a chemical unbalance between this liquid slag and the refractory. Besides, its anti-clogging material and project distribution in the same piece, they propitiated a better result in relation to the clogging for the alumina building up along the body of the submerged nozzle.
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Mauder, Tomáš. "Optimalizace bramového plynulého odlévání oceli za pomoci numerického modelu teplotního pole." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-234003.
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The thesis deals with optimization of the continuous slab casting process. The thesis summarizes the basic analytical and empirical findings concerning to the solidification process, the numerical modeling and the selected optimization techniques. Physical conditions and factors that affect the quality of steel including their relationships are also described. The basis of the solution strategy is the original numerical model of the temperature field in its off-line version. The numerical model was verified by the real historical data. The optimization part is based on the fuzzy logic implemented above the numerical model. The optimization algorithm is used for the optimal control of the casting process. The universal usage of the optimization model is demonstrated on several cases, e.g. the finding of optimal casting parameters that ensure the high quality of products, the optimal reactions on breakdown situations, the determination of an optimal relationship between casting parameters, etc. Based on optimization results, the suitable caster modification to increase the surface temperature at the unbending point was proposed. The whole concept of the numerical and optimization model is general and it can be applied to arbitrary slab or billet continuous casting.
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Spinelli, Jose Eduardo. "Simulação do lingotamento continuo de tiras finas de aços." [s.n.], 2000. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264701.
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Orientador: Amauri Garcia<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica<br>Made available in DSpace on 2018-07-27T19:18:36Z (GMT). No. of bitstreams: 1
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Previous issue date: 2000<br>Resumo: Entende-se por modelagem de processo, o desenvolvimento de uma representação quantitativa ou qualitativa dos fenômenos físicos associados ao processo. Neste trabalho são realizadas simulações do processo twin roll de lingotamento contínuo de tiras de aços, utilizando como referência tecnológica o equipamento piloto instalado nas dependências do Instituto de Pesquisas Tecnológicas do Estado de São Paulo. São construídos dois simuladores para o processo: um simulador da solidificação unidirecional, com molde refrigerado de aço e paredes laterais de material refratário, utilizando-se o aço inoxidável 304 como material de simulação; e variando-se as temperaturas de vazamento; e outro simulador a frio, com componentes feitos de acrílico, água como fluido de simulação e permanganato de potássio como corante. Um modelo matemático previamente desenvolvido é utilizado para confrontar perfis térmicos teóricos com perfis experimentais, para a determinação do coeficiente de transferência de calor metal/molde. O levantamento de valores de espaçamento dendrítico secundário é realizado nas amostras, além da observação simultânea das estruturas de solidificação, o que comprovou a eficiência do simulador em caracterizar o processo de solidificação do equipamento piloto. O uso do modelo frio permitiu a caracterização do posicionamento de barreira a 15 cm ou a 20 cm da lateral esquerda do distribuidor como a melhor configuração<br>Abstract: It can be understood by process modeling the development of a quantitative or qualitative representation of the physical phenomena associated to the process. In this work, simulations concerning the twin roll continuous caster of steels process at IPT (Instituto de Pesquisas Tecnológicas do Estado de São Paulo) are performed. Two simulators were developed: (i) a simulator of unidirectional solidification with cooled steel mold and refractory lateral walls, by using a stainless steel as the reference metal (AISI 304), and varying superheat temperatures; (ii) a physical model, with components made of acrylic, water as the simulation fluid and potassium permanganate as a pigment. A previously developed mathematical model has been used to determine the metal/mold heat transfer coefficient by a method that compares experimenta1ltheoretical temperature curves. Measurement of secondary dendrite arm spacings is performed by microestructural examination of the samples, confirming the simulator efficiency in characterizing the solidification process in the pilot equipment. The use of the physical model has permitted to attain the best configuration for the tundish, by positioning the dam 15 cm or 20 cm from the left side of tundish<br>Mestrado<br>Materiais e Processos de Fabricação<br>Mestre em Engenharia Mecânica
