Effect of Refining Slag Basicity on Inclusions in 304 Stainless Steel

Combining industrial practice,the effect of refining slag basicity on inclusions in Si-killed 304 austenitic stainless steel during LF refining and continuous casting process was researched with quantitative metallography and SEM+EDS statistical analytical methods.The results show that the spherical CaO-Al2O3-SiO2 compound inclusion is mainly formed in molten steel,and properly higher basicity is beneficial to smaller inclusions formation.With refining slag basicity increasing,the CaO content in compound inclusion increases gradually together with SiO2 content reducing,and the variation of Al2O3 content is slight.In industrial process,the containing Al in FeSi alloy is a mainly factor for Al2O3 inclusion formation.When the refining slag basicity is controlled at 1.0 and 1.5 respectively,the Al2O3 content is about 25% in casting billet,and the deformability of inclusion is feeblish accordingly.