0

Full Content is available to subscribers

Subscribe/Learn More  >

Method to Reduce Arc Blow During DC Arc Welding of Pipelines

[+] Author Affiliations
J. H. Espina-Hernández, F. Caleyo, J. M. Hallen, G. L. Rueda-Morales

Instituto Politécnico Nacional, México, DF, México

E. Pérez-Baruch, A. López-Montenegro

Pemex Exploración y Producción, Región Sur, Villahermosa, TAB, México

Paper No. IPC2010-31393, pp. 387-392; 6 pages
doi:10.1115/IPC2010-31393
From:
  • 2010 8th International Pipeline Conference
  • 2010 8th International Pipeline Conference, Volume 3
  • Calgary, Alberta, Canada, September 27–October 1, 2010
  • Conference Sponsors: International Petroleum Technology Institute and the Pipeline Division
  • ISBN: 978-0-7918-4422-9 | eISBN: 978-0-7918-3885-3
  • Copyright © 2010 by ASME

abstract

Arc blow is a phenomenon associated with the deviation of the arc that usually occurs during arc welding of pipelines under repair. This phenomenon is most commonly observed after the pipeline has been inspected using an in-line magnetic flux leakage (MFL) inspection tool, which magnetized the pipe wall during the inspection run. Among the different welding techniques, DC arc welding is one of the most popular in the oil and gas industry due to its versatility and relative low cost. The interaction between the magnetic field associated with the current flowing through the electrode, and the residual magnetic field in the pipeline under repair can produce arc blow. In this work, a simple method to reduce arc blow during DC arc welding of pipelines has been developed. In contrast to the methods so far available in the literature [1,2], the method proposed here gives simple rules to be followed by welders with little background on magnetism. Residual magnetic field levels from different pipelines in southern Mexico were measured in the gap after damaged pipeline sections had been cut, and in the V groove once the new pipeline sections had been inserted. Magnetic finite element simulations were performed with freeware (FEMM) for the residual magnetic field compensation using real-life pipeline dimensions and field parameters. A large number of simulations were performed, using as variables the residual magnetic field in the groove, the number of coil turns required for the residual magnetic field compensation, the DC current flowing through the coil and the electrode, the position of the coil with respect to the groove, and the pipeline wall thickness and diameter. An empirical predictive equation was developed for the compensation of the residual magnetic field from the results obtained during the simulations. Most of the procedures developed in the past propose to adjust the current in order to compensate for the magnetic field in the groove, which is a disadvantage during DC arc welding since the electrodes specifications do not cover a wide range of current values. In contrast, the method proposed herein supersedes this disadvantage by granting the possibility of properly selecting the number of coil turns and the position of the coil with respect to the groove, in order to compensate for the residual magnetic field in the groove.

Copyright © 2010 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In