Ultrasonic ILI Inspection of CRA Pipes

The use of corrosion resistant alloys (CRA) is increasing in the pipeline industry. While CRA clad and lined pipes are less expensive than solid CRA pipes, their main advantage also consists of a balance between good mechanical properties of the carbon-steel carrier pipe and the corrosion resistance of the internal CRA layer. Conventional ILI inspection technology has so far been customized for carbon-steel pipes. The article focuses on the challenges of ILI inspections of CRA solid, clad and lined pipes. It gives an overview of the different types of CRA pipes, elaborates on the different ILI inspections technologies which are suitable for CRA inspection, while demonstrating examples of ILI data from CRA pipes and highlighting typical anomalies detected in different CRA pipes.