Form This specification covers an aluminum alloy in the form of seamless@ drawn tubing having nominal wall thickness of 0.120 to 0.400 inch (3.00 to 10.00 mm) inclusive (see 8.4). Application This material has been used typically for parts requiring a high-strength@ non-weldable alloy@ but usage is not limited to such applications. Parts are usually solution heat treated and aged before use.