Improved 12Cr Rotor Forging for Ultra-Super-Critical Steam Turbine

Abstract

Effect of chemical compositions on creep rupture strength and fracture toughness in 12Cr type steel for 593°C/316 atg Ultra-Super-Critical (USC) steam turbine were investigated. In this study, as a rotor material for 593°C USC steam turbine, 11Cr-1.2Mo-W-V-Nb-N steel were newly developed.
On the basis of preliminary studies, a trial large rotor forging 70 t in weight was manufactured by the developed material. This rotor forging had high creep rupture strength compared with conventional 12Cr steel rotor forging and was superior to quality and the other mechanical properties.