Teses / dissertações sobre o tema "Vacuum Arc Remelting (VAR)"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 16 melhores trabalhos (teses / dissertações) para estudos sobre o assunto "Vacuum Arc Remelting (VAR)".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja as teses / dissertações das mais diversas áreas científicas e compile uma bibliografia correta.
Polton, Richard. "Numerical grid generation and its application in the solution of a model of the Vacuum-Arc Remelting (VAR) process". Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323918.
Texto completo da fontePoullain, Thomas. "Etude numérique et expérimentale de l’évaporation sous vide d’alliages métalliques : application à la refusion VAR de Zircaloy-4". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0189.
Texto completo da fonteComposition and chemical segregation control is primordial when producing high value-added materials, such as zirconium alloys for nuclear industry. Vacuum processing allows production very high purity ingot, however it also presents an additional problematic concerning control and prediction of alloy elements evaporation. This PhD dissertation aims at improving prediction of volatile metallic species evaporation during vacuum elaboration, especially during Zircaloy 4 VAR (Vacuum Arc Remelting).First, the evaporation kinetics and the expansion of the metal vapour produced during vacuum melting is investigated. The study is done with a combination of volatilisation experiments using an experimental electron beam furnace and particle based numerical simulation (FPM) of vapour behaviour. Our volatilisation studies on pure metals, Ti and Zr, show the importance of collisions above the liquid on the vapour expansion and its recondensation. Determination of Fe and Sn vapour expansion during Zy4 vacuum melting combined with particle simulation, allowed us to determine thermodynamic activity coefficients values for these elements in liquid Zy4.Then, metallic vapour expansion under VAR conditions is studied, with particular interest shown to condensation flows on the different surfaces. Application of our numerical model to Zy4 shows that the vapour deposited on the mould has a very different composition compared to the alloy. Finally, the particle model is coupled to an ingot growth model and we study the influence of evaporation, condensation and crown reincorporation with regard to volatile solute segregation and depletion. This coupling also provides a first prediction of crown thickness and composition and we compare them to industrial crown samples
Ghazal, Ghassan. "Etude de la propreté inclusionnaire des lingots VAR - Application aux alliages de titane". Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL016N/document.
Texto completo da fonteThe presence of exogeneous inclusions has always been a major concern for the titanium industry. To help improve the inclusional cleanliness of VAR (Vacuum Arc Remelting) titanium ingots, a numerical and experimental study was undertaken.The numerical model is capable of predicting the motion and dissolution of a hard-α defect falling from the electrode tip into the ingot melt pool during vacuum arc remelting. It is implemented in SOLAR, a CFD code that simulates the ingot growth and solidification. The dissolution of the inclusion is governed by nitrogen diffusion from the defect towards the surrounding molten metal. A model describing this phenomenon predicts the particle size evolution and the nitrogen profile at each moment. The motion of the spherical particle is tracked using a Lagrangian model and the influence of turbulence is accounted for by a modification of the drag coefficient.Results show that inclusion removal is difficult with a single melt since the growth of a β-phase layer leads to an initial increase in the defect size. The inclusion behaviour is highly dependent on the pool hydrodynamics and on inclusion characteristics.In order to clarify dissolution aspects of these defects and to measure their dissolution kinetics, synthetically processed defects were introduced into molten titanium heated in an electron beam melting furnace. Dissolution rates were calculated by measuring the size of the defects before and after the experiments and the results were used to validate the numerical models. Furthermore, the experiments show that dissolution kinetics highly depend on fluid motion and temperature
Revil-Baudard, Mathieu. "Modélisation et étude de la macroségrégation au cours de la refusion à l'arc sous vide : application aux alliages de zirconium". Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0297/document.
Texto completo da fonteVacuum Arc Remelting (VAR) is used to produce high performance alloys for the aeronautic (special steels, superalloys, titanium alloys) and nuclear (zirconium alloys) industries. As for all casting processes, the control of the chemical homogeneity and the metallurgical structure in VAR ingots is an important industrial issue. The goal of this thesis is to identify, for zirconium alloys in particular, the effects of the natural convection and the forced convection due to the electromagnetic stirring on macrosegregation. To this purpose, a numerical model has been developed. It is based on the solution of the coupled transient energy, momentum and solute transport equations, under laminar or turbulent flow conditions. The solidification modeling accounts for a full coupling between energy and solute transport in the mushy zone. The finite diffusion of solutes in both solid and liquid phases can be taken into account to describe microsegregation. In addition, chemically homogeneous Zircaloy-4 and M5® electrodes have been specially remelted in an industrial VAR furnace at the CEZUS plant in Ugine (Savoie, France). The macrosegregation of the ingots has been measured. The comparison between the experimental measurements and the simulation results showed that for an alloy with a large solidification interval (like Zircaloy-4), the solutal convection in the mushy zone could have an essential influence on the macrosegregation in the inner part of the ingot. Furthermore, the motion of equiaxed grains caused by a strong stirring seems to seriously intensify macrosegregation in the outer part of the ingot. For an alloy with a small solidification interval (like M5®), we have shown that the macrosegregation depends more specifically on the forced convection due to the type of stirring applied during the remelting
Hans, Stéphane. "Modélisation des transferts couplés de chaleur, de soluté et de quantité de mouvement lors de la refusion à l'arc sous vide (VAR) : application aux alliages de titane". Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL023N.
