High cycle multiaxial fatigue tests were carried out in fully reversed plane bending on smooth specimens made of 42CrMo4 steel. These specimens were machined and shot peened under different operating conditions. The experimental endurance limits were compared with the predictions of a multiaxial fatigue strength model for shot peened components. This model is based on the Crossland multiaxial fatigue criterion. It is able to take into account the endurance limit, of the biaxial residual stresses due to both the shot peening and the machining process. The roughness effect is considered by using a correction factor. A good estimation of the fatigue strength improvement due to shot peening is predicted by the proposed model. Some evolutions are needed for instance to consider the effect of surface defects such as indents burrs and folds. The influence of such factors on the fatigue strength can not be included in a single roughness parameter.
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