Estimating Toughness for LF and DC Welded ERW Seams

2020 ◽  
Author(s):  
John Kiefner ◽  
Michael Rosenfeld ◽  
Peter Veloo ◽  
Troy Rovella
Keyword(s):  
Low Frequency ◽  
Bond Line ◽  
Large Database ◽  
Manufacturing Defects ◽  
Integrity Assessment ◽  
Level Of Confidence ◽  
Line Region ◽  
Management Plans ◽  
Integrity Management ◽  
Pipe Materials

Abstract ERW pipe materials, particularly those manufactured prior to 1970, have exhibited higher rates of failures from seam manufacturing defects than other types of pipe materials. Typically, the seam bond line regions of low-frequency (LF) and direct-current (DC) welded ERW pipe materials exhibit poor resistance to manufacturing defects. The toughness of the bond line region is difficult to determine, and it is likely to vary from one piece of pipe to another. Pipeline operators must address the risk of ERW seam failures as part of their integrity management plans, but it is unlikely that they will know the toughness levels in the seams of their pipelines comprised of such materials. To avoid having to know the toughness levels in the seams, a pipeline operator can utilize a hydrostatic test to verify the integrity of a vintage ERW pipeline, but there are disadvantages the main one being that the pipeline must be taken out of service. Most likely an operator will choose to use an ILI crack tool to locate ERW seam anomalies to avoid having to take the pipeline out of service. Even if the seam defects can be located, correctly sized, and classified, however, the operator may have no idea of the effective toughness that is the key to deciding whether or not a given crack has to be excavated and repaired. Presented herein are two options for improving the effectiveness of an ILI integrity assessment of a pipeline with low toughness ERW seams. • Option 1 involves assuming a conservative level of toughness. Some such levels are available in the publicly available documents. Data from a large database of ERW seam failures are used to show the effectiveness of a fixed level of toughness at identifying critical defects while minimizing unnecessary digs. • Option 2 consists of first: back-calculating the toughness levels associated with the known crack sizes and failure pressures of the defects in the database of ERW seam failures, and second: calculating the probability that each type of defect would have been correctly identified at a particular level of confidence using a particular level of toughness. Using either of these options, a pipeline operator can improve the effectiveness of an ILI-crack-tool integrity assessment of a pipeline comprised of LF or DC welded ERW seams by reducing the number of unnecessary excavations while still being able to find the critical defects with an acceptable level of confidence.

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.

Track Record of In-Line Inspection as a Means of ERW Seam Assessment in Response to NTSB Recommendation P-09-1, Arising From the Carmichael, MS Rupture

2014 ◽  
Author(s):  
J. F. Kiefner ◽  
J. B. Nestleroth ◽  
J. A. Beavers ◽  
C. J. Maier
Keyword(s):  
Crack Detection ◽  
Bond Line ◽  
Electromagnetic Acoustic Transducer ◽  
Integrity Assessment ◽  
Metallurgical Investigation ◽  
Natural Gas Pipelines ◽  
Track Record ◽  
Detection Technology ◽  
Line Region ◽  
Acoustic Transducer

The track record of in-line inspection crack detection technology with respect to locating and characterizing seam defects in electric-resistance-welded (ERW) pipe was examined on the basis of 13 tool runs on 741 miles of hazardous liquid and natural gas pipelines. Results for three types of tools were examined: (ultrasonic angle beam, circumferential magnetic flux, and electromagnetic acoustic transducer (EMAT). The methods for validating the locations, types, and sizes of anomalies included in-the-ditch NDE (UT and MT), and removal of pipe for metallurgical investigation and/or burst testing. The work indicates that in-the-ditch NDE is not always reliable for confirming the ILI findings. The metallographic examinations and burst tests sometimes confirmed the ILI findings, but in other cases, they revealed defects did not compare well in size with the anomalies indicated by the ILI or the in-the-ditch NDE. In some cases, anomalies that caused failures in burst tests had not been identified by the ILI. Because the toughness of the bond line region may differ significantly from that of adjacent material, predictions of failure pressure based on ILI-indicated dimensions using a single toughness level are unreliable. It is concluded that significant improvements in ILI crack-detection technologies will be needed in order for pipeline operators to be able to have adequate confidence in the ERW seam integrity of a pipeline inspected by means of an ILI crack-detection tool. It is also concluded that significant improvements of in-the-ditch NDE methods are needed for such methods to be considered a reliable means of validating ERW seam anomalies found by ILI. These results should not discourage the use of technologies for ERW seam integrity assessment. The tools clearly are useful for finding and eliminating some seam defects. Only by continuing to use and develop the tools can pipeline operators expect to see the technologies improve to the point where operators can have a high degree of confidence in the ERW seam integrity of an inspected pipeline.

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.

