SAE-AISI H21 Steel vs. G-CoCr28 Cobalt
SAE-AISI H21 steel belongs to the iron alloys classification, while G-CoCr28 cobalt belongs to the cobalt alloys. They have a modest 21% 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 (7, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI H21 steel and the bottom bar is G-CoCr28 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 210 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 76 | |
| 83 |
| Tensile Strength: Ultimate (UTS), MPa | 720 to 1790 | |
| 560 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 320 |
| Melting Completion (Liquidus), °C | 1630 | |
| 1330 |
| Melting Onset (Solidus), °C | 1580 | |
| 1270 |
| Specific Heat Capacity, J/kg-K | 440 | |
| 470 |
| Thermal Conductivity, W/m-K | 27 | |
| 8.5 |
| Thermal Expansion, µm/m-K | 11 | |
| 14 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 23 | |
| 100 |
| Density, g/cm3 | 8.5 | |
| 8.1 |
| Embodied Carbon, kg CO2/kg material | 4.5 | |
| 6.2 |
| Embodied Energy, MJ/kg | 68 | |
| 84 |
| Embodied Water, L/kg | 72 | |
| 440 |
Common Calculations
| Stiffness to Weight: Axial, points | 13 | |
| 15 |
| Stiffness to Weight: Bending, points | 23 | |
| 24 |
| Strength to Weight: Axial, points | 23 to 58 | |
| 19 |
| Strength to Weight: Bending, points | 21 to 38 | |
| 19 |
| Thermal Diffusivity, mm2/s | 7.1 | |
| 2.2 |
| Thermal Shock Resistance, points | 24 to 59 | |
| 14 |
Alloy Composition
| Carbon (C), % | 0.28 to 0.36 | |
| 0.050 to 0.25 |
| Chromium (Cr), % | 3.0 to 3.8 | |
| 27 to 30 |
| Cobalt (Co), % | 0 | |
| 48 to 52 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 |
| Iron (Fe), % | 87.6 to 93.8 | |
| 9.7 to 24.5 |
| Manganese (Mn), % | 0.15 to 0.4 | |
| 0 to 1.5 |
| Molybdenum (Mo), % | 0 | |
| 0 to 0.5 |
| Nickel (Ni), % | 0 to 0.3 | |
| 0 to 4.0 |
| Niobium (Nb), % | 0 | |
| 0 to 0.5 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.040 |
| Silicon (Si), % | 0.15 to 0.5 | |
| 0.5 to 1.5 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Tungsten (W), % | 8.5 to 10 | |
| 0 |
| Vanadium (V), % | 0.3 to 0.6 | |
| 0 |