(eBook version)Need: Pipeline repair by direct deposition of weld metal, or weld deposition repair, is an attractive alternative to the installation of full-encirclement sleeves for repair of wall loss on in-service pipelines. This is particularly true where the installation of full-encirclement sleeves is difficult or impossible, such as for wall loss in bend sections and fittings. The results of recently completed work at Edison Welding Institute and previous work by others has shown that weld deposition repairs have the ability to restore the static strength of a pipeline and are resistant to pressure cycles over a wide range of applications. Prior to the widespread use of this technique, it was necessary to establish guidelines for carrying out repairs using this technique These guidelines must address not only the welding issues, but issues pertaining to inspection following welding, acceptance standards for discontinuities detected during inspection, and other related issues
Benefit: The objective of this project was to provide a report that contains these
guidelines. The guidance provided in this report is contained in two basic parts. The main body of the report contains a review of the various technological factors pertinent to weld deposition repair, Including a review of recently-completed research projects. The second part is an example guideline for carrying out weld deposition repair in the field, which was developed using the information contained in the main body of the report. This example guideline is in the form of a generic company specification and is contained in an appendix to the report.
Result: The successful development of a safe and reliable weld deposition repair method now allows in-service repair of pipelines as an alternative to full encirclement sleeves or pipe replacement. This guideline will facilitate the implementation of this technology. Considerable benefits will be realized by avoiding pipeline shutdown and reducing the use of more costly repair techniques.
