5th International Congress on the Science and Technology of Steelmaking 2012 (ICS2012)
開催地
和文:
Dresden
英文:
アブストラクト
Reflectivities and transmissivities have been measured as functions of wavelength on mould flux samples having various cuspidine grain sizes to investigate the size effects on the radiative heat transfer in mould fluxes. Two types (A and B) of mould flux were prepared: the chemical compositions of flux A was T.CaO/SiO2 = 1, Al2O3 + MgO = 3.3 mass% and Na2O + F = 20.0 mass%, and flux B was prepared by additions of 1 mass % Fe2O3 to flux A. First, these flux samples were pre-melted and then quenched into brass moulds to obtain glassy samples, which were subsequently annealed at temperatures between 913 K and 1143 K for 30 min for crystallisation. The cuspidine grain size was controlled in the range 1000 - 3500 nm for flux A and 1000 - 2500 nm for flux B, whereas the degree of crystallinity was kept to ca 58 % for flux A and ca 53 % for flux B. Reflectivities and transmissivities were measured in the wavelength range 300 ? 2600 nm at room temperature using a spectrophotometer with an integrating sphere. For flux A, the reflectivity showed a maximum value and the transmissivity showed a minimum value in the grain diameter range 2000 ? 3000 nm; in contrast, for flux B, there was no significant dependence on grain size. Calculation of the total radiative heat flux suggests that radiative heat transfer would be smallest in the flux A sample having the highest reflectivity and the lowest transmissivity, and that control of cuspidine grain size would lead to reduction of the total heat flux by 7 ? 8 %.
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