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Mezzomo, Meire. "AVALIAÇÃO DA QUALIDADE DO PROCESSO DE LINGOTAMENTO CONTÍNUO NA PRESENÇA DE CORRELAÇÃO CRUZADA." Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/8290.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>In the current competitive market, a great part of companies has as the main goal the search for continuous improvement of their products and services. Therefore, the application of statistical methods has great relevance in the quality evaluation, helping in the understanding and monitoring of the processes. In such context, the present study concerns to the use of multivariate control charts in the evaluation of the productive processes in the presence of cross-correlation, which the objective is to verify the continuous casting process stability in the production of still billets by means of Hotelling's T2 multivariate control charts applied in the estimated residual mathematical linear models. Initially, the existence of data autocorrelation was verified, it is necessary the ARIMA modeling, because when it happens, it is necessary to determine the residues and apply multivariate control charts to the residues and not on the original variables. The existence of correlation showed to be meaningful among the variables, being one of the assumptions for the statistical application T2. When the T2 chart instability is verified, it was necessary to identify the variable or the set of variables of steel temperatures in the distributor and in the distributor weight, which are responsible for the instability. Later, the estimated residues were decomposed into principal components, and with the help of the correlation of the original variables and the principal components, the variables which most contributed to the formation of each component were identified. Therefore, it was possible to detect the variables which caused the system instability, once for the steel temperature in the distributor were the T4 and T5, followed by T6, T3, T7 and T2 and for the weight of the distributor, PD4, PD5, PD3, PD6 and PD2, respectively. This way, the estimated residues from the mathematical models, the use of multivariate chart control Hotelling's T2 and the decomposition into principal components which were able to represent the productive process. This methodology allowed the understanding of the behavior of the variables and helped the monitoring of this process, as well as, in the determination of the possible variables which caused the instability in the continuous casting process.<br>No atual mercado competitivo, grande parte das empresas tem como principal objetivo a busca da melhoria contínua dos seus produtos e serviços. Assim, a aplicação de métodos estatísticos apresenta grande relevância na avaliação da qualidade, auxiliando na compreensão e monitoramento de processos. Nesse contexto, o presente estudo aborda a utilização de gráficos de controle multivariados na avaliação do processo produtivo na presença de correlação cruzada, cujo objetivo é verificar a estabilidade do processo de lingotamento contínuo na fabricação de tarugos de aço por meio do gráfico de controle multivariado T2 de Hotelling aplicado nos resíduos estimados de modelos matemáticos lineares. Inicialmente, foi verificada a existência de autocorrelação nos dados, sendo necessária a utilização da modelagem ARIMA, pois quando isso ocorre, deve-se proceder à determinação dos resíduos e aplicar os gráficos de controle multivariados aos resíduos e não nas variáveis originais. A existência de correlação cruzada mostrou-se significativa entre as variáveis, sendo um dos pressupostos para a aplicação da estatística T2. Verificada a instabilidade no gráfico T2, buscaram-se identificar a variável ou conjunto de variáveis das temperaturas do aço no distribuidor e peso do distribuidor, responsáveis pela instabilidade. Posteriormente, os resíduos estimados foram decompostos em componentes principais, e com o auxílio da correlação entre as variáveis originais e as componentes principais, identificou-se as variáveis que mais contribuíram para a formação de cada componente. Assim, foi possível detectar as variáveis causadoras da instabilidade do sistema, sendo que para às temperaturas do aço no distribuidor foram às temperaturas T4 e T5, seguidas de T6, T3, T7 e T2 e para o peso do distribuidor, PD4, PD5, PD3, PD6 e PD2, respectivamente. Deste modo, os resíduos estimados oriundos dos modelos matemáticos, a aplicação dos gráficos de controle multivariados T2 de Hotelling e a decomposição em componentes principais foram capazes de representar o processo produtivo. Esta metodologia possibilitou a compreensão do comportamento das variáveis e auxiliou no monitoramento do processo, bem como, na determinação das possíveis variáveis causadoras da instabilidade no processo de lingotamento contínuo.
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Kim, Yong Jin. "Crystal growth by a continuous casting process." 1986. http://catalog.hathitrust.org/api/volumes/oclc/15431470.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1986.<br>Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 19).
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Chih-Hao, Chou, and 周志浩. "Optimal nozzle design in continuous steel casting process." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/00459528037713678280.
