| 摘要 |
PROBLEM TO BE SOLVED: To provide a steam turbine blade composed of an easily manufacturableγ'-phase precipitation strengthening type superalloy having a coefficient of thermal expansion equal to or lower than that of a ferritic heat resistant steel and further combining high temp. strength, much higher than that of a ferritic heat resistant steel, with superior oxidation resistance and notch sensitivity, and its production. SOLUTION: The steam turbine blade is composed of an Ni-base superalloy having a composition containing, by weight, <=0.2% C, <=1% Si, <=1% Mn, 10-24% Cr, either or both of Mo and W in the range satisfying Mo+(1/2)×W=5 to 17%, 0.5-2% Al, 1-3% Ti, <=10% Fe, and either or both of <=0.2% Zr and <=0.02% B, and 48-80% Ni. Further, <=5% Co and <=1.0% Nb can be added, if necessary.
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