Modelling texture change during the static recrystallization of a cold rolled and annealed ultra low carbon steel previously warm rolled in the ferrite region

Abstract

An ultra low carbon steel was finish rolled in the ferrite range, cold rolled and annealed. Quantitative analysis of the deformation and annealing textures indicated that high stored energy nucleation was the dominant recrystallization mechanism after a conventional rolling reduction of 75%. When the rolling reduction was increased to 95%, texture formation during recrystallization was controlled by both oriented nucleation and selective growth; this involves the rapid growth of nuclei that display 32° 〈110〉 and 38°〈111〉 misorientations with respect to the surrounding matrix. Furthermore, variant selection is of critical importance during selective growth; out of six symmetrically equivalent 〈110〉 and four symmetrically equivalent 〈111〉 axes, the one chosen is closest to the maximum shear stress pole of the sample. The lower rolling reduction gives rise to a relatively weak and homogeneous 〈111〉//ND fibre texture (max. = 6 × random). The higher rolling reduction, on the other hand, leads to a much sharper 〈111〉//ND fibre texture (max. = 15 × random) with maxima at orientations that display misorientations of 32°〈110〉 and 38°〈111〉 with respect to the component of maximum intensity of the deformation texture (i.e. {311}〈110〉). It is shown that the combined drawability and in-plane isotropy improve with rolling reduction because selective growth controlled recrystallization favours the formation of more suitable textures.