Titanic bars of BT6 diameter are 16 mm

Alloys like BT6 (Ti — 6A1 — 4V) (a + b) - a class are among the titanium alloys which are most extended abroad. Ti alloy — 6A1 — 4V is used for production of large-size welded and fabricated structures of aircrafts, for production of the cylinders working under internal pressure in a wide interval of temperatures from 196 to 450 °C, and a number of other constructive elements. According to a foreign press, about 50% of the titanium used in the aerospace industry are the share of Ti alloy — 6A1 — 4V which analog are domestic alloys like BT6.
Such wide circulation of this alloy is explained by its successful alloying. Aluminum in Ti — Al system alloys — V increases strength and heat resisting properties, and vanadium is among those few doping elements in titanium which raise not only strength properties, but also plasticity.
Along with high specific strength alloys of this type possess smaller sensitivity to hydrogen in comparison with alloys of OT4 and OT4-1, low tendency to a salt attack and good technological effectiveness.
Alloys are well deformed in a hot state. From alloys like BT6 receive bars, pipes, profiles, forgings, stampings, plates, sheets. They cook all traditional types of welding including diffusion. When welding ELS durability of a welded seam is almost equal to durability of the main material that favourably distinguishes this alloy from BT22.
Alloys like BT6 apply in the annealed and thermally strengthened states. Annealing of sheets, thin-walled pipes, profiles and parts from them carry usually out at 750 — 800 °C with the subsequent cooling on air or together with the furnace. Annealing of bars, forgings, stampings and other large-size semi-finished products and parts from them carry out at 750 — 800 "Page. Cooling together with the furnace of large semi-finished products prevents their buckling, and for fine details allows to avoid .chastichny tempering. However recently it has been proved that it is reasonable to increase annealing temperature to 900 — 950 °C that will lead to increase of fracture toughness and impact strength at preservation of high plastic properties because of forming of the mixed structure with a big share of a lamellar component.