帘线钢中氧化物夹杂在铸坯上的分布与控制

Distribution and control of oxide inclusion in tire cord steel bloom

研究了大方坯连铸生产帘线钢时铸坯横截面上氧化物夹杂的分布规律,得出铸坯不同位置夹杂物数量密度、尺寸、成分、类型变化较大。从铸坯边部到铸坯中心,氧化物夹杂数量密度不断降低、平均尺寸不断升高,但较大尺寸夹杂物（3~15μm）数量密度呈现先增大后减小的趋势,而夹杂物平均Al2O3含量呈现急剧升高后小幅度波动的现象,wCaO＋MgO/wSiO2或wMnO＋MgO/wSiO2比值呈现急剧降低后缓慢增加的趋势。根据研究,柱状晶向等轴晶转变区域（CET区域）是最为特殊区域,该区域较大尺寸夹杂物数量密度最大、MnO-Al2O3-SiO2类夹杂物数量百分含量最低、平均Al2O3含量几乎最高、wCaO＋MgO/wSiO2或wMnO＋MgO/wSiO2比值基本最低。基于氧化物夹杂在铸坯上的分布规律,铸坯取样分析应关注不同位置,夹杂物控制应重点关注CET区域及中心等轴晶区域。

The distribution regularity of oxide inclusions in bloom of tire cord steel was studied and it was found that the number density,size,composition and type of inclusions change greatly with different positions of the bloom.From edge to center,the number density of inclusion decreases,the average size increases,and the number density of larger size inclusion（3-15μm）increases first and then decreases.For inclusion composition,the phenomenon of small-amplitude fluctuations after a sharp rise in average Al2O3 content and the trend of sharp decrease then slowly increasing in the ratio of wCaO＋MgO/wSiO2 or wMnO＋MgO/wSiO2 from bloom edge to center are showed.Based on the study,the CET region is the most special area and in this area the number density of larger size inclusion（3-15μm）is biggest,the number percentage of MnO-Al2O3-SiO2 complex inclusion is lowest,average Al2O3 content is almost highest,and the ratio of wCaO＋MgO/wSiO2 or wMnO＋MgO/wSiO2 is basically lowest.On the basis of the distributing characteristics of oxide inclusions in bloom,different sampling location such as CET region and the equiaxed zone should be focused.