MIL-S-47319A, MILITARY SPECIFICATION, STEEL, BAR, BILLET, AND FORGINGS, COBALT-FREE MARAGING (26 NOV 1991)., This specification defines the requirements of two classes of onetype of steel bar, forgings and stock for forging, cobalt-free maraging, containing 18percent nickel and capable of attaining high ultimate tensile properties by means of arelatively low temperature heat treating process.