G-CoCr28 Cobalt vs. SAE-AISI 4340 Steel
G-CoCr28 cobalt belongs to the cobalt alloys classification, while SAE-AISI 4340 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 27 material properties with values for both materials. Properties with values for just one material (4, in this case) are not shown.
For each property being compared, the top bar is G-CoCr28 cobalt and the bottom bar is SAE-AISI 4340 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 210 | |
| 190 |
| Elongation at Break, % | 6.7 | |
| 12 to 22 |
| Fatigue Strength, MPa | 130 | |
| 330 to 740 |
| Poisson's Ratio | 0.28 | |
| 0.29 |
| Shear Modulus, GPa | 83 | |
| 73 |
| Tensile Strength: Ultimate (UTS), MPa | 560 | |
| 690 to 1280 |
| Tensile Strength: Yield (Proof), MPa | 260 | |
| 470 to 1150 |
Thermal Properties
| Latent Heat of Fusion, J/g | 320 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 1200 | |
| 430 |
| Melting Completion (Liquidus), °C | 1330 | |
| 1460 |
| Melting Onset (Solidus), °C | 1270 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 8.5 | |
| 44 |
| Thermal Expansion, µm/m-K | 14 | |
| 13 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 100 | |
| 3.5 |
| Density, g/cm3 | 8.1 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 6.2 | |
| 1.7 |
| Embodied Energy, MJ/kg | 84 | |
| 22 |
| Embodied Water, L/kg | 440 | |
| 53 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 31 | |
| 79 to 170 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 160 | |
| 590 to 3490 |
| Stiffness to Weight: Axial, points | 15 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 19 | |
| 24 to 45 |
| Strength to Weight: Bending, points | 19 | |
| 22 to 33 |
| Thermal Diffusivity, mm2/s | 2.2 | |
| 12 |
| Thermal Shock Resistance, points | 14 | |
| 20 to 38 |
Alloy Composition
| Carbon (C), % | 0.050 to 0.25 | |
| 0.38 to 0.43 |
| Chromium (Cr), % | 27 to 30 | |
| 0.7 to 0.9 |
| Cobalt (Co), % | 48 to 52 | |
| 0 |
| Iron (Fe), % | 9.7 to 24.5 | |
| 95.1 to 96.3 |
| Manganese (Mn), % | 0 to 1.5 | |
| 0.6 to 0.8 |
| Molybdenum (Mo), % | 0 to 0.5 | |
| 0.2 to 0.3 |
| Nickel (Ni), % | 0 to 4.0 | |
| 1.7 to 2.0 |
| Niobium (Nb), % | 0 to 0.5 | |
| 0 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.035 |
| Silicon (Si), % | 0.5 to 1.5 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.040 |