10Cr9Mo1VNb(equivalent to T91, P91, 1X20CrMoVNb91, STBA28) is a martensitic steel widely used in China in recent years. It was first developed by ORNL(Oak Ridge National Laboratory). Table 15-1g ~ 1J shows its chemical composition and mechanical properties. The steel is based on 9Cr-1Mo (T9, P9). By reducing the carbon content, adding alloying elements V and Nb, and controlling the content of N and Al, the steel not only has high oxidation resistance and high temperature steam corrosion properties, but also has good impact toughness and high and stable long-term plastic and thermal strength. It is mainly used in the manufacture of high temperature superheater, reheater, high temperature collector and steam pipe of subcritical and supercritical boiler. Wall temperature 625 for superheater, 650 for reheater, 600 for collector and steam tube.
