| 摘要 |
PURPOSE:To enable to repair a heat exchanger tube, which is locally corroded, without closing up by a method wherein a locally corroded portion is contrived to be made watertight by tightly contacting a repair tube with the inside of the locally corroded portion, utilizing the thermal restoring property of shape memory alloy. CONSTITUTION:In order to repair a tube to be repaired of a heat exchangaer having a local corrosion 2, a short repair tube 3A, which is made of shape memory alloy and the outer diameter od of which is larger than the inner diameter ID of the tube 1 to be repaired, is prepared and is subjected to cold-draw in liquid nitrogen so as to reduce the outer diameter od' of the tube 3A smaller than the inner diameter ID of the tube 1 to be repaired in order to obtain a repair tube 3B with its diameter reduced, which is inserted in the tube 1 to be repaired to a position for the tube 3B to be spread over the locally corroded portion 2 of the tube 1 to be repaired. After being inserted, the repair tube 3B with its diameter reduced is heat-treated at the predetermined temperature and for the predetermined period of time so as to expand itself in order to tightly contact with the inner surface of the tube 1 to be repaired with stress enough strong for preventing the internal liquid from leaking, resulting in contriving to make the locally corroded portion watertight. |
