ASTM B631 Class C vs. Grade 21 Titanium
ASTM B631 class C belongs to the otherwise unclassified metals classification, while grade 21 titanium belongs to the titanium alloys. There are 14 material properties with values for both materials. Properties with values for just one material (18, in this case) are not shown. Please note that the two materials have significantly dissimilar densities. This means that additional care is required when interpreting the data, because some material properties are based on units of mass, while others are based on units of area or volume.
For each property being compared, the top bar is ASTM B631 class C and the bottom bar is grade 21 titanium.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 180 to 190 | |
| 140 |
| Poisson's Ratio | 0.32 | |
| 0.32 |
| Shear Modulus, GPa | 66 to 71 | |
| 51 |
Thermal Properties
| Latent Heat of Fusion, J/g | 140 to 150 | |
| 410 |
| Melting Completion (Liquidus), °C | 2090 to 2230 | |
| 1740 |
| Specific Heat Capacity, J/kg-K | 180 | |
| 500 |
| Thermal Conductivity, W/m-K | 450 to 490 | |
| 7.5 |
| Thermal Expansion, µm/m-K | 14 | |
| 7.1 |
Otherwise Unclassified Properties
| Density, g/cm3 | 13 to 14 | |
| 5.4 |
| Embodied Carbon, kg CO2/kg material | 55 to 59 | |
| 32 |
| Embodied Energy, MJ/kg | 860 to 920 | |
| 490 |
Common Calculations
| Stiffness to Weight: Axial, points | 7.4 to 7.6 | |
| 14 |
| Stiffness to Weight: Bending, points | 14 | |
| 32 |
| Thermal Diffusivity, mm2/s | 180 to 200 | |
| 2.8 |