OS6-8 インコネル溶接部における超音波の波動観察(OS6 設備診断・運用保全技術,循環型社会における動力エネルギー技術)

概要

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Visualization experiment and numerical simulation using a finite element method are carried out in order to understand the ultrasonic wave propagation behavior in Inconel weld zone of dissimilar metal weld (DMW). In numerical simulation, DMW is modeled as the acoustic anisotropy considering crystal orientation in welds. Numerical simulation is compared with visualization result and the validity of DMW modeling is confirmed. It found that the propagation path of shear wave changes so that it may travel in the growth direction of columnar grain, but DMW has small effect on longitudinal wave propagation. In general, longitudinal wave was used in the inspection of DMW. From results of ultrasonic inspection using phased array probe, it found that only small echoes from slit in welds without echo from boundary of welds are observed by longitudinal wave but clear echoes from slit are observed by shear mode, especially in inspection of a butter zone from the butter zone side. These echoes by shear mode appear at deeper position than longitudinal one.
2007-06-13