Gas Transmission Pipeline Defect Detection Based on New Intense Magnetic Memory ILI Tool

摘要

Large diameter and high pressure is the typical feature of long distance gas transmission pipelines. Pipelines are subjected to corrosion, cracks and other kinds of deformations. Ensuring pipeline integrity and the associated utilization of in-line inspection (ILI) tools have become primary concern of pipeline operators. A novel nondestructive technology named intense magnetic memory (IMM) was introduced to pipeline inspection. Excited by geomagnetic field and intense residual magnetic on workpiece, microdefects can be found only by detecting self-magnetic leakage field (SMLF) in the pipe wall. It is especially suitable for assess damage condition of integral work pieces by indicating the position and severity of stress concentration region, which is the origin of various defects. A special IMM ILI tool was designed for Φ529 gas pipe. Laboratory testing pipeline system was setup and artificial defect was inspected. Signals were processed and characteristic feature was extracted to obtain detail defect information. Initial experimental results show that it is promising for IMM technology being applied to pipeline inspection.