ESDU 78016 discusses methods for improving the fatigue strength and uses results of constant-amplitude fatigue tests from the literature to show their effectiveness. The effect of changing the stress concentration by improving the weld shape by grinding or tungsten inert gas welding is shown graphically by plotting alternating stress against endurance for longitudinal and transverse welds compared respectively with data from ESDU 75016 and 76007 for untreated welds. The effect of introducing compressive stresses by shot-peening is similarly compared with the same ESDU data for untreated welds. These cases all use results with zero mean stress. For longitudinal welds stress relieved by heat treatment@ the fatigue strength at three different mean stresses is compared graphically with the untreated weld data from ESDU 76007@ while for longitudinal welds treated by spot-heating or spot-pressing only zero mean stress data are available for comparison with data from ESDU 76007. A table summarises the improvements achieved by the various methods.