Tracking the Evolution of Annealing Textures from Individual Deformed Grains in a Cross-Rolled Non-oriented Electrical Steel

Abstract

The evolution of microtexture and microstructure of a cross-rolled 0.88 wt pct Si non-oriented electrical steel was investigated using a quasi-in situ electron backscatter diffraction (EBSD) technique, where individual deformed grains with various initial orientations were tracked during annealing at the same temperature for different times. The textures recrystallized from different deformed grains were compared, and the observations were examined against the preferential nucleation and selective growth theories. Although the cold deformed 〈111〉//ND (normal direction) grains recrystallized first during annealing, they started with significantly different nucleation textures, i.e., γ-fiber (〈111〉//ND) in {111}〈112〉 deformed grains, and cube ({001}〈100〉) in {111}〈110〉 deformed grains. Both recrystallization textures were quite stable until the steel was completely recrystallized. Significant grain growth in these grains was only observed after the recrystallization was complete, which resulted in considerably different final textures as compared to the initial nucleation textures. Deformed grains with a rotated cube ({001}〈111〉) orientation were the last to recrystallize, and the recrystallization was accomplished mainly through the “invading” of neighboring grains into the deformed matrix. Analysis of the misorientations between the rotated cube grain (the matrix) and their neighboring recrystallized grains showed that the preferred growth of some of the grains can be attributed to the high grain boundary mobility associated with the coincident site lattices (CSL). During the course of recrystallization, some $\{ 11{\text{h}}\} \left\langle {12\frac{1}{h}} \right\rangle$ and rotated cube grains also formed, but they disappeared quickly when the annealing time was increased.