Method and Apparatus for Providing a Layer of Compressive Residual Stress in the Surface of a Part

Author:  Paul S Prevey, John T. Cammett
Source:  US Patent 7,159,425 B2
Doc ID:  2007033
Year of Publication:  2007
Abstract:  
ABSTRACT The shot peening method and apparatus (FIG 13) of the present invention utilizes control of the shot peening coverage to provide higher surface compression and comparable depth of compression to conventional 100% coverage peening but with reduced cold working providing improved thermal stability and reduction in shot peening time and cost. A preferred embodiment of this invention employs x-ray diffraction (FIG 13) residual stress and percent cold work determinated by line broadening to establish the optimal degree of coverage for a given material and shot peening intensity.