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UNS R30003 (ASTM F1058 Grade 1) Alloy

R30003 cobalt is a cobalt alloy. ASTM F1058 Grade 1 is the ASTM designation for this material. R30003 is the UNS number. It has a fairly high melting temperature among the cobalt alloys in the database.

The properties of R30003 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 R30003 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

10 to 73 %

Fatigue Strength

320 to 560 MPa 46 to 81 x 103 psi

Poisson's Ratio


Shear Modulus

83 GPa 12 x 106 psi

Tensile Strength: Ultimate (UTS)

970 to 1720 MPa 140 to 250 x 103 psi

Tensile Strength: Yield (Proof)

510 to 1090 MPa 74 to 160 x 103 psi

Thermal Properties

Latent Heat of Fusion

310 J/g

Melting Completion (Liquidus)

1400 °C 2560 °F

Melting Onset (Solidus)

1440 °C 2620 °F

Specific Heat Capacity

450 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

13 W/m-K 7.2 BTU/h-ft-°F

Thermal Expansion

13 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

2.0 % IACS

Electrical Conductivity: Equal Weight (Specific)

2.1 % IACS

Otherwise Unclassified Properties

Base Metal Price

95 % relative


8.4 g/cm3 520 lb/ft3

Embodied Carbon

8.0 kg CO2/kg material

Embodied Energy

110 MJ/kg 45 x 103 BTU/lb

Embodied Water

400 L/kg 48 gal/lb

Common Calculations

Resilience: Unit (Modulus of Resilience)

600 to 2790 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

32 to 57 points

Strength to Weight: Bending

26 to 38 points

Thermal Diffusivity

3.3 mm2/s

Thermal Shock Resistance

26 to 45 points

Alloy Composition

Cobalt (Co)Co 39 to 41
Chromium (Cr)Cr 19 to 21
Iron (Fe)Fe 10 to 20.5
Nickel (Ni)Ni 14 to 16
Molybdenum (Mo)Mo 6.0 to 8.0
Manganese (Mn)Mn 1.5 to 2.5
Silicon (Si)Si 0 to 1.2
Carbon (C)C 0 to 0.15
Boron (B)B 0 to 0.1
Phosphorus (P)P 0 to 0.015
Sulfur (S)S 0 to 0.015

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

ASM Specialty Handbook: Nickel, Cobalt, and Their Alloys, Joseph R. Davis (editor), 2000