Titanium tube is of light weight, high strength and excellent mechanical performance. It is widely used in heat exchange equipment, such as tube heat exchanger, coil heat exchanger, coil heat exchanger, condenser, evaporator and pipeline. Many nuclear power industries use titanium tubes as standard tubes for their units.

 

Titanium alloy is a alloy of other elements based on titanium. Titanium has two homogenous different crystal: under 882 ℃ to close the six-party alpha titanium structure, above 882 ℃ for body centered cubic beta titanium.

 

The effects of alloy elements on the phase transition temperature can be divided into three categories:

 

The elements that stabilize alpha phase and improve phase transition temperature are alpha stable elements, including aluminum, carbon, oxygen and nitrogen. Aluminum is the main alloy element of titanium alloy. It has obvious effect on improving the normal temperature and high temperature strength, reducing the proportion and increasing the elastic modulus.

 

The elements that stabilize beta phase and decrease phase change temperature are beta stable elements, and can be divided into two types: crystal type and eutectic type. Titanium alloy products are used

 

The former has molybdenum, niobium, vanadium and so on; The latter has chromium, manganese, copper, iron, silicon and so on.

 

The elements that have little influence on phase transition temperature are neutral elements, such as zirconium, tin and so on.

 

Oxygen, nitrogen, carbon and hydrogen are the main impurities of titanium. The oxygen and nitrogen have a great solubility in the alpha phase, which has a significant effect on the titanium alloy, but the plasticity decreases. The content of oxygen and nitrogen in titanium is usually set at 0.15 ~ 0.2% and 0.04 ~ 0.05% respectively. Hydrogen is very small in the alpha phase, and the dissolved hydrogen in the titanium alloy produces hydrogen compounds that make the alloy brittle. The hydrogen content in titanium alloys is usually controlled below 0.015%. The dissolution of hydrogen in titanium is reversible and can be removed by vacuum annealing.

 

Usage: titanium alloy has high strength and low density, good mechanical properties, good toughness and corrosion resistance. In addition, the process performance of titanium alloy is poor, cutting processing is difficult, and in hot processing, it is very easy to absorb impurities such as hydrogen and oxygen nitrogen. There is also the resistance to wear, the production process is complex. The industrial production of titanium began in 1948. The need for aviation industry development has enabled the titanium industry to grow at an average annual rate of about 8 per cent. At present, the annual production of titanium alloy in the world has reached 40,000 tons and nearly 30 kinds of titanium alloy plate number. The most widely used titanium alloys are ti-6al-4v (TC4), ti-5al-2.5 Sn(TA7) and industrial pure titanium (TA1, TA2 and TA3).

 

Titanium alloys are mainly used to make aircraft engine compressor parts, followed by rocket, missile and high-speed aircraft structure. 60 s, titanium and its alloy has set up a file in the general industrial application, used for making electrode electrolysis industry, power plant condenser, oil refining and seawater desalination heater and environmental pollution control devices, etc. Titanium and its alloys have become an anticorrosive structure. It is also used in the production of hydrogen storage materials and shape memory alloys.

 

The most commonly used of the three titanium alloys are alpha titanium alloy and alpha + beta titanium alloy. Alpha-titanium alloy has the best machinability, alpha + beta titanium alloy and beta titanium alloy is the worst. The alpha-titanium alloy is the TA, the beta titanium alloy is the terabyte, alpha + beta titanium alloy is the TC.

 

Titanium alloy can be divided according to the use, high strength alloy, heat-resistant alloy corrosion resistant alloy, titanium, molybdenum, titanium and palladium alloy etc.), low-temperature alloy and special function (titanium - hydrogen storage materials of iron and nickel titanium memory alloy), etc. The composition and performance of typical alloys are shown in table.

 

Heat treatment titanium alloys can be obtained by adjusting the heat treatment process. It is generally believed that the small axial tissues have good plasticity, thermal stability and fatigue strength. The needle tissue has high persistence strength, creep strength and fracture toughness. The isoaxial and needle-like mixed tissues have better comprehensive performance.