Grade 18 Titanium vs. SAE-AISI 4340 Steel
Grade 18 titanium belongs to the titanium alloys classification, while SAE-AISI 4340 steel belongs to the iron alloys. There are 29 material properties with values for both materials. Properties with values for just one material (3, in this case) are not shown.
For each property being compared, the top bar is grade 18 titanium and the bottom bar is SAE-AISI 4340 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 110 | |
| 190 |
| Elongation at Break, % | 11 to 17 | |
| 12 to 22 |
| Fatigue Strength, MPa | 330 to 480 | |
| 330 to 740 |
| Poisson's Ratio | 0.32 | |
| 0.29 |
| Shear Modulus, GPa | 40 | |
| 73 |
| Shear Strength, MPa | 420 to 590 | |
| 430 to 770 |
| Tensile Strength: Ultimate (UTS), MPa | 690 to 980 | |
| 690 to 1280 |
| Tensile Strength: Yield (Proof), MPa | 540 to 810 | |
| 470 to 1150 |
Thermal Properties
| Latent Heat of Fusion, J/g | 410 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 330 | |
| 430 |
| Melting Completion (Liquidus), °C | 1640 | |
| 1460 |
| Melting Onset (Solidus), °C | 1590 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 550 | |
| 470 |
| Thermal Conductivity, W/m-K | 8.3 | |
| 44 |
| Thermal Expansion, µm/m-K | 9.9 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 1.3 | |
| 7.5 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.7 | |
| 8.6 |
Otherwise Unclassified Properties
| Density, g/cm3 | 4.5 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 41 | |
| 1.7 |
| Embodied Energy, MJ/kg | 670 | |
| 22 |
| Embodied Water, L/kg | 270 | |
| 53 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 87 to 110 | |
| 79 to 170 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 1380 to 3110 | |
| 590 to 3490 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 35 | |
| 24 |
| Strength to Weight: Axial, points | 43 to 61 | |
| 24 to 45 |
| Strength to Weight: Bending, points | 39 to 49 | |
| 22 to 33 |
| Thermal Diffusivity, mm2/s | 3.4 | |
| 12 |
| Thermal Shock Resistance, points | 47 to 67 | |
| 20 to 38 |
Alloy Composition
| Aluminum (Al), % | 2.5 to 3.5 | |
| 0 |
| Carbon (C), % | 0 to 0.080 | |
| 0.38 to 0.43 |
| Chromium (Cr), % | 0 | |
| 0.7 to 0.9 |
| Hydrogen (H), % | 0 to 0.015 | |
| 0 |
| Iron (Fe), % | 0 to 0.25 | |
| 95.1 to 96.3 |
| Manganese (Mn), % | 0 | |
| 0.6 to 0.8 |
| Molybdenum (Mo), % | 0 | |
| 0.2 to 0.3 |
| Nickel (Ni), % | 0 | |
| 1.7 to 2.0 |
| Nitrogen (N), % | 0 to 0.030 | |
| 0 |
| Oxygen (O), % | 0 to 0.15 | |
| 0 |
| Palladium (Pd), % | 0.040 to 0.080 | |
| 0 |
| Phosphorus (P), % | 0 | |
| 0 to 0.035 |
| Silicon (Si), % | 0 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 | |
| 0 to 0.040 |
| Titanium (Ti), % | 92.5 to 95.5 | |
| 0 |
| Vanadium (V), % | 2.0 to 3.0 | |
| 0 |
| Residuals, % | 0 to 0.4 | |
| 0 |