IF钢开浇阶段铸坯洁净度分析

Analysis of cleanliness for IF steel slabs at start of continuous casting

由于IF钢生产过程中对开浇阶段铸坯质量判定不明确,因此在利用时容易导致产品质量问题而增加生产成本。通过对头坯不同位置进行取样,研究IF钢开浇阶段铸坯沿拉坯方向的洁净度变化。实验结果表明,IF钢开浇阶段铸坯中大型夹杂物主要来源于结晶器卷渣和中间包中来不及上浮的脱氧或二次氧化产物;从距离头坯头部2.5m位置开始,由结晶器卷渣所引入的大型夹杂物含量接近正常坯水平;距离头坯头部7.5m位置处开始N含量与正常坯含量基本持平,簇状Al_2O_3夹杂物数量及尺寸接近正常坯水平;距离头坯头部8.5m位置处开始全氧质量分数保持在20×10^(-6)左右。

The usage of IF steel start slabs may cause quality problems and increase production cost because of the uncertain quality determination of the slabs.The cleanliness of IF steel start slab was studied by taking casting billet samples from different positions along casting direction.The results show that the large-sized inclusions in casting start slabs are mainly derived from slag entrapment in mold and the aggregation of deoxidation or secondary oxidation products in tundish.The contents of large-sized inclusions deriving from slag entrapment are decreasing along casting direction,which close to those of normal slabs starting from the point which is 2.5m away from front end of the start slab.The content of N as well as the number and size of cluster Al2O3 inclusions is close to those of normal slabs starting from the point which is 7.5m away from front end of the start slab,the content of total oxygen is also close to those of normal slabs starting from the point which is 8.5m away from front end of the start slab.