Formation Mechanism of Large CaO-SiO2-Al2O3 Inclusions in Si-Deoxidized Spring Steel Refined by Low Basicity Slag

During the refining of Si deoxidized spring steel by low-basicity slag, with the addition of BaCO3 to refining slag, many BaO-containing CaO-SiO2-Al2O3 inclusions existed in steel, which were with approximate chemical compositions to other CaO-SiO2-Al2O3 inclusions. Thermodynamic calculation revealed that (BaO) in slag can be hardly reduced by [Si] in steel, which meant that CaO-SiO2-Al2O3-BaO inclusions in Si-deoxidized spring steel cannot be produced by chemical reactions among slag-steel-inclusion, viz., they were originated from entrapped slag.

Automated summary

During the refining of Si deoxidized spring steel with low-basicity slag, the addition of BaCO3 resulted in the formation of BaO-containing CaO-SiO2-Al2O3 inclusions in steel. These inclusions were found to originate from entrapped slag, rather than chemical reactions among slag, steel, and inclusions.