24-10-2012, 11:14 AM
Development of an EMAT In-Line Inspection System for Detection Discrimination, and Grading of Stress Corrosion Cracking in Pipelines
ABSTRACT
This report describes progress, experiments, and results for a project to develop a pipeline in-line inspection tool that uses
electromagnetic acoustic transducers (EMATs) to detect and grade stress corrosion cracking (SCC). There is a brief
introduction that gives background material about EMATs and relevant previous Tuboscope work toward a tool. This work
left various choices about the modes and transducers for this project. The experimental section then describes the lab systems,
improvements to these systems, and setups and techniques to narrow the choices. Improvements, which involved transducer
matching networks, better magnetic biasing, and lower noise electronics, led to improved signal to noise (SNR) levels. The
setups permitted transducer characterizations and interaction measurements in plates with man-made cracks, pipeline sections
with SCC, and a full pipe with SCC. The latter were done with a moveable and compact EMAT setup, called a lab mouse,
which is detailed.
ABSTRACT
This report describes progress, experiments, and results for a project to develop a pipeline in-line inspection tool that uses
electromagnetic acoustic transducers (EMATs) to detect and grade stress corrosion cracking (SCC). There is a brief
introduction that gives background material about EMATs and relevant previous Tuboscope work toward a tool. This work
left various choices about the modes and transducers for this project. The experimental section then describes the lab systems,
improvements to these systems, and setups and techniques to narrow the choices. Improvements, which involved transducer
matching networks, better magnetic biasing, and lower noise electronics, led to improved signal to noise (SNR) levels. The
setups permitted transducer characterizations and interaction measurements in plates with man-made cracks, pipeline sections
with SCC, and a full pipe with SCC. The latter were done with a moveable and compact EMAT setup, called a lab mouse,
which is detailed.