登入選單

返回Google圖書搜尋

Annual report 1993-94. (in french).

T. E. Rummery

出版	Atomic Energy Of Canada Limited, 1994
URL	http://books.google.com.hk/books?id=xXto0AEACAAJ&hl=&source=gbs_api

註釋

The ultrasonic response characteristics of zircaloy barstock, and of both artificial and naturaly occurring defects contained therein, were determined by frequency spectrum analysis. the investigation showed that the transparency of zircaloy to ultrasonic waves was fairly uniform to longitudinal waves between 4 and 18 mhz and to shear waves only between 2.5 and 7 mhz. the frequency response of defects in all cases was most sensitive above 10 mhz but considerable variation was observed between the spectral quality of signals returning from artificial and natural defects. low signal amplitudes were received from some naturally occurring defects having unfavourable orientation with respect to the ultrasonic beam. an eddy currrent test with encircling differential coils was used for the detection of surface defects which were unfavourably orientated for ultrasonic testing; eddy currents are little affected by the orientation of defects. the sensitivity to defects was best between 25 and 50 khz. on the basis of material transparency and defect detectability, ultrasonic tests using longitudinal and shear waves at 10 mhz are recommended. an eddy current test is recommended for detecting unfavourably oriented defects using differential encircling coils with a high fill factor and a frequency of 40 khz.