| 摘要 |
The present invention relates to a process for forming the root of a turbine blade using the EDM method. EDM machining of the root is done in a manner that any re-cast layer left behind is less than 1 micron. After EDM machining the turbine blade is subjected to MPI to check for depth or presence of surface cracks. A liquid tracer coating is then applied to the root, which allows the ability of the next process to be verified as complete. The root is then subjected to glass beading to remove any re-cast and insure the surface finish prior to shot peening is consistent and contains no scratch marks or machine marks. The root is then subjected to shot peening to reduce residual tensile stresses by imparting to the surface small indentations or dimples and produce a compressed surface which resists further surface cracks.
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