SAE-AISI 8645 Steel vs. R30155 Cobalt
Both SAE-AISI 8645 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 8645 steel and the bottom bar is R30155 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 180 to 200 | |
| 220 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 210 |
| Elongation at Break, % | 12 to 23 | |
| 34 |
| Fatigue Strength, MPa | 280 to 350 | |
| 310 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 81 |
| Shear Strength, MPa | 380 to 400 | |
| 570 |
| Tensile Strength: Ultimate (UTS), MPa | 600 to 670 | |
| 850 |
| Tensile Strength: Yield (Proof), MPa | 390 to 560 | |
| 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 | 77 to 120 | |
| 230 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 420 to 840 | |
| 370 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 23 |
| Strength to Weight: Axial, points | 21 to 24 | |
| 28 |
| Strength to Weight: Bending, points | 20 to 22 | |
| 24 |
| Thermal Diffusivity, mm2/s | 10 | |
| 3.2 |
| Thermal Shock Resistance, points | 18 to 20 | |
| 21 |
Alloy Composition
| Carbon (C), % | 0.43 to 0.48 | |
| 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), % | 96.5 to 97.7 | |
| 24.3 to 36.2 |
| Manganese (Mn), % | 0.75 to 1.0 | |
| 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 |