Form: This specification covers an aircraft-quality@ low-alloy steel in the form of sheet@ strip@ and plate. Application: Primarily for use where welding and moderate physical properties are required. Sheet and strip are extensively used where minimum tensile strength of 180@000 psi (1241 MN/m2) is required in sections up to 0.125 in. (3.18 mm) thick and proportionately lower strength is required in heavier thickness.