| 摘要 |
PURPOSE:To obtain excellent mechanical strength and bond strength by the generation of the residual tensile stress in a binding metal by insert-casting the engaging projection of a revolving shaft inserted into the recess of a turbine wheel when the binding metal cools to solidify. CONSTITUTION:The turbine wheel 20 is disposed atop a jig 56 with a rear side 30 thereof faced upward in the state of aligning a through-hole 50 ad the recess. After the wheel 20 is heated to a high temp., a prescribed molten metal 60 is poured into a bottomed circular hole 36 thereof. The molten metal is thereafter gradually cooled, then the molten metal 60 cools to solidify to the binding metal 62 which contains the engaging projection by casting and generates the residual tensile stress in the axial direction in the hole 50. The metal 62 is securely bound with the engaging projection, while a head part corresponding to the recess of the jig 56 is formed to the metal 62 on the surface 48 side of the turbine wheel 20. The engaging projection is detained to the turbine wheel 20 by such head part.
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