Applications of Laser Ultrasonics in the Pipeline Industry

Managing pipe damaged by Stress Corrosion Cracking (SCC) has been a formidable challenge to the pipeline industry. The development of a practical solution for the measurement and evaluation of SCC has been marred by the complexity of crack shapes, their distribution within a crack colony, and the lack of non-destructive technology capable of reliably measuring the crack depths. Laser ultrasonics is a promising noncontact technique for pipeline inspection. The large frequency bandwidth and small footprint make laser ultrasonics ideally suited for application as a depth sizing tool for closely-spaced cracks in a colony. It has been conclusively proven that laser ultrasonic inspection, using the time of flight diffraction (TOFD) technique, can reliably and accurately measure the depth of naturally occurring SCC, and potentially, other cracks and seam weld anomalies.