Quantum mechanics is one of the theoretical foundations of modern physics. It is the science of studying the laws of microscopic particle motion. It makes people's understanding of the material world move from the macro level to the micro level, and the views on the structure of matter and its interaction are revolutionized. Land change has laid the foundation for modern basic theoretical research including atomic physics, nuclear physics, molecular biology, and nonlinear optics.
Timken, the world's leading bearing manufacturer, applies quantum mechanics research methods to the development of bearings.
Timken's researchers Vikram Bedekar (left) and Rohit Voothaluru are working to improve the bearing manufacturing process by using neutrons on HFIR's HB-2B.
At the US Department of Energy (DOE's) Oak Ridge National Laboratory (ORNL), Timken researchers hope to find an extension by using neutron scattering techniques to better understand how internal residual stresses generated during manufacturing affect bearing life. The method of bearing life.
The bearings are manufactured with high precision, small tolerances, perfect fit, and long design life under extreme loads and long-term use and operation. Bearing performance is especially important in aerospace and mining where safety is paramount. Although the residual stress is a small internal elastic deformation in the material structure, it may have a great influence on the life and reliability of the bearing.
“The residual stress is mainly generated by the manufacturing process. All production processes, including forming and high-temperature machining, generate residual stress. If the stress is too large, the parts will deform and may even distort the parts to VikramBedekar, a material specialist at Timken. Unable to use or restore."
In general, the manufacture of bearings begins with making the steel a ring. Next, use the lathe to get the size you need. Bedka said that until now, this part is still "green", which means it is still soft and can't be used. Subsequent heat treatment hardens the material. Finally, use a lathe or grinder to remove excess material to complete the part.
Large size Timken® bearings commonly used in industrial applications. Because neutrons are highly penetrating, they penetrate deeper into the metal than similar methods, such as X-rays. The residual stress of each bearing comes from the asynchronous process during the manufacturing process. (Source: ORNL/Genevieve Martin)
Because of its strong penetrability, neutrons provide researchers with unique information about the atomic structure of materials. Previously, researchers used laboratory X-ray inspection of bearings, but researchers could only detect the thickness of the inside of the bearing by 200 microns. The neutrons allowed them to look deeper into the bearing.
"Standard X-ray intensity is not enough to penetrate completely from one part. Neutron is the only way to see the complete interior." Bedekar said
Using ORNL's high-throughput isotope reactor (HFIR) neutron residual stress mapping device (NRSF2) HB-2B, researchers were able to map the different internal stresses produced at each step of the manufacturing process. The neutron data allows them to see how the stress state of the bearing changes with each iteration. Researchers say they chose to use NRSF2 because of its unique ability to adapt to such experiments.
Timken's product development expert Rohit Voothaluru said: "We are looking for ways to use residual stress maps. We came to NRSF2 because we felt we could find the overall condition of the same sample and see the residual stress."
The team said they intend to use the residual stress mapping data to improve the computational model to improve internal stress prediction and optimize manufacturing processes.
“In the end, we can adjust the machining process or residual stress according to the performance of different bearings,” says Bedekar.
“We have a computational model that can provide directions qualitatively today. However, to build a more basic quantitative model based on actual physical processes, while also capturing real-time subsurface residual strains, requires a lot of empirical verification. We hope Validate our model and take it to the next level,” Voothaluru said.
HFIR is the Office of Scientific User Facilities of the US Department of Energy. UT-Battelle manages ORNL for the Department of Energy Science Office. The Science Office is the single largest supporter of basic research in the physical sciences of the United States and is working hard to solve some of the most pressing challenges of our time.