2008 年 48 巻 3 号 p. 277-285
In continuous casting of steel, mold fluxes are used to prevent surface defects, such as longitudinal cracks. The crystallization of mold flux promotes mild cooling of the steel shell, but crystallization behavior has been still uncertain. Therefore, this study has been carried out to analyze the crystallization processes of mold flux. Mold flux used in this study has high tendency for crystallization. Quenched specimens were heat-treated in various conditions and characterized. Glassy specimen heat-treated in the electric furnace over 550°C for 180 min crystallized. These crystalline were confirmed to be cuspidine by XRD analysis. The number of grains decreased and the average grain size increased with rise of temperature of heat treatment. The growth velocity also increased with rise of temperature.
In-situ observation by the laser microscope revealed that the glassy specimen crystallized in a moment over 600°C and the surface of the specimen turned to be rough. This may lead to mild cooling in the mold.
