Analysis of PEC technique and external magnetic fields for detection of corrosion under insulation: 3D finite element model

Abstract

Metal piping in industrial plants is subject to corrosion under insulation, which reduces the wall thickness and limits service life and operating conditions. The Pulsed Eddy Current (PEC) technique can be effective in the inspection of isolated metallic materials. However, changes in magnetic permeability make its use difficult in ferromagnetic steels. In this work, we used Neodymium magnets to magnetize the material during tests with a probe. We developed a 3D finite element model to reproduce the magnetic field of the PEC probe and identify defects under insulation. Theoretical results satisfactorily matched the experimental results.