Grade 21 Titanium vs. SAE-AISI O7 Steel
Grade 21 titanium belongs to the titanium alloys classification, while SAE-AISI O7 steel belongs to the iron alloys. There are 21 material properties with values for both materials. Properties with values for just one material (11, in this case) are not shown.
For each property being compared, the top bar is grade 21 titanium and the bottom bar is SAE-AISI O7 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 140 | |
| 190 |
| Poisson's Ratio | 0.32 | |
| 0.29 |
| Shear Modulus, GPa | 51 | |
| 73 |
| Tensile Strength: Ultimate (UTS), MPa | 890 to 1340 | |
| 680 to 2110 |
Thermal Properties
| Latent Heat of Fusion, J/g | 410 | |
| 250 |
| Melting Completion (Liquidus), °C | 1740 | |
| 1480 |
| Melting Onset (Solidus), °C | 1690 | |
| 1430 |
| Specific Heat Capacity, J/kg-K | 500 | |
| 470 |
| Thermal Conductivity, W/m-K | 7.5 | |
| 41 |
| Thermal Expansion, µm/m-K | 7.1 | |
| 12 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 60 | |
| 6.0 |
| Density, g/cm3 | 5.4 | |
| 7.9 |
| Embodied Carbon, kg CO2/kg material | 32 | |
| 2.3 |
| Embodied Energy, MJ/kg | 490 | |
| 33 |
| Embodied Water, L/kg | 180 | |
| 52 |
Common Calculations
| Stiffness to Weight: Axial, points | 14 | |
| 13 |
| Stiffness to Weight: Bending, points | 32 | |
| 24 |
| Strength to Weight: Axial, points | 46 to 69 | |
| 24 to 74 |
| Strength to Weight: Bending, points | 38 to 50 | |
| 22 to 46 |
| Thermal Diffusivity, mm2/s | 2.8 | |
| 11 |
| Thermal Shock Resistance, points | 66 to 100 | |
| 23 to 70 |
Alloy Composition
| Aluminum (Al), % | 2.5 to 3.5 | |
| 0 |
| Carbon (C), % | 0 to 0.050 | |
| 1.1 to 1.3 |
| Chromium (Cr), % | 0 | |
| 0.35 to 0.85 |
| Copper (Cu), % | 0 | |
| 0 to 0.25 |
| Hydrogen (H), % | 0 to 0.015 | |
| 0 |
| Iron (Fe), % | 0 to 0.4 | |
| 92.9 to 97.6 |
| Manganese (Mn), % | 0 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 14 to 16 | |
| 0 to 0.3 |
| Nickel (Ni), % | 0 | |
| 0 to 0.3 |
| Niobium (Nb), % | 2.2 to 3.2 | |
| 0 |
| Nitrogen (N), % | 0 to 0.030 | |
| 0 |
| Oxygen (O), % | 0 to 0.17 | |
| 0 |
| Phosphorus (P), % | 0 | |
| 0 to 0.030 |
| Silicon (Si), % | 0.15 to 0.25 | |
| 0 to 0.6 |
| Sulfur (S), % | 0 | |
| 0 to 0.030 |
| Titanium (Ti), % | 76 to 81.2 | |
| 0 |
| Tungsten (W), % | 0 | |
| 1.0 to 2.0 |
| Vanadium (V), % | 0 | |
| 0 to 0.4 |
| Residuals, % | 0 to 0.4 | |
| 0 |