SAE-AISI 8740 Steel vs. Grade 21 Titanium
SAE-AISI 8740 steel belongs to the iron alloys classification, while grade 21 titanium belongs to the titanium alloys. There are 28 material properties with values for both materials. Properties with values for just one material (4, 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 21 titanium.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 140 |
| Elongation at Break, % | 11 to 23 | |
| 9.0 to 17 |
| Fatigue Strength, MPa | 270 to 350 | |
| 550 to 660 |
| Poisson's Ratio | 0.29 | |
| 0.32 |
| Shear Modulus, GPa | 73 | |
| 51 |
| Shear Strength, MPa | 370 to 400 | |
| 550 to 790 |
| Tensile Strength: Ultimate (UTS), MPa | 580 to 670 | |
| 890 to 1340 |
| Tensile Strength: Yield (Proof), MPa | 380 to 570 | |
| 870 to 1170 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 410 |
| Maximum Temperature: Mechanical, °C | 410 | |
| 310 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1740 |
| Melting Onset (Solidus), °C | 1420 | |
| 1690 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 500 |
| Thermal Conductivity, W/m-K | 39 | |
| 7.5 |
| Thermal Expansion, µm/m-K | 13 | |
| 7.1 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.6 | |
| 60 |
| Density, g/cm3 | 7.8 | |
| 5.4 |
| Embodied Carbon, kg CO2/kg material | 1.5 | |
| 32 |
| Embodied Energy, MJ/kg | 20 | |
| 490 |
| Embodied Water, L/kg | 50 | |
| 180 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 71 to 120 | |
| 110 to 180 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 390 to 850 | |
| 2760 to 5010 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 32 |
| Strength to Weight: Axial, points | 20 to 24 | |
| 46 to 69 |
| Strength to Weight: Bending, points | 20 to 22 | |
| 38 to 50 |
| Thermal Diffusivity, mm2/s | 10 | |
| 2.8 |
| Thermal Shock Resistance, points | 17 to 20 | |
| 66 to 100 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 2.5 to 3.5 |
| Carbon (C), % | 0.38 to 0.43 | |
| 0 to 0.050 |
| Chromium (Cr), % | 0.4 to 0.6 | |
| 0 |
| Hydrogen (H), % | 0 | |
| 0 to 0.015 |
| Iron (Fe), % | 96.5 to 97.7 | |
| 0 to 0.4 |
| Manganese (Mn), % | 0.75 to 1.0 | |
| 0 |
| Molybdenum (Mo), % | 0.2 to 0.3 | |
| 14 to 16 |
| Nickel (Ni), % | 0.4 to 0.7 | |
| 0 |
| Niobium (Nb), % | 0 | |
| 2.2 to 3.2 |
| Nitrogen (N), % | 0 | |
| 0 to 0.030 |
| Oxygen (O), % | 0 | |
| 0 to 0.17 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0.15 to 0.25 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 |
| Titanium (Ti), % | 0 | |
| 76 to 81.2 |
| Residuals, % | 0 | |
| 0 to 0.4 |