R30008 Cobalt vs. SAE-AISI A8 Steel
R30008 cobalt belongs to the cobalt alloys classification, while SAE-AISI A8 steel belongs to the iron alloys. They have a modest 21% of their average alloy composition in common, which, by itself, doesn't mean much. There are 19 material properties with values for both materials. Properties with values for just one material (9, in this case) are not shown.
For each property being compared, the top bar is R30008 cobalt and the bottom bar is SAE-AISI A8 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 210 | |
| 190 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 83 | |
| 74 |
| Tensile Strength: Ultimate (UTS), MPa | 950 to 1700 | |
| 700 to 1920 |
Thermal Properties
| Latent Heat of Fusion, J/g | 320 | |
| 270 |
| Melting Completion (Liquidus), °C | 1400 | |
| 1480 |
| Melting Onset (Solidus), °C | 1330 | |
| 1430 |
| Specific Heat Capacity, J/kg-K | 450 | |
| 470 |
| Thermal Expansion, µm/m-K | 13 | |
| 12 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 95 | |
| 8.5 |
| Density, g/cm3 | 8.4 | |
| 7.9 |
| Embodied Carbon, kg CO2/kg material | 8.1 | |
| 2.3 |
| Embodied Energy, MJ/kg | 110 | |
| 31 |
| Embodied Water, L/kg | 400 | |
| 73 |
Common Calculations
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 31 to 56 | |
| 25 to 68 |
| Strength to Weight: Bending, points | 25 to 37 | |
| 22 to 44 |
| Thermal Shock Resistance, points | 25 to 44 | |
| 22 to 62 |
Alloy Composition
| Boron (B), % | 0 to 0.0010 | |
| 0 |
| Carbon (C), % | 0 to 0.15 | |
| 0.5 to 0.6 |
| Chromium (Cr), % | 18.5 to 21.5 | |
| 4.8 to 5.5 |
| Cobalt (Co), % | 39 to 42 | |
| 0 |
| Copper (Cu), % | 0 | |
| 0 to 0.25 |
| Iron (Fe), % | 7.6 to 20 | |
| 88.5 to 91.9 |
| Manganese (Mn), % | 1.0 to 2.0 | |
| 0 to 0.5 |
| Molybdenum (Mo), % | 6.5 to 7.5 | |
| 1.2 to 1.7 |
| Nickel (Ni), % | 15 to 18 | |
| 0 to 0.3 |
| Phosphorus (P), % | 0 to 0.015 | |
| 0 to 0.030 |
| Silicon (Si), % | 0 to 1.2 | |
| 0.75 to 1.1 |
| Sulfur (S), % | 0 to 0.015 | |
| 0 to 0.030 |
| Tungsten (W), % | 0 | |
| 1.0 to 1.5 |