New Classification Approach for Dents With Metal Loss and Corrosion Along the Seam Weld

2016 ◽  
Author(s):  
J. Bruce Nestleroth ◽  
James Simek ◽  
Jed Ludlow
Keyword(s):  
Magnetic Field ◽  
Low Frequency ◽  
Metal Loss ◽  
Integrity Assessment ◽  
Seam Weld ◽  
Low Field ◽  
Electric Resistance Welding ◽  
Weld Corrosion ◽  
Pipeline Safety

The ability to characterize metal loss and gouging associated with dents and the identification of corrosion type near the longitudinal seam are two of the remaining obstacles with in-line inspection (ILI) integrity assessment of metal loss defects. The difficulty with denting is that secondary features of corrosion and gouging present very different safety and serviceability scenarios; corrosion in a dent is often not very severe while metal loss caused by gouging can be quite severe. Selective seam weld corrosion (SSWC) along older low frequency electric resistance welding (ERW) seams also presents two different integrity scenarios; the ILI tool must differentiate the more serious SSWC condition from the less severe conventional corrosion which just happens to be near a low frequency ERW seam. Both of these cases involve identification difficulties that require improved classification of the anomalies by ILI to enhance pipeline safety. In this paper, two new classifiers are presented for magnetic flux leakage (MFL) tools since this rugged technology is commonly used by pipeline operators for integrity assessments. The new classifier that distinguishes dents with gouges from dents with corrosion or smooth dents uses a high and low magnetization level approach combined with a new method for analyzing the signals. In this classifier, detection of any gouge signal is paramount; the conservatism of the classifier ensures reliable identification of gouges can be achieved. In addition to the high and low field data, the classifier uses the number of distinct metal loss signatures at the dent, the estimated maximum metal loss depth, and the location of metal loss signatures relative to dent profile (e.g. Apex, Shoulder). The new classifier that distinguishes SSWC from corrosion near the longitudinal weld uses two orientations of the magnetic field, the traditional axial field and a helical magnetic field. In this classifier, detection of any long narrow metal loss is paramount; the conservatism of the classifier ensures that high identification of SSWC can be achieved. The relative amplitude of the corrosion signal for the two magnetization directions is an important characteristic, along with length and width measures of the corrosion features. These models were developed using ILI data from pipeline anomalies identified during actual inspections. Inspection measurements from excavations as well as pipe removed from service for lab analysis and pressure testing were used to confirm the results.

Types of Defects That Affect ERW Seam Integrity in Response to NTSB Recommendation P-09-1, Arising From the Carmichael, MS Rupture

2014 ◽  
Author(s):  
J. F. Kiefner ◽  
J. B. Nestleroth ◽  
G. T. Quickel ◽  
J. A. Beavers ◽  
B. N. Leis
Keyword(s):  
Low Frequency ◽  
Manufacturing Defects ◽  
Integrity Assessment ◽  
Seam Weld ◽  
Stress Cracking ◽  
Service Failures ◽  
Sulfide Stress ◽  
Welded Seam ◽  
Weld Corrosion ◽  
Made In

The types of defects that have caused in-service failures and hydrostatic test failures of natural gas and hazardous liquid pipelines comprised of electric resistance welded (ERW) or flash-welded seams were revealed by a study of 569 seam failure incidents that occurred over a period from the 1940s through the present. This study confirmed that ERW and flash-welded seam manufacturing defects, such as cold welds (lack of fusion) and hook cracks, are frequent causes of hydrostatic test failures. Causes of in-service failures included cold welds, hook cracks enlarged by fatigue, other manufacturing defects enlarged by fatigue, selective seam weld corrosion, hydrogen stress cracking, sulfide stress cracking, and stress corrosion cracking (SCC). An important finding with respect to low-frequency-welded ERW and flash-welded materials was that defects in the bond lines of such materials (e.g., cold welds, selective seam weld corrosion) sometimes failed at much lower stress levels than one would predict based on the toughness of the parent metal. This fact complicates seam integrity assessment by means of in line inspection (ILI) because toughness is needed to prioritize anomalies for examination, and the toughnesses of the bond lines of most pipelines are not known. The findings suggest that conservative assumptions may have to be made in order for a pipeline operator to have confidence in a seam integrity assessment by means of ILI even if the ILI technology accurately characterizes the anomalies.

