The objective of the work is to predict the creep behaviour of modified 12% chromium steels mainly from information about their chemical composition and heat treatment, without relying on uncertain extrapolations of experimental data. Such predictions are necessary for the life assessment and safe operation of creep-exposed power plant components beyond approximately 100 000 hours, where no experimental creep data exist for the construction materials. Further, the results will be useful for the development of new steels with improved creep resistance.
In the present project methods for assessment of lifetime and remaining life will be developed. Through our participation in COST 522 and our connection to EPRI, materials that are being developed in Europe and Japan will also be investigated and assessed, before they become commercially available. Special emphasis is put on cobalt-containing steels, which hopefully will be useful up to temperatures close to 650°C.
The work is a collaboration between our group and groups at CTH and DTU (Denmark). The work includes microstructural characterization (LOM, SEM, EFTEM and APFIM), creep testing, thermodynamic and kinetic modelling of microstructural development as well dislocation-based modelling of creep.