R31538 Cobalt vs. AISI 321 Stainless Steel
R31538 cobalt belongs to the cobalt alloys classification, while AISI 321 stainless steel belongs to the iron alloys. There are 27 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 R31538 cobalt and the bottom bar is AISI 321 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 220 | |
| 200 |
| Elongation at Break, % | 13 to 23 | |
| 34 to 50 |
| Fatigue Strength, MPa | 310 to 480 | |
| 220 to 270 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 86 | |
| 77 |
| Tensile Strength: Ultimate (UTS), MPa | 1020 to 1360 | |
| 590 to 690 |
| Tensile Strength: Yield (Proof), MPa | 580 to 930 | |
| 220 to 350 |
Thermal Properties
| Latent Heat of Fusion, J/g | 320 | |
| 290 |
| Melting Completion (Liquidus), °C | 1360 | |
| 1430 |
| Melting Onset (Solidus), °C | 1290 | |
| 1400 |
| Specific Heat Capacity, J/kg-K | 450 | |
| 480 |
| Thermal Conductivity, W/m-K | 13 | |
| 16 |
| Thermal Expansion, µm/m-K | 13 | |
| 17 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.0 | |
| 2.4 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.1 | |
| 2.7 |
Otherwise Unclassified Properties
| Density, g/cm3 | 8.4 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 8.1 | |
| 3.2 |
| Embodied Energy, MJ/kg | 110 | |
| 45 |
| Embodied Water, L/kg | 530 | |
| 140 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 140 to 200 | |
| 190 to 230 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 750 to 1920 | |
| 130 to 310 |
| Stiffness to Weight: Axial, points | 15 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 25 |
| Strength to Weight: Axial, points | 34 to 45 | |
| 21 to 25 |
| Strength to Weight: Bending, points | 27 to 32 | |
| 20 to 22 |
| Thermal Diffusivity, mm2/s | 3.5 | |
| 4.1 |
| Thermal Shock Resistance, points | 25 to 33 | |
| 13 to 15 |
Alloy Composition
| Carbon (C), % | 0.15 to 0.35 | |
| 0 to 0.080 |
| Chromium (Cr), % | 26 to 30 | |
| 17 to 19 |
| Cobalt (Co), % | 58.7 to 68.9 | |
| 0 |
| Iron (Fe), % | 0 to 0.75 | |
| 65.3 to 74 |
| Manganese (Mn), % | 0 to 1.0 | |
| 0 to 2.0 |
| Molybdenum (Mo), % | 5.0 to 7.0 | |
| 0 |
| Nickel (Ni), % | 0 to 1.0 | |
| 9.0 to 12 |
| Nitrogen (N), % | 0 to 0.25 | |
| 0 to 0.1 |
| Phosphorus (P), % | 0 | |
| 0 to 0.045 |
| Silicon (Si), % | 0 to 1.0 | |
| 0 to 0.75 |
| Sulfur (S), % | 0 | |
| 0 to 0.030 |
| Titanium (Ti), % | 0 | |
| 0 to 0.7 |