ASTM B817 Type I vs. ASTM A387 Grade 21 Steel
ASTM B817 type I belongs to the titanium alloys classification, while ASTM A387 grade 21 steel belongs to the iron alloys. There are 29 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 ASTM B817 type I and the bottom bar is ASTM A387 grade 21 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 100 | |
| 190 |
| Elongation at Break, % | 4.0 to 13 | |
| 21 |
| Fatigue Strength, MPa | 360 to 520 | |
| 160 to 250 |
| Poisson's Ratio | 0.32 | |
| 0.29 |
| Shear Modulus, GPa | 40 | |
| 74 |
| Tensile Strength: Ultimate (UTS), MPa | 770 to 960 | |
| 500 to 590 |
| Tensile Strength: Yield (Proof), MPa | 700 to 860 | |
| 230 to 350 |
Thermal Properties
| Latent Heat of Fusion, J/g | 410 | |
| 260 |
| Maximum Temperature: Mechanical, °C | 340 | |
| 480 |
| Melting Completion (Liquidus), °C | 1600 | |
| 1470 |
| Melting Onset (Solidus), °C | 1550 | |
| 1430 |
| Specific Heat Capacity, J/kg-K | 560 | |
| 470 |
| Thermal Conductivity, W/m-K | 7.1 | |
| 41 |
| Thermal Expansion, µm/m-K | 9.6 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 1.0 | |
| 7.6 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.0 | |
| 8.8 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 36 | |
| 4.1 |
| Density, g/cm3 | 4.4 | |
| 7.9 |
| Embodied Carbon, kg CO2/kg material | 38 | |
| 1.8 |
| Embodied Energy, MJ/kg | 610 | |
| 23 |
| Embodied Water, L/kg | 200 | |
| 62 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 30 to 120 | |
| 84 to 110 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 2310 to 3540 | |
| 140 to 320 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 35 | |
| 24 |
| Strength to Weight: Axial, points | 48 to 60 | |
| 18 to 21 |
| Strength to Weight: Bending, points | 42 to 49 | |
| 18 to 20 |
| Thermal Diffusivity, mm2/s | 2.9 | |
| 11 |
| Thermal Shock Resistance, points | 54 to 68 | |
| 14 to 17 |
Alloy Composition
| Aluminum (Al), % | 5.5 to 6.8 | |
| 0 |
| Carbon (C), % | 0 to 0.1 | |
| 0.050 to 0.15 |
| Chlorine (Cl), % | 0 to 0.2 | |
| 0 |
| Chromium (Cr), % | 0 | |
| 2.8 to 3.3 |
| Hydrogen (H), % | 0 to 0.015 | |
| 0 |
| Iron (Fe), % | 0 to 0.4 | |
| 94.4 to 96 |
| Manganese (Mn), % | 0 | |
| 0.3 to 0.6 |
| Molybdenum (Mo), % | 0 | |
| 0.9 to 1.1 |
| Nitrogen (N), % | 0 to 0.040 | |
| 0 |
| Oxygen (O), % | 0 to 0.3 | |
| 0 |
| Phosphorus (P), % | 0 | |
| 0 to 0.025 |
| Silicon (Si), % | 0 to 0.1 | |
| 0 to 0.5 |
| Sodium (Na), % | 0 to 0.2 | |
| 0 |
| Sulfur (S), % | 0 | |
| 0 to 0.025 |
| Titanium (Ti), % | 87 to 91 | |
| 0 |
| Vanadium (V), % | 3.5 to 4.5 | |
| 0 |
| Residuals, % | 0 to 0.4 | |
| 0 |