Grade 31 Titanium vs. SAE-AISI 8645 Steel
Grade 31 titanium belongs to the titanium alloys classification, while SAE-AISI 8645 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 31 titanium and the bottom bar is SAE-AISI 8645 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 110 | |
| 190 |
| Elongation at Break, % | 20 | |
| 12 to 23 |
| Fatigue Strength, MPa | 300 | |
| 280 to 350 |
| Poisson's Ratio | 0.32 | |
| 0.29 |
| Shear Modulus, GPa | 41 | |
| 73 |
| Shear Strength, MPa | 320 | |
| 380 to 400 |
| Tensile Strength: Ultimate (UTS), MPa | 510 | |
| 600 to 670 |
| Tensile Strength: Yield (Proof), MPa | 450 | |
| 390 to 560 |
Thermal Properties
| Latent Heat of Fusion, J/g | 420 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 320 | |
| 410 |
| Melting Completion (Liquidus), °C | 1660 | |
| 1460 |
| Melting Onset (Solidus), °C | 1610 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 540 | |
| 470 |
| Thermal Conductivity, W/m-K | 21 | |
| 39 |
| Thermal Expansion, µm/m-K | 8.7 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 3.4 | |
| 7.3 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 6.9 | |
| 8.4 |
Otherwise Unclassified Properties
| Density, g/cm3 | 4.5 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 36 | |
| 1.5 |
| Embodied Energy, MJ/kg | 600 | |
| 20 |
| Embodied Water, L/kg | 230 | |
| 50 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 99 | |
| 77 to 120 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 940 | |
| 420 to 840 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 35 | |
| 24 |
| Strength to Weight: Axial, points | 32 | |
| 21 to 24 |
| Strength to Weight: Bending, points | 32 | |
| 20 to 22 |
| Thermal Diffusivity, mm2/s | 8.5 | |
| 10 |
| Thermal Shock Resistance, points | 39 | |
| 18 to 20 |
Alloy Composition
| Carbon (C), % | 0 to 0.080 | |
| 0.43 to 0.48 |
| Chromium (Cr), % | 0 | |
| 0.4 to 0.6 |
| Cobalt (Co), % | 0.2 to 0.8 | |
| 0 |
| Hydrogen (H), % | 0 to 0.015 | |
| 0 |
| Iron (Fe), % | 0 to 0.3 | |
| 96.5 to 97.7 |
| Manganese (Mn), % | 0 | |
| 0.75 to 1.0 |
| Molybdenum (Mo), % | 0 | |
| 0.15 to 0.25 |
| Nickel (Ni), % | 0 | |
| 0.4 to 0.7 |
| Nitrogen (N), % | 0 to 0.050 | |
| 0 |
| Oxygen (O), % | 0 to 0.35 | |
| 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), % | 97.9 to 99.76 | |
| 0 |
| Residuals, % | 0 to 0.4 | |
| 0 |