Evaluation of Residual Stress Distribution in Shot-Peened Steel by Synchrotron Radiation
Yoshiaki AKINIWA*, Keisuke TANAKA*, Kenji SUZUKI**, Etsuya YANASE*** Koji NISHIO, Yukihiro KUSUMI, Hideki OKADO and Kazuo ARAI
Abstract:The in-depth distribution of residual stresses in shot-peened steels was measured by using high energy X-rays from a synchrotron radiation source. The relation between the 2ƒÆ and sin2ƒÕ was obtained with the side-inclination method (ƒÕ diffractometer). The distribution of residual stresses was first evaluated by the nonlinearity of the sin2ƒÕ diagram by a simplex method. The estimated stress agreed with the distribution determined through the sin2ƒÕ method by using Cr-Ka radiation combined with the conventional surface removal method. A new method was proposed to estimate the stress value of the distributed residual stress. The new method was a combination of the side-inclination method and the iso-inclination method (ƒÖ diffractometer) to maintain the penetration depth constant. The sin2ƒÕ diagram could be approximated by the linear relationship. The evaluated stress distribution agreed well with the distribution obtained by the surface removal method. Key Words:X-ray stress measurement, Synchrotron radiation, Shot peening, Residual stress, High energy X-rays