ALUMINUM ALLOY SHEET WITH EXCELLENT HIGH-TEMPERATURE PROPERTY FOR BOTTLE CAN

摘要

An aluminum alloy sheet having excellent high-temperature properties for bottle cans which can be prevented from thermally deforming during coating/heat treatment to secure can strength after the heat treatment. The sheet has a composition which contains 0.7-1.5% manganese, 0.8-1.7% magnesium, 0.1-0.7% iron, 0.05-0.5% silicon, and 0.1-0.6% copper, with the remainder being aluminum and unavoidable impurities. It has a crystal grain structure elongated in the rolling direction so that the average aspect ratio of crystal grains, as determined through an examination from above of a part located at the center in the sheet thickness direction, is 3 or higher. In the sheet, the amount of copper present in a solid solution form is 0.05-0.3% in terms of copper amount in a solution separated from a precipitate having a particle size larger than 0.2 µm by the residue extraction method using hot phenol, and the amount of magnesium present in a solid solution form is 0.75-1.6% in terms of magnesium amount in a solution separated from a precipitate having a particle size larger than 0.2 µm by the residue extraction method using hot phenol. The aluminum alloy sheet can have improved high-temperature properties while retaining intact moldability.