SAE-AISI T8 Steel vs. SAE-AISI 4340M Steel
Both SAE-AISI T8 steel and SAE-AISI 4340M steel are iron alloys. They have 75% of their average alloy composition in common. There are 22 material properties with values for both materials. Properties with values for just one material (13, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI T8 steel and the bottom bar is SAE-AISI 4340M steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 190 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 78 | |
| 72 |
| Tensile Strength: Ultimate (UTS), MPa | 780 to 2140 | |
| 2340 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 280 |
| Melting Completion (Liquidus), °C | 1730 | |
| 1440 |
| Melting Onset (Solidus), °C | 1670 | |
| 1400 |
| Specific Heat Capacity, J/kg-K | 420 | |
| 480 |
| Thermal Conductivity, W/m-K | 18 | |
| 38 |
| Thermal Expansion, µm/m-K | 12 | |
| 13 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 45 | |
| 3.9 |
| Density, g/cm3 | 9.0 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 10 | |
| 1.9 |
| Embodied Energy, MJ/kg | 160 | |
| 26 |
| Embodied Water, L/kg | 120 | |
| 55 |
Common Calculations
| PREN (Pitting Resistance) | 30 | |
| 2.2 |
| Stiffness to Weight: Axial, points | 12 | |
| 13 |
| Stiffness to Weight: Bending, points | 22 | |
| 25 |
| Strength to Weight: Axial, points | 24 to 66 | |
| 84 |
| Strength to Weight: Bending, points | 21 to 41 | |
| 51 |
| Thermal Diffusivity, mm2/s | 4.8 | |
| 10 |
| Thermal Shock Resistance, points | 24 to 66 | |
| 70 |
Alloy Composition
| Carbon (C), % | 0.75 to 0.85 | |
| 0.38 to 0.43 |
| Chromium (Cr), % | 3.8 to 4.5 | |
| 0.7 to 1.0 |
| Cobalt (Co), % | 4.3 to 5.8 | |
| 0 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 |
| Iron (Fe), % | 69.3 to 75.4 | |
| 93.3 to 94.8 |
| Manganese (Mn), % | 0.2 to 0.4 | |
| 0.65 to 0.9 |
| Molybdenum (Mo), % | 0.4 to 1.0 | |
| 0.35 to 0.45 |
| Nickel (Ni), % | 0 to 0.3 | |
| 1.7 to 2.0 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.012 |
| Silicon (Si), % | 0.2 to 0.4 | |
| 1.5 to 1.8 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.012 |
| Tungsten (W), % | 13.3 to 14.8 | |
| 0 |
| Vanadium (V), % | 1.8 to 2.4 | |
| 0.050 to 0.1 |