| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of reducing the wall thickness of a turbine nozzle capable of improving yield of casting as well as reducing thermal stress. SOLUTION: For removing material 34 from an inner surface of a cavity 18 in a nozzle stationary blade 16 of a turbine, a process of electric discharge machining(EDM) is used after casting. A thin electrode 28 passes the inside of the cavity 18 between facing ends of the nozzle stationary blade 16 to move along a preset route along a nozzle inner wall for removing the material 34, so a wall thickness of the wall between the nozzle cavity 18 and an outer surface of it is reduced. In another mode, an outline form body 42 is disposed in the cavity 18 in the EDM process using an outline form body 42 as an electrode, and it is advanced toward the wall till a final wall thickness is achieved to set the form of the inner wall surface to be complementary to a surface of the outline form body 42, thereby the material 34 is removed from the wall.
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