This specification covers an aluminum alloy in the form of rolled or forged rings. These rings have been used typically for structural applications requiring good fusion weldability, a combination of good strength and resistance to stress-corrosion cracking, and for parts requiring good stability during machining, but usage is not limited to such applications. Certain design and fabrication procedures may cause these products to become susceptible to stress-corrosion cracking; ARP 823 recommends practices to minimize such conditions. Rings covered by this specification are classified by type of mechanical stress relief as follows: Type 1 - Stress relieved by stretching (2219T351); Type 2 - Stress relieved by compression (2219T352). Either type may be supplied, unless a specific type is ordered.