R30008 Cobalt vs. AISI 440A Stainless Steel
R30008 cobalt belongs to the cobalt alloys classification, while AISI 440A stainless steel belongs to the iron alloys. They have a modest 32% of their average alloy composition in common, which, by itself, doesn't mean much. There are 22 material properties with values for both materials. Properties with values for just one material (10, in this case) are not shown.
For each property being compared, the top bar is R30008 cobalt and the bottom bar is AISI 440A stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 210 | |
| 200 |
| Elongation at Break, % | 1.1 to 73 | |
| 5.0 to 20 |
| Fatigue Strength, MPa | 320 to 530 | |
| 270 to 790 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 83 | |
| 77 |
| Tensile Strength: Ultimate (UTS), MPa | 950 to 1700 | |
| 730 to 1790 |
| Tensile Strength: Yield (Proof), MPa | 500 to 1080 | |
| 420 to 1650 |
Thermal Properties
| Latent Heat of Fusion, J/g | 320 | |
| 280 |
| Melting Completion (Liquidus), °C | 1400 | |
| 1480 |
| Melting Onset (Solidus), °C | 1330 | |
| 1370 |
| Specific Heat Capacity, J/kg-K | 450 | |
| 480 |
| Thermal Expansion, µm/m-K | 13 | |
| 10 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 95 | |
| 9.0 |
| Density, g/cm3 | 8.4 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 8.1 | |
| 2.2 |
| Embodied Energy, MJ/kg | 110 | |
| 31 |
| Embodied Water, L/kg | 400 | |
| 120 |
Common Calculations
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 25 |
| Strength to Weight: Axial, points | 31 to 56 | |
| 26 to 65 |
| Strength to Weight: Bending, points | 25 to 37 | |
| 23 to 43 |
| Thermal Shock Resistance, points | 25 to 44 | |
| 26 to 65 |
Alloy Composition
| Boron (B), % | 0 to 0.0010 | |
| 0 |
| Carbon (C), % | 0 to 0.15 | |
| 0.6 to 0.75 |
| Chromium (Cr), % | 18.5 to 21.5 | |
| 16 to 18 |
| Cobalt (Co), % | 39 to 42 | |
| 0 |
| Iron (Fe), % | 7.6 to 20 | |
| 78.4 to 83.4 |
| Manganese (Mn), % | 1.0 to 2.0 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 6.5 to 7.5 | |
| 0 to 0.75 |
| Nickel (Ni), % | 15 to 18 | |
| 0 |
| Phosphorus (P), % | 0 to 0.015 | |
| 0 to 0.040 |
| Silicon (Si), % | 0 to 1.2 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.015 | |
| 0 to 0.015 |