Atmospheric Induction Direct Chromium Alloying of Steel Using FeAlSiCa as a Metallothermic Reductant

The study investigates the technology of direct Cr alloying of steel in an induction furnace using Cr-containing oxide raw materials and an FeAlSiCa metallothermic reducing agent under atmospheric conditions. The experimental design included four charge variants: scrap-based, DRI-based, A-series (50% scrap/50% DRI), and B-series (75% scrap/25% DRI). For A-series and B-series, the FeAlSiCa content was varied from the baseline value to reduced levels of -10% and -20%. The results demonstrate that Cr recovery strongly depends on the metallic component of the charge. The highest Cr recovery (up to 83%) was consistently achieved for the DRI-based charge, while mixed charges showed intermediate values depending on the DRI fraction and reducer amount. Reduction in FeAlSiCa content led to a decrease in Si transfer to steel, but was accompanied by lower Cr recovery. The produced steels were characterized by a uniform distribution of alloying elements, low impurity levels (S, P < 0.03%), and the formation of a dense, non-disintegrating slag. The results confirm that direct Cr alloying in an induction furnace can be effectively implemented under atmospheric conditions without vacuum or protective gas atmosphere, while the presence of DRI plays a key role in enhancing Cr assimilation.