Pulsed Eddy Current Testing of Carbon Steel Pipes' Wall-thinning Through Insulation and Cladding

作者：Cheng Weiying^*

来源：Journal of Nondestructive Evaluation, 2012, 31(3): 215-224.

DOI：10.1007/s10921-012-0137-9

• Pulsed eddy current testing
• Wall-thinning
• Magnetic field measurement
• AMR sensor
• Analytical solution

Pulsed eddy current testing of wall-thinning through cladding and insulation was studied from both theoretical and experimental aspects. The analytical solution was derived for a simplified four-layered structure and was used to conduct simulations to ascertain the feasibility of this method. A pulsed eddy current testing probe consisting of a circular excitation coil and an AMR-sensor-embedded differential detector was fabricated to measure the time-varying magnetic field signals on the axisymmetric excitation coil's axis. The measurement system was able to measure magnetic field down to a few hundred micro-Gausses in an unshielded environment. Simulation and test results showed that over a certain time after turning off the excitation current the magnetic field signal's decay behavior is almost merely relevant to the pipe's wall thickness. Future development of a carbon steel pipe's wall-thinning can be evaluated by using decay coefficients estimated from previously obtained test data.

• 出版日期2012-9