SAE International: This specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock. These products have been used typically for parts requiring high tensile strength and good ductility with relatively high impact strength, superior transverse properties, and hardness, but usage is not limited to these applications. 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.