This paper describes JFE original ultrasonic testing
(UT) technologies in Non-destructive inspection (NDI) systems that assure quality
of JFE Steel pipe products. To enhance signal-to-noise ratio of UT, the high-speed
digital signal processing techniques of synchronous averaging and chirp pulse
compression have been developed and installed in ultrasonic flaw detectors of welding
pipe. In order to improve detectability of flaws located at middle of wall thickness
of weld, the normal incident beam technique for UOE pipe and the multi-probe
technique for ERW pipe have been developed respectively. The analysis technique
of ultrasonic field and that of ultrasonic wave propagation are applied as basic
technology for the developments.
