Influence of a solution treatment on the evolution of through-thickness texture gradients in dry cold rolled and recrystallized low carbon steel

The influence of a solution treatment on the evolution of through-thickness texture gradients in a low carbon steel was studied. In order to intensify through-thickness variations of the strain state, the samples were cold rolled dry, i.e. without lubrication. The evolution of the texture and the microstructure during rolling and recrystallization was tracked by X-ray texture analysis and TEM microstructure investigations. The strain distribution during rolling was simulated for several layers of the rolled sheets by the finite element method. After the rolling deformation, a specimen taken directly from the hot band showed pronounced through-thickness texture gradients, whereas the solution treated specimen showed a rather uniform rolling texture in all layers analyzed. Analysis of the friction behaviour between the different specimens and the roll material points to a much higher friction between the softer hot band and the rolls. This leads to stronger through-thickness variations in the strain state and, thus, to the pronounced texture gradients observed. The texture gradients in the recrystallized samples reflected those of the as-rolled sheets. In the center layer of the hot band specimen and in all layers of the solution treated specimen characteristic though notably weakened typical plane strain recrystallization textures formed; the textures in outer layers of the hot band sample were even almost random. These weak recrystallization textures could be attributed to the highly inhomogeneous as-deformed microstructure.