Residual stress relaxation induced by shot peening in different materials after quasi-static loading

Author:  J. Hoffmeister,V. Schulze
Source:  Conf Proc 2014: ICSP-12 Goslar, Germany (pgs.256-261)
Doc ID:  2014085
Year of Publication:  2014
Abstract:  
Shot peening is often used to improve the fatigue life of cyclic loaded components. Therefore it is very important to know the changes of the residual stress state due to quasi-static loading. The objective of this work was to describe the changes of the residual stress state of different materials caused by shot peening induced by quasi-static loading. Therefore different shot peened specimens were loaded isothermally up to a specific tensile load. After the different loadings the residual stresses at the surface and for special loadings the residual stress depth distributions were determined experimentally by using X-ray diffraction. With an already existing model, based on the surface-core-model, the deformation behaviour of the surface could be deduced from the results of the quasi-static experiments. The model was adapted so that it is possible to predict the residual stress relaxation according to the residual stress and the full width at half maximum depth distribution and a stress-strain curve of hole drilled specimen. The remaining material in the gauge length of the hollow drilled specimen is much more affected by the mechanical surface treatment. So rather the hardening or the softening of the material could be measured and integrated in the modelling.