Abstract: 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 MoSi₂ 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%.

摘要： 通过500 g MoSi₂电阻炉熔炼试验考察了酸溶铝Als含量对硅镇静钢中夹杂物形貌、组成、数量及熔点的影响,并对KR铁水预处理-BOF-吹Ar-LF-CC流程现场水口残留物进行微观观察,探讨了夹杂物堵塞水口的机理,提出了硅镇静钢中铝含量的合理控制范围。结果表明,随Als含量增加硅镇静钢的夹杂物熔点升高,夹杂物数量减少;观察水口残留物为低熔点夹杂物镶嵌高熔点夹杂物,高Als钢中固态夹杂物以熔融态夹杂物为粘结剂聚集而粘附水口;钢液中Als含量控制在0.0030%~0.007 5%不会生成皮下气孔、不易水口堵塞。

关键词: 硅镇静钢, Als含量, 夹杂物特性, 水口结瘤, 皮下气孔