The steelmaking process flowsheet of tested sulphur bearing non-quenching and tempering steel 36MnVNS4 (/% : 0. 36C

0. 66Si

1. 00Mn

0. 010P

0. 045S

0.26V

0. 011 ON) is hot metal + scrap- 70 t EBT EAF-LF-square billet casting-rolling. The effect of LF both slag series- 19. 82% Al

2

0

3

( CaO)/( SiO

2

) = 2. 64 and 14. 63% Al

2

O

3

(CaO)/( SiO

2

) =2. 15 on oxygen content in liquid after soft argon blowing

S yield after feeding S wire

and compound and morphology of inclusions in steel has been studied. Results show that refining by high basicity white slag is available to decrease the oxygen content in steel

but it is unfavourable to stabilize the sulphur

content in steel； decreasing the refining slag basicity ( CaO)/( SiO

2

) from 2. 64 to 2. 15 is favourable to stabilized control the sulphur content in steel

and the yield of sulphur increases from 35% to 75% ； with both refining process the distribution

morphology and ingredient of inclusions in steel are basically the same. By calcium treatment in ladle the long strip MnS inclusions modify to spheroid compound inclusions.