부산대학교 도서관

Different non-destructive tests carried out on Al 7005 mountain bicycle frames are described. The work was originally undertaken in order to prepare an eddy current technique for the NDT of high-end bicycles at different stages of construction and/or trading. The tested frames had been disposed of after six months' service (the distance travelled is not known) as a consequence of cracking of the head tube near the insertions for the stem and fork. Both had serial numbers and one of them had EN 14766 marking as well. PC-based eddy current equipment was used, with planar and pancake coils mounted on specially-tailored guides, and a calibration piece with artificial defects. A visual test prior to the eddy current testing (ET) showed that one frame had a crack in an expanded section of the fork-stem insertion, while the other had some cracks in a heat-affected zone of the seat tube and in the handlebar-stem insertion, where the head tube exhibits a diameter change, tapering and two welds. X-ray fluoroscopy was also performed in order to study the welds. The fluoroscopic images and the eddy current indications from all the coils and defects are presented. [ABSTRACT FROM AUTHOR]