Relation Between Shot-peening Residual Stress Distribution And Fatigue Crack Propagation Life In Spring Steel

Author:  Tange, Akira and Takamura, N.
Source:  Conf Proc: ICSP-4, (p.243-254)
Doc ID:  1990056
Year of Publication:  1990
Abstract:  
We performed the following study to examine the influence of the residual stress distribution by shot-peening on the fatigue crack propagation life. The results we obtained are as follows; (1) To define the threshold conditions of small crack propagation in spring steels, we proposed a method which consists of applying the hardness and stress ratio dependency to Haddad's consolidation. (2) It is very important to raise the surface residual stress for improving the fatigue crack propagation life. (3) Most of the fatigue crack propagation life is spent while the crack propagates from the surface to the position where the compressive residual stress is maximum. (4) The nearer to the surface the position where the compressive residual stress is maximum, the longer fatigue crack propagation life is extended. (5) The predicted S-N curve by this method shows good correspondence with the actual results of the rotary bending fatigue tests. Descriptors: Shot-peening; Residual stress; Fatigue; Spring steel; Fracture mechanics; Small crack; Crack propagation life