Abstract
Infra-red absorption spectroscopy was applied for structual analysis of silica contained in steels. A probable difference of structure between Si-deoxidation product and silica inclusion which originate from furnace lining or ores are examined: At the first stage of deoxidation, the produced silica contain metallic elements to which 1030 cm−1 shoulder and 950 cm−1 peaks assigned. After 5 minutes of heating at melting temperature of iron, these peaks diminished to approach a cristobalitic structure. Dendritic silica particles in slowly cooled steel showed a characteristic peak at 1030 cm−1. It showed that silica particles formed in cooling process include a larger amount of metallic elements than the spherical deoxidation product. Glassy silica, silicate and quartz added into iron melt show the same IR spectrum as that of the deoxidation product at first stage of reaction, and do not change with duration time at melting temperature of iron. Conclusively, deoxidation product and the exogeneous silica inclusion in steel show a characteristic pattern of IR spectrum but in practical samples with different conditions of steel making, IR spectroscopy may not be effective to distinguish the origin of silica in steels.
