1.1 FormThis specification covers an aluminum alloy in the form of rolled or forged rings.1.2 ApplicationThese rings have been used typically for structural applications requiring material with moderate strength and excellentresistance to stress-corrosion cracking and where good stability is required during machining, but usage is not limited tosuch applications. Alloy is further characterized by excellent fusion weldability.1.3 ClassificationRings covered by this specification are classified by type of mechanical stress relief as follows:Type 1 Stress relieved by stretching (6061T651)Type 2 Stress relieved by compression (6061T652)1.3.1 Either type may be supplied, unless a specific type is ordered.