Managing the Threat of Selective Seam Weld Corrosion Using a State of the Art ILI System

2020 ◽  
Author(s):  
Christopher Davies ◽  
Simon Slater ◽  
Christoper De Leon
Keyword(s):  
Material Properties ◽  
Weld Zone ◽  
Evaluation Process ◽  
Management Plan ◽  
Management Approach ◽  
Metal Loss ◽  
Integrity Assessment ◽  
Seam Weld ◽  
Integrity Management ◽  
Weld Corrosion

Abstract For many years, pipeline safety regulations in the US have defined prescriptive minimum requirements for integrity management combined with a clear expectation that operators should do more than the minimum where appropriate. The regulations have also provided operators with the flexibility to take a performance based integrity management approach leveraging as much information available to manage threats effectively. One the threats that must be managed is Selective Seam Weld Corrosion (SSWC). SSWC is an environmentally assisted mechanism in which there is increased degree of metal loss in the longitudinal weld in comparison to the surrounding pipe body. An appropriate definition is linear corrosion that is deeper in the longitudinal weld zone than the surrounding pipe body. In some cases, the surrounding pipe body may have limited or no corrosion present, and in other cases the pipe body corrosion may have occurred but at a slower rate than the local corrosion in the longitudinal weld zone. Conventional responses to potential or identified threats focus on in-situ investigations, often resulting in expensive and un-planned repairs for features reported by In-line Inspection (ILI) that when assessed properly demonstrate a remnant life well into the next inspection interval. When ILI identifies metal loss indications co-located with the longitudinal seam weld, the current prescribed response is often a blanket call for remediation. Such a response may not be appropriate if an ILI system is deployed to discriminate feature types and integrity assessment is exercised leveraging a sound understanding of the pipe’s material properties. This paper describes an approach that can be taken to manage the threat of SSWC. The foundation of the approach is deployment of an appropriate ILI system incorporating an effective ILI technology, an optimized evaluation process considering the specific threat morphology, material testing and a structured dig program. The evaluation process uses the ILI data and data from the field in combination material properties data and a susceptibility analysis to classify anomalies as “Likely”, “Possible” and “Unlikely” SSWC. This is aligned with the guidance in API RP 1176 “Assessment and Management of Cracking in Pipelines” for defining an appropriate response to ILI calls. Approaching the management of SSWC in this way allows operators to define a structured response for excavation activities to verify the process and remediate features as required. By using likelihood classification the risk to pipeline integrity can be reduced by acting on the most likely SSWC features as a priority, whilst collecting the data needed to make informed decisions on where to focus resources and efforts on what is a very complicated and difficult to manage threat. The output form this work, including a future plan for managing the remaining metal loss features, can be documented in a procedure and incorporated into an existing Integrity Management Plan.

Development of Selective Seam Weld Corrosion Test Method

2014 ◽  
Author(s):  
J. A. Beavers ◽  
C. S. Brossia ◽  
R. A. Denzine
Keyword(s):  
Base Metal ◽  
Field Testing ◽  
Test Method ◽  
Transportation Safety ◽  
Seam Weld ◽  
Corrosion Kinetics ◽  
Pipeline Failures ◽  
Weld Corrosion ◽  
Pipeline Safety ◽  
Non Destructive

Selective seam weld corrosion (SSWC) of electric resistance welded (ERW) pipelines has been identified as a potential risk to pipeline safety. Due to recent pipeline failures, where seam weld defects may have played a significant role, the National Transportation Safety Board called upon the Pipeline and Hazardous Materials Safety Administration (PHMSA) to conduct a comprehensive study to identify actions that can be used by operators to eliminate catastrophic longitudinal seam failures in pipelines. Battelle contracted Kiefner and Associates, Inc. and Det Norse Veritas (U.S.A.) Inc. (DNV GL) with the objective to assist PHMSA in addressing this issue. The objective of one of the tasks performed by DNV GL was to develop a reliable, rapid, non-destructive, field-deployable test method that can quantify SSWC susceptibility on operating pipelines containing ERW seams. For this effort, two different, field deployable, non-destructive methods were evaluated in laboratory testing. The methods were validated using a standard destructive test for assessing SSWC susceptibility. One method was based on measurement of the local potential difference between the seam weld and the adjacent base metal while the second was based on differences in the corrosion kinetics between the seam weld and the base metal. The method that is based on corrosion kinetics was found to be most effective in identifying SSWC susceptible pipe steels. It utilizes a barnacle cell to conduct linear polarization resistance measurements on small, selected areas of the pipe (e.g., the weldment or base metal). Additional laboratory as well as field-testing is planned to further validate the test method.

scholarly journals Self-Organizing Map Classification of the Extremely Low-Frequency Magnetic Field Produced by Typical Tablet Computers

2018 ◽  
Vol 18 (3) ◽  
pp. 94-99
Author(s):  
Darko Brodić ◽  
Alessia Amelio ◽  
Ivo R. Draganov
Keyword(s):  
Magnetic Field ◽  
Low Frequency ◽  
Self Organizing Map ◽  
Tablet Computers ◽  
High Exposure ◽  
Extremely Low Frequency ◽  
Frequency Magnetic Field ◽  
The Magnetic Field ◽  
Self Organizing

Abstract In this paper, the extremely low frequency magnetic field produced by the tablet computers is explored. The measurement of the tablet computers’ magnetic field is performed by using a measuring geometry previously proposed for the laptop computers. The experiment is conducted on five Android tablet computers. The measured values of the magnetic field are compared to the widely accepted TCO safety standard. Then, the results are classified by the Self-Organizing Map method in order to create different levels of safety or danger concerning the magnetic field to which tablet computer users are exposed. Furthermore, a brief comparison of the obtained magnetic field levels with the ones from typical laptops is performed. At the end, a practical suggestion on how to avoid the high exposure to the low frequency magnetic field emitted by the tablet computers is given.

