The Paton Welding Journal, 2015, №11



2015 №11 (08)

DOI of Article 10.15407/tpwj2015.11.09

2015 №11 (01)

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The Paton Welding Journal, 2015, #11, 61-63 pages
 

Influence of metal shrinkage in longitudinal welds of sleeves on contact pressure in main gas pipeline repair

O.I. Olejnik

E.O. Paton Electric Welding Institute, NASU 11 Bozhenko Str., 03680, Kiev, Ukraine. E-mail: office@paton.kiev.ua
 
 
Abstract
Effectiveness of main pipeline repair in service is largely determined by contact pressure, created at sleeve mounting on pipe defective section. At correct selection of contact pressure value, long-term performance of the repaired section is ensured through partial unloading of the pipe wall. Such a result is achieved due to lowering of pressure in the main line before repair, and tight pressing of the sleeve around the pipe with a special device. Arc welding of sleeve reinforcing elements also is of considerable importance, resulting in formation of contact pressure, caused by shrinkage of multilayer longitudinal butt welds. In the work computational method was used to study the influence of sleeve wall thickness and pipeline diameter on the magnitude of contact pressure caused by deposited metal shrinkage. It is shown that contact pressure caused by metal shrinkage during welding performance has the strongest influence on unloading of a defective pipe wall in pipelines of 1020 mm and smaller outer diameter. Further increase of contact pressure magnitude caused by metal shrinkage can be achieved by increasing sleeve wall thickness. Such a technique is not effective for pipes of 1220 mm and greater diameter. 5 Ref., 5 Figures.
 
Keywords: main gas pipeline, sleeve, repair, arc welding, deposited metal shrinkage, contact pressure
 
 
Received:                09.10.15
Published:               21.12.15
 
 
References

1. GBN V.3.1-00013741-12:2011: Main gas pipelines. Repair by arc welding in service conditions. Kiev: Ministry of Energy and Coal Industry of Ukraine. Introd. 06.09.2011.
2. Kiefner, J.F. (1977) Repair of line pipe defects by full-encirclement sleeves. Welding J., 6, 26-34.
3. Aginej, R.V., Puzhajlo, A.F., Aleksandrov, Yu.V. et al. (2012) Methods of safety assurance of long-term service gas pipelines prone to stress-corrosion. Korroziya Territorii Neftegaz, 23(3), 50-61.
4. Okerblom, N.O. (1964) Structural-technological design of welded structures. Moscow-Leningrad: Mashinostroenie.
5. Makhnenko, V.I., Olejnik, O.I., Shekera, V.M. (2013) Determination of contact pressure of reinforcing sleeve in repair of pipelines with surface defects. The Paton Welding J., 6, 11-14.

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