| 摘要 |
<p>Provided is a method for manufacturing a shaft for a turbine rotor, which makes it possible to ensure that the dimensions of a flange, the dimensions of a shaft part, the squareness of the flange with respect to the shaft part, circular runout, and circularity are within a desired accuracy, without the need for a cutting operation. With respect to target values of a final product, flanges (3a, 3b) have an outer diameter tolerance ranging from +0.0% to +0.6%, and a thickness tolerance ranging from -0.8% to -0.0%, a shaft part (2) has a diameter tolerance ranging from +0.0% to +0.6%, the circular runout tolerance is 0.5 mm or less, and the squareness tolerance of the flanges with respect to the shaft part is 0.5 mm or less. The method includes a step of pressing a sintered compact having a sintered density that is equal to or greater than a relative density of 95%. In the pressing step, the sintered compact is pressed using an upper mold and lower mold having the shape of the shaft for the turbine rotor which has been split into two equal parts along the surface including the axis of rotation. In this case, after a first pressing operation is performed, the phase is shifted through no more than 120° to perform a second pressing operation, after which subsequent pressing operations are performed with the phases being sequentially shifted through no more than 120°.</p> |
