Form This specification covers an aluminum alloy in the form of sheet and plate from 0.008 to 4.000 inches (0.20 to 101.60 mm) in thickness@ inclusive (See 8.4). Application These products have been used typically for formed structural parts of good strength. Plate is also suitable for structural machined parts where warpage@ during machining@ due to residual stresses must be minimized@ but usage is not limited to such applications. Certain design and processing procedures may cause these products to become susceptible to stress-corrosion cracking; ARP823 recommends practices to minimize such conditions.