| 摘要 |
PURPOSE:To shorten the time required for processing to generate cracks, by placing a blade construction in an enclosed vessel, applying high pressure and forming cracks in the radial direction of the impeller disc. CONSTITUTION:Notches 3 are provided in the periphery of an impeller disc 1, and an axially stretching through hole 4 of minor diameter is excavated at the position mating with each of the notches 3. This blade construction 5 is put in an enclosed vessel 6, and a high pressure is applied thereto so as to form a crack 9 between each notch 3 and through hole 4. |
