Enhancement of the tool performance of circular saw blades by improving the microstructure and residual stress field using an ultrasonic rolling tensioning process

Circular saw blades, a large diameter-to-thickness ratio tool, are widely used in the aerospace and transportation sectors. However, it is limited due to its thinning tendency and weak stiffness. In this study, a novel tool tensioning technique was developed using the ultrasonic surface rolling process (USRP) to improve the tool performance of circular saw blades by changing the microstructure and residual stress distribution. Archimedean spiral curve textures were successfully created on both sides of a circular saw blade using an ultrasonic rolling experimental platform. The results show that USRP induced a gradual change in the dislocation structure from a microstrip mixing pattern to a lamellar band structure, accompanied by an increase in high-angle boundaries and a decrease in dislocation cell size. These textures result in a "low-high-low" trend in the radial residual stress distribution along the radius of the circular saw blade, and this residual stress variation improves the tool dynamic performance of the circular saw blade by more than 10% based on real-time x-direction (feed direction) cutting vibrations. In addition, a rolling tensioning evolution mechanism is proposed to explain how the synergistic effect of ultrasonic vibration and rolling force generates the residual stress field. This study elucidates the evolutionary mechanism of USRP-induced tensioning of thin circular saw blades, paving the way for a high-quality, cost-effective tensioning process.