Deep Drawing and Anodizing Quality Improvement in AA3003-O Alloy by Optimization of Homogenization, Rolling and Annealing

Abstract

An investigative study was carried out to understand the effect of homogenization, hot and cold rolling as well as annealing cycle on improvement of deep drawing and anodizing quality of thin AA3003-O sheets. Poor drawability of the sheets was attributed to a coarse average grain size, high cube texture intensity and low average normal anisotropy ($\overline{R}$). Amount of Al–TiB grain refiner was increased in the casting stage, leading to a significant reduction in as-cast grain size. The 2-stage homogenization cycle was optimized to maximize the conversion of β-phase (Al6(Mn,Fe)) to α-phase (Al(Mn,Fe)Si), their number density, the area fractions of the precipitates and the electrical conductivity. The degree of hot rolling was increased to reduce the cube texture intensity in annealed circles. The annealing cycle was optimized to obtain the best combination of grain size, mechanical properties (UTS and total elongation), $\overline{R}$ and average planar anisotropy, ΔR. AA3003-O circles successfully passed the deep drawing test without any tearing or deformation, up to a draw ratio of 2. Also the presence of the α-phase led to an improvement in the anodizing quality of the final product.