R30021 Cobalt vs. ASTM Grade HN Steel
R30021 cobalt belongs to the cobalt alloys classification, while ASTM grade HN steel belongs to the iron alloys. They have a modest 26% of their average alloy composition in common, which, by itself, doesn't mean much. There are 21 material properties with values for both materials. Properties with values for just one material (13, in this case) are not shown.
For each property being compared, the top bar is R30021 cobalt and the bottom bar is ASTM grade HN steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 220 | |
| 200 |
| Elongation at Break, % | 9.0 | |
| 9.0 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 86 | |
| 77 |
| Tensile Strength: Ultimate (UTS), MPa | 700 | |
| 500 |
Thermal Properties
| Latent Heat of Fusion, J/g | 330 | |
| 310 |
| Melting Completion (Liquidus), °C | 1350 | |
| 1400 |
| Melting Onset (Solidus), °C | 1190 | |
| 1350 |
| Specific Heat Capacity, J/kg-K | 450 | |
| 480 |
| Thermal Conductivity, W/m-K | 15 | |
| 13 |
| Thermal Expansion, µm/m-K | 11 | |
| 16 |
Otherwise Unclassified Properties
| Density, g/cm3 | 8.4 | |
| 7.9 |
| Embodied Carbon, kg CO2/kg material | 8.0 | |
| 4.6 |
| Embodied Energy, MJ/kg | 110 | |
| 66 |
| Embodied Water, L/kg | 520 | |
| 180 |
Common Calculations
| Stiffness to Weight: Axial, points | 15 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 25 |
| Strength to Weight: Axial, points | 23 | |
| 17 |
| Strength to Weight: Bending, points | 21 | |
| 18 |
| Thermal Diffusivity, mm2/s | 3.8 | |
| 3.5 |
| Thermal Shock Resistance, points | 21 | |
| 11 |
Alloy Composition
| Carbon (C), % | 0.2 to 0.35 | |
| 0.2 to 0.5 |
| Chromium (Cr), % | 26 to 29 | |
| 19 to 23 |
| Cobalt (Co), % | 61.7 to 67.3 | |
| 0 |
| Iron (Fe), % | 0 to 3.0 | |
| 44.9 to 57.8 |
| Manganese (Mn), % | 0 | |
| 0 to 2.0 |
| Molybdenum (Mo), % | 4.5 to 6.0 | |
| 0 to 0.5 |
| Nickel (Ni), % | 2.0 to 3.0 | |
| 23 to 27 |
| Phosphorus (P), % | 0 | |
| 0 to 0.040 |
| Silicon (Si), % | 0 to 1.5 | |
| 0 to 2.0 |
| Sulfur (S), % | 0 | |
| 0 to 0.040 |