In order to ensure that the refining slag has better deoxidation and absorption ability of inclusions

the five top slag modifiers are used to carry out industrial tests on the top slag of the converter tapping ladle of IF steel. ICP-AES (Induction Coupling Plasma-Atomic Emission Spectroscopy) is used to detect the slag composition and FactSage software is used to calculate the viscosity of refining slag. The results show the vacuum circulation degassing (RH) is out the station

after 5 kinds of madifiers are used

that the content of TFe in the refining slag of 5 heats is controlled at 6. 46% ~7. 76%

the ( CaO)/(Al

2

O

3

) ratio is 1

. 60 ~ 1. 86 at 1 600 ℃

the viscosity of refining slag is 0. 057 ~ 0. 068 Pa ·s

the degradation ratio of degradation caused by inclusions is 2. 10% ~ 12. 86%

and No. 3 modifier (48. 5% Al-10. 2% Al

2

O

3

-18. 1% CaO-6. 0% SiO2-8- 0% CaF

2

) has the best comprehensive performance. After the carbon content in the steel increases to 0. 045% from 0. 032% during converter tapping

and the optimized modifier is used in production

the TFe content in slag before RH is controlled at 7. 13%

and the FeO content in slag after RH is controlled at 5. 52% and during hot rolling

the ratio of off-and sub-quality products with top slag modification is 0. 071%

which is reduced by 20. 2%.