铸坯凝固结构对硅钢热轧织构的影响机制

Influence Mechanism of Solidification Structure of Silicon Steel Castings on Hot Rolling Texture of Silicon Steel

基于某钢厂不同电磁搅拌参数调控的Fe–3.2%Si取向硅钢连铸坯凝固结构及热轧工业试验,采用光学显微镜(OM)、X射线衍射(XRD)和电子背散射衍射(EBSD)等检测技术,表征分析连铸过程电磁搅拌参数对铸坯凝固结构中柱状晶率的影响,探讨柱状晶率对热轧板织构的影响机制。结果表明:电磁搅拌器的工作电流(3 Hz)由900 A降到200 A,铸坯凝固结构中柱状晶率由40.1%增加到68.5%,柱状晶初始尺寸也随之增大;热轧板表层以铜型和黄铜织构为主,次表层以Goss织构为主,中心层主要为沿轧向延伸的α纤维织构及较弱的γ纤维织构。随铸坯柱状晶率的提高(40.1%~68.5%),热轧板再结区晶粒尺寸增加,有利于次表层Goss织构的保留;提高铸坯柱状晶率可降低热轧板中心层再结晶程度,中心层变形晶粒变大,不利于{114}<481>织构晶粒的形核与长大,且明显提高了织构强度梯度。

Based on the solidification structure and hot rolling industrial experiments of Fe–3.2%Si oriented silicon steel continuous casting billets controlled by different electromagnetic stirring parameters in a steel plant,the effect of electromagnetic stirring parameters on the proportion of columnar crystal in the solidification structure of cast billet during continuous casting was characterized and analyzed using detection techniques such as optical microscopy(OM),X ray diffraction(XRD),and electron backscatter diffraction(EBSD).The influence mechanism of columnar crystal proportion on the texture of hot-rolled plate was explored.The results show that as the working current(3 Hz)of the electromagnetic stirrer decreases from 900 A to 200 A,the proportion of columnar crystal in the solidification structure of the casting billet increases from 40.1%to 68.5%,and the initial size of columnar crystal also increases.The surface layer of hot-rolled plate is mainly composed of copper type and brass texture,the secondary layer is mainly composed of Goss texture,and the central layer is mainly composed ofαfiber texture extending along the rolling direction and weakγfiber texture.With the increase of columnar grain rate in oriented silicon steel billet(40.1%–68.5%),the grain size in the recrystallization zone of hot-rolled plate increases,which is conducive to the preservation of the Goss texture in the subsurface layer.Increasing of the columnar grain rate of casting billet can reduce the degree of recrystallization in the central layer of the hot-rolled plate,and the deformation grain in the central layer become larger,which is not conducive to the formation of{114}<481>textured grains.