Zhejiang zijinwang Technology Co., Ltd

Present situation and development trend of domestic aviation fasteners

2020-09-11

Aeroengine is known as "the Pearl on the crown" because of its high industrial technical requirements. Among them, as the link in the "Pearl", aeroengine fasteners have more particularity, higher safety and reliability than other fasteners because of their high-pressure, high-temperature and high-strength environmental requirements. Therefore, the United States, Britain and other scientific and technological powers have taken aeroengine fasteners as a basic science and invested a lot of money in R & D. In the domestic aviation field, with the implementation of major projects of the two aircraft, the road of professional development of aeroengine has been officially opened, creating better development conditions for subsequent professional and technical development and basic discipline research.

The main fastener products of aeroengine include various types of bolts, keyed studs, self-locking nuts, screw sleeves, pins, pipeline connectors, etc. Compared with the fastener family, the types of fasteners used in aeroengines are relatively concentrated, but due to the limitations of their working environment, such fasteners, especially hot end fasteners, have high performance requirements.

There are many domestic manufacturers of aero-engine fasteners, mainly scattered in the aviation and aerospace fields and some private enterprises. The manufacturers are independent of each other and have overlapping product coverage. They mainly focus on production and manufacturing, and there is no research and manufacturing base. Most domestic aero-engine parts companies belong to the subsidiary companies engaged in the production of fasteners and small and medium-sized parts separated from aero-engine main engine manufacturers. The process manufacturing level, technical state management level and detection and test ability of each manufacturer are uneven, and there is no professional production base integrating research and manufacturing, It is not conducive to the technical research and development of aviation fasteners.

1. High temperature and high strength bolts and screws

Bolts and screws made of GH4169 and other materials are the most widely used high-temperature and high-strength fasteners in aeroengines. After heat treatment, the tensile strength of these parts reaches σ B ≥ 1250MPa, and the thread warm rolling technology of this kind of high-strength fasteners is the direction of research and development.

2. Tension bolt

Engine turbine bolts and high-precision slender tensioning bolts are the key and important bearing parts of aeroengine. Such fasteners are generally processed from forging blanks, and the materials are mainly high-temperature alloy and titanium alloy. This kind of parts not only have the requirements of high temperature, high strength and high precision, but also have the structural form and requirements of slender shaft parts. The machining difficulties of this kind of parts are mainly in high-strength thread rolling, machining deformation control of slender shaft and so on.

3. Key locking stud and screw sleeve

This kind of fastener is a newly developed aviation fastener connection technology in recent years. This connection technology is mainly changed from the traditional combined connection mode of interference thread and locking plate to pin key locking mode, so as to make its assembly locking structure more compact, more reasonable and more reliable.

4. High temperature alloy self-locking nut

In the past, the form of self-locking nut was relatively single, mainly made of alloy steel and stainless steel. With the continuous progress of aeroengine technology, the self-locking nut of engine fastener is mainly made of high-temperature alloy. The self-locking deformation forms include two points, three points, four points, straight groove, inclined groove and other closing forms, and the implemented standards include Hb GJB and special technical standards of various developed models.

5. Special self-locking nut

With the gradual improvement of advanced aeroengine technology at home and abroad, more reliable, simpler and lighter spindle rotor fasteners are needed to fasten the parts on the high-speed rotating spindle. The diameter and thickness ratio of the special self-locking nut on the high-speed rotating spindle are generally 4:1, 6:1 and 10:1. The self-locking deformation area of this kind of special self-locking nut is short, the process molding is difficult, and the requirements for material heat treatment control, metallurgical quality and self-locking stability are very high. Therefore, the technical difficulties of such fasteners lie in manufacturing process, test technology, inspection technology, etc., and special equipment, test tooling, inspection tooling, etc. shall be assembled.

With the rapid development of aeroengine technology, aviation fastener parts have developed into a huge product system. In order to meet the requirements of higher performance of aeroengine, the future aviation fasteners have the following trends:

1. The development cycle is getting shorter and shorter

From the current development trend, the development cycle of aeroengine is becoming shorter and shorter, so the development cycle of related parts industry is compressed shorter and shorter, which requires greater R & D investment, technical transformation equipment and other resource investment.

2. Product performance requirements are becoming higher and higher

The use performance requirements of aeroengines are higher and higher. Similarly, the performance requirements of aviation fasteners are gradually improving to meet the more and more complex use environment. The technical research and development of new fasteners is also gradually developed.

3. Further lightweight, application of new materials and technologies

From the perspective of economic usability, the smaller the weight requirements of modern aeroengines and aircraft, the better. For example, the R & D and use of new materials such as titanium alloy and composite materials will improve the technical level of aviation fasteners and reduce the weight of the engine as a whole.

4. Application of key manufacturing technologies such as intelligent manufacturing

The development of intelligent manufacturing technology will effectively promote the improvement of aviation fastener manufacturing technology. In the future production plant, flexible production line, manipulator and intelligent manufacturing center will become standard configuration to improve the manufacturing level of aviation fasteners as a whole.

Aviation fastener is an industry with broad market prospect and development potential. Due to the shorter and shorter supporting production cycle of aviation engine, it is particularly necessary to build a professional R & D and production base of fasteners in the aviation engine industry. Under the complex distribution environment of domestic aviation fasteners, concentrating advantageous resources, quickly adapting to the development trends of intelligent manufacturing, manufacturing service and green manufacturing, carrying out research on intelligent manufacturing technology and building a professional "intelligent manufacturing R & D base" of aviation fasteners will play a positive role in promoting the overall development of Aeroengine technology.