TWI Industrial Member Report Summary 34/1977
By G S Booth
Fatigue tests have been conducted, under half tensile and alternating loading, on transverse non-load-carrying fillet welded specimens, which were either heavy disc ground or four-pass hammer peened. Both peening and grinding were found to give a significant increase in fatigue strength at R = -1, but at R = 0.5 the improvement was relatively small. The influence of mean stress on fatigue life was negligible on specimens in the as-welded condition, but an increase in mean stress resulted in a decrease in the fatigue lives of specimens in the peened condition. In the case of heavy disc ground specimens, no difference in fatigue strength (stress range) was found in tests at R = 0 and R = -1, but increasing the stress ratio to R = 0.5 resulted in a decrease in fatigue strength.