ESTUDO DA VARIAÇÃO DA TAXA DE DESCARBURAÇÃO EM FUNÇÃO DA VAZÃO DE ARGÔNIO UTILIZADA NA PERNA DE SUBIDA DO DESGASEIFICADOR A VÁCUO RH
STUDY OF THE VARIATION AT DECARBURIZATION RATE AS FUNCTION OF THE ARGON FLOW RATES IN THE UPLEG SNORKEL OF THE RH DEGASSER
Silva, Marlon José dos A.; Tavares, Roberto Parreiras
http://dx.doi.org/10.4322/tmm.2012.009
Tecnol. Metal. Mater. Min., vol.9, n1, p.53-58, 2012
Resumo
Neste trabalho, desenvolve-se uma investigação sobre a variação da constante aparente de descarburação (kc), em função da vazão de argônio utilizada no desgaseificador a vácuo RH, otimizando a vazão em cada etapa da descarburação. Acompanharam-se 97 corridas de aço ultra baixo carbono, utilizando três vazões de argônio diferentes (80 Nm3/h, 110 Nm3/h e 140 Nm3/h). Foram retiradas amostras de aço aos 0, 6 e 12 minutos de cada corrida. Para a primeira etapa da descarburação obtiveram-se valores semelhantes de kc nas três vazões testadas. Nesse caso, reduziu-se esta vazão de 110 Nm3/h para 80 Nm3/h, o que representa uma redução no consumo de argônio de 18.900 Nm3/ano. Obteve-se, também, uma menor queda de temperatura do aço durante o tratamento e um menor volume de gás a ser succionado pelo sistema de vácuo. Para a segunda etapa da descarburação manteve-se a vazão de 140 Nm3/h, por apresentar o maior valor de kc.
Palavras-chave
Descarburação, Desgaseificador RH, Argônio
Abstract
This work investigates the variation of the apparent decarburization constant (kc) as function of the argon flow rate injected in a RH degasser. It allows optimization of the flow rate at each decarburization stage. For this, 97 ultra low carbon steel heats were analyzed using three different argon flow rates (80 Nm3/h, 110 Nm3/h e 140 Nm3/h). Steel samples were taken at 0, 6 and 12 minutes of each heat. In the first decarburization stage, the kc values were similar for the three tested flow rates. In this case, this flow rate was reduced from 110 Nm3/h to 80 Nm3/h and the argon consumption decreased in 18.900 Nm3/year. With this change, the temperature drop during the treatment and the gas volume to be sucked by the vacuum system were reduced. In the second decarburization stage, the flow rate of 140 Nm3/h remained due to the highest kc value.
Keywords
Decarburization, RH degasser, Argon
Referências
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8 PARK, Y-G.; YI, K-W. A new numerical model for predicting carbon concentration during RH degassing treatment. ISIJ International, v. 43, n. 9, p. 1403-9, 2003. http://dx.doi.org/10.2355/isijinternational.43.1403
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11 RIBEIRO, D. B. et al. Refino secundário dos aços. São Paulo: Associação Brasileira de Metalurgia e Materiais, 2005. [Apostila].
12 TSUKIHASHI, F.; LI, B. Modeling of circulating flow in degassing vessel water model designed for two-and multi-legs operation. ISIJ International, vol. 40, n. 12, p. 1203-9, 2000. http://dx.doi.org/10.2355/isijinternational.40.1203
13 HAHN, F. I. et al. Application of the RH process to the production of ultra low carbon steels at Thyssen Stahl AG. Ironmaking and Steelmaking, v. 17, n. 3, p. 43-7, Mar. 1990.
14 KUWABARA, T.; et al. Investigation of decarburization behavior in RH-reactor and its operation improvement. Transactions ISIJ, v. 28, n. 4, p. 305-14, 1988. http://dx.doi.org/10.2355/isijinternational1966.28.305
15 TEMBERGEM, D.; TEWORTE, R.; ROBEY, R. Vacuum ladle treatment using RH metallurgy. Metallurgical Plant and Technology International, v. 30, n. 3, p. 56-63, mar. 2007.
2 HANNA, R. K. et al. Water modeling to aid improvement of degasser performance for production of ultralow carbon interstitial free steels. Ironmaking and Steelmaking, v. 21, n. 1, p. 37-43, Feb. 1994.
3 SILVA, M. J. A.; VIANA, J. F.; ARAÚJO, T. C. S. Modernização do desgaseificador a vácuo da aciaria 2. In: SEMINÁRIO INTERNO DA QUALIDADE, 5., Ipatinga, Usiminas, 2004.
4 FRUEHAN, R. J. An introduction to vacuum degassing - part II. Iron and Steelmaker, v. 17, n. 7, p. 42-3, July 1990.
5 YANO, M. et al. Recent advances in ultralow-carbon steel refining technology by vacuum degassing processes. Nippon Steel Technical Report, n. 61, p.15-21, Apr. 1994.
6 AHRENHOLD, F. et al. Experience with the second RH degasser at the Beeckerwerth Steel of TKS. In: BRAZILIAN METALS SOCIETY CONGRESS, 2003, Belo Horizonte. Anais… São Paulo: ABM, 2003. p. 19-21.
7 GUO, D; IRONS, G. A. Modelling of gás-liquid reactions in ladle metallurgy; Part 1; Physical modeling. Metallurgical and Materials Transactions B, v. 31, n. 6, p. 1447-55, Dec. 2000. http://dx.doi.org/10.1007/s11663-000-0029-8
8 PARK, Y-G.; YI, K-W. A new numerical model for predicting carbon concentration during RH degassing treatment. ISIJ International, v. 43, n. 9, p. 1403-9, 2003. http://dx.doi.org/10.2355/isijinternational.43.1403
9 WEI, J-H.; YU, N-W. Mathematical modeling for RH refining process of molten steel. In: IRONMAKING CONFERENCE, 61., 2002, Nashville. Proceedings... Warrendale: Iron & Steel Society, 2002. p. 775-92.
10 KATO, Y. et al. Décaburation de l’acier à moins de 10 ppm par dégazage au RH avec insufflation d’oxygène. La Revue de Métallurgie, v. 89, n. 7, p. 616-21, Jul./Out. 1992.
11 RIBEIRO, D. B. et al. Refino secundário dos aços. São Paulo: Associação Brasileira de Metalurgia e Materiais, 2005. [Apostila].
12 TSUKIHASHI, F.; LI, B. Modeling of circulating flow in degassing vessel water model designed for two-and multi-legs operation. ISIJ International, vol. 40, n. 12, p. 1203-9, 2000. http://dx.doi.org/10.2355/isijinternational.40.1203
13 HAHN, F. I. et al. Application of the RH process to the production of ultra low carbon steels at Thyssen Stahl AG. Ironmaking and Steelmaking, v. 17, n. 3, p. 43-7, Mar. 1990.
14 KUWABARA, T.; et al. Investigation of decarburization behavior in RH-reactor and its operation improvement. Transactions ISIJ, v. 28, n. 4, p. 305-14, 1988. http://dx.doi.org/10.2355/isijinternational1966.28.305
15 TEMBERGEM, D.; TEWORTE, R.; ROBEY, R. Vacuum ladle treatment using RH metallurgy. Metallurgical Plant and Technology International, v. 30, n. 3, p. 56-63, mar. 2007.
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