The infuence of ingredient of refining slag(47～64CaO

13～23SiO

2

15～25Al

2

O

3

5～10MgO

0~ 8CaF

2

CaO/SiO

2

=2.0~4.5) on oxygen content and inclusions in 0.95C-1.50Cr CCr15 bearing steel has been tested and studied by MoSi

2

electrical resistance furnace with MgO crucible. It was found in test that with increased refining slag basicity CaO/SiO

2

from 2 to 4.5

the end total oxygen content in liquid steel decreased from 20×10

-6

to 11×10

-6

and the total amount

total area and average size of inclusions in steel decreased; the speed and capability of refining slag to absorb inclusions could remarkably increase with increasing Al2O3 con

tent or adding CaF

2

decreasing MgO content in slag; with low basicity refining slag

the size of inclusions in liquid steel

which contained ≥20% SiO

2

was 15～20 μm with quite good plasticity; and with high basicity slag the typical inclusions in liquid steel were brittle inclusions such as alumina and MgO-Al

2

O

3

spinel

of which the size was ≤5 μm.