| 摘要 |
PURPOSE:To inexpensively obtain turbine rotor shaft without causing bending with the lapse of time at high temp., by cooling rotor shaft material made of Cr-Mo-V steel and uniformly austenitized by heat treatment, then tempering it so that strength and toughness are provided according to each position of shaft. CONSTITUTION:The turbine rotor shaft material is heat treated at 950-990 deg.C and uniformly austenitized. Next, the material after heat treatment is cooled, then tempered while setting the tempering temp. (i.e. 600-650 deg.C) of shaft position, i.e. a shaft center part 1 exposed to high temp. atmosphere at turbine operation lower than that (i.e. 650-700 deg.C) of shaft position exposed to lower temp. at the operation time. Turbine rotor shaft obtd. as the result exhibits a sufficiently high fracture strength at shaft center part compared with that manufactured by conventional process, bending with the lapse of time is not caused even in the use at 566 deg.C temp. limit and turbine can be stably operated.
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