The bearing steel GCrl5 in EAF tapping is pre-deoxidized by specialty refining slag and Al to control the Al content 0. 03% ~0. 06% in liquid

and the ingredient of LF refining slag is (/% ) 53 ~ 58CaO

6 ~ 16SiO

2

15 ~30Al

2

O

3

3~10 MgO

(FeO + MnO). The inclusions in 320 mm x 480 mm casting bloom and hot-rolled Φ45 mm round bar are analyzed by using auto scanning electron microscope ASPEX. Results show that the oxide inclusions in casting bloom and round bar of bearing steel GCr15 are magnesia alumina spinel or calcium aluminate

and the amount of oxide inclusions at edge of bloom and round bar is more than that at center

and the larger than 10μm inclusions are globula

r calcium aluminate or calcium aluminate-magnesia alumina spinel compound inclusion ； the non-oxide inclusions in bloom and round bar are mainly MnS

TiN and cladding inclusions-magnesia alumina spinel covered by MnS

TiN or CaS

and calcium aluminate covered by CaS. It is obtained by using Factsage calculation that MnS and TiN precipitate during solidification process and large amounts precipitate respectively at solid fraction fs being more than 0. 9 and 0. 6； there is large amount CaS in liquid at steelmaking temperature 1 600℃

minor precipitates during liquid cooling process and tiny minority precipitates during solidification process.