低碳含铝钢LF炉精炼工艺及精炼渣的优化

针对低碳含铝钢转炉生产的粗钢水[O]含量高和钢水[C]低的特点,提出了采用CaO-Al₂O₃的LF炉精炼渣系.为兼顾脱硫和吸收同化夹杂的需求,可选取(质量分数)CaO=55%~60%,SiO₂=4%-7%,Al₂O₃=28%~32%,MgO=4%~8%,CaO/Al₂O₃=1.7~1.9作为LF炉精炼终渣组成.出钢过程中采用渣洗工艺向钢包内加入大部分精炼渣、出钢末期对转炉下渣还原处理的造渣模式,结合足够的软吹Ar时间,对16MnR进行精炼,得到了脱硫率为61.8%,铸坯T[O]为22×10^-6,铸坯中大型夹杂总量为15.68mg/10kg钢的良好冶金效果.

Optimization of LF refining process and slag for low carbon aluminum containing steel

Ladle furnace (LF) refining slag plays an important role in desulfurizing and inclusion removal from steel. According to the high[O] content and low[C] in the initial liquid steel from BOF (basic oxygen fur-nace) furnace, the CaO-Al₂O₃ slag system was suggested to use in the LF refining of low carbon aluminum con-taining steel. To enhance the desulfurizing and inclusion absorption for the liquid steel, the compositions of the final refining slag in LF can be chosen as:CaO=55%-60%, SiO₂=4%-7%, Al₂O₃=28%-32%, MgO=4%-8% (mass fraction), and CaO/Al₂O₃=1.7-1.9. During the tapping, most of the refining slag was added into the ladle to real-ize slag filtration. The oxidizing slag tapped into the ladle from BOF was reduced in the end of tapping. And enough time was kept to killing the liquid steel with Ar soft blowing. By all of above methods, the steel grade of 16MnR was refined with a better result as:the desulfurizing ratio was 61.8%, the total oxygen content T[O] in slab decreased to 22×10_-6, and the macro inclusions (≥ 50 μm) in slab also dropped down to 15.68 mg/10 kg steel.