one big customer prohibits the use of 2000 and 7000 series aluminum alloy unless it is in overage condition. what is overage condition? what will be the condition designation?
thanks.
For 7075 and 7050, the T7 (or derivatives like T72, T7351, etc.) temper is solution treatment + overage. Instead of peak aging to maximum strength, overaging uses a somewhat higher aging temperature and produces somewhat lower strength, but improved ductility and fracture toughness. The T7 condition improves resistance to stress corrosion cracking and corrosion fatigue. A Google search will return many thousands of hits on this subject, but here are two documents that you might find useful: