Abstract: Steel samples were taken at the AOD process, LF refining, and slab during the production of 316L stainless steel. The mass fraction of total oxygen and nitrogen,the number density, and composition of inclusions in steel samples were analyzed. The mass fraction of total oxygen in the steel gradually deceased and reached 24×10^-6 after calcium treatment,183×10^-6 lower than that at the end of AOD reduction. Reoxidation occurred during continuous casting and the total oxygen mass fraction in the slab was increased by 8×10^-6. At the end of AOD reduction,the inclusions were mainly SiO₂-MnO. The inclusions were divided into the CaO-Al₂O₃-SiO₂ system and the CaO-Al₂O₃-MgO system at LF arrival. The former was mainly generated by the reaction between the entrained AOD slag and dissolved aluminum in the steel, and the latter was mainly formed by the reaction between the SiO₂-MnO inclusions, dissolved aluminum and slag phase. ForCaO-Al₂O₃-SiO₂ system, the average composition of inclusions at LF arrival was not in the low melting temperature region.With the progress of LF refining,the content of CaO decreased and the content of Al₂O₃ increased in inclusions. Its average composition was in the low melting temperature region. For the CaO-Al₂O₃-MgO system, the content of MgO increased and the number of MgO·Al₂O₃ spinel inclusions increasd. After calcium treatment and holding process, there were no CaO-Al₂O₃-MgO inclusions in the steel, indicating that the inclusion modification was relatively appropriate.

Key words: 316L stainless steel, inclusions, calcium treatment