Form This specification covers an aluminum alloy in the form of flash welded rings 0.062 to 4.499 inches@ incl (1.57 to 114.27 mm incl) in radial thickness@ with cross sectional areas up to 32 in2 (206 cm2) (see 8.5). Application These rings have been used typically for parts requiring high strength and resistance to stress-corrosion cracking@ but usage is not limited to such applications.