In 1948, DuPont company of the United States produced sponge titanium by ton with magnesium method - which marked the beginning of industrialized production of sponge titanium, namely titanium. Titanium alloy,such as Gr5 titanium round bar,Gr5 titanium plate,GR.7 titanium round bar titanium alloy tube are widely used in various fields because of its high specific strength, good corrosion resistance and high heat resistance.
1. Characteristics of titanium:
High strength: 1.3 times of aluminum alloy, 1.6 times of magnesium alloy and 3.5 times of stainless steel. It is the champion in metal materials.
High thermal strength: the service temperature is several Baidu higher than that of aluminum alloy, and can work for a long time at the temperature of 450 ~ 500 ℃.
Good corrosion resistance: acid, alkali and atmospheric corrosion resistance, especially strong resistance to pitting corrosion and stress corrosion.
Good low temperature performance: titanium alloy TA7 with very low interstitial elements can maintain a certain plasticity at - 253 ℃.
High chemical activity: high chemical activity at high temperature, easy to react with hydrogen, oxygen and other gas impurities in the air to form a hardened layer.
Small thermal conductivity and elastic modulus: the thermal conductivity is about 1 / 4 of nickel, 1 / 5 of iron and 1 / 14 of aluminum, while the thermal conductivity of various titanium alloys is about 50% lower than that of titanium. The elastic modulus of titanium alloy is about 1 / 2 of that of steel.
2. Classification and application of titanium alloys
Titanium alloys can be divided into heat-resistant alloys, high-strength alloys, corrosion-resistant alloys (titanium molybdenum, titanium palladium alloys, etc.), low-temperature alloys and special functional alloys (titanium iron hydrogen storage materials and titanium nickel memory alloys), etc.
3. Aviation application of titanium alloy
Titanium alloy is mainly used in aircraft and engine manufacturing materials, such as forged titanium fan, compressor disc and blade, hood, exhaust device and other parts, as well as structural frame parts such as girder spacer frame of aircraft. Spacecraft mainly use the high specific strength, corrosion resistance and low temperature resistance of titanium alloy to manufacture various pressure vessels, fuel tanks, fasteners, instrument straps, frames and rocket shells. Titanium alloy plate weldments are also used in artificial earth satellites, lunar modules, manned spacecraft and space shuttles.
4. Reasons why titanium alloys are widely used in aviation
The maximum speed of modern aircraft has reached more than 2.7 times the speed of sound. Such a fast supersonic flight will cause the aircraft to rub with the air and produce a lot of heat. When the flight speed reaches 2.2 times the speed of sound, the aluminum alloy can't stand it. High temperature resistant titanium alloy must be used.
When the thrust weight ratio of aeroengine is increased from 4 ~ 6 to 8 ~ 10, and the compressor outlet temperature is correspondingly increased from 200 ~ 300 ℃ to 500 ~ 600 ℃, the low-pressure compressor disk and blade originally made of aluminum must be replaced with titanium alloy.
Using titanium alloy instead of stainless steel to make high-pressure compressor disk and blade can reduce the structural weight. Fuel can be saved by 4% for every 10% reduction in weight of the aircraft. For rockets, every 1kg of weight reduced can increase the range of 15km.
