Abstract: The causes of the exceeding silicon content and poor pour ability of low carbon and low silicon-aluminum killed steel C4C-Q (/% ：0. 02 ~0. 06C, ≤ 0. 06Si,0. 02 ~0. 05Al) produced by 120 t BOF-LF-RH-CC flow sheet are analyzed. Through process optimization, adopting BOF tapping twice slag blocking mode and decarburizing process after tap, molten steel to decrease tap oxygen content and reduce Al₂O₃ inclusions forming in the later deoxidation process combining optimizing the deoxidation mode of LF furnace and adjusting the ladle bottom blowing stirring, the silicon increase in molten steel can be controlled within 0. 03% while the desulfurization is ensured, the [Si] ≤ 0. 045% in the tundish, the LF refining slag has good fluidity and strong ability to absorb inclusions ； by casting improving the protective effect during the start casting, adopting high liquid steel level when start casting of first furnace, to promote the inclusion in the tundish to float upwards, improve the molten steel temperature in the tundish, increase the static pressure of the molten steel at the same time, and reduce the Al₂O₃ inclusions nodulation on the inner wall of the nozzle, therefore good pour ability C4C-Q steel composition with /% ：0. 04 ~0. 06C,0. 034 ~ 0. 042Si and 0. 028 ~ 0. 034Al is produced.

摘要： 对120 t BOF-LF-RH-CC流程生产的低碳低硅-铝镇静钢C4C-Q（/%:0.02～0.06C,≤0.06Si,0.02～0.05Al）冶炼硅含量高,可浇性差的原因进行了分析。通过工艺优化,转炉采用出钢两次挡渣模式和出钢后脱碳工艺,降低出钢氧含量,减少后期脱氧过程中生成Al₂O₃夹杂;通过优化LF脱氧模式、结合调节钢包底吹搅拌,可以在保证钢水脱硫的同时,将钢水增硅控制在0.03%以内,中间包[Si]≤0.045%,LF精炼渣流动性好,吸附夹杂物能力强。连铸提高开浇时保护浇铸效果,采用高钢水液面开浇,可以促进中间包夹杂物上浮,提高开浇时中间包钢水温度,同时增加钢水静压力,减少开浇时Al₂O₃夹杂在水口内壁结瘤,从而生产出成分为/%:0.04～0.06C,0.034～0.042Si和0.028～0.034Al可浇性好的C4C-Q钢。