Abstract: Of tested Ti-IF steel (/%：≤0.0035C, ≤0.03Si, 0.08~0.20Mn, ≤0.025P, ≤0.015S, 0.05〜0.07Ti, 0.030~0.055Als, ≤0.0040N) the BOF end [C] is 0.03%〜0.06%, end [O] is 0.0030%~0.0060% , the lime and top slag modification agent containing aluminium are added during lapping process, and the ingredient of RH end slag is/%: 53.38CaO, 7.05FeO, 1.01MnO, 31.4Al₂O₃,5.7MgO, 0.3P₂O₅,0.022S. The analysis results by sampling in RH refining process show that by adding top slag modification agent to control 8% (FeO+MnO) and CaO/Al₂O₃=1.7, it is available to remove the inclusions in steel；the oxygen content in liquid decreases continuously during refining process, in casting slab the oxygen content is 0.0014% and the nitrogen content is 0.0015%；at finishing decarburization the main inclusions in steel is MnO, at finishing deoxidation by aluminium the main inclusions in steel is Al₂O₃ and after alloying modified to Al₂O₃ and Al-O-Ti compound inclusions；and in slab casting the above-mentioned inclusions are removed effectively but the TiN inclusions precipitated in slab solidification process.

摘要： 试验Ti-IF钢（/%:≤0.0035C,≤0.03Si,0.08~0.20Mn,≤0.025P,≤0.015S,0.05~0.07Ti,0.030~0.055Als,≤0.0040N）BOF终点[C]0.03%~0.06%,终点[O]0.0030%~0.0600%,出钢过程加石灰和含Al钢包顶渣改质剂,RH终渣组成/%:53.38CaO，7.05FeO，1.01MnO，31.4Al₂O₃,5.7MgO,0.3P₂O₅,0.022S。RH精炼过程取样分析表明,通过加顶渣改质剂,控制8%（FeO+MnO），CaO/Al₂O₃=1.7,能较好去除钢中夹杂物,精炼过程钢中氧含量逐步下降,铸坯中氧含量为0.0014%,氮含量为0.0015%;脱碳结束时夹杂物主要为MnO;铝脱氧结束之后为Al₂O₃;合金化后为Al₂O₃及Al-O-Ti复合夹杂物;在铸坯中,前述夹杂物有效去除,但在凝固过程析出TiN夹杂。

关键词: 300t-BOF-RH-CC流程, Ti-IF钢, 夹杂物, 衍变行为