低碳铝镇静钢连铸头坯夹杂物

Inclusions in First Slab of Low Carbon Aluminium Killed Plain Steel

利用氧氮分析仪和大样电解法对某厂采用210tBOF—220tLF—CC所生产的低碳铝镇静钢不同浇铸长度头坯夹杂物进行研究,并与正常坯相比较,得到结论如下:随着浇铸长度的增加,头坯中w(T[O]),w([N])和大型夹杂物数量均逐渐下降;头坯中夹杂物主要为TiN,SiO2,Al2O3-SiO2和Al2O3-MgO-CaO复合夹杂物,另外还发现少量的MgO夹杂物;头坯夹杂物数量增加的主要原因是钢水二次氧化、中间包覆盖剂和结晶器保护渣卷入;另外,钢包引流砂和中间包内衬也是导致头坯中夹杂物数量增加的原因。建议该厂该低碳铝镇静钢头坯的切废长度为大于4.0m。

The inclusions in first slab of low carbon aluminium killed steel produced by 220 t BOF-220 t LF-CC and the comparative analysis with the inclusions of normal slab were studied by means of Oxygen and Nitrogen Analyzer and electroanalysis.The results are as follows：w（T[O]）,w（[N]）and large-inclusions were generally decreasing with increasing of length;the inclusions were mainly TiN,SiO2 ,Al2 O3-SiO2 and Al2 O3-MgO-CaO complex inclu-sions;a small amount of MgO inclusions were also found.The reasons for the increasing were mainly reoxidation and entanglement of tundish covering flux and mold powder.Ladle filler sand and tundish lining can also make the inclusions increasing.The recommendation was that the length of slit should be more than 4.0 m.