TWI Industrial Member Report Summary 672/1999
A B Day and A M Lank
This report describes work carried out under the Core Research Programme to assess the use of electromagnetic transducers to generate long range low frequency guided waves for detecting environmental damage in ferritic steel pipes.
The impetus for this work has been the successful development of TeletestT a long range low frequency ultrasonic inspection method which uses guided waves for detecting environmental damage in pipes. This method offers potentially large cost savings from the greatly reduced preparation and reinstatement time when inspecting long lengths of insulated pipe. Currently, rings of piezoelectric transducers are used to generate the guided waves. These require the surface of the pipe to be exposed and any excess corrosion to be removed in the area where the probes are applied. In order to reduce the inspection time, it would be advantageous to electromagnetic transducers (EMATs) since they are not adversely affected by poor surface conditions. They also operate through coatings and are relatively cheap to manufacture. The cost benefits are particularly worthwhile on large diameter pipes, where many piezoelectric transducers are required.
- The principal objective of this work was to determine the feasibility of using EMATs for generating and detecting low frequency guided waves in ferritic steel pipes.