In a recent interview with Northwestern Polytechnic University, the reporter learned that the powerful spinning technology (PTR) developed by Professor Liu Dong and his team in the school of materials of Northwestern Polytechnic University has made a major breakthrough and solved the problems in the development of related industries in China.



   from auto, high-speed railway, aircraft to instrument, mechanical equipment, almost all rotating machinery can find a common core component bearing. Bearing steel, the material needed for bearing manufacturing, is known as the "king of steel" because it is directly related to the service life and reliability of bearings.





   finished products produced by strong spinning technology. Map provided by Northwestern Polytechnic University



   "the working environment of the bearing is severe and complex. It not only needs high-speed and stable rotation, but also bears strong extrusion, friction and even ultra-high temperature experience." Professor Liu Dong told reporters that because of this, the quality and reliability of bearing steel have extremely strict requirements.



   how to improve the quality of bearing steel? According to Professor Liu Dong, firstly, the interior should be clean enough, and the less the inclusions, the better; secondly, it should be uniform enough, and the particles in the material should be as small and dispersed as possible. However, it is a pity that there is a big gap between the quality of bearing steel produced in China and the international advanced level. Taking inclusions as an example, the size of inclusions in foreign products is less than or equal to 10 microns, while the maximum size of inclusions in China is 50-52 microns, "the size difference is as much as five times".



  



   compared with the traditional technology, more fine and dispersed carbides can be obtained by high-power rotary rolling. Map provided by Northwestern Polytechnic University



   many enterprises have to import bearing steel at a high price because they can not find bearing steel with high quality from domestic manufacturers. This means: every time we manufacture a set of products, we need to buy Bearings from abroad.



   as a "steel power", how can it become a "steel power"? After decades of efforts of scientific research workers in China, the technical problems of oxygen content and inclusions in bearing steel have been effectively solved. The last "big problem" in the industry - "carbide" has also been conquered by Professor Liu Dong and his team.



   because bearing steel belongs to high carbon steel, its carbon content is higher in all steels. If the distribution of carbides is not uniform and large, the quality will be seriously affected. Professor Liu Dong made an analogy: "it's like spreading a handful of salt when kneading the dough. If the dough is not crushed and well kneaded, the dough will be salty and hard." "Let the salt be smaller and more evenly distributed in the surface" is the goal of Professor Liu Dong and his team.



                         Professor Liu Dong's team creatively put forward the "strong spinning technology" - "this technology is to make the surface deform in three directions when kneading, and the deformation value is very large, which can be said to knead the surface thoroughly and vigorously."



   sounds simple logic, but it contains the tireless exploration of Professor Liu Dong's team. The team "sharpened a sword in ten years", through continuous research and testing, finally broke through the technical bottleneck, developed three "world first" technologies, and applied for 66 invention patents. One of them is strong spinning technology.



According to Professor Liu Dong, China's bearing industry has formed an industry sales scale of nearly 200 billion yuan, and the annual growth rate is 12% - 15%. However, the production of bearings is mainly low-end bearings and small and medium-sized bearings. Among them, the proportion of auto bearings is about 40%, and the quality control level of inclusions and carbides in bearing steel is low, which seriously affects the service life and reliability of domestic auto bearings. "The appearance of strong spinning technology may change this situation."



  



   compared with the traditional technology, the average grain size of power spinning technology is more optimized. Map provided by Northwestern Polytechnic University



   laboratory data show that the grain size is refined from 50 μ m to 10 μ m, and the carbide size is only 1 / 10 of the original. At the same time, the hardness of bearing steel is greatly improved, which is at the top level in the world. In addition, the service life and reliability of the bearing are greatly improved. This technology can also significantly improve the utilization rate of materials and greatly shorten the production process.