Abstract: “BOF→LF→CC”process was adopted to produce aluminium killed 60Si2MnA spring steel, and high basicity refining slag was made to intensify refining, and then the cleanness of steel during steelmaking process was investigated and analyzed, moreover, the changes of the T.O and nitrogen contents as well as the number, size and type of nonmetal inclusions in steel during steelmaking process were analyzed by theory. Results showed that the T.O content decreased and the nitrogen content increased gradually during steelmaking process, as a result, the average mass fraction of T.O and nitrogen in wire rods were 14.5×10-6and 30.4×10-6, respectively. The change in type of inclusion during smelting process was Al2O3-SiO2 →Al2O3-SiO2-MgO-CaO quaternary inclusions →Al2O3-SiO2-MgO-CaO=CaS quinary inclusions. The aluminum mass fraction of steel should be about 0.03% and the w(Ca)/w(Al) should be 0.08－0.11after calcium treatment, thus the Al2O3 could get the full modification and form the the quaternary inclusions which were in the low melting point area, while the quinary inclusions containing too much CaS with high melting point deviated from the low melting point area.

Key words: spring steel, Alkilled, cleanliness, inclusions, CaS