Form This specification covers two grades of a premium aircraft-quality@ corrosion-resistant steel in the form of bars@ wire@ forgings@ and forging stock. Application These products have been used typically for parts requiring corrosion resistance and high strength up to 800 ??(427 ??. The steel can be precipitation hardened to minimum tensile strengths up to 225 ksi (1551 MPa). Certain design and processing procedures may cause these products to become susceptible to stress-corrosion cracking after heat treatment; ARP1110 recommends practices to minimize such conditions. Classification Steels covered by this specification are classified as follows: Grade 1: Transverse ductility@ not specified Grade 2: Transverse ductility@ specified Unless a specific type is ordered@ Grade 1 shall be supplied for product under 3.00 inches (76.2 mm) in nominal diameter or least distance between parallel sides@ and Grade 2 shall be supplied for larger sizes.