Type

morphology and ingredient of inclusions in stainless steel 304 (/%: 0. 03 ~0. 04C

0. 39 ~0. 41 Si

L20~1.23Mn

0. 014 ~0. 016P

0.001 ~0.002S

7.95 〜8.00Ni

18. 06 ~ 18. 20Cr

0.003 ~ 0. 004Al

0 〜0.002Ti) during 110 t AOD-LF-tundish-160 mm slab casting-hot rolling strip coil process have been studied by SEM

energy dispersive X-ray spectrometer and analysis by electrolysis. Results show that the 5 ~ 10 μm spheroidal SiO

2

-CaO-MgO-Al

2

0

3

type inclusions occur in each steelmaking process

while the 20 μm MnO-Cr

2

O

3

inclusions form in tapping proc

ess of AOD

part of which is removed in LF refining process

and they less occur in liquid in tundish and in normal casting slab

but the MnO-Cr

2

O

3

inclusions easily occur in two heats sequence-casting slab

the size of MnO-Cr

2

O

3

inclusion in hot-rolled strip coil is≤5μm. Electrolytic analysis results show that the inclusion amount in two heats sequence-casting slab (4. 65 mg/ 10 kg) increases by 51% as compared with that in normal casting slab (3. 08 mg/10 kg).