R31538 Cobalt vs. R31539 Cobalt
Both R31538 cobalt and R31539 cobalt are cobalt alloys. Their average alloy composition is basically identical.
For each property being compared, the top bar is R31538 cobalt and the bottom bar is R31539 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 220 | |
| 220 |
| Elongation at Break, % | 13 to 23 | |
| 13 to 22 |
| Fatigue Strength, MPa | 310 to 480 | |
| 310 to 480 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Reduction in Area, % | 13 to 22 | |
| 13 to 23 |
| Rockwell C Hardness | 25 to 35 | |
| 25 to 35 |
| Shear Modulus, GPa | 86 | |
| 86 |
| Tensile Strength: Ultimate (UTS), MPa | 1020 to 1360 | |
| 1000 to 1340 |
| Tensile Strength: Yield (Proof), MPa | 580 to 930 | |
| 590 to 940 |
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 | 8.1 | |
| 8.2 |
| Embodied Energy, MJ/kg | 110 | |
| 110 |
| Embodied Water, L/kg | 530 | |
| 530 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 140 to 200 | |
| 140 to 190 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 750 to 1920 | |
| 780 to 2000 |
| Stiffness to Weight: Axial, points | 15 | |
| 15 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 34 to 45 | |
| 33 to 44 |
| Strength to Weight: Bending, points | 27 to 32 | |
| 27 to 32 |
| Thermal Diffusivity, mm2/s | 3.5 | |
| 3.5 |
| Thermal Shock Resistance, points | 25 to 33 | |
| 24 to 32 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 0.3 to 1.0 |
| Carbon (C), % | 0.15 to 0.35 | |
| 0 to 0.14 |
| Chromium (Cr), % | 26 to 30 | |
| 26 to 30 |
| Cobalt (Co), % | 58.7 to 68.9 | |
| 57.7 to 68.7 |
| Iron (Fe), % | 0 to 0.75 | |
| 0 to 0.75 |
| Lanthanum (La), % | 0 | |
| 0.030 to 0.2 |
| 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 |