Method and apparatus for relieving stress in a pipeline

摘要

A method of treating a pipeline (4) (or other welded structure under tensile stress) to increase resistance to stress corrosion cracking, the method comprising heating the outside surface of a weld of a pipeline (4), and cooling the inside surface (12) of the weld of the pipeline (4) with a cryogenic coolant during and/or after the heating step to provide a tensile stress-relieved layer on the inside of the pipeline.