SAE-AISI 81B45 Steel vs. R31233 Cobalt
SAE-AISI 81B45 steel belongs to the iron alloys classification, while R31233 cobalt belongs to the cobalt alloys. There are 27 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 SAE-AISI 81B45 steel and the bottom bar is R31233 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 220 |
| Elongation at Break, % | 12 to 24 | |
| 17 |
| Fatigue Strength, MPa | 250 to 350 | |
| 220 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 85 |
| Tensile Strength: Ultimate (UTS), MPa | 540 to 670 | |
| 1020 |
| Tensile Strength: Yield (Proof), MPa | 350 to 560 | |
| 420 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 320 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1350 |
| Melting Onset (Solidus), °C | 1420 | |
| 1330 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 440 |
| Thermal Conductivity, W/m-K | 40 | |
| 12 |
| Thermal Expansion, µm/m-K | 12 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.2 | |
| 2.0 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.3 | |
| 2.1 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.8 | |
| 8.6 |
| Embodied Carbon, kg CO2/kg material | 1.5 | |
| 8.4 |
| Embodied Energy, MJ/kg | 20 | |
| 110 |
| Embodied Water, L/kg | 49 | |
| 480 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 77 to 110 | |
| 140 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 320 to 840 | |
| 410 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 23 |
| Strength to Weight: Axial, points | 19 to 24 | |
| 33 |
| Strength to Weight: Bending, points | 19 to 22 | |
| 26 |
| Thermal Diffusivity, mm2/s | 11 | |
| 3.2 |
| Thermal Shock Resistance, points | 17 to 21 | |
| 25 |
Alloy Composition
| Boron (B), % | 0.00050 to 0.0030 | |
| 0 to 0.015 |
| Carbon (C), % | 0.43 to 0.48 | |
| 0.020 to 0.1 |
| Chromium (Cr), % | 0.35 to 0.55 | |
| 23.5 to 27.5 |
| Cobalt (Co), % | 0 | |
| 44.7 to 63.3 |
| Iron (Fe), % | 97 to 98 | |
| 1.0 to 5.0 |
| Manganese (Mn), % | 0.75 to 1.0 | |
| 0.1 to 1.5 |
| Molybdenum (Mo), % | 0.080 to 0.15 | |
| 4.0 to 6.0 |
| Nickel (Ni), % | 0.2 to 0.4 | |
| 7.0 to 11 |
| Nitrogen (N), % | 0 | |
| 0.030 to 0.12 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 to 0.030 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0.050 to 1.0 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.020 |
| Tungsten (W), % | 0 | |
| 1.0 to 3.0 |