For metal pipe with pretension and corrosion defects, local elastic-plastic deformation often occurs at the defects and affects the corrosion electric field characteristics of the metal pipe. This paper takes 20^# steel metal pipe with ellipsoidal corrosion defect as the research object, and establishes a mechanical-electrochemical coupling model of elastic-plastic stressstrain and local electrochemical corrosion to study the effects of different tensile displacements on stress distribution and corrosion electric field characteristics of metal pipes. The results show that mises stress, corrosion potential, corrosion current density and corrosion electric field mode are symmetrically distributed with respect to the defect center under different tensile displacements, with the maximum value occurring at the defect center, and the values all increase with the increase of tensile displacement. The influence of plastic deformation stage on the local electrochemical characteristics of defects is significantly greater than that of elastic deformation stage. The corrosion at the defect is composed of a series of small galvanic cells, and the increase of tensile displacement can accelerate the corrosion rate at the defect.

stress  /  mechanical-electrochemical coupling model  /  corrosion electric field