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-28 chromium-6 molybdenum 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 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 Specification F1537.

1.3 Units—The SI units in this standard are the primary units. The values stated in either primary SI units or secondary inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.