Application Examples Of Titanium Alloy Forging Process in Aviation Industry

With the rapid development of my country's national economy, science and technology, aerospace and aviation industries have ushered in new opportunities for development in recent years, especially after the establishment of the national "big aircraft" project, the civil aviation manufacturing industry will become a new economy leading the development of the national economy growth point, has broad prospects for development. In order to continuously improve the advancement, reliability and applicability of aircraft, and increase the competitiveness of domestic aircraft in the international market, civil aviation manufacturing enterprises have higher and higher requirements for the selection of aviation manufacturing materials; the main characteristics of titanium alloys are small specific gravity and high strength. At the same time, it has good heat resistance and corrosion resistance. It has become the main material of modern aircraft stress components, which greatly reduces the weight of the aircraft. Among them, TC4 (Ti-6AL-4V) and TB6 titanium alloy forgings are widely used in aviation manufacturing. .

According to the microstructure at room temperature, titanium alloys can be divided into three types: α-type alloys, α+β-type alloys and β-type alloys. It has good malleability but the temperature is too low may cause α-phase precipitation. The forging process of titanium alloy is divided into conventional forging and high temperature forging according to the relationship between forging temperature and β transformation temperature.

2.1 Conventional forging of titanium alloy

Commonly used deformed titanium alloys are usually forged below the β transformation temperature, which is called conventional forging. According to the heating temperature of the billet in the (α+β) phase zone, it can be subdivided into upper two-phase zone forging and lower two-phase zone forging. ?

2.1.1 Forging in the lower two-phase region

Forging in the lower two-phase region is generally heated and forged at 40-50°C below the β transformation temperature. At this time, the primary α phase and β are the same and participate in deformation. The lower the deformation temperature, the more α-phase involved in the deformation. Compared with the deformation in the β region, the recrystallization process of the β phase in the lower two-phase region is sharply accelerated, and the new β grains formed by recrystallization not only precipitate along the deformed original β grain boundary, but also in the β grain boundary and α sheet layer. Occurs within the β-intermediate layer. The forging produced by this process has high strength and good plasticity, but its fracture toughness and creep properties still have great potential.

2.1.2 Forging in the upper two-phase region

It is forged at a temperature of 10-15°C below the β/(α+β) transformation point. The final structure after deformation contains more β-transition structure, which can improve the creep performance and fracture toughness of the structure; make the titanium alloy have both plasticity, strength and toughness.

2.2 High temperature forging of titanium alloy

Also known as "β forging", it can be divided into two types: the first is the process in which the billet is heated in the β area, and the forging is started and completed in the β area; the second is that the billet is heated in the β area, and forging is started in the β area. And control a large amount of deformation to complete the forging process in the two-phase region, referred to as "sub-β forging". Compared with forging in two-phase region, β forging can obtain higher creep strength and fracture toughness, and is also beneficial to improve the fatigue performance of titanium alloy.

2.3 Isothermal die forging of titanium alloy

This process utilizes the superplasticity and creep mechanism of the material to produce more complex forgings, and requires the mold to be preheated and kept within the range of 760-980°C; the hydraulic press applies pressure at a predetermined value, and the working speed of the press is controlled by the blank. Deformation resistance is automatically adjusted. Since the mold is heated instead, it is not necessary to use as fast moving beams to avoid quenching. Many forgings used in aircraft have the characteristics of thin wall and rib height, so this process has been applied in aviation manufacturing, such as the isothermal precision die forging process of TB6 titanium alloy for a certain type of domestic aircraft.

The forging process of titanium alloy is widely used in aviation and aerospace manufacturing, and the isothermal forging process has been used to produce engine parts and aircraft structural parts; it is also more and more popular in industrial sectors such as automobiles, electric power and ships. In foreign countries, the application of titanium alloys has been developed to a very high level, TiAL alloys and intermetallic compounds used at higher temperatures have been paid attention to, and a lot of research has been carried out; in order to better apply these materials, at the same time A lot of research has also been done on its deformation process. People are also paying more and more attention to the research of higher strength sub-β titanium alloys. The application of titanium alloy and the research of forging process will still be a hot topic.