NDTnet - June 1996, Vol.1 No.06

FURTHER DEVELOPMENTS IN ULTRASONIC INSPECTION OF PIPELINE GIRTH WELDS

Authors E.Ginzel and M.Hoff


Abstract

Ultrasonic Inspection has been widely used in Canada since the early 1980's for inspecting Mechanized Girth Welds. In 1993 TransCanada PipeLines Limited (TCPL) became the first North American company to use ultrasonics as the primary nondestructive testing (NDT) method on a pipeline construction project. Further enhancements to the ultrasonic systems have increased the reliability, speed and evaluation capabilities of the systems presently approved by TCPL. A review of the systems and the enhancements is presented in this paper.

fig5


  • Background

  • Recent Developments

    Even with the reduced file size technique used by the two companies, production rates of 150 to 200 welds per day could result in a large stack of floppy disks for data storage. Hard disk drives of 1000MB are now common but the rugged terrain that the system is subjected to presents a risk of damage to the hard drive. To avoid potential data losses the mechanised systems now ensure backup files are made. The backup systems used are either Bernoulli drives or Optical disks. The operator transfers files from the system hard drive to the removable mass storage system one or more time each day thereby minimizing the number of files that could be lost. This storage to other locations also speeds up the process as it requires more time to save a file as the hard drive gets filled.

  • Extremes in Test Conditions

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    Figure 5: Positioning scanning head on 48" diameter pipe on the Canadian prairies. Daytime summer temperatures often reach 35°to 40°C. (Shaw Pipeline Services)
    105 Kbyte
    Figure 6: UT inspection truck ready to test within five welds of last weld completed. Winter work in rock cuts in the Canadian Shield near the Manitoba-Ontario border (Shaw Pipeline Services).
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    Figure 7: Loading the scanning head on a 42" diameter pipe in the winter northern Ontario. Equipment must also be able to perform under conditions of daytime highs of -40°C. (RTD Quality Services Ltd.)

  • Future Developments

  • Conclusions


  • Acknowledgments


  • Figures

    1. Weld Zones
    2. Centre of Beam to Targets
    3. Identification of Bead Geometry using B-scans
    4. Identification of Bead Porosity using B-scans
    5. Shaw scanning head on 48" pipe (summer)
    6. Proximity of UT to welding (Shaw)
    7. RTD scanning head on 42" pipe (winter)
    8. TOFD B-scan of a 20" Girth Weld

  • References

    1. E.Ginzel & R.Ginzel, B.Gross, M.Hoff, P.Manuel, Developments in Ultrasonic Inspection for Total Inspection of Pipeline Girth Welds, 8th Symposium on Pipeline Research, Houston, Texas, August 1993
    2. A. Glover et al, Inspection and Assessment of Mechanized Pipeline Girth Welds, Proceedings: Weldtech 88, London, UK, 1988
    3. A.de Sterke, Automatic UT Inspection of Pipeline Welds, NDT International, Dec. 1980
    4. J.A.de Raad, R. van Agthoven, Mechanical Ultrasonic Test Systems for Pipelines Welds, Proceedings: International Conference on Pipeline Inspection, Edmonton, Canada, 1983
    5. J.P. Charlesworth, J.A.G. Temple, Engineering Applications of Ultrasonic Time-of-Flight Diffraction, John Wiley and Son, 1989
    6. CAN CSA-Z184-M92 Appendix K, Gas Pipeline Systems, Canadian Standards Association


    About the authors

    Merv Hoff is the senior NDT coordinator for TransCanada PipeLines Limited.
    He can be contracted at
      TransCanada Pipelines Ltd.
      111 5th Avenue SE
      Calgary, Alberta
      Canada
      T2P 4K5
      tel. (403) 267-6401 fax (403) 267-6242
      email: merv_hoff@tcpl.ca

    Ed Ginzel is an independent consultant with the Materials Research Institute.
    He can be contacted at

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    Rolf Diederichs 1.June 1996, info@ndt.net
    /DB:Article /AU:Ginzel_E_A /IN:MRI /CN:CA /CT:UT /CT:weld /ED:1996-06