Patent ID: 8277580
Filing Date: 2012-10-02
Classification: C22C,C22F

Abstract:
1. A rolled or forged Al—Zn—Cu—Mg aluminum-based alloy wrought product having a thickness from 3 to 9 inches, wherein said product has been treated by solution heat-treatment, quenching and aging, and wherein said product has a volume fraction of recrystallized grains lower than 35% and said product consisting essentially of (in weight-%): Al Zn 6.7-7.0 Mg 1.68-1.8 Cu 1.7-1.97 Fe 0-0.13 Si 0-0.10 Ti 0-0.06 Zr 0.08-0.13 Cr 0-0.04 Mn 0-0.04 impurities and other incidental elements ≦0.05 each, wherein said product comprises the following properties: a) a minimum life without failure after stress corrosion cracking (SCC) of at least 50 days at a short transverse (ST) stress level of 40 ksi, b) a conventional tensile yield strength measured in the L direction at quarter thickness of at least 70-0.32t ksi (t being the thickness of the product in inch), and c) toughness in the L-T direction measured at quarter thickness of at least 42-1.7t ksi √in (t being the thickness of the product in inch).