Titanium alloys have many advantages, such as high strength, good corrosion resistance, and non-magnetic and good welding properties, in addition to many advantages such as superconductivity, hydrogen storage, and memory. titanium alloy forging is widely used in aerospace, military industry, marine development, petrochemicals, and other frontier fields.
Titanium alloy forgings are one of the various titanium alloy products that are mainly used in applications requiring high strength, high toughness, and high reliability, such as turbine compressor discs and medical artificial bones. As a result, the requirements for forged parts include not only highly accurate dimensions but also excellent performance and stability.
Titanium alloy forgings are used in a wide range of applications, the following are some common application areas
1、Aerospace
50 percent of the world's titanium is used in the aerospace industry. Currently, 30% of military aircraft use titanium alloys to manufacture airframes, and the demand for titanium is gradually increasing in civil aircraft. It is reported that the consumption of titanium in Boeing 787 has exceeded 15%. Ti-6Al-4V alloy is the representative of titanium alloy with the highest safety. Titanium alloy forgings play an important role in the aerospace field, they are used in the manufacture of fuel tanks for rocket and satellite drive engines, blades for liquid fuel turbine pumps, and inlets for suction pumps.
2、Steam turbine blades are important components used for power generation
Increasing the length of the blades of steam turbines for thermal power generation is an effective measure to improve the efficiency of power generation, but the lengthening of the blades will increase the load of the rotor. The use of titanium alloy forgings for blades can reduce the load, and the use of 1m-long Ti-6Al-4V alloy blades at the end of high-speed rotating steam turbines was made practical in 1991.
Titanium Forging Technology
Controlling the heating temperature is critical to the thermal processing of titanium alloy forging. As the temperature decreases, the resistance to deformation of the object increases, making it more susceptible to undesirable defects such as cracks. At the same time, the rate of deformation is very much dependent on the hot working process. The temperature of the forging die can be heated to the same or even higher temperature as the forging, as a way to prevent the temperature of the forging from dropping.
1, the application of forging technology in the manufacture of engine disc parts
Forging technology for aircraft engine components requires high fatigue strength and fracture toughness. ti-6Al-2Sn-4Zr-6Mo alloy coatings are suitable for medium temperatures up to 700 K. The traditional processing method is α-β area forging, which is organized as β-phase and equiaxial α grains and small needles α two-phase organization has low fracture toughness values. To improve this problem, we are developing a new β forging method which is carried out using β zone heating.
The β forging method can lead to recrystallization of the material by heating and forging at the β phase transition temperature, so the forging temperature and processing deformation have an important influence on the properties of the material. Re-heating or stopping deformation is not allowed during the forging process. In the beta forging process, the forging temperature and deformation need to be strictly controlled to ensure the quality of the finished product. The Ti-6al-2Sn-4Zr-Mo alloy with a processing temperature between 1073-1323 K should have sufficient processing deformation. After the material is processed, the forging shows a needle-like structure, and this structure improves the value of its fracture toughness.
2, the forging technology of turbine blades
Turbine blades are very thin, so the temperature decreases rapidly during the forging process, so the design of the mold requires great precision. Currently, we are developing a process that effectively utilizes the upper and lower impact energy to form the blade surface. A flat surface is forged first, then bent, and finally finely forged.
3、Environmental manufacturing technology
Ti-engine fan shells and compressor shells are rolled from 6Al-4V alloy. For titanium alloy products with relatively high material costs, reducing material investment is very effective in reducing costs. Often a near-net process is used, which refers to the use of mechanical forming techniques to manufacture parts without extensive machining or no machining at all. Using this technique, material consumption will be reduced by more than 55 percent.
When machining thick rings, pressure should be applied as much as possible to avoid cracking and attention should be paid to ring organization control and temperature reduction. In short, the production of titanium forgings should result in high-quality forgings at appropriate machining temperatures and deformations.
Therefore, in the process of manufacturing titanium alloy forgings, the properties of titanium alloys need to be fully utilized. to obtain high-quality forgings, the temperature and plastic deformation should be properly controlled during the forging process.
