R30021 Cobalt vs. ASTM A229 Spring Steel
R30021 cobalt belongs to the cobalt alloys classification, while ASTM A229 spring steel belongs to the iron alloys. There are 27 material properties with values for both materials. Properties with values for just one material (6, in this case) are not shown.
For each property being compared, the top bar is R30021 cobalt and the bottom bar is ASTM A229 spring steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 220 | |
| 190 |
| Elongation at Break, % | 9.0 | |
| 14 |
| Fatigue Strength, MPa | 250 | |
| 710 to 790 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 86 | |
| 72 |
| Tensile Strength: Ultimate (UTS), MPa | 700 | |
| 1690 to 1890 |
| Tensile Strength: Yield (Proof), MPa | 500 | |
| 1100 to 1230 |
Thermal Properties
| Latent Heat of Fusion, J/g | 330 | |
| 250 |
| Melting Completion (Liquidus), °C | 1350 | |
| 1450 |
| Melting Onset (Solidus), °C | 1190 | |
| 1410 |
| Specific Heat Capacity, J/kg-K | 450 | |
| 470 |
| Thermal Conductivity, W/m-K | 15 | |
| 50 |
| Thermal Expansion, µm/m-K | 11 | |
| 12 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 1.9 | |
| 7.2 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.1 | |
| 8.3 |
Otherwise Unclassified Properties
| Density, g/cm3 | 8.4 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 8.0 | |
| 1.4 |
| Embodied Energy, MJ/kg | 110 | |
| 19 |
| Embodied Water, L/kg | 520 | |
| 46 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 57 | |
| 200 to 230 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 570 | |
| 3260 to 4080 |
| Stiffness to Weight: Axial, points | 15 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 23 | |
| 60 to 67 |
| Strength to Weight: Bending, points | 21 | |
| 40 to 43 |
| Thermal Diffusivity, mm2/s | 3.8 | |
| 14 |
| Thermal Shock Resistance, points | 21 | |
| 54 to 60 |
Alloy Composition
| Carbon (C), % | 0.2 to 0.35 | |
| 0.55 to 0.85 |
| Chromium (Cr), % | 26 to 29 | |
| 0 |
| Cobalt (Co), % | 61.7 to 67.3 | |
| 0 |
| Iron (Fe), % | 0 to 3.0 | |
| 97.5 to 99 |
| Manganese (Mn), % | 0 | |
| 0.3 to 1.2 |
| Molybdenum (Mo), % | 4.5 to 6.0 | |
| 0 |
| Nickel (Ni), % | 2.0 to 3.0 | |
| 0 |
| Phosphorus (P), % | 0 | |
| 0 to 0.040 |
| Silicon (Si), % | 0 to 1.5 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 | |
| 0 to 0.050 |