Three-dimensional modeling and reconstructive change of residual stress during machining process of milling, polishing, heat treatment, vibratory finishing, and shot peening of fan blade

Residual stress during the machining process has always been a research hotspot, especially for aero-engine blades. The three-dimensional modeling and reconstructive laws of residual stress among various processes in the machining process of the fan blade is studied in this paper. The fan blades of Ti-6Al-4V are targeted for milling, polishing, heat treatment, vibratory finishing, and shot peening. The surface and subsurface residual stress after each process is measured by the X-ray diffraction method. The distribution of the surface and subsurface residual stress is analyzed. The Rational Taylor surface function and cosine decay function are used to fit the characteristic function of the residual stress distribution, and the empirical formula with high fitting accuracy is obtained. The value and distribution of surface and subsurface residual stress vary greatly due to different processing techniques. The reconstructive change of the surface and subsurface residual stress of the blade in each process intuitively shows the change of the residual stress between the processes, which has a high reference significance for the research on the residual stress of the blade processing and the optimization of the entire blade process.