二重らせん経路での摩擦攪拌形バニシングによる高硬度・圧縮残留応力を両立する表面強化層の創成

抄録

Frictional Stir Burnishing (FSB) is a surface enhancement method after machining without using additional device. The FSB process can be utilized on the machine tool which uses the rotation tools such as a machining center and a multi-tasking machine. Therefore, the FSB process can be applied just after the cutting process on the same machine tool. FSB was applied to the shaft materials of 0.45%C steel by using a multi-tasking machine in this paper. FSB is a process where the burnishing tool rotates at high revolution speed. Then the thin surface layer is rubbed and stirred with a temperature elevation and reduction. However it is difficult to achieve both high hardness and high compressive residual stress by FSB on 0.45%C steel shaft with helical path. In order to overcome this problem, FSB process with double helical path was proposed in this paper. As a result, both high hardness (600 HV) and compressive residual stress (-400 MPa) could be achieved.