SAE-AISI 8620 Steel vs. R30155 Cobalt
Both SAE-AISI 8620 steel and R30155 cobalt are iron alloys. They have a modest 33% of their average alloy composition in common, which, by itself, doesn't mean much. There are 29 material properties with values for both materials. Properties with values for just one material (5, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI 8620 steel and the bottom bar is R30155 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 150 to 210 | |
| 220 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 210 |
| Elongation at Break, % | 13 to 31 | |
| 34 |
| Fatigue Strength, MPa | 270 to 360 | |
| 310 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 81 |
| Shear Strength, MPa | 340 to 420 | |
| 570 |
| Tensile Strength: Ultimate (UTS), MPa | 520 to 690 | |
| 850 |
| Tensile Strength: Yield (Proof), MPa | 360 to 570 | |
| 390 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 300 |
| Maximum Temperature: Mechanical, °C | 410 | |
| 1100 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1470 |
| Melting Onset (Solidus), °C | 1420 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 450 |
| Thermal Conductivity, W/m-K | 39 | |
| 12 |
| Thermal Expansion, µm/m-K | 13 | |
| 14 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.6 | |
| 80 |
| Density, g/cm3 | 7.8 | |
| 8.5 |
| Embodied Carbon, kg CO2/kg material | 1.5 | |
| 9.7 |
| Embodied Energy, MJ/kg | 20 | |
| 150 |
| Embodied Water, L/kg | 50 | |
| 300 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 86 to 150 | |
| 230 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 340 to 880 | |
| 370 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 23 |
| Strength to Weight: Axial, points | 18 to 24 | |
| 28 |
| Strength to Weight: Bending, points | 18 to 22 | |
| 24 |
| Thermal Diffusivity, mm2/s | 10 | |
| 3.2 |
| Thermal Shock Resistance, points | 15 to 20 | |
| 21 |
Alloy Composition
| Carbon (C), % | 0.18 to 0.23 | |
| 0.080 to 0.16 |
| Chromium (Cr), % | 0.4 to 0.6 | |
| 20 to 22.5 |
| Cobalt (Co), % | 0 | |
| 18.5 to 21 |
| Iron (Fe), % | 96.9 to 98 | |
| 24.3 to 36.2 |
| Manganese (Mn), % | 0.7 to 0.9 | |
| 1.0 to 2.0 |
| Molybdenum (Mo), % | 0.15 to 0.25 | |
| 2.5 to 3.5 |
| Nickel (Ni), % | 0.4 to 0.7 | |
| 19 to 21 |
| Niobium (Nb), % | 0 | |
| 0.75 to 1.3 |
| Nitrogen (N), % | 0 | |
| 0 to 0.2 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 to 0.040 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.030 |
| Tantalum (Ta), % | 0 | |
| 0.75 to 1.3 |
| Tungsten (W), % | 0 | |
| 2.0 to 3.0 |