Life Time Assessment of Real Components Exposed to High Temperatures and Presures

Components in the industry are often exposed to elevated temperatures and high pressures. These conditions cause changes in the microstructure and thermo-mechanical properties of steel components. With the aim to determine the properties of steels after a certain period of operation, thermo-mechanical investigations and microstructure characterization can be made and the results of this investigation can serve for the remaining lifetime assessment of components. From the economic and technological point of view this is a very important information. Creep is one of the major mechanisms which cause the deformation and degradation of steels at elevated temperatures. The creep can occur in local areas due to an increased load or due to a microstructural degradation during the operation at elevated temperatures. The microstructure degradation of the steels can be defined by microstructural investigations on metallographic samples or replicas. The aim of this work is to present some methods for the microstructure characterization of steels used in the Slovenian thermal power plants.