配管減肉測定の高度化を目指した焦点型電磁超音波探触子の開発
Development of point focusing electromagnetic acoustic transducer for accurate pipe wall thinning measurement
著者:
手塚 晃世 孫 宏君 浦山 良一 内一 哲哉 高木 敏行 （東北大）
発刊日:
公開日:
Electromagnetic acoustic transducerFlow accelerated corrosionNondestructive testingPipe wall thinningPoint Focusing EMATUltrasonic testing
概要
Electromagnetic acoustic transducer (EMAT) generates ultrasonic wave without direct contact with the specimen. This feature allows EMAT to be used under higher temperature environment compared with piezoelectric transducer, which means EMAT has a potential to be applied to monitoring of the piping system of operating power plants. However, the conventional EMAT may read thicker than the actual thickness of the pipe wall in the case of degraded pipes with rough surface. This is because the reflected signal is read under the area of the coil. Therefore, observed signal is the average result under the area. To overcome this drawback of conventional EMAT, Point Focusing EMAT (PF EMAT), which concentrates ultrasonic wave at specific point, is applied to thickness gauging. After the fabrication of two types of PF EMATs, the focus on the bottom of the surface was evaluated using piezoelectric transducer. Then, the PF EMAT was applied to thickness gauging on flat plate sample.
