ASTM A227 Spring Steel vs. R30008 Cobalt
ASTM A227 spring steel belongs to the iron alloys classification, while R30008 cobalt belongs to the cobalt alloys. There are 22 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 ASTM A227 spring steel and the bottom bar is R30008 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 210 |
| Elongation at Break, % | 12 | |
| 1.1 to 73 |
| Fatigue Strength, MPa | 900 to 1160 | |
| 320 to 530 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 72 | |
| 83 |
| Tensile Strength: Ultimate (UTS), MPa | 1720 to 2220 | |
| 950 to 1700 |
| Tensile Strength: Yield (Proof), MPa | 1430 to 1850 | |
| 500 to 1080 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 320 |
| Melting Completion (Liquidus), °C | 1450 | |
| 1400 |
| Melting Onset (Solidus), °C | 1410 | |
| 1330 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 450 |
| Thermal Expansion, µm/m-K | 12 | |
| 13 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 1.8 | |
| 95 |
| Density, g/cm3 | 7.8 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 1.4 | |
| 8.1 |
| Embodied Energy, MJ/kg | 19 | |
| 110 |
| Embodied Water, L/kg | 46 | |
| 400 |
Common Calculations
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 61 to 79 | |
| 31 to 56 |
| Strength to Weight: Bending, points | 41 to 48 | |
| 25 to 37 |
| Thermal Shock Resistance, points | 55 to 71 | |
| 25 to 44 |
Alloy Composition
| Boron (B), % | 0 | |
| 0 to 0.0010 |
| Carbon (C), % | 0.45 to 0.85 | |
| 0 to 0.15 |
| Chromium (Cr), % | 0 | |
| 18.5 to 21.5 |
| Cobalt (Co), % | 0 | |
| 39 to 42 |
| Iron (Fe), % | 97.4 to 99.1 | |
| 7.6 to 20 |
| Manganese (Mn), % | 0.3 to 1.3 | |
| 1.0 to 2.0 |
| Molybdenum (Mo), % | 0 | |
| 6.5 to 7.5 |
| Nickel (Ni), % | 0 | |
| 15 to 18 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.015 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 to 1.2 |
| Sulfur (S), % | 0 to 0.050 | |
| 0 to 0.015 |