TOFD Inspection of ERW in Thin Walled Piping

  • TECHTalk Technical Series
  • Tuesday, September 10, 2019
  • 4:00 pm - 4:30 pm

Current methods of inspecting Electric Resistance Welds (ERWs) in thin-walled pipe leave potentially dangerous defects undetected until failure. Adding a specialized Time of Flight Diffraction (TOFD) technique to the inspection will find and measure these defects, allowing mitigation/repair to prevent failure.

Inspection of the ERW in thin wall piping using Magnetic Particle Testing can detect surface breaking defects only. Conventional UT for detection and sizing of vertical defects is slow, not encoded or recorded, and is highly dependent on technician’s skill level. Phased Array UT (PAUT), Total Focusing Method (TFM), or other new techniques are relatively slow, and data file sizes may be prohibitive. Our solution is to use TOFD in a slightly unconventional manner, in order to have a high probability of detection while being able to scan the weld and report the findings quickly.

Preventing failure of current pipelines while keeping them in service is the best outcome for everyone. This presentation will show the results of using TOFD in thin walled pipe (<5.5mm) to detect and size defects as small as 10% wall thickness. A normally competent TOFD technician may use this technique and achieve similar results.