This specification has been declared "NONCURRENT" by the Aerospace Materials Division, SAE, as of April, 2005. It is recommended, therefore, that this specification not be specified for new designs. "NONCURRENT" refers to those specifications which have previously been widely used and which may be required for production or processing of existing designs in the future. The Aerospace Materials Division, however, does not recommend these specifications for future use in new designs. This specification covers a premium aircraft-quality alloy steel in the form of welding wire. This wire has been used typically as filler metal for gas-metal-arc or gas-tungsten-arc welding of steels of similar composition requiring joints with high strength and fracture toughness, but usage is not limited to such applications.