Technical guide · 2026-08-14
Cobalt-Chromium Alloys
Cobalt-chromium alloys rely on a passive chromium-rich surface and route-dependent carbide structure for corrosion, wear and biomedical service, with cast, wrought and additively manufactured conditions requiring separate qualification.
01
Definition and boundary
Covers bulk Co-Cr and Co-Cr-Mo products; excludes hardfacing deposits and WC-Co cemented carbides.
Reference information only: final acceptance is controlled by the ordered product specification, condition, dimensions and certified test results.
02
How the material system works
Chromium supports passivation.
Carbides raise wear resistance.
Casting or thermomechanical route changes ductility and fatigue.
03
Representative grades and systems
| Grade or system | Selection focus | Qualification |
|---|---|---|
| ASTM F75 Co-Cr-Mo | Cast surgical alloy under an exact implant specification. | Confirm the governing product specification, delivery condition, section size and acceptance tests before treating designations as interchangeable. |
| Co-28Cr-6Mo PBF | Additive route requires its own process specification. | Confirm the governing product specification, delivery condition, section size and acceptance tests before treating designations as interchangeable. |
| Co-Cr-W wrought system | Wrought condition changes structure and acceptance. | Confirm the governing product specification, delivery condition, section size and acceptance tests before treating designations as interchangeable. |
04
Properties and trade-offs
Corrosion resistance
Wear resistance
Route-sensitive fatigue
05
Product forms and supply conditions
06
Applications and selection
Applications and selection
- Orthopedic components
- Valve and dental parts
- Corrosion-wear hardware
Properties and trade-offs
- Start with regulated/product scope.
- Match route to fatigue demand.
- Control carbon and carbide morphology.
07
Fabrication, durability and inspection
Prevent contamination during melting.
Qualify heat treatment by route.
Inspect polished surfaces and internal defects.
08
Procurement checklist
- State exact chemistry and product route.
- Define carbide, grain and heat-treatment acceptance.
- Specify NDT, mechanical tests and biocompatibility documentation when applicable.
09
Standards, sources and review
Standards and designation context
- Applicable ASTM or ISO product scope
- Buyer drawing and service qualification
- Agreed inspection and certification plan