By the method of using a full-process system sampling

a systematic analysis and research on the evolution of the oxygen content and the inclusion characteristics in a 20CrMnTi gear steel produced in the process of 120 t BOF-LF- VD-CC have been carried out. The experimental results show that using the technology of aluminum deoxidation and the high-basicity [ (CaO)/(SiO

2

) =3. 8 ~7

]

reduction slag

the T[O

]

in the slab can be less than 20 x 10

-6

the average T[O

]

of liquid in tundish gas increases by 6 x 10

-6

during the steelmaking process of gear steel

the inclusions in steel have completed the transformation from Al

2

O

3

→ Al

2

O

3

-MgO—;Al

2

O

3

-CaO-MgO.