Effects of Replacing Fluorine with Sodium and Titanium Oxides on Continuous Casting of Steel Mold Powders Lubrication

Subject Areas : Ceramics

Ahmadreza Arefpour ¹ , Ahmad Monshi ² , Ali Saidi ³

1 - Department of material engineering, Najaf Abad Branch, Islamic Azad university, Isfahan, Iran
2 - Department of materials Engineering, Najaf Abad branch, Islamic Azad University, Isfahan
3 - Department of materials Engineering, Najaf Abad branch, Islamic Azad University, Isfahan

Received: 2014-05-19 Accepted : 2014-12-23 Published : 2015-03-01

Keywords: Viscosity, Continuous Casting, Mold Powder, Fluorine,

Abstract :

Mold powders are used as raw materials in continuous casting of steel industry; Also they are mostly composed of aluminum, calcium, silica oxides, alkaline and earth-alkaline oxides along with carbon and fluor. Two of the most important duties of mold powders are the lubrication of the space between mold walls and steel shell, and heat transfer control between steel shell and the copper mold. Fluor is one of the most important constituents of mold powders and is employed to control viscosity in order to obtain favorable lubrication and solidification temperature control in order to control heat transfer. The fluor in the mold powder is added to it with the aid of some fluorided compounds like fluorine (CaF2). This study has used Fluorine to make a powder similar to the reference sample, with the use of portland cement clinker and fluorine. Moreover, groove viscometer studies have been conducted here to compare sample viscosities to the viscosity of the reference sample. In addition XRD as well as SEM analyses were conducted. As a result, crystalline phase of cuspidine was found in the glass matrix indicating that the chemical compound in sample 1 may be a suitable substitute, as compared to the reference sample, for the mold powder used in continuous casting steel industry.

References:

 

1. A. B. Fox, K. C. Mills, D. Lever, C. Bezerra,
   C. Valadares, I. Unamuno, J.J. Laraudogoitia, J. Gisby. “Development of Fluoride-free fluxes for billet casting.” ISIJ Int., Vol. 45, 2005,
   pp. 1051-1058.


2. M. L. Koul, S. Sankaranarayanan, D. Apelian, W. L. McCaulery. “Mold Powder Technology” Northeast University of Technol. Press, 1988, pp. 2-14.


3. J. A. Kromhout, S. Melzer, E. W. Zinngrebe,
   A. A. Kamperman, R. Boom. “Mould powder requirements for high- speed casting.” Steel Research Int., Vol. 79, 2008, pp. 143-148.


4. K. W. Yi, Y. T. Kim, D. Y. Kim. “A numerical simulation of the thickness of molten mold flux film in continuous casting.” Metals and Materials Int., Vol. 13, 2007, pp. 223-227.


5. R. W. Soares, et al. “An application of differential thermal analysis to determine the change in thermal properties of mold powders used in continuous casting of steel slabs.” ThermochimicaActa., Vol. 318, 1998,
   pp. 13-136.


6. G. Wen, S. Sridhar, P. Tang, X. QI, Y. Liu. “Development of Fluoride-free moldpowders for Peritecticsteel slab casting.” ISIJ Int.,
   Vol. 47, 2007, pp. 1117-1125.


7. S. Y. Choi, et al. “Properties of F-free glass system as a mold flux: Viscosity, thermal conductivity and crystallization behavior.” J. Non-Crystalline Solids,Vol. 345-346, 2004,
   pp. 157-160.


8. H. J. Shin, S. H. Kim, B. G. Thomas, G. G. Lee, J. M. Park, J. Sengupta. ISIJ Int., “Measurement and prediction of lubrication, powder consumption, and oscillation mark profiles in ultra-low carbon steel slabs.” ISIJ Int., Vol. 46, 2006, pp. 1635–1644.


9. K. C. Mills, A. B. Fox, R. P. Thackray,
   Z. Li. “The performance and properties of mold fluxes.” 7^thInternational Conference on Molten Slags Fluxes and Salts, The South African Institute of Mining and Metallurgy., 2004,
   pp. 713-722.


10. M. Hanao, M. Kawamoto, T. Watanabe. “Influence of Na₂O on phase relation between mold flux composition and cuspidine.” ISIJ Int., Vol. 44, 2004, pp. 827-835.


11. M. Hayashi, T. Watanabe, H. Nakada, K. Nagata. “Effect of Na₂O on crystallization of moldfluxes for continuous casting of steel.” ISIJ Int., Vol. 46, 2006, pp. 1805-1809.

12. M. Persson, M. Gornerup, S. Seetharaman. “Viscosity measurements of some moldflux slags.” ISIJ Int., Vol. 47, 2007, pp. 1533-1540.