Mechanistic approach for prediction of creep deformation, damage and rupture life of different Cr-Mo ferritic steels

摘要

A mechanistic approach based on finite element analysis of continuum damage as proposed by Kachanov has been used to assess and compare creep deformation, damage and rupture behaviour of 2-25Cr-1Mo, 9Cr-1Mo and modified 9Cr-1Mo ferritic steels. Creep tests were carried out on the steels at 873 K over a stress range of 90-230 MPa. Modified 9Cr-1Mo steel was found to have highest creep deformation and rupture strength whereas 2-25Cr-1Mo steel showed the lowest among the three ferritic steels. Creep damage in the steels has been manifested as the microstructural degradation. 2-25Cr-1Mo steer was more prone to creep damage than 9Cr-steels. Finite element estimation of creep deformation and rupture lives were found to be in good agreement with the experimental results.