The measurement of the particle size distribution of oxides in high carbonSi-Mn killed steel

The measurement of the particle size distribution of oxides in high carbon Si-Mn killed steel was achieved by extraction of oxides and the measurement with laser diffraction particle size analyzer, The extraction method of oxide in steel by using nitric acid could nor be a pplied to the present case because nitric acid decomposed the SiO2 formed i n steel. On the other hand bromine-methanol method was suitable for the ext raction of these oxide. Otherwise, the dissolving reaction was disturbed be cause of high carbon content. Decarbonization of the samples in H-2-H2O atm osphere was found to be effective as a pretreatment of the bromine-methanol extraction in order to avoid the disturbance in the extraction procedure f or high carbon content steel. The bromine-methanol extracts the free carbon as well as the desired oxides . But the KMnO4 treatment with citric acid could dissolve only free carbon, and the oxides could be separated. It was found that the amount of oxides at the surface area of bloom was gre ater than that at central area of bloom in case of both fine particle size of the oxides and large particle size of the oxides.