Improvement of the press-formability of aluminium sheets through the control of annealing conditions

1050-Aluminium sheets cold-rolled to 95% reduction reaching a nominal final thickness of 0.60mm. are annealed according to two annealing programmes. In the 1st, specimens are annealed for one hour at different annealing temperatures; while in the 2nd, specimens are annealed at various temperatures for different annealing intervals. The tensile properties, surface and mid-thickness textures, microscopic structure through thickness, and press-formability of sheets annealed according to the 1st programme are carefully examined. The r45- and r^- -values show high peak values for the partially recrystallized sheet. The n-value reaches a relatively large value and remains constant after full recrystallization. The variation of r^- -value is qualitatively correlated with the texture. The development of surface and mid-thickness textures of the (112) [111^-] and (123) [211^-] types are recommended for high r-values. The drawability with a flat-headed punch correlates well with r^- -value; while that with a round-headed one and the stretchability correlate well with the n^- -and the total natural strain 𝜀^-l respectively.