SAE-AISI 8740 Steel vs. Grade 18 Titanium
SAE-AISI 8740 steel belongs to the iron alloys classification, while grade 18 titanium belongs to the titanium 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 SAE-AISI 8740 steel and the bottom bar is grade 18 titanium.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 110 |
| Elongation at Break, % | 11 to 23 | |
| 11 to 17 |
| Fatigue Strength, MPa | 270 to 350 | |
| 330 to 480 |
| Poisson's Ratio | 0.29 | |
| 0.32 |
| Shear Modulus, GPa | 73 | |
| 40 |
| Shear Strength, MPa | 370 to 400 | |
| 420 to 590 |
| Tensile Strength: Ultimate (UTS), MPa | 580 to 670 | |
| 690 to 980 |
| Tensile Strength: Yield (Proof), MPa | 380 to 570 | |
| 540 to 810 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 410 |
| Maximum Temperature: Mechanical, °C | 410 | |
| 330 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1640 |
| Melting Onset (Solidus), °C | 1420 | |
| 1590 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 550 |
| Thermal Conductivity, W/m-K | 39 | |
| 8.3 |
| Thermal Expansion, µm/m-K | 13 | |
| 9.9 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.3 | |
| 1.3 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.4 | |
| 2.7 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.8 | |
| 4.5 |
| Embodied Carbon, kg CO2/kg material | 1.5 | |
| 41 |
| Embodied Energy, MJ/kg | 20 | |
| 670 |
| Embodied Water, L/kg | 50 | |
| 270 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 71 to 120 | |
| 87 to 110 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 390 to 850 | |
| 1380 to 3110 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 35 |
| Strength to Weight: Axial, points | 20 to 24 | |
| 43 to 61 |
| Strength to Weight: Bending, points | 20 to 22 | |
| 39 to 49 |
| Thermal Diffusivity, mm2/s | 10 | |
| 3.4 |
| Thermal Shock Resistance, points | 17 to 20 | |
| 47 to 67 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 2.5 to 3.5 |
| Carbon (C), % | 0.38 to 0.43 | |
| 0 to 0.080 |
| Chromium (Cr), % | 0.4 to 0.6 | |
| 0 |
| Hydrogen (H), % | 0 | |
| 0 to 0.015 |
| Iron (Fe), % | 96.5 to 97.7 | |
| 0 to 0.25 |
| Manganese (Mn), % | 0.75 to 1.0 | |
| 0 |
| Molybdenum (Mo), % | 0.2 to 0.3 | |
| 0 |
| Nickel (Ni), % | 0.4 to 0.7 | |
| 0 |
| Nitrogen (N), % | 0 | |
| 0 to 0.030 |
| Oxygen (O), % | 0 | |
| 0 to 0.15 |
| Palladium (Pd), % | 0 | |
| 0.040 to 0.080 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 |
| Titanium (Ti), % | 0 | |
| 92.5 to 95.5 |
| Vanadium (V), % | 0 | |
| 2.0 to 3.0 |
| Residuals, % | 0 | |
| 0 to 0.4 |