SAE AMS 6435F
This specification covers a premium aircraft-quality, low-alloy steel in the form of sheet, strip, and plate.These products have been used typically for parts, which may be welded during fabrication, requiring through-hardening to high strength levels and which may be used at operational stress levels approaching the yield strength. Steel may become notch sensitive when heat treated to a tensile strength level of 240 ksi (1655 MPa) or higher.