Research on Inclusion Behavior in Continuously Cast Billet for Carbon Structural Steel 40Mn

In view of the converter-argon blowing-continuous casting process for production of carbon structural steel 40Mn,oxygen and nitrogen contents and compositions,amounts and variation of microscopic and macroscopic inclusions in casting blanks were systematically analyzed.The results show that the average contents of oxygen and nitrogen in steadily cast billet are about 65 × 10^-6 and 70 × 10^-6; microscopic inclusions are mainly MnS and aluminosilicate inclusions,and the inclusions in unsteadily cast billet is two times of those in normal blank; major macroscopic inclusion is SiO₂ inclusion,followed by SiO₂-Al₂O₃ and SiO₂-Al₂O₃-MnO inclusions,unsteady casting influences steel cleanliness,unsteady control should be strengthened during casting process.