SAE-AISI T8 Steel vs. SAE-AISI T4 Steel
Both SAE-AISI T8 steel and SAE-AISI T4 steel are iron alloys. They have a very high 96% of their average alloy composition in common.
For each property being compared, the top bar is SAE-AISI T8 steel and the bottom bar is SAE-AISI T4 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 210 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 78 | |
| 80 |
| Tensile Strength: Ultimate (UTS), MPa | 780 to 2140 | |
| 800 to 2140 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 250 |
| Melting Completion (Liquidus), °C | 1730 | |
| 1810 |
| Melting Onset (Solidus), °C | 1670 | |
| 1750 |
| Specific Heat Capacity, J/kg-K | 420 | |
| 410 |
| Thermal Conductivity, W/m-K | 18 | |
| 21 |
| Thermal Expansion, µm/m-K | 12 | |
| 12 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 45 | |
| 55 |
| Density, g/cm3 | 9.0 | |
| 9.4 |
| Embodied Carbon, kg CO2/kg material | 10 | |
| 8.5 |
| Embodied Energy, MJ/kg | 160 | |
| 130 |
| Embodied Water, L/kg | 120 | |
| 120 |
Common Calculations
| PREN (Pitting Resistance) | 30 | |
| 37 |
| Stiffness to Weight: Axial, points | 12 | |
| 12 |
| Stiffness to Weight: Bending, points | 22 | |
| 21 |
| Strength to Weight: Axial, points | 24 to 66 | |
| 24 to 64 |
| Strength to Weight: Bending, points | 21 to 41 | |
| 20 to 39 |
| Thermal Diffusivity, mm2/s | 4.8 | |
| 5.4 |
| Thermal Shock Resistance, points | 24 to 66 | |
| 24 to 64 |
Alloy Composition
| Carbon (C), % | 0.75 to 0.85 | |
| 0.7 to 0.8 |
| Chromium (Cr), % | 3.8 to 4.5 | |
| 3.8 to 4.5 |
| Cobalt (Co), % | 4.3 to 5.8 | |
| 4.3 to 5.8 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 to 0.25 |
| Iron (Fe), % | 69.3 to 75.4 | |
| 66.3 to 72.3 |
| Manganese (Mn), % | 0.2 to 0.4 | |
| 0.1 to 0.4 |
| Molybdenum (Mo), % | 0.4 to 1.0 | |
| 0.4 to 1.0 |
| Nickel (Ni), % | 0 to 0.3 | |
| 0 to 0.3 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.030 |
| Silicon (Si), % | 0.2 to 0.4 | |
| 0.2 to 0.4 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Tungsten (W), % | 13.3 to 14.8 | |
| 17.5 to 19 |
| Vanadium (V), % | 1.8 to 2.4 | |
| 0.8 to 1.2 |