TC16 titanium alloy is a martensitic α-β two-phase titanium alloy. Its composition is Ti-3AI-5Mo-4.5V, containing α-stabilizing element Al and isomorphous β-stabilizing elements Mo and V. The alloy has high strength and good plasticity and can be used to make fasteners such as rivets and bolts. TC16 alloy can undergo strengthening heat treatment, and its solution treatment temperature is lower, only 800°C, which is 150°C lower than TC4 alloy. After solid solution aging treatment, the strength of TC16 alloy can reach more than 1030MPa, and it is less sensitive to stress concentration and can better resist stress concentration phenomena such as notches and deflections. The maximum operating temperature of TC16 alloy is 350℃. The semi-finished products of this alloy mainly include hot-rolled bars and polished bars (wires) for cold heading.
Chemical composition of TC16 titanium alloy (%)
Heat treatment system of TC16 titanium alloy
The heat treatment system of TC16 titanium alloy includes annealing, stress relief annealing, solution treatment and aging.
Annealing: Select the annealing temperature within the range of 770-790°C. The typical annealing system is 780°C±10°C, hold for 2 hours, and furnace cool to 550°C at a rate of 2-4°C/min (no higher than 550°C in vacuum) 500℃) and then air-cooled.
Stress relief annealing: Select the stress relief annealing temperature within the range of 550-650°C, keep it warm for 0.5-4 hours, and then air-cool.
Solid solution treatment: Select the solution treatment temperature within the range of 780-830°C. The typical solution treatment system is 800°C ± 10°C, holding for 2 hours, and then water quenching.
Aging: Select the aging temperature within the range of 500-580°C. The typical aging system is 560°C±10°C, keep warm for 6-10 hours, and then air-cool.
Smelting and casting process of TC16 titanium alloy
The smelting and casting process of TC16 titanium alloy includes the following steps:
Ingot smelting: The ingots used to make bars should be smelted in a vacuum consumable electrode arc furnace more than twice. Choose grade 0-1 small particle sponge titanium with an oxygen content of no more than 0.08%, Al-Mo master alloy with a molybdenum content of 80%-85%, and AI-V master alloy with a vanadium content of 80%-85%. During the smelting process, special attention needs to be paid to the distribution method to ensure the uniform distribution of various alloy elements in the electrode block. Consumable electrodes are welded using argon shielded plasma welding, and tungsten argon arc welding is strictly prohibited.
Vacuum melting: The absolute pressure during one vacuum melting should not be greater than 1.3Pa. Vacuum melting ensures the purity and uniformity of the alloy. The final remelting can be performed in vacuum or in an argon atmosphere.
Thermal capping operation: Thermal capping operation must be performed before the end of smelting. This is to prevent oxidation and contamination of the alloy during cooling.
Heat treatment process of TC16 alloy fasteners
The heat treatment process of TC16 titanium alloy fasteners generally includes three processes: annealing, solution treatment and aging.
Annealing process: Heat the TC16 alloy fastener to 780℃±10℃, keep it warm for 2 hours, then furnace cool to 550℃ at a rate of 2-4℃/min, and then air cool.
Solution treatment process: Heat the annealed TC16 alloy fasteners to 800℃±10℃, keep it warm for 2 hours, and then quickly quench with water.
Aging process: Heat the solution-treated TC16 alloy fasteners to 560℃±10℃, keep warm for 6-10 hours, and then air-cool.
In addition, the strengthening heat treatment of TC16 alloy fasteners can also be carried out according to the following process: keep it at 810-790℃ for 2 hours, furnace cool to 760-780℃ at a speed of 2-4℃/min, keep it for another 2 hours, and then Water quenching; finally aging at 500-540℃ for 4-8 hours, air cooling.
Application of TC16 titanium alloy
TC16 titanium alloy has high strength and good plasticity, and is widely used in aviation, aerospace, automobiles, medical and other fields. Among them, TC16 titanium alloy is the most widely used in the aviation field and is mainly used to manufacture fasteners such as rivets and bolts.
Russia has developed an aerospace titanium alloy fastener material system based on TC16 titanium alloy, with complete varieties and specifications, including bars for cold heading, hot heading and hexagonal bars. Fasteners of this alloy are widely used on various military and civilian aircraft. It has also been put into practical use on new aircraft in my country.
In addition to the aviation field, TC16 titanium alloy is also widely used in the medical field, such as manufacturing artificial joints and dental implants. In addition, TC16 titanium alloy can also be used to manufacture automobile parts and sports equipment.