无取向硅钢中镁铝尖晶石的变性机理  

Evolution mechanisms of MgO- Al_2O_3 in non-oriented silicon steel

作　　者：孙彦辉[1] 赵勇[1] 蔡开科[1] 孙赛阳[1] 马志飞[1] 方忠强[1] 

机构地区：[1]北京科技大学钢铁共性技术协同创新中心,北京100083

出　　处：《工程科学学报》2015年第1期20-29,共10页Chinese Journal of Engineering

摘　　要：对无取向硅钢钙处理过程中镁铝尖晶石夹杂的变性机理进行了研究,重点考察了钙处理前期和中期Mg O-Al2O3的变性过程.钙处理前,钢中除了发现单纯的Mg O-Al2O3外,还发现少量被Al N包裹的Mg O-Al2O3.钙处理1.5 min后,在Mg O-Al2O3表面有中间产物Ca S或Ca O形成;钙处理4.5 min后,生成由内到外依次为Mg O-Al2O3、Ca O-Mg O-Al2O3和Ca OAl2O3的夹杂物;钙处理10 min后,未反应的Mg O-Al2O3消失,Ca O-Mg O-Al2O3和Ca O-Al2O3的成分趋于均匀.通过热力学计算得到了Al2O3/Mg O-Al2O3/Mg O和Mg O-Al2O3/x Ca O·y Al2O3的稳定相图,发现在含铝越高的钢中,镁铝尖晶石变性越困难.结合夹杂物的扫描电镜观察、能谱分析和面扫描图分析结果,提出了夹杂物的变性路径:Mg O或Al2O3→Mg O-Al2O3→Ca O-Mg O-Al2O3→Ca O-Al2O3;在产物的中间层Ca O-Mg O-Al2O3中,Al2O3含量除了一般情况下的逐渐降低外,偶尔还存在突然升高的情况.The evolution mechanisms of MgO-Al2 O3 in the process of calcium treatment in non-oriented silicon steel were studied by laboratory experiments, with focus on the evolution process in the early and middle of calcium treatment. A small amount of MgO-Al2 O3 surrounded by AlN was occasionally detected besides many pure spinels before calcium treatment. CaS or CaO formed as a tran-sient inclusion in the MgO-Al2 O3 surface 1. 5 min after calcium treatment. The composition from the inner part to outer part of inclu-sions was MgO-Al2 O3 , CaO-MgO-Al2 O3 and CaO-Al2 O3 in order 4. 5 min after calcium treatment. 10 min after calcium treatment, unreacted MgO-Al2 O3 spinels disappeared, and simultaneously CaO-MgO-Al2 O3 and CaO-Al2 O3 inclusions became homogeneous in composition. The phase stability diagrams of Al2 O3/MgO-Al2 O3/MgO and MgO-Al2 O3/xCaO·yAl2 O3 were calculated using thermo-dynamic data. The result showed that it was difficult to modify MgO-Al2 O3 spinels with very high aluminum content. In combination with the scanning electron microscopy images, energy-dispersive spectra and element mappings of typical inclusions, the evolution route of an inclusion was described as MgO or Al2 O3→MgO-Al2 O3→CaO-MgO-Al2 O3→CaO-Al2 O3 , and the alumina content occa-sionally showed a sudden increase besides a common decrease in the middle part of the product.

关 键 词：炼钢 硅钢 夹杂物 尖晶石 钙处理 变性 

分 类 号：TF769.4[冶金工程—钢铁冶金]