薄板坯连铸连轧流程制备低温Hi-B钢织构的演变及Goss晶粒的发展

Evolution of Texture and Development of Goss Grains in High Permeability Grain Oriented Silicon Steel Produced by TSCR Process

针对薄板坯连铸连轧流程结合同步脱碳与渗氮工艺所制备的低温Hi-B钢,采用电子背散射衍射和X射线衍射技术系统研究了流程工序中主要织构组分及其含量、分布的演变特征,探讨了位向较为准确的Goss取向晶粒的发展过程。研究结果表明,热轧与常化板均以{001}〈110〉—{112}〈110〉的α织构为主,且沿板厚方向织构分布不均匀,板中与标准{110}〈001〉位向差不大于5°的高斯晶粒基本位于整个板厚的1/10~1/4处,含量仅约为0.1%。冷轧板以{001}〈110〉—{223}〈110〉的α织构为主,且取向密度明显增大。经835℃同步脱碳与渗氮处理后,渗氮板中{001}〈120〉、{114}〈481〉与{110}〈001〉织构的取向密度及晶粒含量明显提升,α织构的取向密度及晶粒含量大幅降低,但板中与标准{110}〈001〉位向差不大于5°的高斯晶粒的分布位置及含量基本未发生变化。同时与渗氮板中其他取向晶粒相比,位向差不大于10°的Goss取向晶粒在尺寸、数量和Σ3—Σ9晶界含量方面均不占优势,但在高能晶界含量方面具有极为明显的优势,即在Goss取向晶粒发生二次再结晶的初始阶段,高能晶界可能会起到较为关键的作用。经高温退火后,磁性能优异的成品板主要为单一的高斯织构,同时高斯织构聚集的锋锐程度较高,且其与标准{110}〈001〉位向的偏离角约为3°。

Based on low-temperature high permeability grain-oriented silicon steel produced by thin slab casting and rolling process with simultaneous decarburization and nitriding,the evolution characteristics of the main texture components and their area fractions and distribution were studied by means of EBSD and XRD.The development of Goss grains with relatively accurate orientation along the processing route was also investigated.It is found that the texture components of hot-rolled band and normalized band are mainlyαfiber textures from{001}〈110〉to{112}〈110〉,and the texture distribution is inhomogeneous along the thickness direction.Moreover,the Goss grains within 5°misorientation against the stan-dard{110}〈001〉are basically located at 1/10—1/4 of the entire band thickness,and the area fraction is only about 0.1%.The texture components of cold-rolled sheet are still mainlyαfiber textures from{001}〈110〉to{223}〈110〉,but the intensities are enhanced significantly.After simutaneous decarburization and nitriding treatment at 835℃,the intensities and area fractions of{001}〈120〉,{114}〈481〉and{110}〈001〉textures in the nitrided sheet are increased obviously,while theαfiber textures are the opposite.However,the distribution position and area fraction of the Goss grains within 5°misorientation are basically unchanged.Furthermore,compared with other specified orientation grains within 10°misorientation in the nitrided sheet,the Goss grains are not dominant in size,area fraction and proportion ofΣ3—Σ9 grain boundaries,but have extremely obvious advantage in the proportion of high energy grain boundaries,which means,in the initial stage of secondary recrystallization of Goss grains,the high energy grain boundaries may play the more critical role.After secondary recrystallization annealing,the final product with excellent magnetic properties is mainly a sharp Goss texture.And the misorientation angle is about 3°against the standard{110}〈001〉.