Influence of Cold Rolling and Annealing on the Mechanical and Corrosion Properties of an AA5182 Al-Mg Alloy

Abstract

In this study we investigated the effect of cold rolling reductions and different annealing conditions, on the mechanical properties and corrosion resistance of an AA5182 type Al-Mg alloy. Material was industrially produced and supplied as hot rolled 12 mm thick plates. Further lab-processing included cold rolling with 40-85% reduction in thickness, and 2h of annealing in the range of temperatures from 300-350°C. Annealed specimens were used for room temperature tensile testing while corrosion testing was performed on the annealed and sensitized specimens. Intergranular corrosion (IGC) susceptibility was determined by nitric acid mass loss test (NAMLT) for the selected states. The results showed that corrosion resistance, tensile strength and yield point elongation were mostly affected by a degree of cold deformation. It was found that increasing in cold rolling reduction from 40-85% before annealing causes an improved strength level due to grain size refinement. However, yield point elongation became more pronounced and a tendency towards Lüdering as undesirable surface appearance was increased. NAMLT testing showed that the material was corrosion resistant in as-annealed condition while it became susceptible to intergranular corrosion after sensitization treatment. IGC susceptibility of sensitized specimens increases with cold rolling reduction and a grain size refinement.