ASTM Grade HP Steel vs. R31538 Cobalt
ASTM grade HP steel belongs to the iron alloys classification, while R31538 cobalt belongs to the cobalt alloys. They have a modest 28% of their average alloy composition in common, which, by itself, doesn't mean much. There are 25 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 grade HP steel and the bottom bar is R31538 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 220 |
| Elongation at Break, % | 5.1 | |
| 13 to 23 |
| Fatigue Strength, MPa | 130 | |
| 310 to 480 |
| Poisson's Ratio | 0.28 | |
| 0.29 |
| Shear Modulus, GPa | 78 | |
| 86 |
| Tensile Strength: Ultimate (UTS), MPa | 490 | |
| 1020 to 1360 |
| Tensile Strength: Yield (Proof), MPa | 260 | |
| 580 to 930 |
Thermal Properties
| Latent Heat of Fusion, J/g | 320 | |
| 320 |
| Melting Completion (Liquidus), °C | 1370 | |
| 1360 |
| Melting Onset (Solidus), °C | 1330 | |
| 1290 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 450 |
| Thermal Conductivity, W/m-K | 12 | |
| 13 |
| Thermal Expansion, µm/m-K | 16 | |
| 13 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.9 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 5.8 | |
| 8.1 |
| Embodied Energy, MJ/kg | 82 | |
| 110 |
| Embodied Water, L/kg | 220 | |
| 530 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 21 | |
| 140 to 200 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 170 | |
| 750 to 1920 |
| Stiffness to Weight: Axial, points | 14 | |
| 15 |
| Stiffness to Weight: Bending, points | 25 | |
| 24 |
| Strength to Weight: Axial, points | 17 | |
| 34 to 45 |
| Strength to Weight: Bending, points | 17 | |
| 27 to 32 |
| Thermal Diffusivity, mm2/s | 3.2 | |
| 3.5 |
| Thermal Shock Resistance, points | 11 | |
| 25 to 33 |
Alloy Composition
| Carbon (C), % | 0.35 to 0.75 | |
| 0.15 to 0.35 |
| Chromium (Cr), % | 24 to 28 | |
| 26 to 30 |
| Cobalt (Co), % | 0 | |
| 58.7 to 68.9 |
| Iron (Fe), % | 29.2 to 42.7 | |
| 0 to 0.75 |
| Manganese (Mn), % | 0 to 2.0 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 0 to 0.5 | |
| 5.0 to 7.0 |
| Nickel (Ni), % | 33 to 37 | |
| 0 to 1.0 |
| Nitrogen (N), % | 0 | |
| 0 to 0.25 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 |
| Silicon (Si), % | 0 to 2.5 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 |