Automated Laser Ultrasonic Testing (ALUT) of Hybrid Arc Welds for Pipeline Construction, #272

This report describes a program for developing, testing, and validating in-process automated laser ultrasonic testing (ALUT) of new hybrid laser arc welding (HLAW) welds in the field. The goal of the project is to apply the proven technologies of laser ultrasonics and modern signal processing techniques to the important problem of evaluating HLAW pipeline welds in high strength steel pipelines. Laser ultrasonic testing (LUT) offers the advantage of true in-process measurement, providing immediate information on weld integrity. As conceived in this application, a small fiber-delivered measurement head would be mounted in tandem with the weld head, so that testing can be performed immediately after the weld is formed. This process monitor function will enable immediate inspection on a per-pass basis and also save the cost of equipment and crew used in post-process inspection. More important, repair costs will be significantly reduced. LUT is a true noncontact technique, with no liquid couplant and a standoff from the pipe surface that can reach up to approximately 0.5 m. LUT can perform measurements at surface speeds far above those used in girth welding. Another major benefit of laser ultrasonics is that the laser beams on the surface are typically 0.1 mm; therefore, spatial resolution is high, and access to tight spaces is enabled. Finally, the measurement bandwidth is typically 50 MHz in a short pulse, providing high depth resolution and high information content in the detected waves. Laser generation produces a rich admixture of ultrasonic waves, covering many wave types, directions, and frequencies.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; Photos; Tables;
  • Pagination: 25p

Subject/Index Terms

Filing Info

  • Accession Number: 01642853
  • Record Type: Publication
  • Contract Numbers: DTPH56-07-T-000008
  • Files: TRIS, ATRI, USDOT
  • Created Date: Jul 31 2017 5:26PM