AISI 321 Stainless Steel vs. R30075 Cobalt
AISI 321 stainless steel belongs to the iron alloys classification, while R30075 cobalt belongs to the cobalt alloys. 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 AISI 321 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, % | 34 to 50 | |
| 12 |
| Fatigue Strength, MPa | 220 to 270 | |
| 250 to 840 |
| Poisson's Ratio | 0.28 | |
| 0.29 |
| Shear Modulus, GPa | 77 | |
| 82 to 98 |
| Tensile Strength: Ultimate (UTS), MPa | 590 to 690 | |
| 780 to 1280 |
| Tensile Strength: Yield (Proof), MPa | 220 to 350 | |
| 480 to 840 |
Thermal Properties
| Latent Heat of Fusion, J/g | 290 | |
| 320 |
| Melting Completion (Liquidus), °C | 1430 | |
| 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 | 17 | |
| 12 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.4 | |
| 2.0 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.7 | |
| 2.1 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.8 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 3.2 | |
| 8.1 |
| Embodied Energy, MJ/kg | 45 | |
| 110 |
| Embodied Water, L/kg | 140 | |
| 530 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 190 to 230 | |
| 84 to 140 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 130 to 310 | |
| 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 | 21 to 25 | |
| 26 to 42 |
| Strength to Weight: Bending, points | 20 to 22 | |
| 22 to 31 |
| Thermal Diffusivity, mm2/s | 4.1 | |
| 3.5 |
| Thermal Shock Resistance, points | 13 to 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), % | 17 to 19 | |
| 27 to 30 |
| Cobalt (Co), % | 0 | |
| 58.7 to 68 |
| Iron (Fe), % | 65.3 to 74 | |
| 0 to 0.75 |
| Manganese (Mn), % | 0 to 2.0 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 0 | |
| 5.0 to 7.0 |
| Nickel (Ni), % | 9.0 to 12 | |
| 0 to 0.5 |
| Nitrogen (N), % | 0 to 0.1 | |
| 0 to 0.25 |
| Phosphorus (P), % | 0 to 0.045 | |
| 0 to 0.020 |
| Silicon (Si), % | 0 to 0.75 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.010 |
| Titanium (Ti), % | 0 to 0.7 | |
| 0 to 0.1 |
| Tungsten (W), % | 0 | |
| 0 to 0.2 |