Deformation behavior during partial diameter-enlarged process at high rotation speeds

Abstract

This paper presents the deformation behavior of SUS304 specimens during partial diameter-enlarged process in a rotation speed region higher than the rotation speed region of conventional diameter-enlarged processing methods. The deformation behavior of the specimen diameter during the process was measured at various axial-compressive forces, bending angles, and rotation speeds. Next, the effect of rotation speed on the deformation behavior was analyzed based on the concept of deformation-induced martensitic transformation and thermally-activated process associated with plastic deformation. The reduction of axial-compressive force and temperature rise during processing in high rotation speeds were investigated. Finally, the time constant of diameter-enlarged was obtained for the above parameters. By increasing the rotation speed, it is possible to shorten the processing time and perform processing at a low axial-compressive force with little temperature rise, which improves the processing efficiency. The time constant of the diameter-enlarged deformation process can be expressed as a function of the effective rotation parameter.

Keywords

• diameter-enlarged working method
• diameter-enlarged ratio
• bending angle
• rotation speed
• deformation-induced martensitic transformation
• thermal activation
• time constant