TWI Industrial Member Report Summary 261/1985
By S J Maddox
Fatigue tests were carried out on specimens consisting of steel plates with transverse fillet welded attachments to investigate some aspects of the beneficial effects of hammer and shot peening the weld toe. It was found that, in contrast to the behaviour of longitudinal fillet welded details, steel strength (up to 824N/mm2 yield) had no effect on the improvement in fatigue strength due to shot peening. The degree of improvement due to both hammer and shot peening was unaffected by the presence of high tensile residual stresses in the untreated joint, but was affected by the peening conditions. A 6mm diameter hammer peening tool achieved better penetration to the weld toe than a 12mm tool, but 4 passes were required in each case to achieve adequate coverage. The improvement due to shot peening was found to increase with increased peening intensity. Furthermore, in the joints tested, the beneficial effects of hammer and shot peening increased with increase in the fatigue strength of the untreated joint.