influence-by-compressive-surface-zonesThe thickness of the compressive stress zone determines the size and distribution of tolerable surface damage and flaws near the surface.Material with pronouncedhardening (steels)HardenedMinimally hardeningmaterial (titanium alloy)Increase in the yield limit Minor increasein the yield limitHardenedHardening should not be equated to the induction of compressive stresses, even though the processes occur simultaneously.Press.Tens.Residual stresspatternS2S1Breakouts of brittlephases, e.g. carbidesCold welding (galling) FrettingTearing open of the surface;chatter marks, comma cracksScratchesMachining groovesThe ratio S1/S2influences the mean stress in thecross-sectionMaterial flaws and weakpoints such as pores and segregations