Mechanical contributions to the plane-strain deformation and recrystallization textures of aluminum-killed steel

Abstract

This work is concerned with the texture changes which underlie the reduction dependence of the plastic anisotropy of cold rolled and recrystallized killed-steel strip. The earlier observations of Whiteley and Wise¹ on the maximum in the intensity of rolling plane (111) were repeated and extended by introducing into the cold-reduction step the variable of deformation-zone geometry (i.e. Δ, the ratio of the mean height of the zone to its length). A range of Δ < 1 to Δ = 4 was covered by cold rolling (<1) and strip drawing (from 1 to 4). Pole figures after rolling reductions of about 98 pct are changed abruptly as if by a 55 deg rotation of part of the stable texture around the transverse direction. It is suggested that the mechanism is localized flow in macroscopic bands along maximum shear planes as strain hardening capacity is exhausted. There is both mechanical and metallographic evi-dence of such bands. Assigning a shear texture to them modifies the parent texture in a way which is consistent with the pole figures. As Δ becomes >1, strain and texture gradients appear and the texture inversion occurs in the more strained regions at smaller total reductions-after as little as 40 pct for surface layers with Δ = 4. The mechanism ap-pears not to be changed, however, only accelerated in terms of the imposed reduction. Implications for practical texture control are discussed.