Comprehensive study on radial coil influence in designing segmented remote field eddy current probe for defect detection in ferromagnetic tubes

ABSTRACT

In the present study, two types of receiver coils, viz axial and radial type receivers, in the Remote field eddy current technique are considered to detect defects in ferromagnetic tubes. The appropriate distance between the exciter and the receiver coils and the excitation frequency are estimated using the finite element model and validated experimentally. Model-assisted probability of detection studies are performed to examine the capability of radial and axial type receiver coils. Experimental studies on various artificial defects reveal the excellent performance of the radial type receiver coil in terms of the higher number of defect detections, sensitivity and imaging. This paper provides a comprehensive study on radial and axial type receiver coils for developing array probes. Radial coil performs better and also preserves localisation of defect, which is more desirable for developing array probe.

KEYWORDS:

• Remote eddy current
• finite element model
• ferritic tubes
• imaging
• segmented coil
• defect sizing

Acknowledgements

The authors thank Dr. B. Sasi and Mr. V. Arjun from Indira Gandhi Centre for Atomic Research, for many helpful technical discussions during the experimental measurements. Authors are also thankful to Dr. Anish kumar, Head, NDED, IGCAR and Dr. Shaju K. Albert, Director, Metallurgy & Materials Group and Materials Science Group, IGCAR for constant encouragements and support in the work. One of the authors, T. Vijayachandrika express thanks to the Department of atomic energy for the fellowship.

Disclosure statement

No potentialconflict of interest was reported by the author(s).