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 a through-hardening steel capable of developing a combination of high tensile strength, ductility, and fracture toughness, but usage is not limited to such 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.