Experimental Investigations on Mechanical Properties of a High Cr Ferritic Steel for USC Steam Turbine Rotor

Abstract

Development of high temperature and high strength material is very essential for the construction of Ultra Super Critical (USC) power plants to improve the thermal efficiency and reduce CO2 emissions. In this work, the chemical composition design of a high Cr ferritic steel 1Cr10NiMoW2VNbN for USC steam turbine rotor is discussed. Tensile tests of the newly developed steel at both room temperature and elevated temperatures and creep rupture tests of smooth bar and Bridgman type notched bar are carried out. Kachanov-Robotnov creep damage function based on the Continuum Damage Mechanics (CDM) is employed to interpret the long-term creep strength. Extrapolation of experimental data and theoretical analysis indicate that the developed steel has the appropriate mechanical properties at 600°C and thus is capable as a candidate material for 600°C class USC steam turbine rotor.