HIGH STRENGTH HIGH TOUGHNESS HIGH CORROSION RESISTANCE MARTENSITE STEEL, STEAM TURBINE BLADE, AND STEAM TURBINE POWER PLANT

摘要

PROBLEM TO BE SOLVED: To provide martenstic steel which is high in all of room temperature strength, toughness and corrosion resistance and consequently can realize the longer blade of a final stage moving blade of a low pressure steam turbine.;SOLUTION: The martensite steel contains, by weight, 0.15 to 0.30% C, 0 to 0.50% Si, ≤0.60% Mn, 1.0 to 4.0% Ni, 8 to 15% Cr, over 2 to ≤3% Mo, 0.02 to 0.3% V, over 0.5% to ≤5.0% Cu, 0.02 to 0.1% N, 0.02 to 0.3% in total at least either of Nb and Ta, 0 to 2% W, 0 to 5% Co, 0 to 1.5% Re, 0 to 0.5% in total at least one of Ti, Zr and Hf and the balance composed of Fe and inevitable impurities and has tensile strength ≥1,200 N/mm² at room temperature, impact energy ≥20 J, and fracture stress ratio ≥70% of SSRT test.;COPYRIGHT: (C)2005,JPO&NCIPI