UNS R30021 Co-Cr-W Alloy
R30021 cobalt is a cobalt alloy. Cited properties are appropriate for the annealed condition. It has a moderately high thermal conductivity among cobalt alloys. In addition, it has a very low melting temperature and a fairly low tensile strength.
The graph bars on the material properties cards below compare R30021 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
Compressive (Crushing) Strength
1300 MPa 190 x 103 psi
Elastic (Young's, Tensile) Modulus
220 GPa 32 x 106 psi
Elongation at Break
9.0 %
Fatigue Strength
250 MPa 37 x 103 psi
Poisson's Ratio
0.29
Rockwell C Hardness
32
Shear Modulus
86 GPa 12 x 106 psi
Tensile Strength: Ultimate (UTS)
700 MPa 100 x 103 psi
Tensile Strength: Yield (Proof)
500 MPa 73 x 103 psi
Thermal Properties
Latent Heat of Fusion
330 J/g
Melting Completion (Liquidus)
1350 °C 2470 °F
Melting Onset (Solidus)
1190 °C 2170 °F
Specific Heat Capacity
450 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
15 W/m-K 8.4 BTU/h-ft-°F
Thermal Expansion
11 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
1.9 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.1 % IACS
Otherwise Unclassified Properties
Density
8.4 g/cm3 530 lb/ft3
Embodied Carbon
8.0 kg CO2/kg material
Embodied Energy
110 MJ/kg 46 x 103 BTU/lb
Embodied Water
520 L/kg 62 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
57 MJ/m3
Resilience: Unit (Modulus of Resilience)
570 kJ/m3
Stiffness to Weight: Axial
15 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
23 points
Strength to Weight: Bending
21 points
Thermal Diffusivity
3.8 mm2/s
Thermal Shock Resistance
21 points
Alloy Composition
| Co | 61.7 to 67.3 | |
| Cr | 26 to 29 | |
| Mo | 4.5 to 6.0 | |
| Ni | 2.0 to 3.0 | |
| Fe | 0 to 3.0 | |
| Si | 0 to 1.5 | |
| C | 0.2 to 0.35 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015