The influence of LF binary refining slag 60CaO-40SiO2 and [O

]

27 x 10

-6

as well as ternary refining slag 47.5 - 50. 2CaO-41. 8 ~45. 7SiO2-5 ~8Al

2

O

3

and [O

]

12 x 10

-6

~ 14 x 10

-6

kinds

morphology

size and number of inclusions in φ 5. 5mm coil produced by BOF-LF-CC-high speed wire rolling process at steelworks and on wire fracture index during wire drawing have been tested and researched. Results show that with higher oxygen content and binary refining slag

the coil has more inclusions with size more than 7 μm and higher Al

2

O

3

cont

ent which concentrate near surface of coil within 1 mm depth

and the wire fracture index is 2. 5 ； with lower oxygen content and ternary slag

the coil surface has not larger size inclusions

the size of most inclusions is ~5 μm and the SiO

2

content in inclusions is higher with lower Al

2

O

3

and the wire fracture index is 1. 0 ~ 1.5

therefore the performance of cold drawing of steel cord for tyre is markedly improved by using ternary slag containing 5% Al

2

O

3

for LF refining and controlling oxygen content in steel- [O

]

≤15 x 10

-6

and decreasing number and size of inclusions in steel.