常化冷却工艺对低温取向硅钢组织及析出相的影响

摘要

利用OM、TEM与EDS技术，对Fe-3.2%Si低温取向硅钢热轧板进行不同常化冷却工艺处理后的显微组织、析出相及最终产品的磁性能进行分析，并与热轧板的组织和析出相进行对比。结果表明，常化板较热轧板的表层组织均匀，基体中再结晶比例增加，带状组织变窄；常化板中析出物的数量明显比热轧板的多，析出物主要有AlN、MnS及复合析出的(Cu,Mn)S等。在常化温度1120℃、保温3 min的条件下，采用二段式冷却较空冷、淬沸水、淬常温水的冷却工艺，常化板表层显微组织更均匀，沿板厚方向的显微组织的不均匀性显著，取向硅钢的磁性能最高；常化后采用二段式冷却工艺析出的细小析出物数量最多，且弥散分布在基体中，抑制剂的抑制效果最好，对成品获得高磁性最有利。%Microstructure, precipitate and magnetic characteristic of final products with different normalizing cooling processes for Fe-3.2%Si low-temperature hot-rolled grain-oriented silicon steel were analyzed and compared with the hot-rolled plate by optical microscopy (OM), transmission electron microscopy (TEM), and energy dispersive spectrometry (EDS). The results show that, the surface microstructure is uniform, the proportion of recrystallization in matrix increases, and the banding textures are narrowed;the precipitates, whose quantity in normalized plate is more than that in hot-rolled plate greatly, are mainly AlN, MnS, composite precipitates (Cu,Mn)S and so on. Normalizing technology with a temperature of 1120 °C, holding for 3 min, and a two-stage cooling is a most advantaged method to obtain oriented silicon steel with sharper Goss texture and higher magnetic properties, owing to the uniform surface microstructures and the obvious inhomogeneity of microstructures along the thickness. The normalizing technology with the two-stage cooling is the optimum process, which can generate more fine precipitates dispersed over the matrix, and be beneficial for finished products to get higher magnetic properties.