Pulsed eddy current differential probe to detect the defects in a stainless steel pipe

Abstract

Pulsed eddy current (PEC) is an electromagnetic nondestructive technique widely used to detect and quantify the flaws in conducting materials. In the present study a differential Hall-sensor probe which is used in the PEC system has been fabricated for the detection of defects in stainless steel pipelines. The differential probe has an exciting coil with two Hall-sensors. A stainless steel test sample with electrical discharge machining (EDM) notches under different depths of 1–5 mm was made and the sample was laminated by plastic insulation having uniform thickness to simulate the pipelines in nuclear power plants (NPPs). The driving coil in the probe is excited by a rectangular current pulse and the resultant response, which is the difference of the two Hall–sensors, has been detected as the PEC probe signal. The discriminating time domain features of the detected pulse such as peak value and time to zero are used to interpret the experimental results with the defects in the test sample. A feature extraction technique such as spectral power density has been devised to infer the PEC response.

Time-domain spectral finite element method for analysis of torsional guided waves scattering and mode conversion by cracks in pipes

“…The study of Ahmad et al [21] showed that pipes were frequently embedded in the soil with insulated coatings. Angani et al [22] studied the use of eddy current to inspect the defects in pipelines but the inspection can be carried out in a limited area only. It is impractical to use inspection methods that require direct access to the pipes since the associated cost of removing the insulation is unpredictably high.…”

Induced circumferential current for transverse crack detection on a pipe string

“…The induced circumferential current is disturbed by a surface defect [17,18] on the surface of the pipe string, which makes the space magnetic field distorted. By measuring the distorted space magnetic field, the defect can be identified and evaluated [19,20] : …”

Locating Underground Pipe Using Wideband Chaotic Ground Penetrating Radar

“…When underground pipes are damaged, they can lead to major financial losses and may cause loss of life. Various techniques have been developed for underground pipe detection, such as acoustic and vibration techniques [1,2], radio-frequency identification (RFID)/sensor techniques [3], infrared thermography [4], magnetic flux leakage method [5,6], eddy current technique [7,8], as well as ground penetrating radar (GPR) [9,10,11]. Among these non-destructive techniques, GPR is widely used because it can locate both non-metallic and metallic objects without prior knowledge.…”