The steelmaking flow sheet for two heats non-oriented silicon steel XG800WR (/% : 0.003 ~ 0.004C

0.71 〜0.75Si

0.32~0.33Mn

0.004 ~ 0.007S

0.016P) is hot metal pretreatment ( KR)-210 t top and combined blown converter-ladle argon blowing-RH decarburization refilling-230 mm X 1 220 mm slab casting. The superheating extent of liquid in 53 t tundish is 25 ~ 30

℃

whole casting is shielded by blowing argon with long nozzle from ladle to tundish and the submerged nozzle is adopted in casting from tundish to mold. Examination results show that the total oxvgen content T[O

]

in liquid and the amount and size of inclusions in steel obviously decrease during RH

tundish and mold p

rocess

but the T[O

]

[N

]

and amount of inclusions increase from ladle to tundish process

it indicates that there is secondary oxidation of liquid in casting process with long nozzle. The T [O

]

and [N

]

in casting slab are respectively 11 x 10

-6

and 30 X 10

-6

the average amount of micro-inclusions is 4 inclusions per square mm. The main micro-inclusions in casting slab are 3 ~5

μm

AIN with minor MnS

Al

2

O

3

• AIN and Al

2

O

3

• MgO • MnS.