TB2 Overview
TB2 alloy is a metastable β - type titanium alloy containing 5% Mo and 5% V of eutectic β - stable elements, 8% Cr of eutectoid β - stable elements, 3% Al of α - stable elements, and a Mo equivalent of 18.15. This alloy has excellent cold forming performance and good welding performance in the solution treated state, and high strength and good plasticity matching in the solution aged state. The main disadvantages of this alloy are high density, low elastic modulus, and low resistance to high-temperature creep.
The main semi-finished products of this alloy include plates, strips, foils, rods, wires, etc. Sheet metal can be used to make sheet metal parts, pressure vessels, and solid rocket engine casings. The strip can be made into a star arrow connecting strip. Foil can be used to make corrugated shells and honeycomb structures. Silk material can be cold forged to produce various head type rivets, and can be cold riveted and hot riveted. Rivets can be directly used after solid solution treatment. Rod can be cold forged into various head type bolts, which can be used in solution treatment or solution aging state.
This alloy is suitable for manufacturing aerospace fasteners that work below 300 ℃, as well as for manufacturing aerospace fasteners that work briefly below 500 ℃.
TB2 Technical Standard
GB/T 3620.1-1994 "Titanium and Titanium Alloy Grades and Chemical Composition"
GB/T 3620.2-1994 "Chemical Composition and Allowable Deviation of Titanium and Titanium Alloy Processing Products"
GB/T 3621-1994 "Titanium and Titanium Alloy Plates"
K/JC 2-1984 Provisional Technical Specification for TB2 Alloy Strip for "Satellite Arrow Connection Belt" of Communication Satellites
GJB 2219-1994 "Specification for Titanium and Titanium Alloy Rod (Wire) Materials for Fasteners"
TB2 heat treatment system
(1) Solid solution treatment
Select the solid solution treatment temperature within the range of 750-800 ℃. The usual solid solution treatment system is 800 ℃± 10 ℃, 3-30min, air cooling or faster cooling.
(2) Timeframe
Select the aging temperature within 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 ℃, 30-60 minutes, air-cooled or furnace cooled.
TB2 Melting and Casting Process
The alloy should be melted in a vacuum consumable electrode arc furnace at least twice.
Overview and Special Requirements of TB2 Application
Various specifications of star arrow connecting strips made of TB2 alloy strip have been used in the aerospace industry for a long time. Various head type rivets made from TB2 alloy wire through cold heading have been applied in the aviation industry. Rod can be cold forged to produce various types of bolts such as internal hexagon, external hexagon, and countersunk head, which can be used in the aviation and aerospace industry. The operating temperature for the solid solution treatment state is below 200 ℃, and the operating temperature for the solid solution aging state is below 300 ℃.
Corrosion resistance of TB2
TB2 alloy has good corrosion resistance and contact corrosion resistance. Stainless steel does not produce corrosion when in contact with it. Aluminum alloy and structural steel come into contact with it, and the alloy itself does not corrode, but dissimilar metals are corroded. The alloy undergoes anodization, 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.