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Development of Single-Channel and Phased Array Electromagnetic Acoustic Transducers for Austenitic Weld Testing

Austenitic welds are widely used in nuclear, petrochemical and process industries. The strong material anisotropy and coarse grain structure in the dendritic weld zone makes these welds very difficult to inspect with conventional techniques. It is well-known that the shear horizontal (SH) wave is well-suited for this inspection and that electromagnetic acoustic transducer (EMAT) is the best technique for generating this wave mode, but the lack of equipment has precluded its application in the field. This paper presents the development of one channel and phased array EMAT systems and results from tests conducted on samples provided by the Electric Power Research Institute (EPRI). The results show the potential of this new equipment for austenitic weld inspection, which opens up new possibilities for research and field use.

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