| 摘要 |
PROBLEM TO BE SOLVED: To provide an impeller having high reliability as an effective means for relaxing stress concentration wherein man-hours of machining is reduced to a half, and stress concentration is relatively easily relaxed at a low cost in comparison with R-part forming by fillet weld and grinder finish without limitation of plate thickness and tilting of blades. SOLUTION: A plating layer is provided in both of a combination of a unit of a blade and an upper shroud with a lower flat shroud and a combination of a unit of a blade and a lower shroud with a flat upper shroud. The upper shroud or the lower shroud provided with a groove having an R-part in both sides thereof are made to abut on each other, and surface roughness of bonding surfaces is set at 3μm or less, and bonding and diffusion processing of the bonding surfaces are continuously performed in a vacuum furnace, and thereafter, quenching and tempering are performed to manufacture the impeller. Since the groove having the R-part is provided in both sides of the blade, stress concentration to a blade fitting part is relaxed to improve the fatigue strength, and the impeller restricted in thermal deformation thereof due to the welding structure is manufactured at a low cost. COPYRIGHT: (C)2004,JPO
|
