*Article* **Twinning Behavior in Cold-Rolling Ultra-Thin Grain-Oriented Silicon Steel**

**Bo Zhang 1, Li Meng 1,\*, Guang Ma 2, Ning Zhang 1, Guobao Li 3, Kun Liu <sup>4</sup> and Sheng Zhong <sup>5</sup>**


**Abstract:** Twinning behaviors in grains during cold rolling have been systematically studied in preparing ultra-thin grain-oriented silicon steel (UTGO) using a commercial glassless grain-oriented silicon steel as raw material. It is found that the twinning system with the maximum Schmid factor and shear mechanical work would be activated. The area fraction of twins increased with the cold rolling reduction. The orientations of twins mainly appeared to be α-fiber (<110>//RD), most of which were {001}<110> orientation. Analysis via combining deformation orientation simulation and twinning orientation calculation suggested that {001}<110> oriented twinning occurred at 40–50% rolling reduction. The simulation also confirmed more {100} <011> oriented twins would be produced in the cold rolling process and their orientation also showed less deviation from ideal {001}<110> orientation when a raw material with a higher content of exact Goss oriented grains was used.

**Keywords:** ultra-thin grain-oriented silicon steel (UTGO); cold rolling; twinning; Goss; {100}<011>
