| 摘要 |
<p>PURPOSE:To reduce residual stress at the joint simply and surely in rolled joint method of a Zr alloy pressure tube used in a heavy water reactor with metal of different kind by applying axial force to the pressure tube and joining. CONSTITUTION:Residual stress at the rolled joint part is generated by displacement delta necessary to expand the Zr alloy pressure tube 1 and inner sleeve 2 to an outer sleeve 4, force (p) that expands the tube 1 due to expansion of the sleeve 2, and working force (f) to the tube 1 due to displacement in axial direction. Residual stress is represented by a curve of total stress caused by (p), (f), delta. Here, delta and (p) are determined by the gap of the tube 1 and sleeves 2, 4 at the time of joint. However, (f) can be changed easily by applying external force. The tube 1 is inserted between sleeves 2, 4 and the sleeve 4 is fixed. Axial load P2 is applied from another end of the tube 1 by a jig 8. Under this condition, a mandrel 3 is pushed in by load P1 to push out a roller 5 in radial direction. At the same time, it is rotated and joined.</p> |
