| 摘要 |
PROBLEM TO BE SOLVED: To provide a quality monitoring method at the tame a pipe is expanded, for detecting existence of failures at a joint part, a position of the failure, size of the failure, or the like in real time when a metallic pipe having plural joint parts is expanded, and also for detecting existence of failures or the like at high accuracy even when overall length of the metallic pipe is extremely long. SOLUTION: Elastic waves generated when a metallic pipe 10 for pipe expansion having plural joint parts 16a, 16b is expanded using a pipe expanding mandrel 24, are detected by an AE sensor 26 which abuts on the pipe expanding mandrel 24. Further, elastic waves generated when a metallic pipe for pipe expansion having plural joint parts is expanded with the pipe expanding mandrel 24, are propagated in liquid filled in the pipe expanding metallic pipe, and the elastic waves propagated in the liquid are detected by the AE sensor 26 attached on the bottom face of a cover 22.
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