ESTUDO DO EFEITO DO CARBONO NA APLICAÇÃO DE FLUXANTES PARA LINGOTAMENTO CONTÍNUO DE AÇOS
EVALUATION OF CARBON EFECT ON MOULD FLUX FOR CONTINUOUS CASTING OF STEEL
Bezerra, Maria Carolina C.; Valadares, Claudio Antônio G.; Capocchi, José Deodoro T.
http://dx.doi.org/10.4322/tmm.00502001
Tecnol. Metal. Mater., vol.5, n2, p.65-71, 2008
Resumo
Os fluxantes são constituídos por óxidos como SiO2, CaO e MgO. O sistema vítreo do fluxante fundido corresponde a um líquido que, com a redução da temperatura durante o lingotamento, gera um material solidificado de altíssima viscosidade. O carbono adicionado ao fluxante possui efeito na sua velocidade de fusão, sinterização, propriedades de isolamento térmico e formação do slag rim. O carbono não se mistura às partículas das matérias-primas minerais ou sintéticas que compõem o fluxante, mantendo-as separadas durante o processo de fusão do material. Quanto maior o teor de carbono, menor será a taxa de fusão do material. A determinação da taxa de fusão dos fluxantes é importante para definir uma composição tal que gere líquido suficiente para alimentar a folga (gap) existente entre a placa de aço em solidificação e o molde, garantindo a lubrificação, mesmo em condições variadas de lingotamento. Neste trabalho, é apresentada a influência de diferentes fontes de carbono para o controle da taxa de fusão de fluxantes por meio de análises térmicas e da utilização de equipamento desenvolvido especialmente para execução deste estudo.
Palavras-chave
Fluxantes, Carbono, Lingotamento contínuo
Abstract
Mould fluxes compositions contain acid oxides such as SiO2 and basic oxides such as CaO and MgO. The amorphous phase of molten mould flux generates a high viscosity material. Carbon is also added in the mould flux composition and, if in an adequate amount and type, it actuates on melting rate and on the control of sintering tendency, insulation properties and slag rim formation. Carbon particles act as a barrier between the raw materials grains keeping them separated. The higher is the carbon content, the lower is the melting rate. The mould flux melting control is very important to guarantee enough liquid flux generation to feed the gap between the solidifying shell and the mould wall, even in hard casting conditions. In this paper it is presented the behavior of different sources of carbon on melting rate evaluation, through thermal analysis and by using specific equipment specially developed for this study.
Keywords
Mould flux, Carbon, Continuous casting
Referências
1 BRANION, R.V. Mould flux for continuous casting. In: STEELMAKING CONFERENCE, 69., 1986, Washingon, DC. Proceedings… Warrendale: Iron and Steel Society, 1986. p. 95-106.
2 PINHEIRO, C.A.; SAMARASEKERA, I.V.; BRIMACOMBE, J.K. Mould flux for continuous casting of steel: part X. Iron and Steelmaker, v. 22, n. 7, p. 41-3, July 1995.
3 BRANION, R.V. Mould flux for continuous casting. King of Prussia, Pensylvania: ISS, 1994. (Course sponsored by ISS).
4 KROMHOUT, J.A.; LUDLOW, V.; McKAY, S.; NORMANTON, S.; THALHAMMER, M.; ORS, F.; CIMARELLI, T. Physical properties of mould fluxes for slab casting. Ironmaking and Steelmaking, v. 29, n. 3, p. 191-3, June 2002
5 KAWAMOTO, M.; NAKAJIMA, K.; KANAZAWA, T.; NAKAI, K. Melting mechanism of mold powder for continuous casting. In: STEELMAKING CONFERENCE, 75., 1992, Toronto. Proceedings… Warrendale: Iron and Steel Society, 1992. p. 389-96.
6 KAWAMOTO, M.; NAKAJIMA, K.; KANAZAWA, T.; NAKAI, K. Design principles of mold powder for high speed continuous casting. ISIJ International, v. 34, n. 7, p. 593-8, 1994.
7 SRIDHAR, S.; MILLS, K.C.; MALLABAND, S.T.; Powder consumption and melting rates of continuous casting fluxes. Ironmaking and Steelmaking, v. 29, n. 3, p. 194-8, June 2002.
8 PRADHAN, N.; GHOSH, M.; BASU, D.S.; MAZUMBAR, S.;Prediction of slag pool thickness in continuous casting mould. ISIJ International, v. 39, n. 8, p. 804-8, 1989.
9 MOORE, J.A.; PHILLIPS, R.J.; GIBBS, T.R.; An overview for the requirements of continuous casting mold fluxes. In: STEELMAKING CONFERENCE, 74., 1991, Washington. Proceedings… Warrendale: Iron and Steel Society, 1991. p. 615-21.
10 MILLS, K. Mold powder for continuous casting. San Nicolas, Argentina: Instituto Argentino de Siderurgia, 2003. (Course sponsored by IAS).
