R30008 Cobalt vs. ASTM A231 Spring Steel
R30008 cobalt belongs to the cobalt alloys classification, while ASTM A231 spring steel belongs to the iron alloys. There are 22 material properties with values for both materials. Properties with values for just one material (10, in this case) are not shown.
For each property being compared, the top bar is R30008 cobalt and the bottom bar is ASTM A231 spring steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 210 | |
| 190 |
| Elongation at Break, % | 1.1 to 73 | |
| 14 |
| Fatigue Strength, MPa | 320 to 530 | |
| 1000 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 83 | |
| 73 |
| Tensile Strength: Ultimate (UTS), MPa | 950 to 1700 | |
| 1790 |
| Tensile Strength: Yield (Proof), MPa | 500 to 1080 | |
| 1570 |
Thermal Properties
| Latent Heat of Fusion, J/g | 320 | |
| 250 |
| Melting Completion (Liquidus), °C | 1400 | |
| 1460 |
| Melting Onset (Solidus), °C | 1330 | |
| 1410 |
| Specific Heat Capacity, J/kg-K | 450 | |
| 470 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 95 | |
| 2.3 |
| Density, g/cm3 | 8.4 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 8.1 | |
| 2.0 |
| Embodied Energy, MJ/kg | 110 | |
| 28 |
| Embodied Water, L/kg | 400 | |
| 51 |
Common Calculations
| Stiffness to Weight: Axial, points | 14 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 31 to 56 | |
| 64 |
| Strength to Weight: Bending, points | 25 to 37 | |
| 42 |
| Thermal Shock Resistance, points | 25 to 44 | |
| 53 |
Alloy Composition
| Boron (B), % | 0 to 0.0010 | |
| 0 |
| Carbon (C), % | 0 to 0.15 | |
| 0.48 to 0.53 |
| Chromium (Cr), % | 18.5 to 21.5 | |
| 0.8 to 1.1 |
| Cobalt (Co), % | 39 to 42 | |
| 0 |
| Iron (Fe), % | 7.6 to 20 | |
| 96.7 to 97.7 |
| Manganese (Mn), % | 1.0 to 2.0 | |
| 0.7 to 0.9 |
| Molybdenum (Mo), % | 6.5 to 7.5 | |
| 0 |
| Nickel (Ni), % | 15 to 18 | |
| 0 |
| Phosphorus (P), % | 0 to 0.015 | |
| 0 to 0.040 |
| Silicon (Si), % | 0 to 1.2 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 to 0.015 | |
| 0 to 0.040 |
| Vanadium (V), % | 0 | |
| 0.15 to 0.3 |