L51657 Remote Field Eddy Current Detection of Stress-Corrosion Cracks - Phase II

Abstract

Stress-corrosion cracking (SCC) can occur in gas transmission pipelines. These cracks initiate on the exterior of the bulk pipe material and grow in the axial and radial direction. Access for comprehensive nondestructive inspection systems is generally limited to inside the pipe itself. Since these defects can lead to leaks and failures, a need of the gas pipeline industry is the in-line detection and characterization of stress-corrosion cracks. Previous research has shown the remote field eddy current (RFEC) technique can detect SCC in gas transmission lines. The objective of this program is to quantify the SCC detection and characterization capability of this technique. The internal nature of the RFEC technique identifies it as a potential candidate for in-line inspection. The through-transmission nature of RFEC technique is a major advantage over other nondestructive tests since it ensures the complete inspection of the entire pipe wall. This electromagnetic inspection technique requires no coupling agent to transmit inspection energy from a source, to the defect, and then to the sensor. If it can be shown that the RFEC technique is effective in detecting, identifying, and sizing SCC and other defects, the technique is a candidate for in-line inspection implementation.