Cr-Mo-V steel has been used as a material of turbine rotor of thermal power plant, and it will be used under the conditions of high temperature and creep. The life of creep crack growth for Cr-Mo-V heat-resistant steal is considered to be sensitive to differences in material micro-structure. In this study, creep crack growth tests were conducted using Cr-Mo-V steel with four kinds of materials with variation in micro-structural dimensions in order to clarify the effects of material structures such as grain size on the creep crack growth characteristics.
