The effect of converter end [ C

]

and (TiO

2

) in LF slag on converter end [Ti

]

and A [Ti

]

during LF refining process

as well as the effect of [ S

]

and [ N

]

on formation of TiN in ultra-low oxygen ([ 0

]

10 x 10

-6

) steel 20CrMoH and steel 60Si2MnA have been studied. Results showed that there were two kinds of TiN inclusion: (1) individual TiN and (2) compound TiN with core of CaS； TiN was minor in inclusions in steel 20CrMoH

but TiN accounted fbr 50% - 60% of total inclusions in steel 60Si2MnA； with increasing S content in cast billet the TiN content increased；as [Ti

]

was (69 -80) x 10

-6

[N

]

and [S

]

respectively decreased from (60 〜74) x 10

-6

and (30 ~35) x 10

-6

to (27

- 35) x 10

-6

and (14 -20) x 10

-6

the TiN number decreased from 4.4 -6.1 per cm

2

to 0.4 - 1

1 per cm

2

and as [S

]

W0. 002%

there was no CaS-TiN compound inclusion precipitated in steel.