含钛低碳钢LF精炼渣的优化

含钛低碳钢(/%:0.05~0.10C、0.70~0.95Si、1.45~1.65Mn、≤0.025P、≤0.025S、0.10~0.20Ti)的生产流程为高炉铁水-35 t LD-LF-150 mm×150 mm连铸工艺。用少量铝脱氧的含钛低碳钢,由于LF精炼渣(/%:55~59CaO、21.9~26.5SiO₂、9.4~14.3Al₂O₃)中Al₂O₃含量较高,使LF精炼过程中钢水铝含量增加和20 t中间包水口结瘤,影响连铸顺行。在热力学计算的基础上,优化了冶炼工艺,转炉出钢不加铝锰铁,使用低铝硅铁代替普通硅铁,精炼渣不加高铝矾土,优化精炼渣成分(/%:56.1~65.6CaO、19.3~27.2SiO₂、5.1~9.1Al₂O₃),钢水中Al含量由0.007%~0.018%降至0.001%~0.009%,有效减少中间包水口结瘤的发生。连浇炉数由原来的3~6炉提高到9~16炉。

Optimization of LF Refining Slag for Titanium-Containing Low Carbon Steel

The production flow sheet for titanium-containing low carbon steel (/% : 0.05-0.10C, 0.70-0.95Si, 1.45-1.65Mn, ≤0.025P, ≤0.025S, 0.10-0.20Ti) is BF hot metal-35 t LD-LF-150 mm x 150 mm casting process. For titanium-containing low carbon steel deoxidizing by minor aluminium due to higher A1₂O₃ content in LF refining slag (/% : 55 ~59CaO, 21.9-26.5SiO₂, 9.4-14.3A1₂O₃) , during LF process the aluminium content in liquid increases and the 20 t tundish nozzle blocking easily occurs to effect casting smooth-going. Based on thermodynamics calculation, the steelmaking process is optimum including in BOF tapping non-adding manganese-aluminium iron and using low aluminium silicon iron to replace common silicon iron, non-adding high alumina in refining slag and optimizing refining slag ingredient (/% ： 56.1-65.6CaO, 19.3-27.2SiO₂, 5.1-9.1 Al₂O₃) , the Al content in liquid decreases from original 0.007%-0.018% to 0.001%-0.009% , it is available to decrease the occurrence of nozzle blocking. The continuous-continuous casting heats increase from original 3 ~6 heats to 9-16 Heats.