SAE-AISI 4340 Steel vs. R30003 Cobalt
SAE-AISI 4340 steel belongs to the iron alloys classification, while R30003 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 4340 steel and the bottom bar is R30003 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 210 |
| Elongation at Break, % | 12 to 22 | |
| 10 to 73 |
| Fatigue Strength, MPa | 330 to 740 | |
| 320 to 560 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 83 |
| Tensile Strength: Ultimate (UTS), MPa | 690 to 1280 | |
| 970 to 1720 |
| Tensile Strength: Yield (Proof), MPa | 470 to 1150 | |
| 510 to 1090 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 310 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1400 |
| Melting Onset (Solidus), °C | 1420 | |
| 1440 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 450 |
| Thermal Conductivity, W/m-K | 44 | |
| 13 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.5 | |
| 2.0 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.6 | |
| 2.1 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 3.5 | |
| 95 |
| Density, g/cm3 | 7.8 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 1.7 | |
| 8.0 |
| Embodied Energy, MJ/kg | 22 | |
| 110 |
| Embodied Water, L/kg | 53 | |
| 400 |
Common Calculations
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 590 to 3490 | |
| 600 to 2790 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 24 to 45 | |
| 32 to 57 |
| Strength to Weight: Bending, points | 22 to 33 | |
| 26 to 38 |
| Thermal Diffusivity, mm2/s | 12 | |
| 3.3 |
| Thermal Shock Resistance, points | 20 to 38 | |
| 26 to 45 |
Alloy Composition
| Boron (B), % | 0 | |
| 0 to 0.1 |
| Carbon (C), % | 0.38 to 0.43 | |
| 0 to 0.15 |
| Chromium (Cr), % | 0.7 to 0.9 | |
| 19 to 21 |
| Cobalt (Co), % | 0 | |
| 39 to 41 |
| Iron (Fe), % | 95.1 to 96.3 | |
| 10 to 20.5 |
| Manganese (Mn), % | 0.6 to 0.8 | |
| 1.5 to 2.5 |
| Molybdenum (Mo), % | 0.2 to 0.3 | |
| 6.0 to 8.0 |
| Nickel (Ni), % | 1.7 to 2.0 | |
| 14 to 16 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 to 0.015 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 to 1.2 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.015 |