2014 Volume 63 Issue 4 Pages 338-344
Evaluation of the failure under creep deformation is essential in design and life management of high-temperature components constituting power generation plants. Deformation model as well as life evaluation rule plays an important role in such a evaluation and their accuracy needs to be qualified. In order to estimate variation of stress distribution with time due to creep deformation, creep strain equations are required to be used and their accuracy is important for the reliability of the assessment of creep damage. Creep strain equations for ka-SUS410J3 (ASME Grade 122) steel which is widely used in ultra-super critical thermal power plants were developed in this study. Expressions for the primary and the tertiary creep deformations were developed as well as those for the secondary creep deformation with special attentions to the difference between short-term and long-term behavior as well as dependency of the starting point of the tertiary creep phase on temperature and rupture time.