The Significance of Almen Intensity for the Generation of Shot Peening Residual Stresses

Author:  Herzog, Zinn, Scholtes, Wholfahrt
Source:  Conf Proc: ICSP-6, (p.270-281)
Doc ID:  1996074
Year of Publication:  1996
Abstract:  
Basic peening parameters of shot peening processes are mean shot velocity, mass flow an dpeening time as well as material, geometry, demension and hardness of the shots and the parts to be treated respectively. Nevertheless, in practice besides specifications of type and harndess of the material and the shot peening medium resp., peening operations are pragmatically characterized by Almen intensity and coverage. Whereas reproducibility of shot peening processes can be obtaned in this way, it is not unambiguous with respect to the resulting shot peening residual stress distributions. In this paper, this aspect is investigated using quenched and tempered shot peened steel of the German grade X35CrMo17 and aluminium base alloy AI 7020 as examples. Characteristic residual stress depth profiles are shown, realized using a variation of Almen intensities and shot diameters. The resulting residual stress distributions are discussed taking into accunt the amounts of compressive residual stresses as well as thicknesses of affected surface layers.