Ferrosilicon alloy for deoxidising molten steels - contg. magnesium, calcium and aluminium, to reduce amt. of non-metallic inclusions in steel

摘要

Alloy contains 60-80% Si, 0.5-2% Mg, 0.01-2% Al, 0.01-2% Ca, 0.01-0.5%C, remainder Fe and refining of molten steel, the latter is pref. treated with 0.5-10, esp. 1-6kg/t of the FeSi-Mg alloy. Prior to adding the FeSi-Mg, the oxygen content of the molten steel is pref. reduced in a conventional manner to 0.05 wt.%; and the FeSi-Mg is pref. added after removing all slag contg. 5 wt.% Fe oxides. Presence of Mg in the FeSi-Mg improves sepn. of non-metallic inclusions so cleaner steel is obtd. Mg also produces finer, and spheroidal inclusions, so the mechanical properties of steel are improved.