Application of X-ray Diffraction Residual Stress Measurement to Shot Peened Surfaces

Author:  Paul Prevey, Lambda Research
Source:  The Shot Peener magazine, Vol 04/Issue 3, Fall 1990
Doc ID:  1990154
Year of Publication:  1990
Abstract:  
Shot Peening is commonly used to produce a layer of compressive residual stress at the surface of components subject to fatigue or stress corrosion failure. The shot peening process is controlled by monitoring the Almen intensity. However, no simple relationship exists between the peening intensity measured with the Almen strip and the residual stress-depth distribution produced. The Almen arc height depends upon the form of the residual stress-depth curve, and quite different stress distributions can produce equivalent arc heights. Conversely, peening to the Almen intensity with different shot sizes will generally produce different subsurface residual stress distributions. The stress distribution produced by shot peening depends upon the properties of the material being shot peened, prior to processing, and the specific peening parameters used. Shot peening can only be reliably controlled and optimized by measuring the subsurface residual stress distributions produced.