Abstract:In asymmetric rolling (ASR) the circumferential velocities of the working rolls are different. This yields a complex deformation mode with shear, compression and rigid body rotation components. The main microstructural modification is on crystallographic texture, and, for aluminium alloys, this may improve the deformability after recrystallization. This work correlated the process variables, thickness reduction per pass (TRP) and velocity ratio between the upper and bottom rolls, with the texture development and the plastic properties after annealing. Finite element (FE) simulations were performed to quantify the influence of the strain components. Experimental data on texture, and plastic anisotropy were analyzed. In the sheet centre a crystallographic rotation of the compression components about the TD (transverse direction) axis was obtained, which yielded the development of {111}//ND (normal direction) texture components. On the surfaces the local variation of the velocity gradients caused an extra rotation component about ND. This yielded the increment of rotated cube components. After annealing the main texture components at the sheet centre were maintained and the texture intensity decreased. The planar anisotropy (？r) was reduced but the normal anisotropy and deep drawability obtained by the Erichsen test were similar for all conditions. The most favourable reduction of ？r was obtained at a velocity ratio of 1.5 and TRP of 10%.

Key words: asymmetric rolling; aluminium alloy; X-ray diffraction; finite element analysis; stress/strain measurements; plasticity