SAE-AISI A7 Steel vs. R30155 Cobalt
Both SAE-AISI A7 steel and R30155 cobalt are iron alloys. They have a modest 39% of their average alloy composition in common, which, by itself, doesn't mean much. There are 22 material properties with values for both materials. Properties with values for just one material (10, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI A7 steel and the bottom bar is R30155 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 210 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 72 | |
| 81 |
| Tensile Strength: Ultimate (UTS), MPa | 800 to 2150 | |
| 850 |
Thermal Properties
| Latent Heat of Fusion, J/g | 260 | |
| 300 |
| Melting Completion (Liquidus), °C | 1470 | |
| 1470 |
| Melting Onset (Solidus), °C | 1430 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 450 |
| Thermal Conductivity, W/m-K | 37 | |
| 12 |
| Thermal Expansion, µm/m-K | 12 | |
| 14 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 10 | |
| 80 |
| Density, g/cm3 | 7.7 | |
| 8.5 |
| Embodied Carbon, kg CO2/kg material | 13 | |
| 9.7 |
| Embodied Energy, MJ/kg | 200 | |
| 150 |
| Embodied Water, L/kg | 100 | |
| 300 |
Common Calculations
| PREN (Pitting Resistance) | 11 | |
| 37 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 23 |
| Strength to Weight: Axial, points | 29 to 77 | |
| 28 |
| Strength to Weight: Bending, points | 25 to 48 | |
| 24 |
| Thermal Diffusivity, mm2/s | 10 | |
| 3.2 |
| Thermal Shock Resistance, points | 27 to 72 | |
| 21 |
Alloy Composition
| Carbon (C), % | 2.0 to 2.9 | |
| 0.080 to 0.16 |
| Chromium (Cr), % | 5.0 to 5.8 | |
| 20 to 22.5 |
| Cobalt (Co), % | 0 | |
| 18.5 to 21 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 |
| Iron (Fe), % | 81.4 to 87.7 | |
| 24.3 to 36.2 |
| Manganese (Mn), % | 0 to 0.8 | |
| 1.0 to 2.0 |
| Molybdenum (Mo), % | 0.9 to 1.4 | |
| 2.5 to 3.5 |
| Nickel (Ni), % | 0 to 0.3 | |
| 19 to 21 |
| Niobium (Nb), % | 0 | |
| 0.75 to 1.3 |
| Nitrogen (N), % | 0 | |
| 0 to 0.2 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.040 |
| Silicon (Si), % | 0 to 0.5 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Tantalum (Ta), % | 0 | |
| 0.75 to 1.3 |
| Tungsten (W), % | 0.5 to 1.5 | |
| 2.0 to 3.0 |
| Vanadium (V), % | 3.9 to 5.2 | |
| 0 |