TB5 (beta titanium alloy) material introduction

Brief introduction of TB5

TB5 alloy is a sub-stable β-type titanium alloy with the nominal composition of Ti-15V-3O-3Sn-3Al, containing homo-crystalline β-stabilizing element V, eutectic β-stabilizing element Cr, neutral element Sn, and α-stabilizing element AI. The alloy has excellent cold-rolling and cold-forming properties, and the deformation of the cold-rolling can reach more than 90%, and it can be used to form the medium-complex sheet-metal parts at the room temperature, and can be superplasticized above 700℃, and can be used for cold upsetting rivets and bolts. It can be formed into moderately complex sheet metal parts at room temperature and can also be superplasticized at 700°C or above, and can be used for cold heading rivets and bolts. The alloy can also be aging treatment to achieve more than 1080MPa strength, and has excellent welding performance.TB5 alloy is mainly used in the manufacture of various sheet metal components, but also the manufacture of fasteners, to meet the high structural efficiency, high productivity and low manufacturing cost requirements, solid solution treatment state of the working temperature of 200 ℃, the solid solution aging state of the working temperature up to 290 ℃. Semi-finished products of this alloy are mainly sheet, strip and bar (wire), and tubes can also be produced.

TB5 technical standards

GB/T 3620.2-1994 Chemical Composition and Allowable Deviation of Composition of Titanium and Titanium Alloy Processed Products

Q/6S 1058-1995 "Solid solution treatment of Ti-15V-3Cr-3Sn-3Al titanium alloy sheet".

Q/6S 1206-1995 《Ti-15V-3Cr-3Sn-3Al titanium alloy bars (wires) for fasteners》.

AMS 4914A-1992 Solution-treated 15V-3Al-3Cr-3Sn Titanium Alloy Cold Rolled Sheets and Strips
TB5 Heat treatment system

Heat treatment system according to GBJ 3763-1999 "Titanium and Titanium Alloy Heat Treatment Specification".

TB5 solid solution treatment

The solution treatment temperature is selected in the range of 760-815°C or 790-815°C. The usual solution treatment regime is 800°C ± 15°C for 3-30 min with air or faster cooling.

TB5 Aging

Aging temperature of 480-675 ° C, aging time of 2-24h according to the strength level is usually used in three aging system, the temperature fluctuation range of ± 6 ° C.

TB5 melting and special requirements

Manufacture of thin plates and bars (wire) with ingots should be more than two times through the vacuum self-consumption electrode arc furnace melting. Choose 0-1 grade titanium sponge with oxygen mass fraction not more than 0.07%, high quality 85V-15AI intermediate alloy with oxygen mass fraction not more than 0.25%, 80Sn-20Ti intermediate alloy, and metal chromium with low oxygen mass fraction.

Special attention should be paid to the way the electrode block is fabricated and the uniformity of the distribution of various alloying elements. Self-consumption electrode welding using argon protection plasma welding method, strictly prohibit the use of tungsten argon arc welding.

TB5 alloy melting pressure should not be higher than 1.3Pa, after a remelting can be carried out in a vacuum or argon atmosphere.

TB5 application overview

TB5 alloy sheet developed by the success of the resistance of the parachute beam sheet metal components and rods (wire) material test success of the rivets have been applied in the fighter aircraft. TB5 titanium alloy parachute beam instead of the original 30CrMnSiA structural steel parachute beam weight reduction of 1.13kg (28.6%). TB5 alloy plate, strip, by blow molding processing of satellite engine corrugated plate and bracket cone has been applied in several types of satellites.

TB5 special requirements

(1) TB5 alloy high-strength titanium alloy, on the gap and other surface defects of high sensitivity, in the design of parts should be noted. For parts subjected to repeated loads, the edges of the parts in the tensile zone should be polished smooth, surface abrasions shall not exceed the provisions of the material technical standards.

(2) TB5 alloy is suitable for cold forming of sheet metal parts of medium complexity, from a cross-section of the part to another cross-section of the transition radius and part corners, bending radius in the structure should try to use the larger value, while the height of the flap, tensile contraction of the curved edge of the height and the depth of the sinking as far as possible to use a smaller value. Temporarily not suitable for the design of the skin stretching parts.

(3) Like all β alloys, the alloy has a greater affinity for hydrogen and is more susceptible to hydrogen enrichment than α and α-β type titanium alloys, so chemical milling is not allowed for TB5 alloy.

(4) TB5 alloy can be subjected to aging treatment directly after cold forming, which should generally be carried out in a vacuum or under the protection of inert gases, and in order to minimize the deformation of the parts, suitable fixtures should be used for restrained aging.

TB5 Corrosion Resistance

Like most titanium alloys, TB5 alloy has excellent resistance to general corrosion when exposed to common environmental conditions TB5 alloy does not require specialized surface treatment for use in aircraft structures. However, for hydrogenation reasons, when TB5 alloys are operated in environmental conditions where significant amounts of hydrogen are likely to be generated, surface modification treatments must be applied to stop the hydrogenation.

The contact corrosion behavior of TB5 titanium alloy with structural steel and aluminum alloys is the same as that of TC4 titanium alloy.

TB5 Recommendations

TB5 titanium alloy is recommended for use in aircraft and satellite structures. Cold forming or blow molding processes are used to manufacture structural parts, and cold heading processes are used to manufacture TB5 titanium alloy rivets that can be cold riveted.