The types and quantity density of non-metallic inclusions

and the change of total oxygen in steel ML08Al produced by the two processes BOF-RH-CC and BOF-LF-CC are analyzed. The results show that the main non-metallic inclusions in steel after BOF deoxidizing alloying of two process are Al

2

O

3

in the process of "BOF-LF-CC"

the partial non- metallic inclusions in steel at the end of LF refining are changed from Al

2

O

3

to Al

2

O

3

・ CaO and Al

2

O

3

• MgO

but in the process of "BOF-RH-CC"

after RH vacuum the non-metallic i

nclusions Al

2

O

3

are still dominated. After deoxidizing alloying

the total oxygen content in BOF molten steel is 27. 8 x 10

-6

~31. 5 x 10

-6

the total oxygen content in steel at LF end is 20. 2 x 10

-6

~22. 5 x 10

-6

but the total oxygen content in steel at RH end is 14. 7 X 10

-6

~ 15. 3 x 10

-6

. The removal rates of inclusions by LF refining and RH vacuum treatment are 49. 6% and 80. 9% respectively. Therefore

the cleanness of the cold heading steel ML08Al produced by the process of "BOF-RH-CC" is better than that produced by the process of “BOF-LF-CC”.