摘要
漏磁检测是管道在线检测中应用最广泛的一种无损检测方式,该检测技术获得理想结果的前提是励磁系统将管道磁化至饱和状态。这一要求在大壁厚管道检测中面临显著挑战:一方面需要庞大的励磁系统以实现足够的磁化强度,另一方面过大的励磁系统体积及其产生的强磁吸附力,反而成为制约该技术在大壁厚管道检测中实际应用的主要瓶颈。针对这一问题,提出了一种基于磁涡流效应的低磁化强度下缺陷检测技术。该技术以缺陷处磁导率异常检测为核心,研究了铁磁性材料在低直流磁场作用下缺陷处磁导率的不同变化规律,对磁涡流效应内外壁缺陷检测的机理进行了分析以及有限元仿真;设计了磁涡流传感器,对刻有深度分别50%、40%、30%、20%及10%wt、不同类型缺陷的15 mm厚钢板同时进行了磁涡流及漏磁内外壁缺陷检测对比实验;实验结果显示磁化电流为0.7~1.1 A时磁涡流检测技术不但可以有效识别不同深度及类型缺陷、区分缺陷内外壁分布情况,且检测效果明显优于相同条件下的漏磁检测;仿真和实验结果均表明在磁涡流效应在低磁化强度下可实现对铁磁性材料的内外壁缺陷检测,验证了所提检测技术的可行性及有效性,为大壁厚管道全壁厚缺陷检测提供有效方法。
Magnetic flux leakage detection is one of the most widely used non-destructive testing techniques in online pipeline inspection.The prerequisite for obtaining ideal results in this detection technology is that the excitation system magnetizes the pipeline to the saturation state.This requirement encounters significant challenges in the inspection of large-wall-thickness pipelines.On one hand,a substantial excitation system is required to achieve adequate magnetization intensity.On the other hand,the considerable size of the excitation system and the intense magnetic attraction force it produces have become the primary constraints limiting the practical application of this technology in such pipeline inspections.To overcome this constraint,a novel defect detection method based on the Magnetic eddy current effect under low magnetization intensity is proposed.This approach focuses on detecting anomalies in magnetic permeability at defect sites.The study investigates how the magnetic permeability of ferromagnetic materials changes at defect locations under low DC magnetic fields,The mechanism analysis and finite element simulation of the detection of inner and outer wall defects by the magnetic eddy current effect are carried out.A magnetic eddy current sensor was designed.Comparative experiments of magnetic eddy current and magnetic leakage ID and OD defect detection were simultaneously carried out on 15 mm thick steel plates engraved with different types of defects at depths of 50%,40%,30%,20%and 10%wt(wt,wall thickness)respectively.The experimental results show that when the magnetization current is 0.7~1.1 A,the magnetic eddy current detection technology can not only effectively identify defects of different depths and types and distinguish the distribution of the inner and outer walls of the defects,but also the detection effect is significantly better than the magnetic leakage detection under the same conditions.Both the simulation and experimental results show that the inner and outer wall defects of ferromagnetic materials can be detected under the magnetic eddy current effect at low magnetization intensity,verifying the feasibility and effectiveness of the proposed detection technology and providing an effective method for the full-wall thickness defect detection of large-wall thickness pipelines.Magnetic flux leakage detection is one of the most widely used non-destructive testing techniques in online pipeline inspection.The prerequisite for obtaining ideal results in this detection technique is that the excitation system magnetizes the pipeline to a saturated state.This requirement presents significant challenges in the detection of large-wall-thickness pipelines.On the one hand,a large excitation system is needed to achieve sufficient magnetization intensity.On the other hand,the oversized excitation system and the strong magnetic attraction it generates have become the major bottlenecks restricting the practical application of this technique in such scenarios.To address this problem,a defect detection technique based on the magnetic eddy current effect under low magnetization intensity is proposed.This technique focuses on detecting magnetic permeability anomalies at defect locations.The variations in magnetic permeability at defect sites in ferromagnetic materials under low DC magnetic fields are investigated,and the mechanism analysis and the mechanism of inner and outer wall defect detection based on the magnetic eddy current effect is analyzed through finite element simulation.A magnetic eddy current sensor was designed,and comparative experiments on magnetic eddy current and magnetic flux leakage detection of inner and outer wall defects were conducted on 15mm thick steel plates with artificially machined defects of different types and depths(50%,40%,30%,20%and 10%of wall thickness).Experimental results show that when the magnetization current is between 0.7 A and 1.1A,the magnetic eddy current detection technique not only effectively identifies defects of varying depths and types and distinguishes between inner and outer wall defect locations,but also achieves significantly better detection performance than magnetic flux leakage detection under the same conditions.Both simulation and experimental results demonstrate that inner and outer wall defects in ferromagnetic materials can be detected under low magnetization intensity using the magnetic eddy current effect,verifying the feasibility and effectiveness of the proposed detection technique and providing an effective method for the full-wall thickness defect detection in large-wall-thickness pipelines.
作者
高波
杨理践
黄平
Gao Bo;Yang Lijian;Huang Ping(School of Information Science and Engineering,Shenyang University of Technology,Shenyang 110870,China)
出处
《仪器仪表学报》
北大核心
2025年第6期205-214,共10页
Chinese Journal of Scientific Instrument
基金
国家自然科学基金(62301338)
辽宁省自然科学基金联合基金面上资助计划(2023-MSLH-261)项目资助。
关键词
无损检测
磁涡流
低磁化强度
缺陷检测
non-destructive testing
magnetic eddy currents
low magnetization
defect detection
