| 摘要 |
PROBLEM TO BE SOLVED: To provide high-temperature strength and to improve the toughness after high-temperature, long-time heating by using a martensite steel having tensile strength at room temperature, creep rupture strength, V-notch Charpy impact value of specified values for the component of a gas turbine. SOLUTION: In this gas turbine having a three-stage blade having closed steam cooling system, its components, for example, turbine discs 11-13, a turbine spacer 18, a compressor disc or the like are formed of a martensite steel having a tensile strength at room temperature of 120 kg/mm2 or more, a 105-hr creep rupture strength at 500 deg.C of 35 kg/mm2 or more and a V-notch Charpy impact value at 25 deg.C after heating at 540 deg.C for 103 hrs of 2 kg-m/cm2 or more. The martensite steel used has the composition consisting of 0.5-0.35 wt.% of C, 0.5 wt.% or more of Si, 0.5 wt.% or more of Mn, 8-13 wt.% or more of Cr, 1.5-4 wt.% of Mo, 2-3.5 wt.% of Ni, and 0.50-0.35 wt.% of V.
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