Recrystallization Textures in Coarse Grained Low Carbon and Interstitial Free Steels

Abstract

The microstructures and textures of coarse grained cold rolled, partially recrystallized and fully recrystallized low carbon and interstitial free steel were examined by optical microscopy, scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The recrystallization textures of the two grades are markedly different, with the low carbon steel having a predominantly {11O} texture and the interstitial free steel having a /1ND texture with a strong {III } component. One possible explanation for the texture difference is that less severe localization of flow during deformation of interstitial free steels causes less nuclei to be generated. While some support for this view is provided by the results presented in this paper, the results suggest that another mechanism may be at least partially responsible. Examination of micro shear bands on the surface of pre-polished samples showed that a higher proportion of micro shear bands remained active at high rolling reductions in the low carbon steel, compared with the interstitial free grade. Regions of orientation within bands that have ceased to operate rotate to near-{ III } orientations with further deformation. Consequently, the recrystallization texture of coarse grained interstitial free steels can be rationalized by a reduction in the availability of nuclei and an increase in the availability of {Ill } nuclei due to a Goss to {Ill } rotation within micro shear bands that have ceased to operate.