The effect of cold working and annealing practice on earing in 3104 Al alloy sheet

Abstract

A study was conducted with a 3104 Al alloy on the effect on earing of five annealing and cold-rolling practices preceeding a final cold reduction of 88%. Included in these were the effect of slow heating (15°C/h) to the annealing temperature of 332°C, which simulated batch annealing; and the effect of rapid heating (about 140°C/min), which simulated strip annealing. The annealing time was 2 h. The starting condition was hot-rolled material; some of the practices involved an intermediate cold reduction of 35%. The tensile mechanical properties were independent of the test direction for the final 88% cold-rolled material for all practices. The yield and tensile strengths were slightly lower for practices involving the intermediate 35% cold rolling. These practices also had markedly higher 45° earing. The rapid heating rate gave a finer annealed grain size, but the heating rate had no effect (other steps of the processing being the same) on the earing behavior. The primary particle density of the annealed condition that preceded the final 88% cold rolling did not correlate with the earing. It appears that the finer microstructural features produced after the 35% cold rolling and annealing are responsible for the high earing observed.