Abstract

The eddy-current non-destructive evaluation of pipes is performed at present by two main procedures

-with encircling absolute or differential transducer;
- with laid-on transducer rotating around the controlled product.

In the case of the pipes welded along their generatrix are well-known the systems especially dedicated to weld control by means of the laid-on transducers.
This work presents a new eddy-current method for pipe control using the method of the rotating magnetic field.The emission part of the transducer generates a radial magnetic field which rotates about the inspected product at a frequency equal to the frequency of the driving currents. The reception part picks-up the response of the eddy currents induced in the material [1].For this type of transducer the theory of its operation has been studied [2], the adequate e.c. equipment has been elaborated and laboratory determinations have been performed on the probability of detection of the type of specific flaws and on the reliability using the method presented in [3].

The equipment enables to render evident with almost equal sensitivities on their length the long and short cracks placed along the pipe generatrix, as well as the pores, pinches etc.

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:377

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.