NDT.net - July 2001, Vol. 6 No. 7

Flaw sizing using mechanized ultrasonic inspection on pipeline girth welds

Ben Gross. Alliance Pipeline Ltd.
Thomas S Connelly. Alliance Pipeline Ltd.
Henk van Dijk. Weldsonix International Inc
Alan Gilroy-Scott. Integrity Management Inc
Corresponding Author Contact:
Email:tom.connelly@pipelinetech.com, Web: http://www.pipelinetech.com/

1.0 Abstract

2.0 Introduction

3.0 Experimental Method

4.0 Development of Reference Blocks

5.0 Developing an Optimized Ultrasonic Inspection Procedure.

6.0 Differentiating between stacked and inter-zonal flaws

Flaw Type Step 1 Step 2 Step 3 Step 4 Step 5 Step 6
Amplitude Response Flaw size Amplitude - 12 dB Calculated % FSH Same Signature Flaw size MM
Zone 1 Zone 2 Zone 3 Zone 1 Zone 2 Zone 3 Zone 1 Zone 2 Zone 3
LOF 0-40% ~40% 0-40% ~0.5 mm               ~0.5 mm
LOF 0-40% < 100% 0-40% < 1.5 mm       0-40% ~120% 0-40% n/a 0.5 - 1.5
LOF 0-40% > 100% 0-40% _ 0-10% ~30% 0-10% 0-40% ~120% 0-40% n/a 0.5 - 1.5
LOF 0-40% > 100% > 100% _ 0-10% ~30% ~30% 0-40% ~120% ~120% yes 0.5 - 1.5  
LOF 0-40% > 100% > 100% _ 0-10% ~30% ~30% 0-40% ~120% ~120% no 1.5 - 3.0
LOF 0-40% > 100% 0-40% _ 0-10% ~65% 0-10% 0-40% ~260% 0-40% n/a 1.5 - 3.0
LOF > 100% > 100% 0-40% _ ~65% ~65% 0-10% ~260% ~260% 0-40% yes 1.5 - 3.0
LOF > 100% > 100% 0-40% _ ~75% ~65% 0-10% ~300% ~260% 0-40% yes or no 3.0 - 6.0
LOF > 100% > 100% 0-40% _ ~65% ~65% 0-10% ~260% ~260% 0-40% no 3.0 - 6.0
LOF > 100% > 100% > 100% _ ~65% ~65% ~65% ~260% ~260% ~260% yes or no >6.0
Table 4: Categorization instructions for ultrasonic operators.

7.0 Production of Two GMAW Seeded Girth Welds

8.0 Experimental Results

9.0 Discussion of Results

10 Conclusions

Foot Note

References

  1. Ultrasonic Testing of Materials 4thedition - J Krautkrämer, H. Krautkrämer
  2. DIN 54 127 part 1 - Calibration of ultrasonic flaw detection equipment and echo height evaluation
  3. BS 3923 part 1 1986 Ultrasonic examination of welds. Methods of manual examination of fusion welds in ferritic steel.
  4. BS 3923 part 1 1972 Ultrasonic examination of welds. Automatic examination of fusion welded butt joints in ferritic steel.
  5. ASTM 1961 1998 Standard Practice for Mechanized Ultrasonic Examination of Girth Welds using Zonal Discrimination with Focused Search Units.
  6. BS 7706 1993 Calibration and setting up of the ultrasonic time of flight diffraction technique for the detection, location and sizing of flaws. Critical Assessments of the TOFD Approach for Ultrasonic Weld Inspection A. Erhard, E. Schulz, G. Brekow, H. Wüstenberg Bundesanstalt für Materialforschung und -prüfung P. Kreier Innotest AG, Eschlikon CH
  7. Reliability of Mechanized UT Systems to Inspect Girth Welds during Pipeline Construction R. van Agthoven. J.A. de Raad Röntgen Technische Dienst BV, P.O. Box 10065, 3004 AB ROTTERDAM, THE NETHERLANDS
  8. University of Ghent, Belgium, IPLOCA conference and proceedings, London, March 1999.
  9. API 1104, Eighteenth Edition, "Standard for Welding Pipelines and Related Facilities".

© NDT.net - info@ndt.net |Top|