Quality requirement for 350 km/h high-speed rail steel is total oxygen content in steel- T[O

]

≤20 x 10

-6

and B

C and D series inclusions rating ≤1.0. In domestic heavy rail steel steelmaking process

it is normally to using non-aluminium deoxidation process

i. e. intensifying deoxidation by using SiCaBa alloy to form low melting point Mn-Al-Si- Ba-Ca multicomponent oxide inclusions which all remove from liquid during refining process. The behavior of inclusions in rail steel U71MnG steelmaking by hot metal desulphurization pretreatment-150 t top and bottom combined blowing convert- er-LF-VD-280 mm x 380 mm CC flow sheet is studied

including the ingredient and characteristics of oxide inclusions in rail s

teel steelmaking by non-aluminium deoxidation process

the effect of converter end [C

]

on oxygen activity of liquid and the effect of basicity of LF refining slag and soft argon stirring process in later period of VD process on inclusions and oxygen content in steel. It is obtained that the ≤20 μm oxide inclusions in head of rail is seconadry deoxidation products during refining process

with controlling converter end [C

]

＞0.15%

controlling basicity of refining slag- (CaO)/(SiO

2

) =2.5-3 and S (FeO + MnO) ≤1.0%

it is available to decrease the quantity and size o£ oxides in rail steel.