This specification has been declared NONCURRENT by the Aerospace Materials Division, SAE, as of May 2006. It is recommended, therefore, that this specification not be specified for new designs. This specification covers a premium aircraft-quality, low-alloy steel in the form of sheet, strip, and plate. This product has been used typically for heat treated parts, which may be welded during fabrication and which require through-hardening to high strength levels, for use up to 600 degrees F (316 degrees C), but usage is not limited to such applications.