Patent attributes
A method for detecting internal coating defects in a pipe sample with an electromagnetic acoustic transducer sensor. The method includes recording a plurality of Lamb mode scans of the pipe sample with the EMAT sensor, where each Lamb mode scan is measured along a length of the pipe sample in axial alignment with the pipe sample; and processing the Lamb mode scans by applying a singular spectrum analysis to the Lamb mode scans to generate data from which the internal coating defects in the pipe sample are identified. The Lamb mode scans are at a frequency from dispersion curve of from 0.3 to 2 MHz, at a frequency of from 0.4 MHz to 2 MHz, a group velocity of from 1 mm/μs to 3 mm/μs, a phase velocity of from 5 mm/μs to 25 mm/μs, and a wave count of from 3 to 10.
