R31539 Cobalt vs. R31538 Cobalt
Both R31539 cobalt and R31538 cobalt are cobalt alloys. Their average alloy composition is basically identical.
For each property being compared, the top bar is R31539 cobalt and the bottom bar is R31538 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 220 | |
| 220 |
| Elongation at Break, % | 13 to 22 | |
| 13 to 23 |
| Fatigue Strength, MPa | 310 to 480 | |
| 310 to 480 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Reduction in Area, % | 13 to 23 | |
| 13 to 22 |
| Rockwell C Hardness | 25 to 35 | |
| 25 to 35 |
| Shear Modulus, GPa | 86 | |
| 86 |
| Tensile Strength: Ultimate (UTS), MPa | 1000 to 1340 | |
| 1020 to 1360 |
| Tensile Strength: Yield (Proof), MPa | 590 to 940 | |
| 580 to 930 |
Thermal Properties
| Latent Heat of Fusion, J/g | 320 | |
| 320 |
| Melting Completion (Liquidus), °C | 1360 | |
| 1360 |
| Melting Onset (Solidus), °C | 1290 | |
| 1290 |
| Specific Heat Capacity, J/kg-K | 450 | |
| 450 |
| Thermal Conductivity, W/m-K | 13 | |
| 13 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.0 | |
| 2.0 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.1 | |
| 2.1 |
Otherwise Unclassified Properties
| Density, g/cm3 | 8.4 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 8.2 | |
| 8.1 |
| Embodied Energy, MJ/kg | 110 | |
| 110 |
| Embodied Water, L/kg | 530 | |
| 530 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 140 to 190 | |
| 140 to 200 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 780 to 2000 | |
| 750 to 1920 |
| Stiffness to Weight: Axial, points | 15 | |
| 15 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 33 to 44 | |
| 34 to 45 |
| Strength to Weight: Bending, points | 27 to 32 | |
| 27 to 32 |
| Thermal Diffusivity, mm2/s | 3.5 | |
| 3.5 |
| Thermal Shock Resistance, points | 24 to 32 | |
| 25 to 33 |
Alloy Composition
| Aluminum (Al), % | 0.3 to 1.0 | |
| 0 |
| Carbon (C), % | 0 to 0.14 | |
| 0.15 to 0.35 |
| Chromium (Cr), % | 26 to 30 | |
| 26 to 30 |
| Cobalt (Co), % | 57.7 to 68.7 | |
| 58.7 to 68.9 |
| Iron (Fe), % | 0 to 0.75 | |
| 0 to 0.75 |
| Lanthanum (La), % | 0.030 to 0.2 | |
| 0 |
| Manganese (Mn), % | 0 to 1.0 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 5.0 to 7.0 | |
| 5.0 to 7.0 |
| Nickel (Ni), % | 0 to 1.0 | |
| 0 to 1.0 |
| Nitrogen (N), % | 0 to 0.25 | |
| 0 to 0.25 |
| Silicon (Si), % | 0 to 1.0 | |
| 0 to 1.0 |