The aviation industry is the main field of titanium, and jet engines are an important part of the main field of titanium. According to statistics from relevant sources in the United States, from 1959 to 1973, the US jet engine manufacturing industry accounted for 37%-50% of the country’s total consumption of titanium, while small subsonic jet engines used 1/of its total mass. 3. In aero-engines, the intermediate-temperature components made of titanium have higher fatigue strength, yield, creep strength, and lower modulus of elasticity than steel, which can reduce the stress during fatigue loading. Titanium alloy has high corrosion resistance and can greatly relieve the compression performance of jet engines. Increasing the boost ratio of the engine compressor and the gas temperature of the turbine inlet can increase the overall efficiency of the engine, thereby increasing the engine thrust, improving the thrust-to-weight ratio, and reducing fuel consumption. The total pressure ratio of engine compressors in the United States and the United Kingdom has increased from 10-13 in the early 1960s to 20-27 in the 1970s and is increasing year by year. The total pressure is expected to increase to 50. Without the use of cooling technology, the air intake temperature of the multi-role fighter turbine has already exceeded 1650°C.
Due to the harsh working conditions of the engine and the increase in size, light alloys and stainless steels are difficult to handle, so the amount is not reduced. However, due to the decline in production costs of titanium alloys and high-temperature alloys, the continuous improvement of processing performance, and the use of new Processes, its advantages are more apparent and prominent, and its applications in engines are increasing year by year. From 1950 to 1980, the materials used for several major aero engines in the United States are summarized in the table below.
The titanium used in the jet engine produced by Pratt & Whitney is 7%-15% of the total mass, and the titanium used in the J73 jet engine of General Electric (GE) is 6%, J79 The engine rotor was originally made of grade 17 stainless steel and later changed to grade 11 titanium alloy. The J79-8 engine uses 20% titanium and the J79-3 engine uses 4% titanium.
The use of titanium for American aviation engines began in 1954. At that time, the B52 bomber was equipped with 4 titanium engines, J57, using 7%-15% titanium. The air intake and low-pressure brakes were made of industrial pure titanium and the blades of the low-pressure compressor. The Ti-6Al-4V alloy is used for the disk and the disk separator. The amount of titanium used in the JT3D turbofan engine is 15%: the low-pressure compressor fan blades, blade partitions, and fan valves are all Ti-6Al-4V, and the fan blades are 406mm long, which is more than 2 times longer than the compressor blades. The components are all made of titanium alloy, and the engine performance has been greatly improved.
The fan blades of the JT9D engine are 711 mm long, which is almost 10 times longer than the compressor blades. The military JT3D modified engine and TF33 engine use 2% titanium. The amount of titanium used in the JT9D turbofan engine accounts for 28% of its total mass, about 1.035t, and its 46 fan blades are all made of Ti-6Al-4V alloy; 9 of the low-pressure compressor rotor and the 11-stage high-pressure compressor The grades are all made of Ti-6Al-4V, Ti-8Al-1Mo-1V, Ti-6Al-2Sn-4Zr-2Mo alloys. The latter alloy is a high-temperature alloy with a working temperature of 480℃, a dosage of 450kg, and a static The blades are Ti-5AI-2.5Sn, and the modified JT9F engine uses 4.5t titanium, and the cost of titanium accounts for 5% of the engine. The TF39 fan engine uses 33% titanium. It is equipped with a C5A military transport aircraft and weighs about 3t. The compressor disc and blades are made of Ti-6Al-4V and Ti-5AI-2.5Sn. The compressor blank is forged, and the original weight is 312kg, and then changed to precision forging, reduced to 126kg, the original gross weight of the blade was 21.5kg, only 5.7kg after forging.
The GE4 turbojet engine has a total weight of about 5t and uses 10% titanium. The first four stages of hollow compressors use Ti-6Al-2Sn-4Zr-2Mo alloy. It is a high-creep alloy with a working temperature of 500℃, which is higher than that of Ti. The high of -6Al-4V alloy is 100°C. The use of titanium instead of steel to manufacture some components of the lift engine can increase the thrust-to-weight ratio. For example, the thrust-to-weight ratio of the JR200 engine made of titanium alloy and heat-resistant aluminum alloy is increased from 10. To 16. Its first compressor blades, front axle, compressor disc, turbo rear axle, and disc are all made of Japanese KS150 alloy (Ti-5AI-2Cr-1Fe), and the static blades of the compressor are made of Ti-6Al-4V The alloy replaces Cr12 stainless steel, reducing the quality by 43%.
In Russia, the HK8 turbofan engine equipped with the Il-62 transport aircraft uses about 40% of its mass of titanium alloy, and the HK144 turbofan engine equipped with the Tu-144 supersonic transport aircraft also uses a lot of titanium alloy.
The high-pressure compressor drum of the RB172 engine of British RR Company ((Rolls-Royce) is made of titanium alloy IMI685 (Ti-6Al-5Zr-0.5Mo-0.25Si), which has high creep resistance and fracture resistance. Toughness and excellent weldability.
The V2500 engine used on Airbus A320 and McDonnell Douglas MD-90 civil aircraft is a twin-shaft turbofan jet type, with a mass of 2.2t, and titanium alloy structural parts accounting for 31%. It is jointly developed by the United Kingdom, the United States, Germany, Italy, and Japan. . The high-pressure compressor is manufactured by RR Company, and its grades 3-6 are made of IMl550 (Ti-4Al-4Mo-2Sn-0.5Si) alloy with high creep resistance; fans and low-pressure compressors made in Japan mainly use Ti-6Al-4V alloy.
