The effect of degassing technology parameters and the quality of periclase-chromite refractories on their wear resistance in vacuum chamber lining

Visloguzova, É. A.; Metelkin, A. A.; Zorikhina, L. V.; Maryasev, I. G.; Tereshchenko, D. A.; Mikhailovskaya, L. M.

doi:10.1007/s11148-006-0110-1

Cited by 4 publications

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“…Specialists at OAO EVRAZ NTMK pay great attention to the refractory components obtained from suppliers and, in particular, their susceptibility to wear [4]. Research shows that the unit wear of refractories in the discharge tube does not depend on the overall properties but is largely determined by the characteris tics of the intake refractories.…”

Section: Properties Of the Refractoriesmentioning

confidence: 99%

Extending the lining life in circulatory vacuum units at OAO EVRAZ NTMK

et al. 2013

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In efforts to reduce metal costs, it is important to extend the lining life in metallurgical systems [1]. In particular, the linings of vacuum units account for a considerable portion of total refractory costs.Three groups of factors affect the lining life in cir culatory vacuum units [2]:(1) structural factors (the shape and size of the metal framework, the lining design, the format of the refractory pieces, and so on);(2) the physicochemical properties of the refracto ries, which depend on the quality of the raw materials, the manufacturing technology, and so on; (3) technological factors (the operating conditions of the metallurgical system, the slag composition and properties).Specialists at OAO EVRAZ NTMK have been studying these factors, in order to improve the refrac tory components and optimize their operating condi tions. The results assist in the development and intro duction of new lining configurations with improved performance and longer life.On that basis, measures have been taken to improve the operation of the vacuum units at OAO EVRAZ NTMK. STRUCTURAL FACTORSIn the converter shop at OAO EVRAZ NTMK, the lining configuration illustrated in Fig. 1 is employed in the vacuum unit. A deficiency of this configuration is that the junction of the refractory ring and the refrac tory concrete at the end is rapidly worn, as is the region where the transporting gas is supplied (Fig. 2). During operation, the liquid steel penetrates into the damaged surface and erodes the metallic plate that supports the refractory rings at the end of the tube. That leads to settling of the lower ring of the tube and the formation of a gap between the rows of components. In subse quent operation, metal melt leaks into the gaps, pro ducing local erosion around the circumference (Fig. 3). The vacuum chamber requires premature repair [2,3]. This problem at the junction of the refractory concrete and the refractory rings may be eliminated by adopting the design in Fig. 4. In that case, there is no horizontal junction between the concrete and the refractory ring, and the lower ring is rigidly fixed. In the course of operation, the modified structure does not permit per ceptible settling of the refractory rings. The mean life in experimental vacuum chambers was 106.0 melts (as against 102.0 melts for mass produced components). PROPERTIES OF THE REFRACTORIESSpecialists at OAO EVRAZ NTMK pay great attention to the refractory components obtained from suppliers and, in particular, their susceptibility to wear [4]. Research shows that the unit wear of refractories in the discharge tube does not depend on the overall properties but is largely determined by the characteris tics of the intake refractories. The operating condi tions are most intense at the intakes: additional cool ing of the refractory surface in the period between melts by neutral gas and considerable turbulence of the metal, which tends to erode the brick.It is evident from the table that the components dif fer considerably in properties and working life. For more detaile...

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Section: Properties Of the Refractoriesmentioning

confidence: 99%

Extending the lining life in circulatory vacuum units at OAO EVRAZ NTMK

et al. 2013

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“…Refratários de magnésia-cromo, empregados em fornos destinados ao tratamento e degasifi cação de aços, são os materiais que [11][12][13]. A aplicação combinada de cálculos termodinâmicos de equilíbrio e o modelamento computacional do comportamento de fl uxo do líquido têm permitido obter melhores previsões sobre o desgaste dos materiais refratários contendo óxido de cromo [13].…”

Section: Dissociação E Volatilizaçãounclassified

Simulação termodinâmica e sua aplicação na avaliação do desempenho de materiais refratários

Luz

Pandolfelli

2011

Cerâmica

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INTRODUÇÃODados e cálculos termodinâmicos são importantes para entender o fenômeno de corrosão e oxidação de refratários. Estes cálculos são baseados na minimização da energia livre do sistema, sendo possível deduzir a natureza das fases sólidas, líquidas e gasosas, assim como, sua composição química e reação na condição de equilíbrio [1,2].A corrosão de materiais refratários ocorre normalmente a elevadas temperaturas e sob condições extremas de uso, as quais são difi cilmente reproduzidas em escala laboratorial. A forma mais efi ciente de se avaliar o fenômeno de corrosão envolve: cálculos termodinâmicos; fatores cinéticos; ensaios

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