Desenvolvimento de um protótipo para inspeção de tubos isolados por meio da técnica não destrutiva de correntes parasitas pulsadas

Abstract

In the industrial context, pipes, tanks and heat exchangers play fundamental roles, but over time, these vital components suffer degradation due to microstructural changes and corrosion under insulation, which leads to a loss of thickness in the asset. Often, these problems are difficult to ide ntify visually, making periodic maintenance costly,and it is common to replace parts with a useful life remaining or a more serious problem, which is the possible occurrence of a destructive structural failure. To solve this challenge, non-destructive testing (NDT) is used, allowing defects to be detected without compromising the functionality of the equipment. One effective approach is the pulsed eddy current (PEC) technique, which is based on Faraday's law of electromagnetic induction. Currently, companies offer PEC equipment, but the development of a national, efficient and affordable alternative is essential to meet the demands of Brazilian industry, providing flexibility and customized solutions. This work aims to develop a national PEC prototype to meet the specific needs of the country's industry. Tests were carried out on two specimens with different diameters and defect volumes, varying the lift -off height by 16, 21 and 24 mm. The signals captured by the prototype were classified using signal decay and peak value. Defects with a lift-off of 16 mm were successfully measured. With a lift -off of 21 mm, it was possible to separate only the region without defects from those with defects. At 24 mm, classification was not possible. Signals were also capture d using EddyFi equipment and the results were compared with the prototype developed.