Through 3 heats IF steel of 210 t RH refining process test

the effect of titanium-adjusted time on cleanliness of IF steel in RH refining process is studied by scanning electron microscopy. The results indicate that titanium adjustment after adding aluminum for 2

4 and 6 min

the average N content in molten steel at RH end is 26. 7 x 10

-6

23. 6 x 10

-6

and 27. 4 x 10

-6

respectively. When the oxygen blowing amount for heating

the oxygen consumption is 30 〜40 m

3

and the average initial oxygen content in liquid of RH is 579 x 10

-6

the T[O

]

is 70. 3 x 10

-6

at the RH end； When the oxygen blowing amount for heating

the oxygen consumption is 75 ~ 90 m

3

and the average ar

rival oxygen of RH is 669 x 10

-6

the T[O

]

is 109. 2 x 10

-6

at the RH end. The T[O

]

at the RH end shows an increase trend with the increase of oxygen activity before adding aluminum. The quantity density of inclusions with 5μm equivalent diameter in steel is 9. 32 /mm

2

when adjusted Ti alloy after adding aluminum 6 min

it is lowest.