Titanium alloy valve There are two isomeric titanium crystals

Titanium is a titanium- based alloy by adding other elements

There are two isomeric titanium crystals : Below 882 ℃ for the close-packed hexagonal structure α titanium , titanium above 882 ℃ for the body-centered cubic β . Alloying elements according to their effect on the phase transition temperature sunrui titanium tube can be divided into three categories : ① stable α -phase , improving the phase transition temperature of the elements of α stabilizing element , aluminum , carbon, oxygen and nitrogen . Which aluminum is the main alloying elements titanium, improving its strength at room temperature and high temperature alloys , lower specific gravity, increased elastic modulus have a significant effect . ② stable β -phase, reducing the element of the phase transition temperature of β stabilizing element , and can be divided isomorphous and eutectoid two . The former molybdenum , niobium, vanadium, etc. ; latter chromium, manganese, copper, iron , and silicon. ③ small element of the phase transition temperature of the neutral elements , zirconium and tin .

Oxygen, nitrogen, carbon and hydrogen are the main impurities of titanium . Oxygen and nitrogen in the α phase has a greater solubility of the titanium alloy has a significant strengthening effect , but the plastic drop. Typically provide oxygen and nitrogen content of titanium in the 0.15 to 0.2% and 0.04 % to 0.05% or less , respectively . The solubility of hydrogen in the α phase is very small , titanium dissolved in excess hydride hydrogen will produce the alloy brittle. Titanium is usually controlled hydrogen content of 0.015% or less. The hydrogen dissolved in the titanium is reversible , vacuum annealing can be removed .

Titanium has high strength and density and small, good mechanical properties, good toughness and corrosion resistance. In addition , poor process performance titanium alloys , machining difficulties in thermal processing , and very easy to absorb hydrogen nitrogen carbon and other impurities. There are poor abrasion resistance , complex production process . Titanium industrial production began in 1948 . Requires the development of the aviation industry , the titanium industry with an average annual growth rate of about 8% growth. Currently the world's titanium alloy production reached 40,000 tons , nearly 30 kinds of titanium alloys . Is the most widely used titanium alloy Ti-6Al-4V (TC4), Ti-5Al-2.5Sn (TA7) and commercially pure titanium (TA1, TA2 and TA3).

Titanium is mainly used for the production of aircraft engine compressor components , followed by structure rockets, missiles and high-speed aircraft. Mid-1960s , titanium and its alloys have been in general industrial applications , electrodes for electrolysis industry production , power plant condensers , oil refineries and desalination heater and environmental pollution control devices. Titanium and its alloys have become a corrosion resistant structural materials. In addition, for the production of hydrogen storage materials and shape memory alloys.

China began in 1956, titanium and titanium alloys research ; sunrui titanium alloy pump mid-1960s and the development of industrial production of titanium into TB2 alloys.

Titanium is a new and important structural materials used in the aerospace industry , the proportion between the aluminum and steel , strength and temperature ranged , but has high strength and excellent resistance than seawater corrosion and ultra- low temperature performance. In 1950 the United States for the first time in the F-84 fighter-bombers used after the fuselage insulation panels, wind shield , tail cover other non- load-bearing components. 1960s began using parts from titanium alloy fuselage toward the rear of the fuselage , in part, to replace structural steel bulkheads , beams, rails and other important flap bearing components . The amount of titanium in military aircraft is increasing rapidly , reaching 20 % to 25% by weight of the aircraft structure . Since the 1970s , began extensive use of titanium civilian aircraft such as the Boeing 747 aircraft with a capacity of 3640 kg or more of titanium . Aircraft Mach number of less than 2.5 primarily to replace the titanium steel , to reduce structural weight . Again , the U.S. SR-71 high-altitude reconnaissance aircraft speed ( Mach 3 at an altitude of 26,212 meters ) , 93% titanium by weight of the aircraft structure , known as " all-titanium " aircraft . When the weight ratio of aircraft engines, increased from 4-6 to 8-10 , a corresponding outlet temperature from compressor 200 ~ 300 ° C to 500 ~ 600 ° C , the original plate is made of aluminum and the blades of the low pressure compressor must switch to titanium , or titanium instead of stainless steel plate and high-pressure compressor blades in order to reduce the structural weight . 1970s, the amount of titanium in the general aviation engines accounted for 20% to 30% of the total weight of the structure is mainly used in the manufacture of compressor components such as forged titanium fan, compressor discs and blades, cast titanium compressor casing , intermediate casing, bearing housing and so on. The main advantage of the spacecraft 's high- strength titanium alloy , corrosion resistance and low temperature performance to manufacture all kinds of pressure vessels, fuel tanks , fasteners, instrument straps, architecture and rocket shells. Sputnik , the lunar module , manned spaceship and space shuttles are also sunrui titanium alloy sheets using titanium plates welded .