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碩士<br>國立臺灣大學<br>化學工程學研究所<br>87<br>Abstract
A mathematical model was employed to calculate the fluid flow and temperature distribution within the molten steel region of a continuous slab caster. Numerical calculations were based on the real geometry of the slab caster of the China Steel Corporation. Fluid flow and heat transfer phenomena are studied in this research.
The FIDAP code was applied to calculate the three-dimension highly turbulent fluid flow and heat transfer using high Renold number K- model and finite element method. This research studied two kinds of submerged entry nozzle (Cases A and B), and investigated the influence of different operating conditions, such as the submerged depth of nozzles and the length of mold wide face, on the fluid flow and heat transfer. The calculated results indicate that :(1)By means of the converging and diverging parts of its SEN pipe , Case B can result in more even steel flow and temperature distribution. The symmetrisity will be increased about 20% and the average temperature difference between the right and left meniscus will be decreased about 1.5℃.(2)If the submerged depth is increased to 160%,the fluctuation level of meniscus will be decreased by 50% and the average temperature of meniscus will be decreased about 3 to 4℃simultaneously .(3) If the length of the mold wide face is increased to 150%, the fluctuation level of meniscus will be increased by 20% and the average temperature of meniscus will also be decreased about 3 to 5℃. The optimal operating condition depends on the product qualities and the purpose of our processing.
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De, Kock Daniel Johannes. "Optimal Tundish design methodology in a continuous casting process." Thesis, 2005. http://hdl.handle.net/2263/28496.
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The demand for higher quality steel and higher production rates in the production of steel slabs is ever increasing. These slabs are produced using a continuous casting process. The molten steel flow patterns inside the components of the caster play an important role in the quality of these products. A simple yet effective design method that yields optimum designs is required to design the systems influencing the flow patterns in the caster. The tundish is one of these systems. Traditionally, experimental methods were used in the design of these tundishes, making use of plant trials or water modelling. These methods are both costly and time consuming. More recently, Computational Fluid Dynamics (CFD) has established itself as a viable alternative to reduce the number of experimentation required, resulting in a reduction in the time scales and cost of the design process. Furthermore, CFD provides more insight into the flow process that is not available through experimentation only. The CFD process is usually based on a trial-and-error basis and relies heavily on the insight and experience of the designer to improve designs. Even an experienced designer will only be able to improve the design and does not necessarily guarantee optimum results. In this thesis, a more efficient design methodology is proposed. This methodology involves the combination of a mathematical optimiser with CFD to automate the design process. The methodology is tested on a four different industrial test cases. The first case involves the optimisation of a simple dam-weir configuration of a single strand caster. The position of the dam and weir relative to inlet region is optimised to reduce the dead volume and increase the inclusion removal. The second case involves the optimisation of a pouring box and baffle of a two-strand caster. In this case, the pouring box and baffle geometry is optimised to maximise the minimum residence time at operating level and a typical transition level. The third case deals with the geometry optimisation of an impact pad to reduce the surface turbulence that should result in a reduction in the particle entrainment from the slag layer. The last case continues from the third case where a dam position and height is optimised in conjunction with the optimised impact pad to maximise the inclusion removal on the slag layer. The cases studies show that a mathematical optimiser combined with CFD is a superior alternative compared to traditional design methods, in that it yields optimum designs for a tundish in a continuous casting system.<br>Thesis (PhD (Mechanical Engineering))--University of Pretoria, 2006.<br>Mechanical and Aeronautical Engineering<br>unrestricted
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YOU, MING-LONG, and 尤明隆. "Mathematical simulation of the macrosegregation in the continuous casting process." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/25864880007034232188.
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Sheu, Shane Rong, and 許顯榮. "Heat Transfer and Liquid Flow in a Continuous Casting Process." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/50809227418012095416.
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碩士<br>國立清華大學<br>動力機械學系<br>81<br>To simulate a continuous casting process the temperature and
flow field during solidification of steel in a moving slab is
considered. The analysis includes forced convection effects in
the liquid pool. In the present investigation, the APPLE
algorithm and the modified weighting function scheme are
applied to the solidication process of the continuous casting.
