PURPOSE: To improve the reliability of rolled joint part between a pressure tube made of Zirconium and a stainless steel tube of a different kinds of metal by providing a device for monitoring abnormality during the mechanical joining, which is performed through expanding the tube from the inside surface of an inner sleeve by an expander, and a device for non-destructive inspection after joining.
CONSTITUTION: The material of a tube end at a rolled joined part is repeatedly deformed, by the expansion in the radial direction of the roller and the polygonal deviation by the number of the roller, during the expanding operation by the roller on a pressure tube 1 made of zirconium alloy and a stainless steel sleeve 2, 3 of a different kinds of metal. AE signal is generated if cracking is caused by the repeated deformation. Then, a device 7 for monitoring abnormality is provided which monitors the presence of the AE signal due to the cracks generated during an expanding operation. In case the AE signal is detected due to the generation of cracks, a non-destruction inspection is carried out which examines the position and the size of the cracks after the expanding operation, and hence the reliability for the rolled joint of a pressure tube is enhanced.
KOIKE HIROMITSU
DOGE HIDENORI
SUZUKI KENICHI
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