Advances in Creep Damage/Life Assessment Technology for Creep Strength Enhanced Ferritic Steels

The creep damage/life assessment technology for creep strength enhanced ferritic (CSEF) steels such as Gr.91, 92, 122, etc. has been strongly demanded by power plant operator and equipment manufacturers however creep damage mechanisms of these steels are not well clarified. Since the creep degradation mechanism of CSEF steels is very complicated in comparison with the conventional CrMo steels, the study on CSEF steels must be grounded on the findings on microstructural degradation and creep softening in martensitic structure composed of very fine martensite lath, block, packet and prior austenite grains, and precipitation and dislocation structures. This paper presents new find ngs on microstructural creep degradation, the hardness creep life model and the simplified tertiary creep modeling of the Omega method for creep life assessment of CSEF steels as the advances in creep damage/life assessment technology for its practical applications in future.