Investigation of the Conditions of Formation of Aluminum-Magnesium Spinel Inclusions in Low-Carbon Automotive Sheet Steels of 08Yu type and Ultralow-Carbon Automotive Sheet Steels of the if and IF-HS Types

Resumo

We study the regularities of reduction of MgO from the lining and surface slag accompanied by the formation of adverse corrosion-active nonmetallic inclusions (CANI) based on aluminum-magnesium spinel in the course of treatment of the melts of 08Yu-type low-carbon steel and ultralow-carbon steels of the IF and IF-HS types with ten different compositions. It is shown that the amount of formed CANI regularly increases with the aluminum content of steel up to 0.05–0.06 wt.% and the MgO content of slag, especially over 12–14 wt.%. We proposed some efficient techniques aimed at guaranteeing the required purity of steel (from the viewpoint of these inclusions). For the first time, it is shown that the deposition of titanium sulfide and carbosulfide on the surfaces of aluminum-magnesium spinel inclusions increases their corrosive activity.