AWS E318 vs. R31539 Cobalt
AWS E318 belongs to the iron alloys classification, while R31539 cobalt belongs to the cobalt alloys. They have a modest 23% of their average alloy composition in common, which, by itself, doesn't mean much. There are 23 material properties with values for both materials. Properties with values for just one material (8, in this case) are not shown.
For each property being compared, the top bar is AWS E318 and the bottom bar is R31539 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 220 |
| Elongation at Break, % | 29 | |
| 13 to 22 |
| Poisson's Ratio | 0.28 | |
| 0.29 |
| Shear Modulus, GPa | 78 | |
| 86 |
| Tensile Strength: Ultimate (UTS), MPa | 620 | |
| 1000 to 1340 |
Thermal Properties
| Latent Heat of Fusion, J/g | 290 | |
| 320 |
| Melting Completion (Liquidus), °C | 1440 | |
| 1360 |
| Melting Onset (Solidus), °C | 1400 | |
| 1290 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 450 |
| Thermal Conductivity, W/m-K | 15 | |
| 13 |
| Thermal Expansion, µm/m-K | 14 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.2 | |
| 2.0 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.6 | |
| 2.1 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.9 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 4.4 | |
| 8.2 |
| Embodied Energy, MJ/kg | 62 | |
| 110 |
| Embodied Water, L/kg | 160 | |
| 530 |
Common Calculations
| Stiffness to Weight: Axial, points | 14 | |
| 15 |
| Stiffness to Weight: Bending, points | 25 | |
| 24 |
| Strength to Weight: Axial, points | 22 | |
| 33 to 44 |
| Strength to Weight: Bending, points | 20 | |
| 27 to 32 |
| Thermal Diffusivity, mm2/s | 4.0 | |
| 3.5 |
| Thermal Shock Resistance, points | 16 | |
| 24 to 32 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 0.3 to 1.0 |
| Carbon (C), % | 0 to 0.080 | |
| 0 to 0.14 |
| Chromium (Cr), % | 17 to 20 | |
| 26 to 30 |
| Cobalt (Co), % | 0 | |
| 57.7 to 68.7 |
| Copper (Cu), % | 0 to 0.75 | |
| 0 |
| Iron (Fe), % | 57.6 to 69.5 | |
| 0 to 0.75 |
| Lanthanum (La), % | 0 | |
| 0.030 to 0.2 |
| Manganese (Mn), % | 0.5 to 2.5 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 2.0 to 3.0 | |
| 5.0 to 7.0 |
| Nickel (Ni), % | 11 to 14 | |
| 0 to 1.0 |
| Niobium (Nb), % | 0 to 1.0 | |
| 0 |
| Nitrogen (N), % | 0 | |
| 0 to 0.25 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 |
| Silicon (Si), % | 0 to 1.0 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 |