LF处理过程中钢水增铝问题的研究

硅镇静钢及少量铝脱氧的钢在LF处理过程中会发生钢水中铝含量增加以及夹杂物组成改变的现象.通过理论计算和工业生产实践研究了不同的渣系、钢水成分、处理时间等对LF精炼过程增铝的影响,不同精炼渣系下钢中夹杂的组成,结果表明采用CaO-SiO2渣系LF处理过程几乎不发生增铝现象,而采用CaO-Al2O3渣系随着处理时间的延长以及钢种成分的区别,钢中铝有不同程度的增加,生产实践结果与理论计算趋势基本一致.采用CaO-Al2O3渣系精炼与CaO-SiO2渣系相比,钢中Al2O3夹杂数增加4倍,氧化物复合夹杂中w(Al2O3)提高113%,w(CaO)提高24.5%.在帘线钢72A以及HRB400、SS400钢的生产实践中加以应用,使得LF处理后72A的w(Al)小于0.000 5%,HRB400、SS400的小于0.003%,避免了有害夹杂物的形成,消除了在小方坯连铸过程中的水口堵塞现象.

Study on Al Pick-up in LF Refining Process

The increase of AI content and change of inclusion composition is occurred for Si-killed or lightly Al-killed steels in LF process. Factors related to increase ot Al content such as refining slag compositions,molten steel composition LF refining time etc. were studied theoretic ally and practicaley. The practical result shows that the Al content is hardly increased during LF treatment with CaO-SiO2 refining slag, but Al content is increased at different degree with refining time for different steel grades with CaO-Al2O3 refining slag, and the trend is nearly consistent with theoretical calculation, Comparing with CaO-SiO2 refining slag, the content of Al2O3 inclusion increases 4 times, and in complex oxide inclusions the Al2O3 content increasesly 113%, and the CaO increases by 24.5% respectively duriug LD treatment with CaO-Al2O3 refining stag. Applying the result to practical production of tire wire steel 72A and other steels, it is able to control Al under 0.0005% for 72A and under 0.003% for other steels in LF refining process to avoid forming harmful inclusion and eliminate the nozzle clogging.