HAYNES® Ti-3Al-2.5V alloy
Principal Features
Lightweight, High Strength
HAYNES® Ti-3Al-2.5V alloy (UNS R56320) is both lightweight and strong. It has a high strength-to-weight ratio which provides a major design advantage – saving weight. Ti-3Al-2.5V alloy is about 43 percent lighter than 21-6-9 stainless steel. Comparative typical weights per foot for 1 in (25.4 mm) x 0.035 in (0.89 mm) wall tubing are as follows:
| 21-6-9 | 0.36 lb (0.16 kg) |
| Ti-3Al-2.5V | 0.21 lb (0.09 kg) |
Developed as Tubing Alloy
In the initial examination of titanium alloys for specific aircraft/aerospace tasks, commercially pure titanium was alloyed with selected elements to improve the performance characteristics and to obtain higher strength levels. Specific alloying additives, notably aluminum, raise the temperature at which the alloy transforms completely to the beta phase. This point on, the temperature scale is known as the beta transus temperature. The addition of vanadium, on the other hand, lowers the temperature of transformation of alpha to beta phases.
Titanium 6% aluminum 4% vanadium (Ti-6Al-4V) was chosen as an ideal aircraft/aerospace alloy because it had a good strength-to-weight ratio as annealed combined with resistance to cracking during forging, fair to good weldability, and was heat treatable to higher strengths.
But, because Ti-6Al-4V alloy did not have good cold forming characteristics, the titanium alloy with 3% aluminum and 2.5% vanadium (Ti-3Al-2.5V) was developed for tubing and foil applications. This alloy is intermediate in strength between commercially pure titanium and Ti-6Al-4V. It has properties 30 to 50 percent higher than pure titanium, but more importantly, has the excellent cold formability needed to make seamless tubing.
Good Weldability
HAYNES® Ti-3Al-2.5V alloy tubing is readily welded by the standard gas tungsten arc process with inert gas shielding and by the use of automatic welding tools with built-in gas purge chambers. Machine settings similar to those used for stainless steels are used when welding Ti-3Al-2.5V tubing.
Applications
Seamless tubing of HAYNES® Ti-3Al-2.5V alloy was developed for aircraft hydraulic and fuel systems. Its performance has been proven in high technology military aircraft and spacecraft as well as in commercial aircraft. Another application for HAYNES® Ti-3Al-2.5V alloy is tubing for bicycle frames. The high strength and light weight characteristics are ideal for this product.
Strict Quality Controls
The latest in quality control equipment is available at Haynes International, Inc. To provide maximum product integrity. Tubing lots are 100% visually, dimensionally and ultrasonically tested. Samples also are examined metallographically as well as tested for conformance to the chemical composition and mechanical property requirements of the applicable specification.
Heat-treatment
HAYNES® Ti-3Al-2.5V alloy seamless tubing is normally supplied in either the annealed or cold worked and stress relieved condition. Temperatures used generally range from 700°F to 1450°F (371°C 790°C) depending on the degree of re-crystallization or stress relief that is required for a given end use.
Heat-treatment is done in vertical vacuum annealing furnaces. Vertical annealing has two advantages over horizontal annealing. Tubes hung vertically can be arranged so that each tube receives uniform furnace heat. Also, tubes annealed vertically tend to remain straight and round.
Nominal Composition
Weight %
Titanium
Balance
Aluminum
3
Vanadium
2.5
Iron
0.25 max.
Carbon
0.05 max.
Hydrogen
**
Oxygen
0.12 max.
Nitrogen
0.02 max.
