抄録
The paper describes methods to characterise creep, fatigue and creep fatigue loading for modern martensitic steels used in advanced fossile fired power plants. To increase efficiency of fossile fired power plants the process parameters, in particular the temperature, have been increased more and more. There is a strong need to know the long time behaviour of materials and weldments in components. Numerical models based on unified constitutive equations developed by Chaboche and Ohno and Wang are used as well as conventional creep laws. Special emphasis is put on the modelling of different material properties in the different zones of a weldment (heat affected zones, weld metal and base metal) in order to describe stress redistribution, strain and damage behaviour and failure location. Feature tests with hollow cylinder, spinning cylinders as well as component tests on pipes and T-pieces partly containing welds are simulated in order to support the development of DBA methods and lifetime assessment methods for components including weldments.
