S17400 Stainless Steel vs. R30021 Cobalt
S17400 stainless steel belongs to the iron alloys classification, while R30021 cobalt belongs to the cobalt alloys. They have a modest 21% 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 (9, in this case) are not shown.
For each property being compared, the top bar is S17400 stainless steel and the bottom bar is R30021 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 220 |
| Elongation at Break, % | 11 to 21 | |
| 9.0 |
| Fatigue Strength, MPa | 380 to 670 | |
| 250 |
| Poisson's Ratio | 0.28 | |
| 0.29 |
| Rockwell C Hardness | 27 to 43 | |
| 32 |
| Shear Modulus, GPa | 75 | |
| 86 |
| Tensile Strength: Ultimate (UTS), MPa | 910 to 1390 | |
| 700 |
| Tensile Strength: Yield (Proof), MPa | 580 to 1250 | |
| 500 |
Thermal Properties
| Latent Heat of Fusion, J/g | 280 | |
| 330 |
| Melting Completion (Liquidus), °C | 1440 | |
| 1350 |
| Melting Onset (Solidus), °C | 1400 | |
| 1190 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 450 |
| Thermal Conductivity, W/m-K | 17 | |
| 15 |
| Thermal Expansion, µm/m-K | 11 | |
| 11 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.3 | |
| 1.9 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.6 | |
| 2.1 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.8 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 2.7 | |
| 8.0 |
| Embodied Energy, MJ/kg | 39 | |
| 110 |
| Embodied Water, L/kg | 130 | |
| 520 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 140 to 160 | |
| 57 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 880 to 4060 | |
| 570 |
| Stiffness to Weight: Axial, points | 14 | |
| 15 |
| Stiffness to Weight: Bending, points | 25 | |
| 24 |
| Strength to Weight: Axial, points | 32 to 49 | |
| 23 |
| Strength to Weight: Bending, points | 27 to 35 | |
| 21 |
| Thermal Diffusivity, mm2/s | 4.5 | |
| 3.8 |
| Thermal Shock Resistance, points | 30 to 46 | |
| 21 |
Alloy Composition
| Carbon (C), % | 0 to 0.070 | |
| 0.2 to 0.35 |
| Chromium (Cr), % | 15 to 17 | |
| 26 to 29 |
| Cobalt (Co), % | 0 | |
| 61.7 to 67.3 |
| Copper (Cu), % | 3.0 to 5.0 | |
| 0 |
| Iron (Fe), % | 70.4 to 78.9 | |
| 0 to 3.0 |
| Manganese (Mn), % | 0 to 1.0 | |
| 0 |
| Molybdenum (Mo), % | 0 | |
| 4.5 to 6.0 |
| Nickel (Ni), % | 3.0 to 5.0 | |
| 2.0 to 3.0 |
| Niobium (Nb), % | 0.15 to 0.45 | |
| 0 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 |
| Silicon (Si), % | 0 to 1.0 | |
| 0 to 1.5 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 |