ASTM A387 Grade 91 Class 2 vs. R30155 Cobalt
Both ASTM A387 grade 91 class 2 and R30155 cobalt are iron alloys. They have 41% of their average alloy composition in common. There are 30 material properties with values for both materials. Properties with values for just one material (4, in this case) are not shown.
For each property being compared, the top bar is ASTM A387 grade 91 class 2 and the bottom bar is R30155 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 200 | |
| 220 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 210 |
| Elongation at Break, % | 20 | |
| 34 |
| Fatigue Strength, MPa | 330 | |
| 310 |
| Poisson's Ratio | 0.28 | |
| 0.29 |
| Shear Modulus, GPa | 75 | |
| 81 |
| Shear Strength, MPa | 420 | |
| 570 |
| Tensile Strength: Ultimate (UTS), MPa | 670 | |
| 850 |
| Tensile Strength: Yield (Proof), MPa | 470 | |
| 390 |
Thermal Properties
| Latent Heat of Fusion, J/g | 270 | |
| 300 |
| Maximum Temperature: Mechanical, °C | 600 | |
| 1100 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1470 |
| Melting Onset (Solidus), °C | 1420 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 450 |
| Thermal Conductivity, W/m-K | 26 | |
| 12 |
| Thermal Expansion, µm/m-K | 13 | |
| 14 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 7.0 | |
| 80 |
| Density, g/cm3 | 7.8 | |
| 8.5 |
| Embodied Carbon, kg CO2/kg material | 2.6 | |
| 9.7 |
| Embodied Energy, MJ/kg | 37 | |
| 150 |
| Embodied Water, L/kg | 88 | |
| 300 |
Common Calculations
| PREN (Pitting Resistance) | 13 | |
| 37 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 120 | |
| 230 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 580 | |
| 370 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 23 |
| Strength to Weight: Axial, points | 24 | |
| 28 |
| Strength to Weight: Bending, points | 22 | |
| 24 |
| Thermal Diffusivity, mm2/s | 6.9 | |
| 3.2 |
| Thermal Shock Resistance, points | 19 | |
| 21 |
Alloy Composition
| Aluminum (Al), % | 0 to 0.020 | |
| 0 |
| Carbon (C), % | 0.080 to 0.12 | |
| 0.080 to 0.16 |
| Chromium (Cr), % | 8.0 to 9.5 | |
| 20 to 22.5 |
| Cobalt (Co), % | 0 | |
| 18.5 to 21 |
| Iron (Fe), % | 87.3 to 90.3 | |
| 24.3 to 36.2 |
| Manganese (Mn), % | 0.3 to 0.6 | |
| 1.0 to 2.0 |
| Molybdenum (Mo), % | 0.85 to 1.1 | |
| 2.5 to 3.5 |
| Nickel (Ni), % | 0 to 0.4 | |
| 19 to 21 |
| Niobium (Nb), % | 0.060 to 0.1 | |
| 0.75 to 1.3 |
| Nitrogen (N), % | 0.030 to 0.070 | |
| 0 to 0.2 |
| Phosphorus (P), % | 0 to 0.020 | |
| 0 to 0.040 |
| Silicon (Si), % | 0.2 to 0.5 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.010 | |
| 0 to 0.030 |
| Tantalum (Ta), % | 0 | |
| 0.75 to 1.3 |
| Titanium (Ti), % | 0 to 0.010 | |
| 0 |
| Tungsten (W), % | 0 | |
| 2.0 to 3.0 |
| Vanadium (V), % | 0.18 to 0.25 | |
| 0 |
| Zirconium (Zr), % | 0 to 0.010 | |
| 0 |