S21900 Stainless Steel vs. R30075 Cobalt
S21900 stainless steel belongs to the iron alloys classification, while R30075 cobalt belongs to the cobalt alloys. They have a modest 22% of their average alloy composition in common, which, by itself, doesn't mean much. There are 28 material properties with values for both materials. Properties with values for just one material (6, in this case) are not shown.
For each property being compared, the top bar is S21900 stainless steel and the bottom bar is R30075 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 210 to 250 |
| Elongation at Break, % | 50 | |
| 12 |
| Fatigue Strength, MPa | 380 | |
| 250 to 840 |
| Poisson's Ratio | 0.28 | |
| 0.29 |
| Reduction in Area, % | 57 | |
| 20 |
| Shear Modulus, GPa | 78 | |
| 82 to 98 |
| Tensile Strength: Ultimate (UTS), MPa | 710 | |
| 780 to 1280 |
| Tensile Strength: Yield (Proof), MPa | 390 | |
| 480 to 840 |
Thermal Properties
| Latent Heat of Fusion, J/g | 290 | |
| 320 |
| Melting Completion (Liquidus), °C | 1400 | |
| 1360 |
| Melting Onset (Solidus), °C | 1350 | |
| 1290 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 450 |
| Thermal Conductivity, W/m-K | 14 | |
| 13 |
| Thermal Expansion, µm/m-K | 17 | |
| 12 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.5 | |
| 2.0 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.9 | |
| 2.1 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.7 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 3.0 | |
| 8.1 |
| Embodied Energy, MJ/kg | 43 | |
| 110 |
| Embodied Water, L/kg | 160 | |
| 530 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 300 | |
| 84 to 140 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 380 | |
| 560 to 1410 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 to 17 |
| Stiffness to Weight: Bending, points | 25 | |
| 24 to 25 |
| Strength to Weight: Axial, points | 26 | |
| 26 to 42 |
| Strength to Weight: Bending, points | 23 | |
| 22 to 31 |
| Thermal Diffusivity, mm2/s | 3.8 | |
| 3.5 |
| Thermal Shock Resistance, points | 15 | |
| 21 to 29 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 0 to 0.1 |
| Boron (B), % | 0 | |
| 0 to 0.010 |
| Carbon (C), % | 0 to 0.080 | |
| 0 to 0.35 |
| Chromium (Cr), % | 19 to 21.5 | |
| 27 to 30 |
| Cobalt (Co), % | 0 | |
| 58.7 to 68 |
| Iron (Fe), % | 59.4 to 67.4 | |
| 0 to 0.75 |
| Manganese (Mn), % | 8.0 to 10 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 0 | |
| 5.0 to 7.0 |
| Nickel (Ni), % | 5.5 to 7.5 | |
| 0 to 0.5 |
| Nitrogen (N), % | 0.15 to 0.4 | |
| 0 to 0.25 |
| Phosphorus (P), % | 0 to 0.045 | |
| 0 to 0.020 |
| Silicon (Si), % | 0 to 1.0 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.010 |
| Titanium (Ti), % | 0 | |
| 0 to 0.1 |
| Tungsten (W), % | 0 | |
| 0 to 0.2 |