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Heat treatment process of titanium alloy tube!

2022-08-25 11:42:58

Commonly used heat treatment methods for titanium tubes include annealing, solution and aging treatment. Annealing is to eliminate internal stress, improve plasticity and organizational stability, and obtain better comprehensive properties. Usually, the annealing temperature of α alloy and (α+β) alloy is selected at 120-200℃ below the (α+β)-→β phase transformation point; solution and aging treatment is fast cooling from high temperature region to obtain martensite α′ phase and metastable Then, these metastable phases are decomposed by heat preservation in the medium temperature zone, and finely dispersed second phase particles such as α phase or compounds are obtained to achieve the purpose of strengthening the alloy.


The heat treatment process of titanium alloy tube can be summarized as:


(1) Solution treatment and aging: The purpose is to improve its strength. The α titanium tube and the stable β titanium tube cannot be subjected to strengthening heat treatment, and only annealing is carried out in production. α+β titanium tubes and metastable beta titanium tubes containing a small amount of α phase can be further strengthened by solution treatment and aging.


(2) Complete annealing: The purpose is to obtain good toughness, improve processability, facilitate reprocessing and improve the stability of size and structure.


(3) Stress relief annealing: The purpose is to eliminate or reduce the residual stress generated during processing. Prevent chemical attack and reduce deformation in some corrosive environments.


In addition, in order to meet the special requirements of the workpiece, industrial titanium tubes also use metal heat treatment processes such as double annealing, isothermal annealing, beta heat treatment, and deformation heat treatment.


Titanium tubes are mainly used to make aircraft engine compressor parts, followed by structural parts of rockets, missiles and high-speed aircraft. In the mid-1960s, titanium and its alloys have been used in general industry for making electrodes in the electrolysis industry, condensers in power stations, heaters in petroleum refining and seawater desalination, and environmental pollution control devices. Titanium and its alloys have become a corrosion-resistant structural material. In addition, it is also used in the production of hydrogen storage materials and shape memory alloys.


Titanium tube has high strength and low density, good mechanical properties, good toughness and corrosion resistance. In addition, the process performance of titanium tube is poor, cutting is difficult, and it is very easy to absorb impurities such as hydrogen, oxygen, nitrogen and carbon during hot processing. There is also poor wear resistance and complex production process. The industrial production of titanium started in 1948. The need for the development of the aviation industry makes the titanium industry develop at an average annual growth rate of about 8%. At present, the annual output of titanium tube processing materials in the world has reached more than 40,000 tons, and there are nearly 30 kinds of titanium tube grades. The most widely used titanium tubes are Ti-6Al-4V (TC4), Ti-5Al-2.5Sn (TA7) and industrial pure titanium (TA1, TA2 and TA3).