Recrystallization Textures of Al-Mg-Si Alloy Sheets Produced by Symmetric and Asymmetric Combination Rolling

Abstract

In order to improve deep drawability of 6000 series aluminum alloys for automotive body panels, texture control for increasing r-value of the sheets was attempted by combination of symmetric and asymmetric rolling. Asymmetric warm rolling at relatively low reduction after symmetric rolling made it possible to form TD-rotated β-fiber texture including {111} components. Recrystallization textures of the T4-treated materials varied significantly depending on roll speed ratio and reduction in asymmetric warm rolling. On appropriate rolling conditions, {111}<110> orientation with high r-value was formed as a main component of recrystallization texture. On the other hand, two-stage heat treatment consisting of low temperature annealing and subsequent T4-treatment led to a significant change in recrystallization texture. In the sample annealed for long time at a low temperature, TD-rotated β-fiber rolling texture was retained even after solution treatment at a much higher temperature, because recovery or recrystallization took place to some extent during low temperature annealing.