Abstract
We found some damage at the forks of low-pressure turbine blades caused by random vibration and
steam-flashback vibration at nuclear power plant. In this study, to improve fatigue property, we
developed and examined laser peening technology for 12Cr stainless steel and material properties. Laser
peening induces compressive residual stress on material surfaces. We fabricated fatigue specimens that
simulate the stress concentration zone of the forks and applied laser peening to the specimen surfaces.
The residual stress was measured by X-ray diffraction and compressive residual stress was formed on the
peened surface. From the fatigue test results, the fatigue strength of the laser peened specimens
improved about 40% more than the unpeened specimens.
