SAE-AISI 4340 Steel vs. R30155 Cobalt
Both SAE-AISI 4340 steel and R30155 cobalt are iron alloys. They have a modest 34% of their average alloy composition in common, which, by itself, doesn't mean much. There are 29 material properties with values for both materials. Properties with values for just one material (5, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI 4340 steel and the bottom bar is R30155 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 210 to 360 | |
| 220 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 210 |
| Elongation at Break, % | 12 to 22 | |
| 34 |
| Fatigue Strength, MPa | 330 to 740 | |
| 310 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 81 |
| Shear Strength, MPa | 430 to 770 | |
| 570 |
| Tensile Strength: Ultimate (UTS), MPa | 690 to 1280 | |
| 850 |
| Tensile Strength: Yield (Proof), MPa | 470 to 1150 | |
| 390 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 300 |
| Maximum Temperature: Mechanical, °C | 430 | |
| 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 | 44 | |
| 12 |
| Thermal Expansion, µm/m-K | 13 | |
| 14 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 3.5 | |
| 80 |
| Density, g/cm3 | 7.8 | |
| 8.5 |
| Embodied Carbon, kg CO2/kg material | 1.7 | |
| 9.7 |
| Embodied Energy, MJ/kg | 22 | |
| 150 |
| Embodied Water, L/kg | 53 | |
| 300 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 79 to 170 | |
| 230 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 590 to 3490 | |
| 370 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 23 |
| Strength to Weight: Axial, points | 24 to 45 | |
| 28 |
| Strength to Weight: Bending, points | 22 to 33 | |
| 24 |
| Thermal Diffusivity, mm2/s | 12 | |
| 3.2 |
| Thermal Shock Resistance, points | 20 to 38 | |
| 21 |
Alloy Composition
| Carbon (C), % | 0.38 to 0.43 | |
| 0.080 to 0.16 |
| Chromium (Cr), % | 0.7 to 0.9 | |
| 20 to 22.5 |
| Cobalt (Co), % | 0 | |
| 18.5 to 21 |
| Iron (Fe), % | 95.1 to 96.3 | |
| 24.3 to 36.2 |
| Manganese (Mn), % | 0.6 to 0.8 | |
| 1.0 to 2.0 |
| Molybdenum (Mo), % | 0.2 to 0.3 | |
| 2.5 to 3.5 |
| Nickel (Ni), % | 1.7 to 2.0 | |
| 19 to 21 |
| Niobium (Nb), % | 0 | |
| 0.75 to 1.3 |
| Nitrogen (N), % | 0 | |
| 0 to 0.2 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 to 0.040 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.030 |
| Tantalum (Ta), % | 0 | |
| 0.75 to 1.3 |
| Tungsten (W), % | 0 | |
| 2.0 to 3.0 |