PURPOSE: To obtain a turbine rotor with superior corrosion resistance, corrosion fatigue strength, notch toughness, etc. in geothermal environment by forming an Fe alloy having restricted composition into a turbine rotor, followed by austenizing, hardening and tempering.
CONSTITUTION: An Fe alloy consisting of, by wt., 0.05W0.25% C, 0.01W0.3% Si, 0.01W1.0% Mn, 10.0W14.0% Cr, 0.3W2.0% Mo, 0.1W0.5 V and the balance Fe with accompanying impurities or further contg. 0.01W0.1% N is formed into the shape of a turbine rotor. This mateial is austenized at 930W1,100°C and hardened at ≥100°C/ hr cooling rate. It is then tempered at 550W700°C to produce a martensite structure. Thus, a steam turbine rotor for the geothermal generation of electric power with superior mechanical properties and characteristics such as superior corrosion resistance and corrosion fatigue strength is obtd.
WATANABE OSAMU
KAWAGUCHI KANJI
SUZUKI YASUHIRO
