Novel aluminum alloy, continuously cast aluminum alloy shapes, method of

Abstract

Continuously cast aluminum alloy castings are provided which may be cold worked to thin gages without the need for a homogenizing thermal treatment. The castings comprise an aluminum alloy which consists essentially of 0.30-0.50% of copper, 0.35-0.60% of magnesium, up to 0.50% of zinc, residual silicon in an amount up to 0.40%, residual iron in an amount up to 0.70%, residual manganese in an amount up to 0.10%, residual chromium in an amount up to 0.10%, residual sodium in an amount up to 0.0006%, other residual elements in a total amount up to 0.15% and in an amount up to 0.05% for each, and the remainder aluminum. The castings are preferably in the form of continuously cast strip having an initial thickness not greater than about one inch. The strip may be cold rolled in a plurality of cold rolling passes to a final thickness of about 0.001-0.01 inch in the absence of a homogenizing thermal treatment. The strip is annealed at least once intermediate the first and last cold rolling passes at an annealing temperature of 600-800.degree.F. for a period of 1-6 hours. Following the last cold rolling pass, if desired the strip may be given a further anneal at a temperature of about 350-800.degree.F. for about 0.5-10 hours. The resulting semirigid container stock is especially useful in the manufacture of disposable containers.