Effect of Niobium and Nickel Additions and Heat Treatment on Mechanical Properties of 1Cr-lMo-0.25V Steel

Abstract

One housing 200 MW class steam turbine requires a rotor with both high temperature creep rupture strength and low temperature toughness.
A new rotor forging has been investigated in terms of the effects of additional elements (Nb and Ni) and heat treatments on 1Cr-1Mo-0.25V steel creep rupture strength and toughness. The additional elements and differential heat treatment (DHT) showed synergistic improvement in these mechanical properties. Thus, the 1Cr-1Mo-0.25V-Nb-Ni steel can be employed after DHT as rotor material for the one housing 200 MW class steam turbine.