Guides/Comparisons
Ti-6Al-4V vs grade 2 titanium
ti-6al-4v-vs-grade-2-titaniumTi-6Al-4V and Commercially pure titanium, Grade 2 (UNS R50400) at a glance
This page compares Ti-6Al-4V and Commercially pure titanium, Grade 2 (UNS R50400) using only values that carry a source, a test condition and an evidence level. Ranges run across temper, heat treatment and product form, measured at room temperature where the source says so.
- Composition: Iron (Ti-6Al-4V up to 0.4%; grade 2 up to 0.30%), Oxygen (Ti-6Al-4V up to 0.2%; grade 2 up to 0.25%).
- Yield strength: Ti-6Al-4V is higher (Ti-6Al-4V 830 to 1,100 MPa; grade 2 275 to 352 MPa), about 3.1 times the midpoint of grade 2.
- Density: grade 2 is higher (Ti-6Al-4V 4.43 g/cm³; grade 2 4.51 g/cm³), a difference of under 10% at the midpoint.
- Young's modulus: Ti-6Al-4V is higher (Ti-6Al-4V 114 GPa; grade 2 103 GPa), about 1.1 times the midpoint of grade 2.
- Thermal conductivity: grade 2 is higher (Ti-6Al-4V 6.7 W/(m·K); grade 2 22 W/(m·K)), about 3.3 times the midpoint of Ti-6Al-4V.
- Yield strength for each unit of density (calculated from each grade's midpoint values): Ti-6Al-4V 218 MPa per g/cm³; Commercially pure titanium, Grade 2 (UNS R50400) 69.5 MPa per g/cm³.
"Higher" means the whole range is higher, not just one value. Where a value is a specified minimum, the table says "at least".
Side by side
| Property | Ti-6Al-4V | Commercially pure titanium, Grade 2 (UNS R50400) |
|---|---|---|
| Yield strength | 830 to 1,100 MPa | 275 to 352 MPa |
| Tensile strength | no data | 345 to 483 MPa |
| Density | 4.43 g/cm³ | 4.51 g/cm³ |
| Young's modulus | 114 GPa | 103 GPa |
| Thermal conductivity | 6.7 W/(m·K) | 22 W/(m·K) |
| Melting point | 1,604 to 1,660 °C | no data |
| Thermal expansion | 8.6 ppm/K | no data |
| Yield strength per densitycalculated | 218 MPa per g/cm³ | 69.5 MPa per g/cm³ |
Composition
| Element | Ti-6Al-4V | Commercially pure titanium, Grade 2 (UNS R50400) |
|---|---|---|
| Titanium | balance | balance |
| Aluminium | 5.5 to 6.75% | not listed |
| Vanadium | 3.5 to 4.5% | not listed |
| Iron | up to 0.4% | up to 0.30% |
| Oxygen | up to 0.2% | up to 0.25% |
| Carbon | not listed | up to 0.08% |
| Nitrogen | not listed | up to 0.03% |
| Hydrogen | not listed | up to 0.015% |
Shares are as printed in the sources, by weight.
When to use which
| Material | Best for | Weakest at |
|---|---|---|
| Ti-6Al-4V | Strength-to-weight structures that must stay strong up to about 400 degC, such as aerospace forgings and bars (the datasheet gives 4.43 g/cm3 density and 830 to 950 MPa yield) | Low thermal conductivity (6.7 W/(m K) at 20 degC), and lower ductility once it is solution-treated and aged (6 to 10 % elongation) |
| Commercially pure titanium, Grade 2 (UNS R50400) | Seawater, brine and chloride service where corrosion resistance and formability matter more than strength (Alleima and Smiths datasheets) | Strength: 345 MPa minimum tensile, well below Ti-6Al-4V (see the Ti-6Al-4V profile). Crevice attack in hot seawater from about 80 °C (Pang and Blackwood 2016) |
Where each is used
| Material | Use |
|---|---|
| Ti-6Al-4V | Aerospace forging and bar (example of an AMS 4928 bar forging) |
| Ti-6Al-4V | Aircraft and spacecraft structural parts made to AMS 4928 and AMS 4911 |
| Ti-6Al-4V | Aero-engine components and airframe components |
| Ti-6Al-4V | Marine equipment and offshore oil and gas equipment |
| Commercially pure titanium, Grade 2 (UNS R50400) | Seawater-cooled heat exchanger and condenser tubing |
| Commercially pure titanium, Grade 2 (UNS R50400) | Desalination pipe and reverse-osmosis pressure vessels |
| Commercially pure titanium, Grade 2 (UNS R50400) | Aerospace hydraulic tubing (AMS 4943 annealed; AMS 4944 and 4945 cold worked and stress relieved) |