THE RELATION BETWEEN MICROSTRUCTURE AND CREEP PROPERTIES OF MARTENSITIC 9-12 CR STEELS

摘要

In all industrialized countries great efforts are undertaken to lower CO2 emissions. In the sector of electricity generation progress can be achieved by the improvement of the efficiency of fossil, especially coal fired, power plants. Efficiency improvements can be obtained by increasing the steam parameters, temperature and pressure. For components exposed to critical steam cycle loads the availability of improved high temperature creep resistant materials, including their weldments, is required. Research activities on ferritic/martensitic 9-12% Cr steels at Graz University of Technology are represented by a network of interacting projects focusing on mechanical properties of base and weld metal, damage kinetics, weldability, microstructure analysis in the course of creep, modelling of precipitation and coarsening kinetics, simulation of complex heat treatments and the deformation behaviour under creep loading. The individual projects are briefly described and the conceptual approach towards a quantitative description of the creep behaviour of 9-12% Cr steels is outlined.