| Weight % | |
| Titanium | Balance |
| Aluminum | 3 |
| Vanadium | 2.5 |
| Iron | 0.25 max. |
| Carbon | 0.05 max. |
| Hydrogen | ** |
| Oxygen | 0.12 max. |
| Nitrogen | 0.02 max. |
** Varies with specification
Average Physical Properties
| Physical Property | British Units | Metric Units | ||
| Density | RT |
0.162 lb/in3 |
RT |
4.48 g/cm3 |
| Melting Temperature | Approx. 3100°F | – | Approx. 1705°C | – |
RT= Room Temperature
Minimal Mechanical Properties
| Condition | Specification | Yield Strength0.2% Offset | Ultimate TensileStrength | Elongation* | |||
| Annealed | AMS 4943 | ksi | MPa | ksi | MPa | % | – |
| 75.0 | 517 | 90.0 | 621 | 15 | - | ||
| CWSR | AMS 4944/4945 | 105.0 | 724 | 125.0 | 862 | 8 | Above 0.016 in Wall |
| CWSR | AMS 4944/4945 | 105.0 | 724 | 125.0 | 862 | 10 | Above 0.016 in Wall |
| CWSR | DAN 2700.9 | 95.0 | 655 | 100.0-133.0 | 690-920 | 14 | 1/4 in Diameter |
| 106.0 | 730 | 126.0-149.0 | 870-1030 | 14 | 3/8 in Diameter | ||
| 106.0 | 730 | 126.0-149.0 | 870-1030 | 14 | 3/8 in Diameter | ||
*2in (50.8 mm) gage length for AMS 4944 and AMS 4945. 1.969 in (50.0 mm) gage length for DAN 2700.9
Common Tubing Sizes
Listed in the following table are some of the common sizes produced for major aircraft companies. Sizes other than those shown can be produced depending on the quantity required.
| Outside Diameter | Wall Thickness | Outside Diameter | Wall Thickness | ||||
| in (mm) | in (mm) | in (mm) | in (mm) | ||||
| 1/4 (6.4) | 0.016 | 0.41 | 3/4 (19.1) | 0.020 | 0.51 | ||
| 0.020 | 0.51 | 0.028 | 0.71 | ||||
| 0.028 | 0.71 | 0.035 | 0.89 | ||||
| - | - | 0.039 | 0.99 | ||||
| - | - | 0.054 | 1.37 | ||||
| - | - | 0.081 | 2.06 | ||||
| 3/8 (9.5 | 0.019 | 0.48 | 7/8 (22.2) | 0.028 | 0.53 | ||
| 0.022 | 0.56 | 0.032 | 0.71 | ||||
| 0.028 | 0.71 | 0.035 | 0.89 | ||||
| 0.035 | 0.89 | 0.049 | 1.24 | ||||
| 0.042 | 1.07 | 0.061 | 1.55 | ||||
| 1/2 (12.7) | 0.023 | 0.58 | 1 (25.4) | 0.021 | 0.53 | ||
| 0.026 | 0.66 | 0.028 | 0.71 | ||||
| 0.028 | 0.71 | 0.035 | 0.89 | ||||
| 0.036 | 0.91 | 0.051 | 1.30 | ||||
| 0.056 | 1.42 | 0.070 | 1.78 | ||||
| - | - | 0.073 | 1.85 | ||||
| 5/8 (15.9) | 0.023 | 0.58 | 11/4 (31.8) | 0.028 | 0.71 | ||
| 0.028 | 0.71 | 0.032 | 0.81 | ||||
| 0.032 | 0.81 | 0.035 | 0.89 | ||||
| 0.035 | 0.89 | 0.040 | 1.02 | ||||
| 0.044 | 1.12 | 0.065 | 1.65 | ||||
| 0.049 | 1.24 | 0.087 | 2.21 | ||||
| - | - | - | 1 1/2 (38.1) | 0.035 | 0.89 | ||
| - | - | 0.054 | 1.37 | ||||
Dimensional Tolerances
Commercial OD/Wall (ASTM B-338)
| Nominal Outside Diameter | Diameter Tolerance | Ovality Tolerance | Wall Tolerance | ||
| in | mm | in | mm | Tolerance* Included in Diameter Tolerances | +/- 10% Nominal Wall Thickness |
| Under 1. | 25.4 excl. | +/-0.004 | 0.102 | ||
| 1 to 1.5 | 25.4 to 38.1 excl. | +/-0.005 | 0.127 | ||
| 1.5 to 2 | 38.1 to 50.8 excl. | +/-0.006 | 0.152 | ||
| 2 to 2.5 | 50.8 to 63.5 excl. | +/-0.007 | 0.178 | ||
| 2.5 to 3.5 | 63.5 to 88.9 excl. | +/-0.010 | 0.254 | ||
Aerospace OD/Wall (AMS)
| Nominal Outside Diameter, in. | Diameter Tolerance, in. | Ovality Tolerance | Wall Tolerance |
| Over 0.093 to 0.188, incl. | +0.002/-0.000 | Tolerance Included in Diameter Tolerances | + 10%, – 5% Nominal Wall Thickness for Tubing under 1.500 in. (38.1 mm) Nominal OD +/- 10% Nominal Wall Thickness for Tubing over 1.500 in (38.1 mm) Nominal OD |
