Detection of Corrosion and Wall Thinning in Carbon Steel Pipe Covered With Insulation Using Pulsed Eddy Current

Abstract

Non Destructive Testing (NDT) methods that are capable of detecting the wall thinning and defects through insulation and cladding sheets are necessary. In this study we developed a Pulsed Eddy Current (PEC) system to detect wall thinning of ferro magnetic steel pipes covered with 95 mm thick fiber glass thermal insulator and shielded with aluminum plate of thickness 0.4 mm. In order to confirm the thickness change due to wall thinning, two different sensors, a hall sensor and a search coil sensor were used as a detecting element. In both the cases, the experimental data indicates a considerable change in the detected pulse corresponding to the change in sample thickness. The thickness of the tube was made to change such as 2.5 mm, 5 mm and 8 mm from the inner surface to simulate wall thinning. Fast Fourier Transform (FFT) was calculated using window approach and the results were summarized which shows a clear identification of thickness change in the test specimen by comparing the magnitude spectra.

Circular-arc array for the pulsed eddy current inspection of thermally insulated pipelines

“…Extensive studies on the application of the PEC technique in the CUI inspection of pipelines have been conducted to improve the inspection performance for metal pipes [15][16][17][18][19][20][21][22]. Fundamental studies of the analytical and numerical solutions of PEC testing of layered structures have been undertaken in [15,16].…”

“…The differential detector could avoid the storage of the reference signal before starting the measurements [20]. Additionally, two different sensors, a hall sensor and a search coil sensor, were employed as detectors to confirm the thickness change due to wall thinning in [21]. Another approach involves using a PEC probe consisting of a circular excitation coil and an anisotropic magnetoresistive sensor-embedded differential detector to measure the time-varying magnetic field signals on the axisymmetric excitation coil's axis [22].…”

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

“…As regiões mais susceptíveis à deposição se concentram nas regiões mais quentes dos tubos do gerador de vapor, principalmente as extremidades inferiores dos tubos da parede frontal das caldeiras que usam queimadores. Algumas técnicas de inspeção são empregadas na avaliação da integridade de tubos de troca térmica das paredes de caldeiras, no entanto, poucas delas são capazes de avaliar a perda de espessura em tubos que não possuem acesso ao seu interior (IBP, 2022;HELLIER, 2020;PARK et al, 2016;XIONG et al, 2020). A medição de espessura por ultrassom é o ensaio mais empregado para a estimativa da vida remanescente dos tubos que não possuem acesso ao seu interior, esse ensaio utiliza o tempo decorrido entre a emissão da onda ultrassônica pelo transdutor e o retorno da sua reflexão na parede oposta do corpo medido (ANDREUCCI, 2014).…”

A Uniform Linear Multi-Coil Array-Based Borehole Transient Electromagnetic System for Non-Destructive Evaluations of Downhole Casings

“…This technique, which is also known as transient (pulsed) eddy-current testing [ 6 , 7 , 8 ], enables highly effective nondestructive evaluations (NDEs) of downhole casings [ 9 , 10 ]. However, unlike surface measurements that use large loop coils [ 1 ] or high performance magnetometers [ 11 , 12 ], the structure of borehole TEM sensors is strongly restricted by the physical limitations of the downhole conditions, including limited sensor sizes, low sampling performance due to high temperatures, and cumbrous metal tool housings against the high pressure, thereby, reducing the signal strength, as well as signal-to-noise ratio (SNR) of the borehole TEM measurements, and making NDEs of downhole casings very different.…”