This specification covers the material requirements for low-carbon (UNS R31537), high-carbon (UNS R31538), and dispersion-strengthened (UNS R31539) cobalt-28chromium-6molybdenum alloy high-strength forgings used for the manufacture of surgical implants. The properties specified here specifically apply to finished or semifinished parts that receive no subsequent thermomechanical processing. The materials shall be in the form of bars, rods, or wires suitable for forging by hammering, pressing, rolling, extruding, or upsetting. The forgings shall adhere to chemical composition, ultimate tensile strength, yield strength, elongation, reduction of area, and hardness requirements.

1.1 This specification covers requirements of cobalt-28chromium-6molybdenum alloy (UNS R31537, R31538, R31539) high-strength forgings for the manufacture of surgical implants. The properties specified in this document specifically apply to finished or semifinished parts that receive no subsequent thermomechanical processing.

1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.3 Wrought material to be used as forging stock in the manufacture of forgings conforming to this specification, typically hot worked and unannealed with a surface finish suitable for forging, shall be fabricated and supplied in accordance with F 1537.