TB2 Overview
TB2 alloy is a sub-stabilized β-type Titanium Alloy containing homo-crystalline β-stabilizing elements 5% Mo and 5% V, eutectic β-stabilizing element 8% Cr, α-stabilizing element 3% Al, and a Mo equivalent of 18.15. The alloy has excellent cold-forming properties and good weldability in the solid solution processed state, and high strength matched with good plasticity in the solid solution aged state. The main disadvantages of the alloy are its high density, low modulus of elasticity and resistance to high-temperature creep.
The main semi-finished products of this alloy are plates, strips, foils, rods and wires. Plate can be made into sheet metal parts, pressure vessels, solid rocket motor shell. Strips can be made into star-arrow connecting straps. Foil can be made into corrugated shell and honeycomb structure. Wire can be cold heading out of a variety of head type rivets, and can be cold riveting and hot riveting, rivets in the solid solution treatment state upsetting rivets directly after use. The rods can be cold headed for bolts of various head types and can be used in solution treated or solution aged condition.
The alloy is suitable for the manufacture of aerospace fasteners operating at 300°C or less, and for the manufacture of aerospace fasteners operating at 500°C or less for a short period of time.
TB2 technical standard
GB/T 3620.1-1994 Titanium and Titanium Alloys Brand Numbers and Chemical Composition
GB/T 3620.2-1994 Titanium and Titanium Alloy Processed Products Chemical Composition and Allowable Deviation of Composition
GB/T 3621-1994 Titanium and Titanium Alloy Plates and Sheets
K/JC 2-1984 Provisional Technical Specification for TB2 Alloy Strips for Communication Satellite “Star and Arrow Connecting Strips”.
GJB 2219-1994 Specification for Titanium and Titanium Alloy Bars (Wire) for Fasteners
TB2 heat treatment system
(1) Solid solution treatment
Solid solution treatment temperature is selected within the range of 750-800℃, and the usual solid solution treatment system is 800℃±10℃, 3-30min, air-cooling or faster cooling.
(2) Aging
Selected aging temperature in the range of 450-550 ℃, the usual aging system is 500 ℃ ± 10 ℃, 8-24h, air cooling or furnace cooling.
(3) Stress relief annealing
650-700℃, 30-60min, air cooling or furnace cooling.
TB2 melting and casting process
The alloy should be melted in vacuum self-consumption electrode arc furnace for more than two times.
TB2 application profile and special requirements
TB2 alloy strips have been used in the aerospace industry for a long time, and TB2 alloy wires have been used in the aerospace industry for cold heading of rivets with various heads. The rods can be cold headed to produce hexagonal, hexagonal and countersunk head bolts, which can be used in the aviation and aerospace industries. The use temperature of solid solution treatment state is below 200℃, and the use temperature of solid solution aging state is below 300℃.
TB2 corrosion resistance
TB2 alloy has good corrosion resistance and contact corrosion resistance. Stainless steel in contact with it basically does not produce corrosion. Aluminum alloy and structural steel in contact with it, the alloy itself does not corrode, but the dissimilar metal is corroded by the alloy by anodization, the mechanical properties of its influence is not great, but can slow down the structural steel and aluminum alloy in contact with the corrosion rate.
