Abstract

The protective coatings and surface treatments of the cylindrical conductive materials have found extensive technological applications. Therefore the possibility to determine the coating thickness is very important for both the control process in itself and the in-service inspection. By now, many inspections method are used such as ultrasonic, thermal or eddy current methods depending on the circumstances.

The cylindrical conductive material testing using the pulsed eddy current method shows as compared to the simple frequency technique, the advantage of reducing the coil sensitivity to the lift-off variations and increasing the magnetic field penetration into the material under test, due to the large frequency band of the excitation current.

In this work, pulsed eddy current numerical modelation by means of the finite element method is extended to complex situations closely related to the practical situations. Thus the protective coatings on wires, bars and pipes are determined and the influence of materials parameters (electrical conductivity, magnetic permeability) on the measurements results is studied. The data coming from the transitory finite element model are used to produce a frequency response, which is compared to experimental values, a good concordance being found between them.

Keywords: Eddy Current Testing

Source: Conference Proceedings of the 4th International Conference of the Slovenian Society for Nondestructive Testing, 24 - 25 April 1997, Ljubljana, Slovenia.
Pages:381

Publisher:
Slovenian Society for Nondestructive Testing, Faculty of Mechanical Engineering, Askerceva 6, SLO 1000 Ljubljana, Slovenia. Tel +386 61 177 12 03, Fax +386 61 218 567, Email: janez.grum@fs.uni-lj.si.