| 摘要 |
<p>PURPOSE:To ultimately leave residual compressive stress and to prevent the stress corrosion cracking of a pipeline by applying a load on the outer surface of a pipe at the weld zone in a pipeline to produce tensile stress above the yield point of the material on the inner surface side of the pipe and then removing the load. CONSTITUTION:A load is applied by a looking jig 10 on the outer surface of a pipeline 1 at the fillet weld zone 3 of a blow nozzle 2 or its vicinity from the upper part in the radial direction. The pipeline 1 is transiently strained, and tensile stress T is produced on the inner surface side of the pipeline 1 having the weld zone 3. However, a load is applied by the jig 10 so that the stress T is controlled to the stress above the yield point of the material for the pipeline 1, and then the load is removed after a specified time. Consequently, the stress produced in the pipeline 1 is relieved, compressive stress P remains on the inner surface side of the pipeline 1, and stress corrosion cracking is prevented.</p> |
