Fatigue resistance of MAG welded steel elements

The present paper describes the results of a research programme carried out to assess the fatigue properties of MAG (Metal Active Gas) welded elements, built in Fe510 D1 steel. Tests on both small and large specimens were carried out to evaluate the effects, on fatigue resistance, of the residual stresses produced by the welding process. The joints examined were butt welded and longitudinally welded. Crack propagation tests were also carried out on welded plates. The data available, together with results taken from the literature, allowed us to analyse the fatigue test results on the basis of the methodologies of Fracture Mechanics; by calibrating the initial defects using the results of the tests carried out on small specimens, a good prediction of the fatigue resistance of large specimens was obtained.