Analysis of the technical feasibility of the use of PEC inspection in the detection of thickness loss in boiler tubesa

Abstract

PEC inspection is a multifrequency technique for eddy currents that measures the variation in the electromagnetic field caused by induced electrical currents in the metal, correlating the obtained signal with the desired property variation. The speed of execution of the test and the ease of interpreting the obtained signals are advantageous characteristics of this technique, which allows the evaluation of thickness loss in boiler tubes and thus increases the operational reliability of these systems. Pulsed eddy current tests were performed on specimens taken from boilers that had localized thickness loss due to corrosion under deposit and on a specimen with machined depressions that simulated thickness loss. To assess the effectiveness of pulsed eddy currents in identifying corroded regions, thickness measurements were taken using an ultrasonic thickness measuring device. This research work demonstrated that, qualitatively, all regions with thickness values below a pre-established limit were identified, concluding that PEC inspection technique can be used in the evaluation of equipment components with localized thickness loss.