Pipe-Wall Thickness Measurement at High Temperature by Electromagnetic Acoustic Transducer

This paper is concerned with a high temperature tolerance electromagnetic acoustic transducer (EMAT). In order to use in high temperature environments, the EMAT is composed from samarium- cobalt magnets and a heatproof coil. Measurements of pipe-wall thicknesses require the ultrasonic velocities in the high temperature environment. The ultrasonic velocities are measured, and are used in the electromagnetic resonance (EMAR) method. The thicknesses measured by using 17 pipe specimens with a simulated corrosion are nearly equal to the reference values corrected with thermal expansions. The feasibility and effectiveness of the high temperature tolerance EMAT are confirmed.