UNS R30008 (ASTM F1058 Grade 2) Cobalt
R30008 cobalt is a cobalt alloy. ASTM F1058 Grade 2 is the ASTM designation for this material. R30008 is the UNS number. It has a moderately high melting temperature among the cobalt alloys in the database.
The properties of R30008 cobalt include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare R30008 cobalt to other cobalt alloys (top) and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
210 GPa 31 x 106 psi
Elongation at Break
1.1 to 73 %
Fatigue Strength
320 to 530 MPa 46 to 77 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
83 GPa 12 x 106 psi
Tensile Strength: Ultimate (UTS)
950 to 1700 MPa 140 to 250 x 103 psi
Tensile Strength: Yield (Proof)
500 to 1080 MPa 73 to 160 x 103 psi
Thermal Properties
Latent Heat of Fusion
320 J/g
Melting Completion (Liquidus)
1400 °C 2550 °F
Melting Onset (Solidus)
1330 °C 2430 °F
Specific Heat Capacity
450 J/kg-K 0.11 BTU/lb-°F
Thermal Expansion
13 µm/m-K
Otherwise Unclassified Properties
Base Metal Price
95 % relative
Density
8.4 g/cm3 530 lb/ft3
Embodied Carbon
8.1 kg CO2/kg material
Embodied Energy
110 MJ/kg 46 x 103 BTU/lb
Embodied Water
400 L/kg 48 gal/lb
Common Calculations
Resilience: Unit (Modulus of Resilience)
590 to 2720 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
31 to 56 points
Strength to Weight: Bending
25 to 37 points
Thermal Shock Resistance
25 to 44 points
Alloy Composition
| Co | 39 to 42 | |
| Cr | 18.5 to 21.5 | |
| Ni | 15 to 18 | |
| Fe | 7.6 to 20 | |
| Mo | 6.5 to 7.5 | |
| Mn | 1.0 to 2.0 | |
| Si | 0 to 1.2 | |
| C | 0 to 0.15 | |
| P | 0 to 0.015 | |
| S | 0 to 0.015 | |
| B | 0 to 0.0010 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM F1058: Standard Specification for Wrought 40Cobalt-20Chromium-16Iron-15Nickel-7Molybdenum Alloy Wire and Strip for Surgical Implant Applications (UNS R30003 and UNS R30008)
ISO 5832-7: Implants for Surgery - Metallic Materials - Part 7: Forgeable and Cold-Formed Cobalt-Chromium-Nickel-Molybdenum-Iron Alloy