Mechanism of alumina buildup in tundish nozzles during continuous casting of aluminum-killed steels

Singh, S. N.

doi:10.1007/bf02643930

Cited by 110 publications

(65 citation statements)

References 2 publications

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“…chemical, and phase composition were not satisfactorily estimated within this study. Nevertheless, the morphology closely investigated by SEM is in excellent agreement with reports of endogenous inclusions that originate from aluminum killing during steelmaking [15][16][17]26,27] and component failure that was traced back to alumina inclusions. [3,28] 3.4.…”

Section: Deposited Clustersupporting

confidence: 73%

“…To diminish clogging, several studies have focused on the origin, formation, and growth of non-metallic inclusions in Al-killed steel on the one hand, as well as on the interactions of Alkilled steel and carbon-bonded alumina refractories. [1,[12][13][14][15][16][17] For steel melt filtration, however, the time factor of these interactions is essential. To the authors' knowledge, such tests have been carried out by Storti et al [18] only in form of shorttime immersion tests (10 s and 30 s) of multi-walled carbon nanotubes coated Al 2 O 3 -C filters.…”

Section: Introductionmentioning

confidence: 99%

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Functionalized Carbon‐Bonded Filters with an Open Porous Alumina Coating: Impact of Time on Interactions and Steel Cleanliness

et al. 2017

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Understanding interactions between filter and molten steel is essential to improve the purity of casted products by filtration. Characteristic, in situ formed layers on the surface of carbon-bonded alumina filters result from these interactions. To comprehend their formation, this study illustrates the time dependency of the layer buildup. Therefore, reactions at the filter/steel interface under quasi static conditions are examined using spark plasma sintering (SPS) equipment. Immersion tests in a steel casting simulator, which provides close-to-reality conditions, complement these investigations. Microstructure and phase analyses reveal that interfacial reactions between filter and steel lead to a thin in situ formed layer on the filter surface. During a "reactive" stage, large polycrystalline alumina structures are formed. Thereby, material is transported both from the carbon-bonded material underneath (i.e., gaseous reaction products) and from the molten steel (i.e., precipitating particles and endogenous inclusions) to the filter/steel interface. The formation of these alumina particles comes to an end as soon as the carbon supply, which triggers the dissolution and precipitation processes at the interface, is cut-off. From that point on, endogenous inclusions are deposited on them ("active" stage). The filters were most efficient during the reactive stage, that is, as long as the interfacial reactions take place.

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Section: Deposited Clustersupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Functionalized Carbon‐Bonded Filters with an Open Porous Alumina Coating: Impact of Time on Interactions and Steel Cleanliness

et al. 2017

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“…(2) Vários autores buscaram entender quais são os mecanismos responsáveis por esse fenômeno. Singh (3) realizou estudos em uma planta piloto, utilizando aço com uma elevada quantidade de inclusões para amplificar a ocorrência de clogging. Observou que as inclusões localizadas na região próxima à camada limite possuem baixa velocidade e, com isso, têm maior tendência em aderir às paredes da válvula.…”

Section: Introductionunclassified

Estudo Do Mecanismo De Clogging Na Região Da Válvula Tampão Empregando CFD

Contini¹,

Morales²,

Trindade³

et al. 2011

TMM

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ResumoA deposição de inclusões (clogging) na válvula submersa e na válvula tampão do distribuidor é um problema que pode ocorrer em todas as aciarias, provocando a interrupção de veios, desestabilização da operação e aumento nos custos. Este trabalho pretende avaliar a influência do escoamento do aço líquido na deposição de inclusões de alumina na válvula tampão. Para isso, é empregado um modelo fluidodinâmico computacional para caracterizar o escoamento do aço na região da válvula tampão. Para o cálculo foi construída uma geometria tridimensional da região próxima à sede. A solução do escoamento e a previsão da deposição de inclusões foram implementadas usando uma formulação euleriana e o modelo lagrangeano, respectivamente. São avaliadas diferentes aberturas da válvula para visualizar o comportamento do aço e relacioná-lo à taxa de deposição de inclusões. Consegue-se observar que ocorre uma recirculação na ponta do tampão e que está relacionada com a abertura da válvula. Observa-se que, quanto maior a abertura da válvula, menor é a taxa de deposição de inclusões. Palavras-chave: Lingotamento contínuo de aço; Válvula tampão; Clogging; CFD. INVESTIGATION OF CLOGGING MECHANISM IN THE STOPPER ROD REGION EMPLOYING CFD ANALYSIS AbstractInclusions deposition on stopper rod and submerged entry nozzle is a problem which may occur in every steel plant, leading to casting interruption, operational instabilities and increase in costs. This paper seeks to analyze the influence of molten steel flow pattern on alumina inclusions deposition at stopper rod. A computational fluid dynamical model is employed in order to characterize the flow in that region. A 3-dimensionalgeometry of the nozzle region was built. Molten steel flow and inclusions deposition are computed through eulerian and lagrangian approaches, accordingly. Different nozzle openings are evaluated in order to visualize the steel flow and to relate alumina deposition rate with it. The results show that there is a recirculation that occurs in the stopper rod tip and it is related to the nozzle openings. It is seen that larger nozzle openings tends to lower the inclusions deposition rate.

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“…Nevertheless, a high percentage of inclusions are not removed in the tundish reaching the nozzle where some of them are no uniformly deposit at typical zones of the nozzle [1][2][3][4][5][6][7][8]. For aluminum killed steel, alumina inclusions are the most common cluster material, which is produced during the deoxidation, from the interaction of refractory material and molten steel [1][2][3][4][5][6][7][8][9][10][11][12][13][14], and finally from the re-oxidation of steel. This inclusion deposition induces a problem known as clogging phenomenon which has been studied for many researchers.…”

Section: Introductionmentioning

confidence: 99%

Fluidynamic Effects on the Deposition of Alumina Particles at the Upper Tundish Nozzle

Guerrero¹,

Hernandez²,

Sandoval³

et al. 2017

Anais Do Seminário De Aciaria, Fundição E Metalurgia De Não-Ferrosos

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Inclusion deposition is still a standing problem in the continuous casting of steel since the deposition of alumina inclusions inside the SEN affects the productivity and the product quality. The present work studies the factors involved in the inclusion deposition at the nozzle and the effects of inertial, gravitational, buoyant, pressure gradient, and Saffman forces on the inclusion trajectories. The results show that the inclusions reaching the nozzle, only 30% get deposited along its walls mainly at the Upper Tundish Nozzle (UTN). This area of higher deposition is identified close to a low static pressure and a high turbulent kinetic energy dissipation zones where the effects of the gravitational and buoyant forces do not promote a significant inclusion radial movement since these are aligned with the direction of the flow stream lines. In contrast, in this zone, the Saffman force shows an important effect on the deposited inclusions, slowing down the inclusions in the vertical axis and increasing their radial movement.

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Mechanism of alumina buildup in tundish nozzles during continuous casting of aluminum-killed steels

Cited by 110 publications

References 2 publications

Functionalized Carbon‐Bonded Filters with an Open Porous Alumina Coating: Impact of Time on Interactions and Steel Cleanliness

Functionalized Carbon‐Bonded Filters with an Open Porous Alumina Coating: Impact of Time on Interactions and Steel Cleanliness

Estudo Do Mecanismo De Clogging Na Região Da Válvula Tampão Empregando CFD

Fluidynamic Effects on the Deposition of Alumina Particles at the Upper Tundish Nozzle

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