| 摘要 |
PROBLEM TO BE SOLVED: To provide an impeller of high reliability with any unwelded portion eliminated capable of effectively relieving a stress concentration simply at a low cost, compared with a conventional method including a projection on a rounded part, fillet welding and formation of rounded part by finishing with a grinder. SOLUTION: Using a brazing filler material 7, a part where the impeller 3 and a lower shroud 4 are consolidated is placed on an upper shroud 2 furnished on both sides with grooves 14 each having a rounded part, and a stress concentration at the root part of each vane is relieved by subjecting the boundary part with the vane part to an electron beam welding from the upper shroud part, and it is possible to manufacture low-cost impeller 1 equipped with an enhanced fatigue strength, free of defects an unwelded portion, and involving less risk of welding deformation.
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