Determination of Thermal Diffusivities of Continuous Casting Powders for Steel by Precisely Excluding the Contribution of Radiative Component at High Temperature

Abstract

Thermal diffusivity measurements of continuous casting powders for steel have systematically been made at high temperature by applying the differential three layered laser flash method recently proposed by the present authors. The powder consists of SiO₂, Al₂O₃, MgO, CaO, Na₂O and CaF₂. New data processing has also been developed in order to separate the contribution due to radiative component from measured values at high temperature by considering the variation of the absorption coefficients of these powders when adding TiO₂, ZrO₂ or iron oxide. Then, the thermal diffusivity values of continuous casting powders for steel were quantitatively estimated with sufficient reliability. Thermal diffusivity values of continuous casting powders are found to be 4 ± 0.5 × 10^-7m²/s and insignificant with the variation of temperature and concentration presently investigated. It would be interesting to extend the present systematic results for discussing the heat transfer phenomena in the continuous casting process for steel.