Designation
- Grade
- Co-28Cr-6Mo (F75)
- UNS
- R30075
- Standard
- ASTM F75
- Family
- Cobalt-based alloys
- Density
- ≈ 8.30 g/cm³
- Usual delivery condition
- As agreed per specification
Chemical composition
| Element | Mass fraction, % |
|---|---|
| Cr | 27.0–30.0 |
| Mo | 5.0–7.0 |
| Ni | ≤ 0.50 |
| Fe | ≤ 0.75 |
| C | ≤ 0.35 |
| Si | ≤ 1.00 |
| Mn | ≤ 1.00 |
| Co | bal. |
Main elements only. Phosphorus, sulphur and residual-element limits are specified in the standard and are not reproduced here.
Mechanical properties
| Condition | Tensile strength Rm, min. (MPa) | Yield strength Rp0.2, min. (MPa) | Elongation, min. (%) |
|---|---|---|---|
| As cast | 655 | 450 | 8 |
Minimum values (or ranges) for separately cast test bars as specified in ASTM F75.
Characteristics
- Corrosion and oxidation behaviour
- Good general corrosion resistance
- Weldability
- Limited; crack-sensitive, welding only by agreement
- Machinability
- Difficult; rigid set-ups, low cutting speeds or grinding
- Typical applications
- Medical Wear parts Turbine components General engineering
International cross-reference
| System | Designation | Relationship |
|---|---|---|
| ISO | ISO 5832-4 (Co-Cr-Mo casting alloy) | Similar composition |
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.