| Over 0.188 to 0.500, incl. | +0.003/-0.000 | ||
| Over 0.500 to 1.000, incl. | +0.004/-0.000 | ||
| Over 1.000 to 1.500, incl. | +0.004/-0.001 | ||
| Over 1.500 to 2.000, incl. | +0.005/-0.001 | ||
| Diameter, mm | Tolerance, mm | ||
| Over 2.3 to 4.70, incl. | +0.05/-0.00 | ||
| Over 4.7 to 12.50, incl. | +0.08/-0.00 | ||
| Over 12.5 to 25.00, incl. | +0.10/-0.00 | ||
| Over 25.0 to 37.50, incl. | +0.10/-0.02 | ||
| Over 37.5 to 50.0, incl. | +0.12/-0.02 |
Aerospace OD/ID (AMS/DAN)
| Nominal Outside Diameter, in. | Diameter Tolerance, in. | Ovality Tolerance | Wall Tolerance |
| Over 0.093 to 0.187, incl. | +0.002/-0.000 | Tolerance Included in Diameter Tolerances | All Tubing 1.500 in. (38.1 mm) And Under in Nominal O.D. Shall Have a Wall Thickness Not Less Than 95% of Nominal |
| Over 0.187 to 0.499, incl. | +0.003/-0.000 | ||
| Over 0.499 to 0.749, incl. | +0.004/-0.000 | ||
| Over 0.749 to 0.999, incl. | +0.004/-0.001 | ||
| Over 0.999 to 1.499, incl. | +0.004/-0.002 | ||
| Over 1.499 to 1.999, incl. | +0.005/-0.002 | ||
| Diameter, mm | Tolerance, mm | ||
| Over 2.36 to 4.75, incl. | +0.05/-0.00 | ||
| Over 4.75 to 12.67, incl. | +0.08/-0.00 | ||
| Over 12.67 to 19.02, incl. | +0.10/-0.00 | ||
| Over 19.02 to 25.37, incl. | +0.10/-0.025 | ||
| Over 25.37 to 38.07, incl. | +0.10/-0.05 | ||
| Nominal Inside Diameter, in. | Diameter Tolerance, in. | ||
| Up to 0.338, incl. | +0.0015/-0.0015 | ||
| Over 0.338 to 0.499, incl. | +0.002/-0.002 | ||
| Over 0.499 to 0.637, incl. | +0.0025/-0.0025 | ||
| Over 0.637 to 0.900, incl. | +0.003/-0.003 | ||
| Over 0.900 and over | +0.004/-0.004 | ||
| Diameter, mm | Tolerance, mm | ||
| Up to 8.59, incl. | +0.038/-0.038 | ||
| Over 8.59 to 11.40, incl. | +0.05/-0.05 | ||
| Over 11.40 to 17.09, incl. | +0.064/-0.064 | ||
| Over 17.09 to 22.86, incl. | +0.08/-0.08 | ||
| Over 22.86 and above | +0.10/-0.10 |
Inside diameter is equal to the nominal OD minus twice the nominal wall
Specifications
Specifications
| HAYNES® Ti-3AL-2.5V alloy (R56320) | |
| Sheet Plate and Strip | - |
| Biller Rod/Bar | - |
| Coated Electrodes | - |
| Bar Welding Rods | - |
| Seamless Pipe & Tube | AMS 4943 AMS 4944 AMS 4945 AMS 4946 AS5620 D210-12096-1 DMS 2241 MMS 1205 MS 330 SB 338/ B 338Gr9 |
| Weld Pipe & Tube | - |
| Fittings | - |
| Forgings | - |
| DIN | - |
| TÜV | - |
| Others | - |
Disclaimer
Haynes International makes all reasonable efforts to ensure the accuracy and correctness of the data displayed on this site but makes no representations or warranties as to the data’s accuracy, correctness or reliability. All data are for general information only and not for providing design advice. Alloy properties disclosed here are based on work conducted principally by Haynes International, Inc. and occasionally supplemented by information from the open literature and, as such, are indicative only of the results of such tests and should not be considered guaranteed maximums or minimums. It is the responsibility of the user to test specific alloys under actual service conditions to determine their suitability for a particular purpose.
For specific concentrations of elements present in a particular product and a discussion of the potential health affects thereof, refer to the Safety Data Sheets supplied by Haynes International, Inc. All trademarks are owned by Haynes International, Inc., unless otherwise indicated.