Advanced Eddy Current Array Tools for Stress Corrosion Cracking Direct Assessment on Pipelines

2021 ◽  
Author(s):  
michael sirois ◽  
Mathieu Bouchard ◽  
Ahmed Sweedy
Keyword(s):  
Stress Corrosion ◽  
Eddy Current ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Direct Assessment

Advanced Eddy Current Array Tools for Stress Corrosion Cracking Direct Assessment on Pipelines

2020 ◽  
Author(s):  
Michael Sirois ◽  
Mathieu Bouchard ◽  
Ahmed Sweedy
Keyword(s):  
Stress Corrosion ◽  
Eddy Current ◽  
Stress Corrosion Cracking ◽  
Human Factor ◽  
Corrosion Cracking ◽  
Probability Of Detection ◽  
Ease Of Use ◽  
Process Efficiency ◽  
Screening Process ◽  
Direct Assessment

Abstract Magnetic Particle Inspection (MPI) has been the main reference for Stress Corrosion Cracking (SCC) detection in pipeline integrity for years. Although this technique is relatively economical and easy to deploy — thanks to a large pool of certified technicians — it remains time consuming and highly user dependent. Some of the factors impacting results during SCC Direct Assessment (SCCDA) include the total surface area requiring examination, hard-to-reach positions underneath pipes during inspection, improper surface preparation due to poor sandblast or contrast, condensation on pipes, and operator fatigue. Recent trials have proved that Eddy Current Array (ECA) technology compares favorably against MPI on many aspects in the field, and that ECA has the potential to become the new standard for SCCDA on pipelines. Offering an impressive speed, combined with a particularly high Probability of Detection (PoD), ECA could transform the work of technicians in ditches and above all, offer greater control over the human factor. Besides detection, ECA has also proven its reliability for SCC characterization on real SCC colonies in both lab and field environments. Comparisons to metallography sections, grinding measurements and X-Ray Computed Tomography (XCT) data have greatly contributed to optimized depth sizing algorithms for this new solution, providing accurate SCC depth readings. Although ECA and Phased Array Ultrasonic Testing (PAUT) are often complementary techniques in the field, the main advantage of ECA over PAUT resides in the short amount of time required to locate and size the deepest cracks among colonies containing sometimes thousands of cracks. Within a few minutes, technicians and engineers know where to concentrate and how critical SCC really is so that decisions can be made instantly. Combining ease of use and repeatability (ways to control the human factor) is another key benefit of ECA technology. This paper provides information about a complete ECA solution for SCC detection and depth sizing on pipelines. It reveals results from the field, comparing ECA with MPI, covering several key points and demonstrating how ECA stands out as improving the overall screening process efficiency during examinations in digs. Furthermore, it also exposes and compares ECA data with both destructive and non-destructive testing performed on test pieces containing real SCC.

A Statistical Predictive Model to Prioritize Site Selection for Stress Corrosion Cracking Direct Assessment

2006 ◽  
Author(s):  
Anthony Merle ◽  
P. F. Ehlers
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Environmental Parameters ◽  
Predictive Modelling ◽  
Corrosion Cracking ◽  
Direct Assessment ◽  
Degree Of Certainty ◽  
Regression Techniques ◽  
Selection For ◽  
High Degree

Pipeline stress-corrosion cracking (SCC) is an ongoing integrity concern for pipeline operators. A number of different strategies are currently employed to locate and mitigate SCC. Ultrasonic in-line inspection tools have proven capable of locating SCC, but reliability of these tools in gas pipelines remains in question. Rotating hydrotest programs are effectively employed by some companies but may not provide useful information as to the location of SCC along the pipeline. NACE Standard RP0204-2004 (SCC Direct Assessment Methodology) outlines factors to consider and methodologies to employ to predict where SCC is likely to occur, but even this document acknowledges that there are no well-established methods for predicting the presence of SCC with a high degree of certainty. Predictive modelling attempts to date have focused on establishing quantitative relationships between environmental factors and SCC formation and growth; these models have achieved varying degrees of success. A statistical approach to SCC predictive modelling has been developed. In contrast to previous models that attempted to determine direct correlations between environmental parameters and SCC, the new model statistically analyzed data from dig sites where SCC was and was not found. Regression techniques were used to create a multi-variable logistic regression model. The model was applied to the entire pipeline and verification digs were performed. The dig results indicated that the model was able to predict locations of SCC along the pipeline.

Caution when applying eddy current inversion to stress corrosion cracking

2006 ◽  
Vol 236 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Noritaka Yusa ◽  
Ladislav Janousek ◽  
Mihai Rebican ◽  
Zhenmao Chen ◽  
Kenzo Miya ◽  
...  
Keyword(s):  
Stress Corrosion ◽  
Eddy Current ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Eddy Current Inversion ◽  
Current Inversion

The Study of Stress Corrosion Cracking in Aluminum Alloy 7075(W) under Tensile Loading by Eddy Current Measurement

2011 ◽  
Vol 83 ◽  
pp. 216-223
Author(s):  
Mahmood Dollah
Keyword(s):  
Aluminium Alloy ◽  
Stress Corrosion ◽  
Cantilever Beam ◽  
Eddy Current ◽  
Stress Corrosion Cracking ◽  
Double Cantilever Beam ◽  
Tensile Loading ◽  
Corrosion Cracking ◽  
Active Path ◽  
Aluminum Alloy 7075

The double cantilever beam has been widely used in the past and has proved one of the most popular designs for measuring the growth rate of stress corrosion cracks in materials. In this study, the double cantilever beam specimens were used to study the effect of tensile loading on stress corrosion cracking behaviour in aluminium alloy 7075(W). Cracks initiated readily in 3.5%NaCl solution with tensile loading conditions. Stress Corrosion Cracking (SCC) development was found to follow an intergranular path, which strongly depended on microstructure of material. Tests also were carried out to measure the threshold stress intensity, KISCC, which SCC would not occur. The SCC test was explained by an active path mechanism due to the galvanic interaction between grain boundary precipitates and adjacent precipitate-free zones. Crack lengths were measured with an eddy current bore probe and confirmed by optical metallography. The data from the eddy current tests on real stress corrosion cracks were used to construct an eddy current calibration curve for predicting stress corrosion crack lengths of aluminium alloy 7075(W).

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