All of the computations are performed on a Cartesian coordinate
system without recourse to coordinate transformation or grid
generation for the shape of the solidification interface. In
conjunction with an enthaopy formulation, solutions of the
coupled mass continuity, momentum and energy have been
obtained. The effects of withdrawal velocity and the size of
nozzle were investigated and compared with that from slug flow.
The present numerical technique produces smooth streamlines,
isobars and isotherms even in the vicinity of the
solidification interface. The results reveals that near the
bottom of the pool, the jet seems to result in a temperature
gradient higher than it's counter part in case of slug flow.
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黃振東. "A study of twin roll strip casting process and the continuous metal sheet." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/81801499018010318745.
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HONG, ZHI-JIANG, and 洪志疆. "Computer simulation and analysis of the solidification problem in the continuous casting process." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/47269090757787627541.
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Lin, Cin-San, and 林馨山. "The temperature distribution of the strip in the continuous casting and rolling process." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/16309386814944765956.
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Liu, Fuhai Material Science & Engineering UNSW. "Fundamental investigation of refractory reactions occurring at high temperatures in continuous steel casting process." 2007. http://handle.unsw.edu.au/1959.4/40626.
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An in-depth study has been carried out to investigate refractory degradation during continuous steel casting processes. Slag/refractory interactions have been investigated through a study of the wetting behaviour and gas generation phenomena at the slag/refractory interface at 1550oC using sessile drop experiments. The influence of carbon content and slag composition was investigated. Two different steel casting slags (slag1: MnO 50%, SiO2 25%, Al2O3 25%; and slag2: MnO 40%, SiO2 60%) have been studied along with yttria stabilized zirconia refractory substrates respectively containing 10%, 15% and 20% carbon. The gas generation has been measured using the Infrared gas analyser, and its influence has also been investigated by taking optical images at varying times. The total amount of gases emitted has shown the dependence on the compositions of refractory substrates and the existence of casting slags. Under the investigation of zirconia-carbon refractory, a new phenomenon that the gas generated can push the liquid slags away and minimise the contact of slags and refractory substrates has been proven.
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Tzeng, Shu-Wen, and 曾淑雯. "Numerical Simulation of the In-Mold Electromagnetic Stirring of Slabs in a Continuous Casting Process." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/92422107247007792729.
Full textAbstract:
碩士<br>國立臺灣大學<br>化學工程學研究所<br>93<br>A three-dimensional numerical simulation for the steel continuous casting process with the in-mold electromagnetic stirring (MEMS) of slabs was investigated using the commercial FIDAP code. Electromagnetic stirring is used to reduce the defects and to improve the quality of the final products. In this study, a simplified model for the electromagnetic force was used to simplify the electromagnetic force (EMF) problem. Three port angles for the SEN design and two intensities of magnetic forces were simulated.
The results show that: (1) In EMS off operation, maximum velocities at the meniscus are all about 10cm/s while average fluctuation levels at the meniscus are about 0.1mm, and average temperatures at meniscus are about 1528℃. Furthermore, the case mold15d has smaller F-factor, lower impingement point, and higher average temperature at meniscus. The results show the mold with noz15d could be a better design. (2) In EMS on operation, the velocity profiles and temperature distribution are distinct from those without EMS. The impingement points have been lifted up to almost same position about 22~23cm below the meniscus at two narrow sides. Average temperature at meniscus is decreased by 2~3℃. It is seen that regular circulations of velocity pattern and temperature pattern at meniscus. Since the velocity at meniscus has increased, the temperature profiles at same narrow position became uniform. (3) For cases with 0.13T maximum magnetic density, the maximum velocity has increased by a factor 8 and average fluctuation level increased to be 10mm. For cases with 0.07T maximum magnetic density, the maximum velocity has increased by a factor 4 and average fluctuation level increased to be 2mm. (4) Comparisons of the results of F-factors for molds with EMS show that similar results are obtained. Molds with noz25d have smallest values of F-factor and better in symmetry for the two maximum magnetic flux densities. The results show that noz25d could be a better design for molds with EMS.
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Bouhouche, Salah [Verfasser]. "Contribution to quality and process optimisation in continuous casting using mathematical modelling / vorgelegt von Salah Bouhouche." 2002. http://d-nb.info/966041208/34.
