TB2 (β type) titanium alloy material introduction

TB2 alloy is a metastable β-type titanium alloy, containing isomorphic β-stable elements 5%Mo and 5%V, eutectoid β-stable elements 8%Cr, α-stable elements 3%Al, Mo equivalent of 18.15. The alloy has excellent cold forming properties and good weldability in the solution treatment state, and has high strength and good plasticity in the solution aging state. The main disadvantages of the alloy are high density, low elastic modulus and high temperature creep resistance.

The main semi-finished products of the alloy are sheet, strip, foil, bar, wire and so on. The sheet metal can be made into sheet metal parts, pressure vessels, solid rocket motor shells. The strip can be made into a star-arrow connection belt. Foil can be made into corrugated shell and honeycomb structure. The wire can be cold headed out of various head rivets, and can be cold riveted and hot riveted, and the rivets are directly used after upsetting and riveting in the state of solid solution treatment. The bar can be cold headed out of various head bolts, which can be used in solution treatment state or solution aging state.

The alloy is suitable for manufacturing aerospace fasteners that work below 300 ℃, and is also suitable for manufacturing aerospace fasteners that work for a short time below 500℃.

TB2 heat treatment system
(1) Solid solution treatment
The solution treatment temperature is selected in the range of 750-800℃, the usual solution treatment system is 800℃ ± 10℃, 3-30min, air cooling or faster cooling.

(2) Time limitation
The aging temperature is selected in the range of 450-550℃, and the usual aging system is 500℃ ± 10℃, 8-24h, air-cooled or furnace cooled.

(3) Stress relief annealing
650-700℃, 30-60min, air-cooled or furnace cooled.

TB2 melting and casting process
The alloy should be melted by more than two vacuum consumable electrode arc furnaces.
TB2 application overview and special requirements
Various specifications of star and arrow connection belts made of TB2 alloy strip have been used in the aerospace industry for a long time. Various head rivets made of TB2 alloy wire by cold heading have been applied in aviation industry. The bar can be cold headed out of hexagon, outer hexagon and countersunk bolts for aviation and aerospace industry applications. The use temperature of the solid solution treatment state is below 200℃, and the use temperature of the solid solution aging state is below 300℃.

TB2 corrosion resistance
TB2 alloy has good corrosion resistance and contact corrosion resistance. Stainless steel and its contact basically does not produce corrosion. Aluminum alloy and structural steel contact with it, the alloy itself does not corrode, but dissimilar metals are corroded by anodizing the alloy, which has little effect on its mechanical properties, but can slow down the corrosion rate of structural steel and aluminum alloy in contact with it.