Metal Magnetic Memory Testing of the Drilling Riser Pipeline Steel Based on Pulsating-Impact-Fatigue Test

摘要

To know the fatigue damage state of X80 pipeline steel which is used for the drilling riser and prevent the occurrence of fatigue fracture accidents. Pulsating-impact-fatigue tests were conducted in laboratory, magnetic memory signals were measured during the whole fatigue process. The distribution of stress and magnetic field vector with different crack depth was analyzed by using finite element (FE) method. During fatigue crack initiation stage, magnetic signals increased slowly with fatigue loading cycles because of the effect of stress-magnetization. When fatigue crack appeared, magnetic signals were mainly affected by magnetic flux leakage (MFL) which was induced by fatigue crack. Magnetic memory characteristic parameters had a good linear relationship with fatigue crack depth. Magnetic memory signals were able to reflect the change of fatigue damage status.