Correlation of Mechanical Surface Treatments, induced Surface States and Fatigue Performance of Steel Components

Mechanical surface treatments such as shot peening are widely used to induce surface states leading to enhanced fatigue properties of steel components. The effects of shot peening on the surface layer state are well understood and can be simulated using actual finite element simulation tools. The stability of the residual stresses during service can also be predicted using appropriate models. Knowing this relaxed surface state and the distribution of loading stresses the fatigue performance of components can be predicted using approaches like the concept of local fatigue properties or of the ability of crack propagation. In the paper exemplary results on shot peening, surface state and its stability as well as prediction of fatigue properties will be shown for the steel AISI 4140 in different heat treatment conditions.