Remote field eddy current detection of stress-corrosion cracks
The feasibility of detecting stress-corrosion cracks (SSC) using the Remote Field Eddy Current (RFEC) technique was demonstrated. The RFEC technique interrogates the entire thickness of the pipe and is applicable for in-line inspection. If it can be shown that the RFEC technique is effective in detecting SSC, then the technique is an ideal method for detecting the defects of interest. A defect detection model is proposed for explaining the mechanism for crack detection. For axially oriented, closed cracks, such as SCC, the conventional defect detection model proved to be too simplistic and not applicable. Therefore, a new detection mode that examines the flow of circumferential eddy currents was developed based on experimental results. This model, though not rigorous, provides a general understanding of the applicability of the RFEC technique for finding SSC. The data from the cracks and various artificial defects is presented in three formats: isometric projections, pseudocolor images and line-of-sight data. Though only two cracks were found, the experimental results correlate well with the circumferential eddy current theory. A theoretical analysis of the effects of motion on the output signal of the receiver is presented. This analysis indicates that inspection speed of simple implementations may be limited to a few miles per hour. Remote field eddy current inspection has excellent potential for inspection of gas transmission lines for detecting stress corrosion cracks that should be further developed.
- Research Organization:
- Battelle, Columbus, OH (United States)
- Sponsoring Organization:
- AGA; American Gas Association, Inc., Arlington, VA (United States)
- OSTI ID:
- 6002174
- Report Number(s):
- PR-3-823
- Resource Relation:
- Other Information: Submitted to NDT Supervisory Committee, Pipeline Research Committee, American Gas Association
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
42 ENGINEERING
PIPELINES
EDDY CURRENT TESTING
INSPECTION
CRACKS
DEFECTS
NATURAL GAS
PROGRESS REPORT
STRESS CORROSION
CHEMICAL REACTIONS
CORROSION
DOCUMENT TYPES
ELECTROMAGNETIC TESTING
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
MATERIALS TESTING
NONDESTRUCTIVE TESTING
TESTING
032000* - Natural Gas- Transport
Handling
& Storage
360105 - Metals & Alloys- Corrosion & Erosion
420500 - Engineering- Materials Testing