Oxide Inclusions in Ferromanganese and Its Influence on the Quality of Clean Steels

Low and medium carbon ferromanganese produced by oxygen decarburization process and electric silicothermic process was briefly introduced, and the quality of products by these two processes was analyzed. Results showed that the total oxygen content in medium carbon ferromanganese by electric silicothermic process in China, which ranged from 0.039% to 0.171%, was between those of the common and refined products by oxygen decarburization process outside of China. The increments of total oxygen content in liquid steel were estimated when ferromanganese was added for the purpose of Mn element adjustment at the end of smelting. Refined low and medium carbon ferromanganese, which had low total oxygen content, was recommended for composition adjustment of clean steels during final stage of a heat. It is possible that the inclusions in the ferromanganese alloy greatly influenced the quality of clean steel indirectly by affecting the amount, size and composition of inclusions in steel.