AISI 309 Stainless Steel vs. R31538 Cobalt
AISI 309 stainless steel belongs to the iron alloys classification, while R31538 cobalt belongs to the cobalt alloys. They have a modest 25% 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 (9, in this case) are not shown.
For each property being compared, the top bar is AISI 309 stainless steel and the bottom bar is R31538 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 220 |
| Elongation at Break, % | 34 to 47 | |
| 13 to 23 |
| Fatigue Strength, MPa | 250 to 280 | |
| 310 to 480 |
| Poisson's Ratio | 0.27 | |
| 0.29 |
| Shear Modulus, GPa | 78 | |
| 86 |
| Tensile Strength: Ultimate (UTS), MPa | 600 to 710 | |
| 1020 to 1360 |
| Tensile Strength: Yield (Proof), MPa | 260 to 350 | |
| 580 to 930 |
Thermal Properties
| Latent Heat of Fusion, J/g | 290 | |
| 320 |
| Melting Completion (Liquidus), °C | 1450 | |
| 1360 |
| Melting Onset (Solidus), °C | 1400 | |
| 1290 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 450 |
| Thermal Conductivity, W/m-K | 16 | |
| 13 |
| Thermal Expansion, µm/m-K | 15 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.2 | |
| 2.0 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.5 | |
| 2.1 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.8 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 3.6 | |
| 8.1 |
| Embodied Energy, MJ/kg | 51 | |
| 110 |
| Embodied Water, L/kg | 170 | |
| 530 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 200 to 230 | |
| 140 to 200 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 170 to 310 | |
| 750 to 1920 |
| Stiffness to Weight: Axial, points | 14 | |
| 15 |
| Stiffness to Weight: Bending, points | 25 | |
| 24 |
| Strength to Weight: Axial, points | 21 to 25 | |
| 34 to 45 |
| Strength to Weight: Bending, points | 20 to 23 | |
| 27 to 32 |
| Thermal Diffusivity, mm2/s | 4.3 | |
| 3.5 |
| Thermal Shock Resistance, points | 14 to 16 | |
| 25 to 33 |
Alloy Composition
| Carbon (C), % | 0 to 0.2 | |
| 0.15 to 0.35 |
| Chromium (Cr), % | 22 to 24 | |
| 26 to 30 |
| Cobalt (Co), % | 0 | |
| 58.7 to 68.9 |
| Iron (Fe), % | 58 to 66 | |
| 0 to 0.75 |
| Manganese (Mn), % | 0 to 2.0 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 0 | |
| 5.0 to 7.0 |
| Nickel (Ni), % | 12 to 15 | |
| 0 to 1.0 |
| Nitrogen (N), % | 0 | |
| 0 to 0.25 |
| Phosphorus (P), % | 0 to 0.045 | |
| 0 |
| Silicon (Si), % | 0 to 0.75 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 |