SAE-AISI 8740 Steel vs. R30035 Cobalt
SAE-AISI 8740 steel belongs to the iron alloys classification, while R30035 cobalt belongs to the cobalt alloys. There are 28 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 8740 steel and the bottom bar is R30035 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 220 to 230 |
| Elongation at Break, % | 11 to 23 | |
| 9.0 to 46 |
| Fatigue Strength, MPa | 270 to 350 | |
| 170 to 740 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 84 to 89 |
| Tensile Strength: Ultimate (UTS), MPa | 580 to 670 | |
| 900 to 1900 |
| Tensile Strength: Yield (Proof), MPa | 380 to 570 | |
| 300 to 1650 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 320 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1440 |
| Melting Onset (Solidus), °C | 1420 | |
| 1320 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 440 |
| Thermal Conductivity, W/m-K | 39 | |
| 11 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.3 | |
| 1.7 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.4 | |
| 1.8 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.6 | |
| 100 |
| Density, g/cm3 | 7.8 | |
| 8.7 |
| Embodied Carbon, kg CO2/kg material | 1.5 | |
| 10 |
| Embodied Energy, MJ/kg | 20 | |
| 140 |
| Embodied Water, L/kg | 50 | |
| 410 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 71 to 120 | |
| 160 to 320 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 390 to 850 | |
| 210 to 5920 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 to 15 |
| Stiffness to Weight: Bending, points | 24 | |
| 23 to 24 |
| Strength to Weight: Axial, points | 20 to 24 | |
| 29 to 61 |
| Strength to Weight: Bending, points | 20 to 22 | |
| 24 to 39 |
| Thermal Diffusivity, mm2/s | 10 | |
| 3.0 |
| Thermal Shock Resistance, points | 17 to 20 | |
| 23 to 46 |
Alloy Composition
| Boron (B), % | 0 | |
| 0 to 0.015 |
| Carbon (C), % | 0.38 to 0.43 | |
| 0 to 0.025 |
| Chromium (Cr), % | 0.4 to 0.6 | |
| 19 to 21 |
| Cobalt (Co), % | 0 | |
| 29.1 to 39 |
| Iron (Fe), % | 96.5 to 97.7 | |
| 0 to 1.0 |
| Manganese (Mn), % | 0.75 to 1.0 | |
| 0 to 0.15 |
| Molybdenum (Mo), % | 0.2 to 0.3 | |
| 9.0 to 10.5 |
| Nickel (Ni), % | 0.4 to 0.7 | |
| 33 to 37 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 to 0.015 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 to 0.15 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.010 |
| Titanium (Ti), % | 0 | |
| 0 to 1.0 |