Influence of columnar grains on the recrystallization texture evolution in Fe-3%Si electrical steel

Abstract

Columnar grains commonly exist in the cast slabs of Fe-3%Si electrical steels and exert, due to their topographic and crystallographic anisotropies, strong influence on the microstructure and texture during following hot-rolling, cold-rolling and annealing. Based on the previous paper addressing the cold-rolling texture evolution in the electrical steels with different alignments of columnar grains, this work illustrates further the recrystallization texture evolution at different annealing temperatures by means of XRD and EBSD techniques. The results show that the recrystallization texture evolution represents, on the one hand, the 'heritage' of the initial orientations, concerning the formation of cube and Goss texture. On the other hand, specific features are determined from different types of recrystallized columnar grains specimens, namely, the formation of the {113} texture, the more significant growth of Goss grains than that of cube grains in RD specimens (with initial columnar grains' longitudinal axis being along rolling direction) and the vanishing of {110}<110> grains in TD specimens, which have been scarcely reported in single crystals or in polycrystalline bcc materials composed of equiaxed grains. The dissimilar recrystallization environments lead to distinct evolution of cube texture at various annealing temperature, and the highest intensity of cube texture at low annealing temperature in TD specimen is believed to be related with the strong effect of transverse directional alignments of columnar grain boundaries. Regarding the cube and Goss recrystallization textures, their formation can be explained in terms of the theories of both oriented nucleation and oriented growth. In addition, this study also confirms that {111} texture can be suppressed effectively in the columnar grain specimens after cold-rolling at intermediate reduction and annealing. © Rright.