Effect of Residual Stresses on the Fatigue Resistance of Welded Joints of Steels of Different Strength Levels

Limiting cyclic stress diagrams of welded joints of a low-carbon and low-alloy steels of different strength levels are analyzed under conditions that they contain the same level of steady residual stresses. For tests of butt-welded joints as an example, a procedure for calculating the endurance limit at different values of limiting steady residual stresses is proposed. Limiting cyclic stress diagrams are constructred by calculation. It is shown that in the studied range of relative values of mean cyclic and steady residual stresses, the endurance limit of welded joints of steels with high strength level is higher. It was found that at the same relative values of mean cyclic stresses, the welded joints of stronger steels are characterized by higher steady residual stresses and endurance limit, which growth with residual stresses.