Evolution of Non-metallic Inclusions in Si-Killed Stainless Steelmaking

The evolution of non-metallic inclusions (> 10 μm) for the Si-killed stainless steelmaking process is studied. The effects of the slag basicity in the AOD (argon oxygen decarburization) process, Ca treatment, refractory in the casting ladle, impurities (Ti, Al) in scraps and tapping temperature in the AOD process on the evolution of the non-metallic inclusions are investigated using the thermo-chemical program (FactSageTM) and SEM analysis of the non-metallic inclusions at each process (AOD—ladle treatment—tundish—continuous casting). A new phase stability diagram of the non-metallic inclusion was developed from the analysis results, and we discuss the mechanism of the formation of spinel Mg[Al,Cr]2O4 in the inclusion with the aid of the diagram.