Abstract The aim of this research is to evaluate the inaccuracies of pipe wall flaws sizing derived from an axial excitation magnetic flux leakage technology (MFL), in respect to the defect field checking. During direct assessment, construction and metallurgical features such as rolling anomalies and ingot imperfections were discovered on the natural gas pipeline serviced for many years. MFL tool sizing accuracy of pipe wall losses was individually compared with a limited number of excavations. The inspection equipment errors were estimated based on a small-scale of the verified anomalies within tolerances and the correct pipe surface classifications. The quality of diagnostic results and their correspondence to the pipeline maximum admissible operating pressure calculations was highlighted. However, certain flaws on the considered pipeline are not metal loss-type and, for this reason, cannot be assessed by the code based level 1 engineering method. A deterministic approach to the pipeline pigging time intervals was analyzed. The impact of the defect growth rate on the inspection schedule was presented in the current paper in the simplest way. Based on the considered analysis and author's experience, expert judgment guidelines for conducting in-line inspection on underground gas transmission pipelines were formulated in this publication.

中文翻译：

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在线检测数据质量的验证和对钢管诊断间隔的影响

摘要 本研究的目的是评估由轴向励磁漏磁技术 (MFL) 得出的管壁缺陷尺寸在缺陷场检查方面的不准确性。在直接评估中，在服务多年的天然气管道上发现了轧制异常和铸锭缺陷等构造和冶金特征。管壁损失的 MFL 工具尺寸精度分别与有限数量的挖掘进行了比较。检测设备误差是根据在公差范围内验证的小规模异常和正确的管道表面分类来估计的。重点强调了诊断结果的质量及其与管道最大允许工作压力计算的对应关系。然而，所考虑管道上的某些缺陷不是金属损失型的，因此无法通过基于代码的 1 级工程方法进行评估。分析了管道清管时间间隔的确定性方法。当前论文以最简单的方式介绍了缺陷增长率对检查计划的影响。在综合分析和作者经验的基础上，本出版物制定了地下输气管道在线检测的专家判断指南。