ASTM A387 Grade 2 Steel vs. R30021 Cobalt
ASTM A387 grade 2 steel belongs to the iron alloys classification, while R30021 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 ASTM A387 grade 2 steel and the bottom bar is R30021 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 220 |
| Elongation at Break, % | 25 | |
| 9.0 |
| Fatigue Strength, MPa | 190 to 250 | |
| 250 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 86 |
| Tensile Strength: Ultimate (UTS), MPa | 470 to 550 | |
| 700 |
| Tensile Strength: Yield (Proof), MPa | 260 to 350 | |
| 500 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 330 |
| Melting Completion (Liquidus), °C | 1470 | |
| 1350 |
| Melting Onset (Solidus), °C | 1420 | |
| 1190 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 450 |
| Thermal Conductivity, W/m-K | 45 | |
| 15 |
| Thermal Expansion, µm/m-K | 13 | |
| 11 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.2 | |
| 1.9 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.3 | |
| 2.1 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.9 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 1.6 | |
| 8.0 |
| Embodied Energy, MJ/kg | 20 | |
| 110 |
| Embodied Water, L/kg | 50 | |
| 520 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 98 to 120 | |
| 57 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 180 to 320 | |
| 570 |
| Stiffness to Weight: Axial, points | 13 | |
| 15 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 16 to 20 | |
| 23 |
| Strength to Weight: Bending, points | 17 to 19 | |
| 21 |
| Thermal Diffusivity, mm2/s | 12 | |
| 3.8 |
| Thermal Shock Resistance, points | 14 to 16 | |
| 21 |
Alloy Composition
| Carbon (C), % | 0.050 to 0.21 | |
| 0.2 to 0.35 |
| Chromium (Cr), % | 0.5 to 0.8 | |
| 26 to 29 |
| Cobalt (Co), % | 0 | |
| 61.7 to 67.3 |
| Iron (Fe), % | 97.1 to 98.3 | |
| 0 to 3.0 |
| Manganese (Mn), % | 0.55 to 0.8 | |
| 0 |
| Molybdenum (Mo), % | 0.45 to 0.6 | |
| 4.5 to 6.0 |
| Nickel (Ni), % | 0 | |
| 2.0 to 3.0 |
| Phosphorus (P), % | 0 to 0.025 | |
| 0 |
| Silicon (Si), % | 0.15 to 0.4 | |
| 0 to 1.5 |
| Sulfur (S), % | 0 to 0.025 | |
| 0 |