| 摘要 |
PURPOSE:To enhance the stress corrosion cracking resistance of a tube, by cooling the tube subjected to solution heat-treatment from the inside thereof with water while removing the stream film formed between the inner peripheral surface of the tube and cooling water by rotating a propeller. CONSTITUTION:A tube 1 to be subjected to solution heat-treatment is heated to be held at a solution heat-treatment temp. and, directly after heating, the flexible connecting coil 8 of a stirrer 4 is inserted into the tube 1 while each propeller cover 11 of said stirrer is moved along the inner peripheral surface of the tube 1. In the next step, water cooled by a cooling apparatus is injected and supplied into the tube 1 from a nozzle 2 and, at the same time, the coil 8 is rotated by a drive device 7 to rotate each propeller 10. Whereby, the steam film being apt to be formed between the inner peripheral surface of the tube and cooling water 3 is removed by the turbulent flow of the stirred cooling water 3. The cooling water 3 after cooling is collected by a receiving tray and recirculated to the cooling apparatus to be reused. By this method, compression residual stress is generated to the inner peripheral surface of the tube 1 to enhance the stress corrosion cracking resistance of the tube. |
