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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 m2/s

Thermal Shock Resistance

21 points

Alloy Composition

Cobalt (Co) 61.7 to 67.3
Chromium (Cr) 26 to 29
Molybdenum (Mo) 4.5 to 6.0
Nickel (Ni) 2.0 to 3.0
Iron (Fe) 0 to 3.0
Silicon (Si) 0 to 1.5
Carbon (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