Signal Judgment Method of Three-Axis Flux Leakage Internal Detection Line for Crack-like Defects in Pipeline Girth Weld

Abstract

The invention discloses to a triaxial magnetic leakage inner detection line signal determination method for girth joint crack defects of a pipeline, and relates to the technical field of magnetic variable and pipeline system measurement. The method for determining the dimensions of the girth joint crack defects of the pipeline comprises the following steps: 1, an axial signal is a monopulse wave, the waveform direction of the axial signal is opposite to a metal increase signal direction, and there is an index relation between a defect depth d1 and a signal height amplitude h1, that is, the formula of the index relation is d1=0.60*h1^0.40; 2, a radial signal is a bidirectional pulse wave, the waveform direction of the radial signal is opposite to the metal increase signal direction, and there is an index relation between a defect depth d2 and a signal height amplitude h2, that is, the formula of the index relation is d2=0.30*h2^0.45; and 3, a defect depth d which is an average of the depths obtained in step 1 and step 2, that is, the calculation formula of the defect depth is d=1 / 2(d1+d2). The triaxial high-definition magnetic leakage inner detection line signal characteristic is utilized to determine the dimensions of the girth joint crack defects of the pipeline.

Description

technical field [0001] The invention relates to a method for judging signals of three-axis magnetic flux leakage internal detection line for crack defects in pipeline girth welds. It relates to the technical fields of measuring magnetic variables and pipeline systems. Background technique [0002] Due to the limitations of the technical level and basic equipment conditions at that time, the pipelines constructed on site in my country in the 1970s contained a large number of annular crack defects, resulting in multiple oil seepage incidents. How to determine the size of detected girth weld crack defects has become an urgent problem for pipeline managers. However, in the current internal inspection technology, traditional magnetic flux leakage testing equipment cannot detect crack defects in girth welds, and only three-axis high-definition magnetic flux leakage detection technology can detect crack defects in girth welds. At present, the three-axis high-definition magnetic f...

AI Technical Summary

Problems solved by technology

However, in the current internal detection technology, traditional magnetic flux leakage testing equipment cannot detect crack defects in girth welds, and only three-axis high-definition magnetic flux leakage detection technology can detect cracks in girth welds

At present, the three-axis high-definition magnetic flux leakage internal detector can detect crack defects in girth welds, but the size of the defects cannot be determined

If the size of girth weld crack defects cannot be determined through internal inspection, it cannot be evaluated and repaired in a targeted manner, which may cause girth weld leakage accidents at any time, which is a major safety hazard in the operation of old pipelines

[0003] CN101968463A discloses a three-axis magnetic flux leakage internal detection line signal identification method for pipeline spiral weld crack defects, but it can only identify pipeline girth weld crack defects, and cannot determine the size of the defects, which has great impact on practical applications. great inconvenience

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