Integrity assessment of a corroded API X70 pipe with a single defect by burst pressure analysis

Abstract

Gas pipes invariably develop defects. Assessment and repairing methods vary depending on the defect type. When evaluating corrosion in the base metal of a pipe, the burst pressure is usually calculated using conventional evaluation equations, and the possibility of operating the pipe is determined. These equations are applied differently depending on the pipe's physical properties and environment. Therefore, in this study, the failure behavior and burst pressure of a pipe are determined through a full scale hydrostatic burst test; the results are used to simulate the lengths and depths of defects through the finite element method for the shapes and physical properties identical to those of a full-scale pipe. Thus, the corrosion in the base metal of an API X70 pipe was assessed by a stress-based method, and an evaluation equation suitable for use was proposed.