Cobalt-chromium alloys retain hardness and wear resistance at temperatures where steels soften, and resist galling, cavitation and many corrosive media. Because they are extremely difficult to machine and cannot readily be forged, components are typically investment cast close to final shape and finished by grinding.
Grades in this family
| Grade | Type | UNS | Standard | Tensile strength Rm, min. (MPa) | Yield strength Rp0.2, min. (MPa) |
|---|---|---|---|---|---|
| Co-28Cr-6Mo (F75) | Cobalt-chromium-molybdenum casting alloy | R30075 | ASTM F75 | 655 | 450 |
| Co-Cr-W Alloy 6 | Cobalt-chromium-tungsten wear-resistant alloy | R30006 | Nominal composition; supplier and AMS specifications vary | — | — |
Minimum values (or ranges) for separately cast test bars as specified in
Casting and processing considerations
Design the casting so that functional surfaces need grinding only. Carbide-containing wear grades have limited ductility and are sensitive to thermal shock during cooling and finishing. Where a specification for implant alloys is referenced, its additional requirements for melting, testing and documentation apply in full and must be agreed explicitly.
Reference data compiled from the cited standards for orientation. Always work from the current edition of the governing specification; values are not a guaranteed LOSTWAX delivery specification.