三维远场涡流探头的设计与实验研究

远场涡流检测技术能检测导电管材整个管壁缺损而不受集肤效应和提离效应的影响。但是，由同轴的激励线圈和检测线圈构成的传统远场涡流探头只能检测管壁周向缺损的平均情况而不能确定其缺损的周向具体位置。本文设计了一种新型内通过式三维远场涡流探头，实验证实了其远场效应的存在并确定了甲型探头结构。以油田实际的采抽钢管为检测对象对管壁的对称缺损和不对称缺损进行了对比检测实验，证明了新型探头对缺损的三维位置的可确定性，同时也证明了局部磁场变化对管壁周向其他位置的磁场也有影响。

Design and experiment of 3 D remote field eddy-current probe

The remote field eddy current(RFEC)technique is a through-wall non-destructive method of in- specting high conductive tube for defects.The traditional RFEC probe with one excitation coil and one pick- up coil can not indicate the defect location around tube wall.A typical prototype RFEC probe was designed and its RFEC effect was verified with test results.Experimental tests in detecting symmetry and asymmetry defects in tube wall show that the designed RFEC probe is capable of indicating the 3 D defect location.Ex- periment results also approve that local aberration of magnetic field can influence the magnetic field in other place around wall.