Optimization of the Fatigue Strength of Heat Treated Steels as a Consequence of an Optimum State of the Surface and of Subsur

Author:  A. Sollich, H. Wohlfahrt
Source:  Conf Proc: ICSP-6, (p.251-262)
Doc ID:  1996039
Year of Publication:  1996
New experimental results on the improvement of the fatigue strength of differently heat treated steels due to shot peening with steel shot, with ceramic beads and also with steel shot plus ceramic beads are compared. The results indicate that the benefical effects of shot peening depend in a rather complicated way upon the ratio of surface hardness, surface reoughness and the magnitude of compressive residual stresses at the surface or - if subsurface crack initiation is forced - upon the distribution of residual stresses versus depth below surface. Detailed explanations can be given considering the surface state and the distribution of residual stresses after peening. Comparisons with the fatigue strength after CBN-grinding under a tensile prestress confirm the results and explanations.

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