BOF-LF-CSP工艺低碳铝镇静钢精炼过程的夹杂物变化

Evolution of inclusions during refining in low carbon Al-killed steel produced by BOF-LF-CSP process

对BOF-LF-CSP工艺生产低碳铝镇静钢精炼过程连续密集取样,运用ASPEX扫描电镜统计分析了夹杂物成分、尺寸分布和数量变化.发现喂铝线后夹杂物数密度和面积分数都急剧增加.精炼20 min至钙处理前软吹期间,夹杂物数密度变化不大,但夹杂物面积分数却明显下降.精炼结束时主要为含有少量CaO的MgO-Al_2O_3尖晶石类夹杂.钙处理后,夹杂物数密度和面积分数都有增加,主要为钙铝酸盐和由于喂入过量钙生成的CaS夹杂.

Intensive steel samples were taken from industrial beats at various time in a ladle furnace during BOF- LF-CSP process. The compositions, size distribution and change in number of inclusions in the samples were statistically analyzed by using an ASPEX scanning electron microscope. It is found that the number density and area fraction of inclusions in the samples sharply increase after A1 addition. Then the number density has little changes while the area fraction obviously decreases during the period between 20 min-refining and soft blowing before Ca treatment. At the end of refining, the inclusions are mainly MgO-A12O3 spinels containing little amounts of CaO. Both the number density and area fraction increase after Ca treatment, and the typical inclusions at this moment are calcium-aluminates and CaS due to excessive Ca treatment.