HAYNES® Ti-3Al-2.5V alloy 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% valadium (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.

Readily Formed
Seamless tubing of HAYNES Ti-3Al-2.5V alloy is readily formed cold on conventional tube bending equipment of the same type used for stainless steel. Tubing can be bent 180 degrees around a suitable bend die with a centerline radius equal to 3 to 5 times the normal outside diameter of the tubing. Relative thin wall tubing should be bent using tubing fillers or other inside diameter constraints.

Good Weldability
HAYNES Ti-3Al-2.5V 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.