自动扫描电镜在无取向电工钢析出物分析上的应用

Application of automatic scanning electron microscope on analysis of precipitates in non-oriented electrical steels

析出物的数量、尺寸和种类是影响无取向电工钢磁性能的重要因素之一。采用Aspex自动扫描电镜对一种商用无取向电工钢的退火板和热轧板进行了析出物分析,发现在退火板中析出物的类型主要为纯AlN和AlNMnS复合析出物两类。析出物在退火板截面上沿轧板厚度方向的分布不均匀,退火板中心AlN和AlN-MnS尺寸大、数量少,而边部相反。热轧板截面上析出物的分布也有相同的规律,热轧板中的析出物分布对退火板具有遗传性。对于析出物尺寸较大的样品,晶粒尺寸也大,磁性能较好。同时还验证了退火过程中发生的渗氮会在退火板表面形成一层细小的AlN和细晶层,也会恶化铁损。

Amount,size and species of precipitates are key factors affecting the magnetic properties of non-oriented electrical steels.An automatic scanning electron microscope(Aspex)is employed to analyze the precipitates in the annealed and hot-rolled sheets of a commercial non-oriented electrical steel,finding that pure AlN and AlN-MnS complex precipitates are the main precipitates.Precipitates distribute unevenly on the longitude section of annealed sheets where AlN and AlN-MnS are larger and less in the center while smaller and more in the edge.The distribution of precipitates in the hot-rolled sheets also shows the same rule with that in the annealed sheet.Samples with larger precipitates show larger grain size and better magnetic properties.Besides,nitriding layer is also verified to be detrimental to magnetic properties.