远场涡流检测技术不受集肤效应的限制,其相对于传统涡流检测技术而言,能够对金属构件的更深层缺陷进行检测,首先介绍了平板远场涡流的一些研究现状,分析了平板远场涡流的检测原理和传感器设计要求,在此基础上,设计了基于圆柱和矩形结构的2种传感器模型,分析了2种模型在平板构件中所感应磁场的分布规律,并对比了其对不同板厚的检测能力。结果表明:矩形激励线圈能在平板中感应出定向传播的磁场,可以利用矩形结构的远场涡流传感器对较厚平板构件中缺陷的深度和长度进行定量检测。
Remote field eddy current (RFEC) technique in combination with the advantages of infinitive from skin effect and ability to detect the inner crack of metal member is characterized by its equal sensitivity to a flaw irre- spective to its location in the tube wall, and has a small relationship with the magnetic field from the exciting coil. This paper applies the traditional pipeline RFECT to detection for plate member. In this paper the basis of the prin- ciple of RFEC is analyzed, the cylindrical and rectangular exciting coils are designed; the detection effect of plate and the law of magnetic flux density of two sensor models are simulated. The result of simulation shows that rectan- gular exciting coil can induce the directional magnetic field in the plate and RFECT can be used to detect the crack in plate and perform quantitative determination of the depth and length.