| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a steam turbine blade having proper toughness together with strength by setting the blade part length of a blade to a plurality of specified numerical values to a plurality of specified numerical values related to the rotating speed of the blade, setting the tensile strength at room temperature of a dovetail part to a specified numerical value or more, and forming the blade of a Ti-base alloy. SOLUTION: In a final stage steam turbine blade for steam turbine low- pressure turbine, the length of a blade part 51 is set to 43 inches or more at a blade revolution of 3600 rpm, and the steam temperature is set to 538-650 deg.C. A dovetail 52 is formed of eight forks, and the tensile strength is set to 110 kg/mm2 or more. Further, a Ti-base alloy or Do-base alloy of stelite is brazed to an erosion shield 54. The blade is formed of a Ti-base alloy containing 4-8% al, 4-8% V and 1-4% Sn by weight. In the manufacture, solution treatment and aging treatment for hot forging a blade material and cooling it after heating within prescribed aging temperature and solution treatment temperature are performed. |
