The effect of acid-soluble aluminium Als content in steel on morphology

ingredient

number and melting point of inclusions in silicon killed steel has been studied by 500 g MoSi

2

electric resistance furnace melting trial

and the micro-observation on residue of nozzle clogging at situ of KR metal pretreatment-BOF-Ar blowing-LF-CC process is carried out to explore the mechanism of nozzle clogging by inclusions and propose a reasonable control range of Als content in silicon killed steel. Results show that with increasing Als content in steel the melting point of inclusions in silicon killed steel increases and the number of inclusions decreases ； the observation on residue in nozzle gets that the high melting point inclusions are embedded in low melting point inclusions

it is indicated the solid inclusions in high Als steel are accumulated and adhered at nozzle

by molten inclusions which are coherent agent； the subskin blowhole shall not occurred and nozzle is not easily clogging as Als content in liquid is controlled in 0.003 0% ~0. 007 5%.