MIL-S-46850D, MILITARY SPECIFICATION: STEEL: BAR, PLATE, SHEET, STRIP, FORGINGS, AND EXTRUSIONS, 18 PERCENT NICKEL ALLOY, MARAGING, 200 KSI, 250 KSI, 300 KSI, AND 350 KSI, HIGH QUALITY (22 MAR 1991)., This specification covers steel bars, plate, sheet, strip, forgings and extrusions containing 18 percent nickel and capable of attaining high ultimate tensile properties by means of a relatively low temperature heat treating process