Inclusions in commercial low and medium carbon ferromanganese

The microstructures of commercial low and medium carbon ferromanganese have been studied by optical microscopy and electron microprobe techniques. Element analysis and mapping have been performed on impurities in the matrix and nonmetallic inclusions present. The results show that the most common nonmetallic inclusion is managanese oxide, followed by complex compounds of managanese oxide, silicon oxide, and manganese sulfide. The different inclusions have been assessed according to the SS 111116 method. It follows that over 85 pct of the present nonmetallic inclusions are manganese oxides and that the amount of manganese oxide inclusions is inversely proportional to the carbon content in standard refined ferromanganese.