R30605 Cobalt vs. S21904 Stainless Steel
R30605 cobalt belongs to the cobalt alloys classification, while S21904 stainless steel belongs to the iron alloys. They have a modest 30% of their average alloy composition in common, which, by itself, doesn't mean much. There are 25 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 R30605 cobalt and the bottom bar is S21904 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 210 | |
| 200 |
| Elongation at Break, % | 34 | |
| 17 to 51 |
| Fatigue Strength, MPa | 260 to 590 | |
| 380 to 550 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 81 | |
| 78 |
| Tensile Strength: Ultimate (UTS), MPa | 1130 to 1900 | |
| 700 to 1000 |
| Tensile Strength: Yield (Proof), MPa | 470 to 1600 | |
| 390 to 910 |
Thermal Properties
| Latent Heat of Fusion, J/g | 290 | |
| 290 |
| Melting Completion (Liquidus), °C | 1410 | |
| 1400 |
| Melting Onset (Solidus), °C | 1330 | |
| 1350 |
| Specific Heat Capacity, J/kg-K | 410 | |
| 480 |
| Thermal Conductivity, W/m-K | 9.6 | |
| 14 |
| Thermal Expansion, µm/m-K | 12 | |
| 17 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.0 | |
| 2.5 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 1.8 | |
| 2.9 |
Otherwise Unclassified Properties
| Density, g/cm3 | 9.6 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 9.8 | |
| 3.0 |
| Embodied Energy, MJ/kg | 140 | |
| 43 |
| Embodied Water, L/kg | 450 | |
| 160 |
Common Calculations
| Stiffness to Weight: Axial, points | 12 | |
| 14 |
| Stiffness to Weight: Bending, points | 21 | |
| 25 |
| Strength to Weight: Axial, points | 33 to 55 | |
| 25 to 36 |
| Strength to Weight: Bending, points | 25 to 36 | |
| 23 to 29 |
| Thermal Diffusivity, mm2/s | 2.5 | |
| 3.8 |
| Thermal Shock Resistance, points | 31 to 52 | |
| 15 to 21 |
Alloy Composition
| Carbon (C), % | 0.050 to 0.15 | |
| 0 to 0.040 |
| Chromium (Cr), % | 19 to 21 | |
| 19 to 21.5 |
| Cobalt (Co), % | 46.4 to 57 | |
| 0 |
| Iron (Fe), % | 0 to 3.0 | |
| 59.5 to 67.4 |
| Manganese (Mn), % | 1.0 to 2.0 | |
| 8.0 to 10 |
| Nickel (Ni), % | 9.0 to 11 | |
| 5.5 to 7.5 |
| Nitrogen (N), % | 0 | |
| 0.15 to 0.4 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.045 |
| Silicon (Si), % | 0 to 0.4 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Tungsten (W), % | 14 to 16 | |
| 0 |