Inspection of Thin-Walled Pipe Welds Using Mechanized Ultrasonic Techniques

In this paper an effective way to optimize the inspection of welds in thin-walled pipe less than 6 mm (0.24 in.) thick using automated ultrasonic testing (AUT) is described. AUT offers a better solution than radiography for detecting and sizing of planar defects. However, cap width, weld shrinkage and defect sizing put constraints on the actual ultrasonic approach for inspection of pipes with wall thickness less than 6 mm (0.24 in.). The applications of high-frequency single/multiprobe techniques and phased-array technology for inspection of thin-walled pipe welds have been investigated in this paper. It has been demonstrated that combining these techniques with modeling and simulation of UT have potentially significant advantages for enhanced detectability, better sizing and improved flaw characterization of randomly oriented planar fabrication imperfections in thin-walled pipe welds.