Texto completo da fonteBanos, Julien. "Modélisation du procédé de refusion à l’arc sous vide : Échanges thermiques et défauts de solidification". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0117.
Texto completo da fonteThe Vacuum Arc Remelting (VAR) process is used in the production of high-added value metals such as titanium alloys or nickel-based superalloys for the aerospace industry. The control of solidification conditions is an important industrial issue in order to process ingots of adequate chemical homogeneity and free of solidification defects. The work presented in this manuscript aims at improving the description of heat exchanges in a VAR process model (SOLAR) and at proposing a new approach for the prediction of segregated channels type solidification defects. First, the description of the heat exchanges in the model between the electrode, the ingot, the mould and the cooling circuit has been improved. These modifications were validated by comparing the numerical results with measurements from real industrial melts. An original experimental apparatus for measuring the external mould temperature adapted to industrial melts was designed. This apparatus was used during an experimental campaign on an industrial site during the remelting of a titanium alloy. The measurements obtained were compared with the numerical results from SOLAR. These two activities led to a first implementation of the side-arcing phenomenon in the model. In parallel, a multi-scale numerical approach was developed to predict the formation of segregated channels as a function of local solidification conditions. A first study on a Sn-Pb alloy was carried out and a mathematical criterion was calculated from the results. This first study shows a much lower impact of the thermal gradient on the formation of segregated channels than that generally considered in the literature
Wani, Nitin Yashwant. "Simulation of thermal stresses in vacuum arc remelting process". Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1178820121.
Texto completo da fonteHosamani, Laxmappa G. "Experimental and theoretical heat transfer studies in vacuum arc remelting /". Full text open access at:, 1988. http://content.ohsu.edu/u?/etd,166.
Texto completo da fonteXu, Xuahua. "Grain development during vacuum arc remelting of nickel based superalloys". Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368958.
Texto completo da fonteMUCSI, CRISTIANO S. "Estudo sobre o processo V.A.R. (Vacuum Arc Remelting) escala de laboratorio". reponame:Repositório Institucional do IPEN, 1996. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10472.
Texto completo da fonteMade available in DSpace on 2014-10-09T14:06:54Z (GMT). No. of bitstreams: 1 02949.pdf: 9168361 bytes, checksum: 474a2e1dcf103e26b6863b7d40ff33a1 (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Yuan, Lang. "Multiscale modelling of the influence of convection on dendrite formation and freckle initiation during vacuum arc remelting". Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/5683.
Texto completo da fonteDelzant, Pierre-Olivier. "Refusion sous vide d’alliages de titane : comportement de l’arc électrique et conditions aux limites". Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0020/document.
Texto completo da fonteIn the vacuum arc remelting process, the structure and dynamics of the electric arc are responsible for the spatial distributions of energy and current at the top of the remelted ingot. Those distributions strongly impact the ingot temperature field and the liquid metal velocity field, which govern the ingot solidification conditions, hence the final product quality. A study based on the optical measurement of the electric arc dynamics at a long time-scale during vacuum arc remelting of titanium alloys was undertaken. This analysis was performed either qualitatively using melt video recordings, or quantitatively by a new specifically developed diagnostic technique based on the use of photodiodes. The analysis of the electric arc dynamics confirmed the presence of an ensemble arc motion during vacuum arc remelting of titanium alloys and showed a strong correlation between the observed dynamics and the magnitude of the imposed electromagnetic stirring. Furthermore, our results allow to predict the arc dynamics in non-studied conditions and to propose possible origins for the observed behaviors. Finally, a first simulation of the influence of the arc behavior is proposed in order to study its impact on the ingot solidification. This work comprises also a detailed modelling of the thermal radiation at the ingot top, based on the radiosity method
Lopez, Luis Felipe. "Implementation of a high-fidelity axisymmetric model in a Vacuum Arc Remelting process". Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-05-2770.
Texto completo da fontetext
Viosca, Alan Lee. "A method for the characterization of white spots in vacuum-arc remelted superalloys". Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-12-4858.
Texto completo da fontetext
Lin, Chi-ming, e 林啟明. "The study of TiVMn hydrogen storage powders prepared by Mechanically Alloyed and Vacuum Arc Remelting methods". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/67460991720560599397.
Texto completo da fonteLopez, Luis Felipe active 21st century. "Cyber-enabled manufacturing systems (CeMS) : model-based estimation and control of a solidification process". Thesis, 2014. http://hdl.handle.net/2152/28082.
Texto completo da fontetext