11 LIDEFELT, H.; HASSELSTRÖM, P. Characterization of the functional properties of mould powders for continuous casting of steel. In: INTERNATIONAL IRON AND STEEL CONGRESS, 4., 1982, London. Proceedings… London: The Metals Society, 1982. p. 10.1-10.9.
12 XIE, B.; WU, J. YONGNIAN, G. Study on amount and scheme of carbon mixed in cc mold fluxes. In: STEELMAKING CONFERENCE, 74., 1991, Washington. Proceedings… Warrendale: Iron and Steel Society, 1991. p. 647-51.
13 TAKEUCHI, H.; MORI, H.; NISHIDA, T.; YANAI, T.; MUKUNASHI, K. Development of a carbon-free casting powder for continuous casting of slabs. Transactions ISIJ, v. 19, p. 274-82, May 1979.
14 TERADA, S.; KANEKO, S.; ISHIKAWA, T.; YOSHIDA, Y. Research on substitution for carbon (Development of Mold Fluxes for ultra low carbon). In: Steelmaking Conference, 74., 1991, Washington. Proceedings… p. 635-8. : Iron and Steel Society, 1991.
15 PHELPS DODGE INDUSTRIES COMPANY. Disponível em: www.columbianchemical.com.br/plástico.asp. Acesso em: 25 fev 2005.
2 PINHEIRO, C.A.; SAMARASEKERA, I.V.; BRIMACOMBE, J.K. Mould flux for continuous casting of steel: part X. Iron and Steelmaker, v. 22, n. 7, p. 41-3, July 1995.
3 BRANION, R.V. Mould flux for continuous casting. King of Prussia, Pensylvania: ISS, 1994. (Course sponsored by ISS).
4 KROMHOUT, J.A.; LUDLOW, V.; McKAY, S.; NORMANTON, S.; THALHAMMER, M.; ORS, F.; CIMARELLI, T. Physical properties of mould fluxes for slab casting. Ironmaking and Steelmaking, v. 29, n. 3, p. 191-3, June 2002
5 KAWAMOTO, M.; NAKAJIMA, K.; KANAZAWA, T.; NAKAI, K. Melting mechanism of mold powder for continuous casting. In: STEELMAKING CONFERENCE, 75., 1992, Toronto. Proceedings… Warrendale: Iron and Steel Society, 1992. p. 389-96.
6 KAWAMOTO, M.; NAKAJIMA, K.; KANAZAWA, T.; NAKAI, K. Design principles of mold powder for high speed continuous casting. ISIJ International, v. 34, n. 7, p. 593-8, 1994.
7 SRIDHAR, S.; MILLS, K.C.; MALLABAND, S.T.; Powder consumption and melting rates of continuous casting fluxes. Ironmaking and Steelmaking, v. 29, n. 3, p. 194-8, June 2002.
8 PRADHAN, N.; GHOSH, M.; BASU, D.S.; MAZUMBAR, S.;Prediction of slag pool thickness in continuous casting mould. ISIJ International, v. 39, n. 8, p. 804-8, 1989.
9 MOORE, J.A.; PHILLIPS, R.J.; GIBBS, T.R.; An overview for the requirements of continuous casting mold fluxes. In: STEELMAKING CONFERENCE, 74., 1991, Washington. Proceedings… Warrendale: Iron and Steel Society, 1991. p. 615-21.
10 MILLS, K. Mold powder for continuous casting. San Nicolas, Argentina: Instituto Argentino de Siderurgia, 2003. (Course sponsored by IAS).
11 LIDEFELT, H.; HASSELSTRÖM, P. Characterization of the functional properties of mould powders for continuous casting of steel. In: INTERNATIONAL IRON AND STEEL CONGRESS, 4., 1982, London. Proceedings… London: The Metals Society, 1982. p. 10.1-10.9.
12 XIE, B.; WU, J. YONGNIAN, G. Study on amount and scheme of carbon mixed in cc mold fluxes. In: STEELMAKING CONFERENCE, 74., 1991, Washington. Proceedings… Warrendale: Iron and Steel Society, 1991. p. 647-51.
13 TAKEUCHI, H.; MORI, H.; NISHIDA, T.; YANAI, T.; MUKUNASHI, K. Development of a carbon-free casting powder for continuous casting of slabs. Transactions ISIJ, v. 19, p. 274-82, May 1979.
14 TERADA, S.; KANEKO, S.; ISHIKAWA, T.; YOSHIDA, Y. Research on substitution for carbon (Development of Mold Fluxes for ultra low carbon). In: Steelmaking Conference, 74., 1991, Washington. Proceedings… p. 635-8. : Iron and Steel Society, 1991.
15 PHELPS DODGE INDUSTRIES COMPANY. Disponível em: www.columbianchemical.com.br/plástico.asp. Acesso em: 25 fev 2005.
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