Managing and Addressing Fitness for Service of Vintage Pipelines

2012 ◽  
Author(s):  
Steven V. Nanney ◽  
Kenneth Y. Lee
Keyword(s):  
United States ◽  
Low Frequency ◽  
The United States ◽  
United States Department ◽  
Department Of Transportation ◽  
Safety Standards ◽  
Electric Resistance Welding ◽  
Standards And Regulations ◽  
Pipeline Safety

Recent pipeline accidents in the United States have highlighted concerns with older vintage natural gas and hazardous liquid pipelines. The United States Department of Transportation (USDOT) Pipeline and Hazardous Materials Safety Administration (PHMSA) is performing a comprehensive review to determine the fitness for service of vintage pipelines, and if the risks associated with vintage pipelines can be better managed by changes to US pipeline safety standards and regulations. Concerns with vintage pipelines include weld seam manufacturing issues, such as low frequency electric resistance welding (LF-ERW) and submerged arc welding (SAW), cast iron pipe, plastic pipe and certain coatings. This paper presents findings from vintage pipeline failure investigations, recent PHMSA actions, and some approaches to address key vintage pipe concerns. These approaches include knowledge assurance (adequacy and quality of historical data), methods to systematically obtain missing data, and processes and criteria for determining fitness-for-service, including assessment, remediation, and replacement programs.

Anomalous Low-Field Magnetic Behaviour of High-TC Superconductors

1992 ◽  
Vol 275 ◽  
Author(s):  
M. F. Tai ◽  
H. J. Wang ◽  
C. C. Lin ◽  
H. L. Wang
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Low Temperature ◽  
Low Frequency ◽  
Magnetic Behaviour ◽  
Zero Field ◽  
Field Range ◽  
Low Field ◽  
Complex Susceptibility ◽  
Applied Fields

ABSTRACTWe report on the studies of low-field magnetic properties in the well-characteristic superconducting LaCaBaCu3Oy, YBa2Cu3Oy, YaBa4Cu8Oy, (La1–85Sr0–15)CuO4-y, (Tl0–5Pb0–5)Ca2Sr2Cu3Oy and (Bi2−xPbx)Ca2Sr2Cu3Oy oxides. The studies of magnetic properties include ac zero-field cooled (ZFC), field-cooled (FC), and ac susceptibilities, and their dependences on the applied magnetic field and temperature. As the applied dc magnetic field is low enough, the FC susceptibility varies flat with the increasing of temperature from low temperature, but the diamagnetic signal becomes increasing at some temperature and reaches to the maximum values, and then continously decreases with temperature, at last the diamagnetism rapidly transfers to paramagnetism with temperature going to above Tc. The magnetization reduction at low temperature significantly appears at the low dc magnetic field and exists within a lot of single-phase high-Tc superconductors. However, this phenomenon is not observed in the measurements of low-frequency ac complex susceptibility for the ac applied fields from 0.001 G to 10 G and disappears for higher dc applied field. But, there exists a two-step drop in ac and ZFC susceptibilities curve and the drop correlates with the de FC magnetization dip. The magnetic field range of the dip occurrence is dependent on specimens. The strange magnetic property may be regard with superconducting coupling link in grain boundaries and interpreted by the grain-cluster model associated with Josephson effect.

Dealing With Low-Frequency-Welded ERW Pipe and Flash-Welded Pipe With Respect to HCA-Related Integrity Assessments

2002 ◽  
Author(s):  
John F. Kiefner
Keyword(s):  
Low Frequency ◽  
Metal Loss ◽  
Electric Resistance ◽  
Integrity Assessment ◽  
Systematic Procedure ◽  
Pipe Line ◽  
Welded Pipe ◽  
Integrity Assessments ◽  
Pipe Materials

The new regulations, Part 195 Section 195.452, require that special integrity assessments be made to address potential seam-defect problems in low-frequency-welded ERW (electric-resistance-welded) pipe materials where a failure of such materials could have an impact on a high-consequence area (HCA). The spirit of this requirement appears to require action if, and only if, significant seam-related deficiencies are in evidence or if they can be reasonably anticipated. This leaves open the option of categorizing these types of pipelines by performance such that potentially problematic pipeline segments can be subjected to special (i.e., seam-quality) inspections while those that show little or no propensity for such problems can be subjected to metal loss and deformation inspections only. This document is intended to establish a systematic procedure to permit an operator to characterize the relevant ERW pipe segments as to the likelihood of significant seam-related deficiencies. The author is particularly grateful to Rich Turley of Marathon Ashland Pipe Line LLC for helping to formulate the essential steps in deciding when an integrity assessment is needed. Rich made significant inputs to Figure 1 of this document.

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