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TSAI, MAO-CHANG, and 蔡茂昌. "The Effect of Bottom Blowing Conditions on Floating Inclusion Behavior in the Vacuum Continuous Casting Process by Water Modeling." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/10856600199584215391.
Full textAbstract:
碩士<br>義守大學<br>材料科學與工程學系碩士班<br>95<br>This research aims at enhancing the quality of melting metal solution in the vacuum continuous casting by using air blowing and floating inclusion to remove the nonmetallic impurity. Modify the air blowing in melting process by water model. Analyze the behavior of air bubbles to find the optimum parameters.
In this experiment we made an Id112mm*H200mm acrylic water model. Confirm the similarity between the cold model and the hot model by the Buckingham theorem. Set the parameters of the water model experiment. Substitute copper melting by water and argon by air. Modify the real air blowing to float inclusion of hot model by water model. This research is divided into the static experiment and dynamic tests. (1)Static experiment：Without water entering from the water mold. Change the number of tuyeres (1~4) the tube, the liquid level (40, 80, 120mm), the air flow rate (1.0~2.5L/min) to analyze the influence of air bubble movement behavior by the tubes arrangement , the air bubble size, the air bubbles density of distribution. Estimate the optimum parameters combination. (2)Dynamic experiment：With water entering from the top of water mold and leaving from the bottom respectively. Modify the air blowing to float inclusion process whether the air bubble sink down to bottom and induce the flaw.
(1) Result of static experiment: 1.With liquid level 80mm, four tuyeres, gas flowing rate below 1.5 L/min can make bubble size smaller and even. The air bubble flow field is stable and the turbulence of liquid surface may decrease. 2. With liquid level 80mm, 2 tuyeres, the gas flowing rate must be below 1.0 L/min. Converts in the actual casting system the optimum floating inclusion condition is:1. Melted fluid level is 80mm. The tuyere number is four. The argon flow rate must be below 6.67 L/min. 2. Melted fluid level is 80mm. The tuyere number is two. The argon flow rate must be below 4.44 L/min. (2) Result of dynamic test : The quantity of sinking air bubble is 0 %, that means that in the real casting process all air bubble float is upward. No air bubble will flow back to the flow channel.
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(8812070), Edwin A. Mosquera Salazar. "AIR-MIST SPRAY MODEL DEVELOPMENT IN STEEL SECONDARY COOLING PROCESS." Thesis, 2020.
Find full textAbstract:
Continuous casting is an important process to transform molten metal into solid. Arrays of spray nozzles are used along the process to remove heat from the slab letting it solidify. Efficient and uniform heat removal without slab cracking is desired during steel continuous casting, and air-mist sprays could help to achieve this goal.Air-mist nozzles are one of the important keys for determining the quality of steel as well as energy consumption for pumping the water. Based on industrial data, it is estimated that a 1% reduction in scrapped production due to casting related defects can result in annual savings of 40.53 million dollars in the U.S. Computational simulations studies can minimize defects in steel such as cracks, inclusions, macro-segregations, porosity, and others, which are closely related to the heat transfer between water droplets and hot slab surface.<div><br></div><div>Conducting multiple spray experiments in order to find optimum operating conditions might be impractical and expensive in some cases. Thus, Computational Fluid Dynamics (CFD) simulation is aimed to be used for simulating the air-mist spray process. Because it is a challenging process due to strong air and water interaction, then numerical models have been developed to simulate water droplets. The first model involves air and water phases which then are transformed in single-phase water droplets. To do so, a Volume of Fraction (VOF) to the Discrete Phase Model (DPM) is used.<br></div><div><br></div><div>VOF-TO-DPM transition model involves the primary and secondary breakup which occurs in the water atomization process, starting with a single water core, followed by a smaller compact mass of water known as lumps or ligaments due to the interaction of air, and finally converted into water droplets.The second model is using the Nukiyama-Tanasawa function size distribution which injects water droplets based on defined size range and velocity profile. A validation of droplet size and velocity against experimental data has been accomplished. The models can avoid acquiring expensive equipment in order to understand nozzle spray performance, and droplets generated. Quality, water droplet velocity, size, energy, and water consumption are the core of the current study. Last but not least, the methodology for this model can be used in any other air-mist nozzle design.<br></div>