Effect of plastic pre-strain on the fatigue properties of welded joints of X80 LSAW pipes

Abstract The fatigue properties of the original, 1%, 2%, and 3% plastic pre-strained welded joints of X80 pipeline steels were tested to find the effect of plastic deformation on the service of pipelines. Results showed that the fatigue cracks growth period remarkably decreased with the increasing plastic pre-straining extent, reducing the safety of pipeline transportation. The decrease was caused by the cleavage fractures generated by dislocation synthesis reactions during the fatigue process. The results reveal the effects of dislocation distribution on fatigue property of the welded pipe after plastic deformation and provide a reference for the safety design of pipelines.