P91 alloy steel is equivalent to Chinese steel grade 10Cr9Mo1VNbN. P91 steel not only has high oxidation resistance and high temperature steam corrosion resistance. Because of its comprehensive properties such as high temperature endurance strength, thermal stability and high temperature creep resistance, P91 steel pipes are widely used in Superheater, reheater and main steam pipe of power plant boiler.

P91 alloy steel chemical composition:
C: 0.08 - 0.12, Mn: 0.30 - 0.60, Si: 0.20 - 0.50, P: ≤ 0.02, Sulfur S: ≤ 0.01;
Chromium Cr: 8.0 - 9.5, Mo: 0.85 - 1.05, V: 0.18 - 0.25, NB: 0.06 - 0.1, N: 0.03 - 0.07, Al: ≤ 0.04 Ni: ≤ 0.4

Application of P91 alloy steel:
Because of its oxidation resistance, high temperature steam corrosion resistance, impact toughness, high and stable permanent plasticity and thermal strength, P91 steel pipes can be used for high temperature superheater and reheater of subcritical supercritical boiler with wall temperature ≤ 625℃, as well as high temperature header and steam pipe with wall temperature ≤ 600℃. Material P91 can also be used to manufacture nuclear electric heat exchanger and furnace pipe of petroleum cracking unit.