Ti-3Al-2.5V(Grade 9)
Titanium Grade 9 alloy is a near-α-type titanium alloy with a nominal composition of Ti-3Al-2.5V, which was developed as a cold-workable pipe application. At room temperature and high temperature, its strength is 20% to 50% higher than pure titanium, and its welding performance and cold forming performance are better than Ti-6Al-4V(Grade 5) alloy. Titanium Grade 9 alloy is generally used in the annealed state, and can also be used in the cold-worked and stress-relieved annealed state. The maximum operating temperature is about 315°C.
Titanium Grade 9 alloy seamless pipe is suitable for hydraulic and fuel pipeline systems of aircraft and engines. It can also be rolled into foil and strip. The former is mostly used in airplane honeycomb structures.
Ti-3Al-2.5V(Grade 9) chemical composition (mass fraction) %
Grade | Alloy Element | Impurities≤ | |||||||||
Al | V | Ti | Fe | C | N | H | O | Y | Other Element | ||
Single | Total | ||||||||||
Ti-3Al-2.5V(Grade 9) | 2.5~3.5 | 2.0~3.0 | Balance | 0.3 | 0.05 | 0.025 | 0.015 | 0.12 | 0.005 | 0.1 | 0.4 |
Forms of Ti-3Al-2.5V(Grade 9) We Can Provide
Physical and chemical properties of Ti-3Al-2.5V(Grade 9)
1. Melting temperature is 1700~1726℃ 2. Density ρ=4.47g/cm33. Thermal conductivity
Thermal conductivity | ||||||||
θ/℃ | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 |
λ/W·m-1·K-1 | 11.7 | 13 | 13.4 | 14.2 | 14.7 | 16.3 | 17.6 | 19.3 |
The specific heat capacity at room temperature is 858J/(kg.K)
5. Coefficient of linear expansion
Coefficient of linear expansion | ||||||||
θ/℃ | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 |
α/10-6·K-1 | 8.77 | 9.56 | 9.66 | 9.7 | 9.65 | 9.68 | 9.84 | 9.73 |
6. Resistivity
Resistivity | |||||||||
θ/℃ | 20 | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 |
ρ/μΩ·m | 1.25 | 1.31 | 1.42 | 1.52 | 1.6 | 1.66 | 1.71 | 1.74 | 1.74 |
Non-magnetic
8. Antioxidant properties
The oxidation resistance temperature of the alloy can reach 316°C. At 800°C, keep it for 1 hour, and the surface oxidation depth does not exceed 0.05mm.
9. Corrosion resistance
The general corrosion performance is similar to that of industrial titanium.
Corrosion resistance | ||||||||
Thermal exposure stress/MPa | 294 | |||||||
Heat exposure temperature/℃ | 350 | 400 | 450 | |||||
Amount of salt applied to the surface/mg.cm-2 | 0 | 10.1 | 17 | 0 | 36.5 | 0 | 1.6 | 3.0~7.7 |
Heat exposure time/h | 100 | 100 | 100 | 100 | 100 | 53.3 | 45.9 | 4.8 |
Room temperature tensile strength/MPa | 738 | 739 | 760 | 746 | 742 | 0 | 0 | 0 |
Phase Transformation and Microstructure of Ti-3Al-2.5V(Grade 9)
Phase transition temperature
α+β↔β transition temperature 925°C±10°CMicrostructure
The structure of the alloy in the annealed state is mainly equiaxed α phase and a small amount of β phase. In the cold-worked state, it presents an elongated α structure. In the solid solution aging state, it is equiaxed α phase and β transformation structure.Phase transition temperature
Start: 560°C; End: 700°CManufacturing process and properties of Ti-3Al-2.5V(Grade 9)
Heat treatment process
Ordinary annealing
Plates, bars, pipes, forgings: 650℃~800℃, 0.5~2h, air coolingVacuum annealing
650 ℃ ~ 790 ℃, 0.5 ~ 2h, furnace cooling to below 200 ℃ out of the furnace air cooling, the absolute pressure in the furnace should not exceed 9 x 10-2PaStress relief annealing
Removal of internal stress formed during parts forming, welding and machining annealing: 370°C~600°C, 0.5~4h, air cooling and furnace cooling.Application of Ti-3Al-2.5V(Grade 9)
As early as the 1970s, Ti-3Al-2.5V(Grade 9) was used as hydraulic, fuel and other pipeline systems on various high-tech military, aerospace and civil aircrafts in the United States. It was also used in the air conditioning pipelines of my country’s transport aircraft in the early 1990s and will be used in aero engines. Application in piping system. In recent years, it has been used as a fire gun with a complex shape, medium strength, and weldable flamethrower.
Ti-3Al-2.5V(Grade 9) has also achieved good applications in various civil industries, such as: oil exploration well instrument jacket pipe fittings, heat exchanger pipe fittings, titanium fishing rod body, spectacle frame profiled wire, golf clubs, etc.