Relation between Residual Stress and Fatigue Strength for Electron Beam Welded Joints of Sheet Metal

Abstract

The relationship between residual stress and fatigue strength has been researched for electron beam welded joints made of sheet metals with a thickness of approx. 10 mm. Residual stresses were analyzed by the Finite Element Method, and fatigue strength was obtained by the three-point bending fatigue test. From the results of examining the effect of heat input, a particular relationship was observed between fatigue strength and residual stress, but the effect of stress concentration on fatigue strength was not significant within the tested range of stress concentration factors with varied bead shapes. As a result of testing the effect of steel type, the correlation between fatigue strength and residual stress was confirmed with exception of S50C steel that resulted in lower fatigue strength deviating from the correlation, the deviation of which can presumably be attributed to localized hardening and narrowed area where compressive residual stress was induced.