R30075 Cobalt vs. S21904 Stainless Steel
R30075 cobalt belongs to the cobalt alloys classification, while S21904 stainless steel belongs to the iron alloys. They have a modest 22% of their average alloy composition in common, which, by itself, doesn't mean much. There are 27 material properties with values for both materials. Properties with values for just one material (7, in this case) are not shown.
For each property being compared, the top bar is R30075 cobalt and the bottom bar is S21904 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 210 to 250 | |
| 200 |
| Elongation at Break, % | 12 | |
| 17 to 51 |
| Fatigue Strength, MPa | 250 to 840 | |
| 380 to 550 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 82 to 98 | |
| 78 |
| Tensile Strength: Ultimate (UTS), MPa | 780 to 1280 | |
| 700 to 1000 |
| Tensile Strength: Yield (Proof), MPa | 480 to 840 | |
| 390 to 910 |
Thermal Properties
| Latent Heat of Fusion, J/g | 320 | |
| 290 |
| Melting Completion (Liquidus), °C | 1360 | |
| 1400 |
| Melting Onset (Solidus), °C | 1290 | |
| 1350 |
| Specific Heat Capacity, J/kg-K | 450 | |
| 480 |
| Thermal Conductivity, W/m-K | 13 | |
| 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 | 2.1 | |
| 2.9 |
Otherwise Unclassified Properties
| Density, g/cm3 | 8.4 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 8.1 | |
| 3.0 |
| Embodied Energy, MJ/kg | 110 | |
| 43 |
| Embodied Water, L/kg | 530 | |
| 160 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 84 to 140 | |
| 160 to 310 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 560 to 1410 | |
| 380 to 2070 |
| Stiffness to Weight: Axial, points | 14 to 17 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 to 25 | |
| 25 |
| Strength to Weight: Axial, points | 26 to 42 | |
| 25 to 36 |
| Strength to Weight: Bending, points | 22 to 31 | |
| 23 to 29 |
| Thermal Diffusivity, mm2/s | 3.5 | |
| 3.8 |
| Thermal Shock Resistance, points | 21 to 29 | |
| 15 to 21 |
Alloy Composition
| Aluminum (Al), % | 0 to 0.1 | |
| 0 |
| Boron (B), % | 0 to 0.010 | |
| 0 |
| Carbon (C), % | 0 to 0.35 | |
| 0 to 0.040 |
| Chromium (Cr), % | 27 to 30 | |
| 19 to 21.5 |
| Cobalt (Co), % | 58.7 to 68 | |
| 0 |
| Iron (Fe), % | 0 to 0.75 | |
| 59.5 to 67.4 |
| Manganese (Mn), % | 0 to 1.0 | |
| 8.0 to 10 |
| Molybdenum (Mo), % | 5.0 to 7.0 | |
| 0 |
| Nickel (Ni), % | 0 to 0.5 | |
| 5.5 to 7.5 |
| Nitrogen (N), % | 0 to 0.25 | |
| 0.15 to 0.4 |
| Phosphorus (P), % | 0 to 0.020 | |
| 0 to 0.045 |
| Silicon (Si), % | 0 to 1.0 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.010 | |
| 0 to 0.030 |
| Titanium (Ti), % | 0 to 0.1 | |
| 0 |
| Tungsten (W), % | 0 to 0.2 | |
| 0 |