优化保护渣提高超低碳IF钢表面质量

 通过优化调整保护渣成分，保护渣熔点由1 222降至1 188 ℃，黏度由0.26提高到0.32 Pa·s，并进行工业试验，利用Aspex对铸坯不同部位大于2 μm的夹杂进行检测，发现铸坯边部和1/4宽、1/2宽、1/2厚度位置夹杂物均有所降低，同时热轧板卷表面临时封锁率由4.51%降低至2.55%。对采用改进保护渣后铸坯中不同部位夹杂物降低的原因进行分析，研究了保护渣吸附不同质量分数Al2O3夹杂后，保护渣熔化温度、黏度的影响规律，发现当添加Al2O3为12%时，保护渣A熔化温度最高至1 259 ℃；保护渣B熔化温度为1 203 ℃，保护渣A与B的黏度分别为0.79和0.59 Pa·s，黏度过大不利于吸附Al2O3夹杂。

Optimization of mold flux to improve surface quality of ultra-low carbon IF steel

By optimizing the chemical compositions of the mold flux,the melting point of the mold flux reduced from the 1222 to 1188℃,and the viscosity increased from 0.26 to 0.32 Pa·s. The conducted industrial experiments showed that>2μm inclusions detected by ASPEX scanning on the edge,1/4 width,1/2 width and 1/2 thickness all decreased af-ter the optimization of mold flux.The temporary surface blockade ratio reduced from 4.51%to 2.55%. To explain the im-provement of steel slab cleanliness after apply the optimized mold flux,the variation of melting temperature and viscosi-ty of mold flux were studied after adsorbing different mass fraction Al2O3 inclusions.It found that after adding 12%Al2O3,the melting temperatures of mold flux A and B are 1259 and 1203 ℃,respectively. While the viscosities of mold flux A and B are 0.79 and 0.59 Pa · s,respectively. Larger viscosity is harmful for the absorption of Al2O3 inclu-sions.