Shot Peening - Control and Measurement

The Almen strip has for many years been the standard of control and measurement o£ the shot-peening process. The fatigue life increase obtained by peening, however, is not generally predictable by Almen intensity. In this paper, results of laboratory tests showing the Almen intensities and surface residual compressive stresses obtainable with glass and steel peening media of several sizes are reported. No correlation was found between residual stress and Almen intensity. The tests indicated that greater residual stresses were developed by smaller peening media.