Finite elements analysis and experimental verification of residual strength of steel pipe with flat bottom corrosion defect

In order to reveal the influence of the defects size on the load capacity of a corroded line pipe of X65 steel, the distribution of the von Mises stress and strain as well as the relation of the residual strength of the line pipe with the depth and diameter of the flat bottom defects were analyzed by the finite element methods (FEM), meanwhile, the lab experiment was carried out to verify the calculated results. The results showed that, the deeper of the corroded defects, as well as the bigger the diameter of the defects, the less residual strength was, and the depth exhibited much significant influence than the diameter. Tensile tests were carried out for the specimens with flat bottom defects of 6 mm in diameter and of 0.25t (t, thickness) and 0.5t in depth respectively, it follows that the experimental results were coincident to those of calculated by FEM, especially that of the specimen with the bigger defect depth.