R30155 Cobalt vs. ASTM A356 Grade 8
Both R30155 cobalt and ASTM A356 grade 8 are iron alloys. They have a modest 34% of their average alloy composition in common, which, by itself, doesn't mean much. There are 30 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 R30155 cobalt and the bottom bar is ASTM A356 grade 8.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 220 | |
| 190 |
| Elastic (Young's, Tensile) Modulus, GPa | 210 | |
| 190 |
| Elongation at Break, % | 34 | |
| 21 |
| Fatigue Strength, MPa | 310 | |
| 270 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Reduction in Area, % | 34 | |
| 50 |
| Shear Modulus, GPa | 81 | |
| 73 |
| Tensile Strength: Ultimate (UTS), MPa | 850 | |
| 630 |
| Tensile Strength: Yield (Proof), MPa | 390 | |
| 390 |
Thermal Properties
| Latent Heat of Fusion, J/g | 300 | |
| 260 |
| Maximum Temperature: Mechanical, °C | 1100 | |
| 440 |
| Melting Completion (Liquidus), °C | 1470 | |
| 1470 |
| Melting Onset (Solidus), °C | 1420 | |
| 1430 |
| Specific Heat Capacity, J/kg-K | 450 | |
| 470 |
| Thermal Conductivity, W/m-K | 12 | |
| 38 |
| Thermal Expansion, µm/m-K | 14 | |
| 13 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 80 | |
| 3.5 |
| Density, g/cm3 | 8.5 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 9.7 | |
| 2.0 |
| Embodied Energy, MJ/kg | 150 | |
| 26 |
| Embodied Water, L/kg | 300 | |
| 55 |
Common Calculations
| PREN (Pitting Resistance) | 37 | |
| 4.7 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 230 | |
| 110 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 370 | |
| 390 |
| Stiffness to Weight: Axial, points | 14 | |
| 13 |
| Stiffness to Weight: Bending, points | 23 | |
| 24 |
| Strength to Weight: Axial, points | 28 | |
| 22 |
| Strength to Weight: Bending, points | 24 | |
| 21 |
| Thermal Diffusivity, mm2/s | 3.2 | |
| 10 |
| Thermal Shock Resistance, points | 21 | |
| 18 |
Alloy Composition
| Carbon (C), % | 0.080 to 0.16 | |
| 0 to 0.2 |
| Chromium (Cr), % | 20 to 22.5 | |
| 1.0 to 1.5 |
| Cobalt (Co), % | 18.5 to 21 | |
| 0 |
| Iron (Fe), % | 24.3 to 36.2 | |
| 95.4 to 97.4 |
| Manganese (Mn), % | 1.0 to 2.0 | |
| 0.5 to 0.9 |
| Molybdenum (Mo), % | 2.5 to 3.5 | |
| 0.9 to 1.2 |
| Nickel (Ni), % | 19 to 21 | |
| 0 |
| Niobium (Nb), % | 0.75 to 1.3 | |
| 0 |
| Nitrogen (N), % | 0 to 0.2 | |
| 0 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.035 |
| Silicon (Si), % | 0 to 1.0 | |
| 0.2 to 0.6 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Tantalum (Ta), % | 0.75 to 1.3 | |
| 0 |
| Tungsten (W), % | 2.0 to 3.0 | |
| 0 |
| Vanadium (V), % | 0 | |
| 0.050 to 0.15 |