On October 24, the fatigue life test of key components of aero-engine implemented by Beijing Institute of Aerospace Materials exceeded 50,000 hours, marking a new breakthrough in China's high-end equipment manufacturing technology.

The key component of the fatigue test is the main bearing of the aero-engine developed independently by China, which has not failed for 50,000 hours of equivalent accelerated test fatigue life on the tester, creating a new record in China.

 

 

Beijing Aviation Materials Research Institute senior engineer Tang Chunfeng: aircraft to fly thousands of hours tens of thousands of hours, if the bearing failure, the engine can not be used, it is the engine pivot. The test simulates the working conditions of the aircraft engine, so far, has been tested to accelerate the equivalent life of 50,000 hours has not failed, the test is still in progress.

 

 

 

 

According to reports, like aircraft, high-speed rail and other high-end equipment in operational service process, which key components will occur fatigue phenomenon, cracking, fracture leading to product failure, is a major problem in the world of engineering.

The main bearing position of commercial aircraft engines

After technical research, our researchers have independently developed a number of anti-fatigue manufacturing key technologies, established anti-fatigue manufacturing technology system, solved the fatigue failure of key components, laying a more solid foundation for the full autonomy of China's high-end equipment.

 

 

 

 

 

Researcher of Beijing Institute of Aeronautical Materials Academician of the Chinese Academy of Engineering Zhao Zhenye: our fatigue-resistant manufacturing technology, almost all the key components can be done. The life and reliability of the equipment are taken to reflect the key components, with key components, you can do high-end equipment. So China's manufacturing technology on the whole surface of the promotion, to reach three limits, limit life, limit reliability, limit weight reduction, that is, in the international leading level.

Fatigue, wear, corrosion, is the world's recognized mechanical engineering manufacturing three major problems.

The so-called fatigue, refers to the material under the action of cyclic stress and strain, in one or several places gradually produce local permanent cumulative damage, after a certain number of cycles to produce cracks or sudden complete fracture process. In layman's terms, like a wire, after repeated bending, it will get hot until it breaks, which is due to fatigue.

The development of the "fatigue" problem can be traced back to as early as 1830, although after nearly two hundred years of research and exploration, to this day, the "fatigue failure" problem is still at the top of the three major problems. Because wear can be prevented in advance through early warning, corrosion can be extended through repair, protection, but fatigue is suddenly broken without any signs, it can not be prevented.

"Forming" manufacturing technology is the world's first generation of engineering manufacturing technology, has been inherited for a century, it is the pursuit of "shape and position precision", the goal is to "nearly defect-free" direction, but did not Solve the fatigue problem, resulting in key components have a short life, poor reliability and heavy structure and other outstanding problems.

The United States from 1948 to 1970, the national effort, research and invention of the second generation of manufacturing technology ---- "surface integrity" manufacturing technology, which is a "cutting + fatigue" interdisciplinary technology, through the component surface strengthening, improve Fatigue strength stress concentration sensitivity to extend product life. This technology makes the West in the high-end manufacturing monopoly, but the fatigue problem is still not solved, the world manufacturing has not upgraded transformation.

Key components, the core of high-end manufacturing, mainly include transmission components, such as gears, bearings, etc.; rotating components, such as blades, wheel discs, etc.; and the main bearing components landing gear, docking bolts, etc. Zhao Zhenye, who has long been engaged in aviation materials research, believes that the key components are the integration of design, manufacturing and material technology systems, and their basic characteristics are: to determine the main function of the equipment, reflect the life and reliability, failure breeds catastrophic consequences, fatigue is the main failure mode.

Bearings are called the "joints" of industry. In World War II, the Soviet and German armies attacked each other and bombed each other's bearing plants, which shows the importance of bearings. High-performance bearings and gears are key components of mechanical systems, widely used in helicopters, aero engines, racing cars and other precision machinery, its performance has become an important factor in limiting the life and reliability of various mechanical properties.

In the 1960s, the United States introduced the double vacuum melting technology into the gear steel, solving the key challenges of the transmission system, they manufactured the main bearing life of thousands of hours or even tens of thousands of hours of aviation. For this reason, the United States and the West 5 companies in up to 50 years monopolized the world's high-end bearings 80% of the market, aviation and high-speed rail 100% of the market. At that time, China's high-performance gear bearing steel technology is very backward, aviation main bearing life of less than 200 hours, seriously restricted the development of aero engines, helicopters and other weaponry and high-end mechanical products.

In 2009, the relevant state departments deployed a major project of "Basic Research on Fatigue Resistant Manufacturing of High Strength Fatigue Resistant Aero Components", which required the study of a verification part to evaluate the availability of fatigue resistant manufacturing theory and method. Because the main bearing of the aero-engine is the most important and difficult key component, Academician Zhao Zhenye's team chose a certain main point main bearing, which could complete the validation and solve the problem at the same time.

In the next 13 years, Zhao Zhenye presided over the new bearing gear steel M50NiL purification research. Through the process route of "purifying raw materials, refining outside the furnace, VIM+VAR double vacuum melting, pier pulling and billet opening", he made the purity of M50NiL exceed the international leading level. He also designed a surface-hardened stainless gear bearing steel composition system, which for the first time upgraded the gear bearing steel to ultra-high strength, high toughness and ultra-hardness levels.

On July 28, 2021, the new bearing gear steel M50NiL aviation main bearing and the international most advanced products for fatigue test "the same stage", China's main bearing ball life reached a million hours, 15 times higher than foreign products; in 1.6 times the highest load spectrum under the accelerated test life (conversion) more than 30,000 hours without failure, breaking the international record of 20,000 hours without failure of similar products. The relevant national departments have successfully accepted and passed the basic research project of anti-fatigue manufacturing, including 5 mechanisms of anti-fatigue manufacturing, 4 methods of anti-fatigue manufacturing, and technical standards such as improving fatigue strength by 100% and fatigue life by 100 times, all of which have been completed in accordance with the standards.

 

 

 

 

 

On October 24, 2022, another exciting news came from Beijing Aviation Material Institute: Zhao Zhenye's academician team's research and development of aviation main bearing fatigue test reached 50,000 hours without failure. This is an epoch-making milestone, and another world record in mechanical engineering manufacturing was born!