Mechanical Properties of Secondary Wall and Compound Corner Middle Lamella near the Phenol-Formaldehyde (PF) Adhesive Bond Line Measured by Nanoindentation

2011 ◽  
Vol 236-238 ◽  
pp. 1746-1751 ◽  
Author(s):  
Kun Liang ◽  
Guan Ben Du ◽  
Omid Hosseinaei ◽  
Si Qun Wang ◽  
Hui Wang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Secondary Wall ◽  
Phenol Formaldehyde ◽  
Middle Lamella ◽  
Adhesive Bond ◽  
Cellular Level ◽  
Bond Line ◽  
Line Region ◽  
Penetration Behavior

To find out the penetration of PF into the wood cell wall and its effects onthe mechanical properties in the cellular level, the elastic modulus and hardness of secondary wall (S2layer) and compound corner middle lamella (CCML) near PF bond line region were determined by nanoindentation. Compare to the reference cell walls (unaffected by PF), PF penetration into the wood tissues showed improved elastic modulus and hardness. And the mechanical properties decreased slowly with the increasing the distance from the bond line, which are attributed to the effects of PF penetration into S2layer and CCML. The reduced elastic modulus variations were from18.8 to 14.4 GPa for S2layer, and from10.1 to 7.65 GPa for CCML. The hardness was from 0.67 to 0.52 GPa for S2layer, and from 0.65 to 0.52 GPa for CCML. In each test viewpoint place, the average hardness of CCML was almost as high as that of S2layer, but the reduced elastic modulus was about 50% less than that of S2layer. But the increase ratio of mechanical properties was close. All the results showed PF penetrates into the CCML. The penetration behavior and penetration depth from bond line were similar in both S2layer and CCML.

Pipeline Corrosion Integrity Management by Direct Assessment

2015 ◽  
Author(s):  
Shailesh Javia
Keyword(s):  
Integrated Approach ◽  
Assessment Process ◽  
Regulatory Requirements ◽  
Integrity Assessment ◽  
Advantages And Disadvantages ◽  
Direct Assessment ◽  
Pipeline Segment ◽  
Integrity Management ◽  
Post Assessment ◽  
Pipeline Corrosion

Integrity management of pipelines is a systematic, comprehensive and integrated approach to proactively counter the threats to pipeline integrity. Pressure testing, in-line inspection and direct assessment methods are used to verify the integrity of a buried pipeline. The Paper Discuses Direct Assessment Methodologies for Hydrocarbon Non Piggable Pipelines. Advantages and Disadvantages of Direct Assessment methodology and DA Protocols. The DA process accomplishes this by utilizing and integrating condition monitoring, effective mitigation, meticulous documentation and timely structured reporting processes. DA is a structured, iterative integrity assessment process through which an operator may be able to assess and evaluate the integrity of a pipeline segment. TIME DEPENDENT THREATS INEVITABLY LED TO NUMEROUS FAILURES WITH A COMMON DEFINING MECHANISM OR SOURCE – CORROSION. This Paper will focus on internal, external and stress corrosion cracking direct assessment along with pre and post assessment, quality assurance, data analysis and integration, and remediation and mitigation activities. This paper will discuss some of the regulatory requirements for Pipeline Integrity Management System.

Pipeline Integrity Management: Estimating and Prioritizing the Risk Resulting From Pipeline Facility Operations

2008 ◽  
Author(s):  
Larry C. Decker
Keyword(s):  
Risk Model ◽  
Risk Profile ◽  
Logical Approach ◽  
Relative Safety ◽  
Management Plans ◽  
Integrity Management ◽  
Cross Country ◽  
Consistent Approach ◽  
Cost Risk

Recent efforts to develop a consistent approach to understanding the risk associated with operating a cross country pipeline have focused primarily on the pipe itself. Integrity management plans often include a prioritized risk profile that all but ignores the specific risks associated with operating tank farms, terminals, pumps and compression. This paper outlines a detailed logical approach that can be utilized to evaluate the relative safety, environmental and cost risk associated with operating diverse types of equipment within a pipeline station. Topics covered include the basic objectives of a facility risk model while providing the detail (granulation) necessary to continuously improve. A specific methodology is suggested as a systematic tactic to make an “apples to apples” comparison of diverse stations, lines and types of equipment, from a risk standpoint.

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.

Effect of Pressure Loading on Integrity Management

2008 ◽  
Author(s):  
Sanjay Tiku ◽  
Aaron Dinovitzer ◽  
Scott Ironside
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Operating Pressure ◽  
Integrity Assessment ◽  
Pipeline Segment ◽  
Pressure Cycle ◽  
Integrity Management ◽  
Pump Compressor ◽  
Life Predictions

Integrity assessment or life predictions for in-service pipelines are sensitive to the assumptions they rely upon. One significant source of uncertainty is the pipeline operating pressure data often captured and archived using a Supervisory Control and Data Acquisition (SCADA) system. SCADA systems may be programmed to collect and archive data differently from one pipeline to another and the resulting pressure records can be significantly different on the basis of the sampling techniques, data processing and the distance from pump and compressor stations. This paper illustrates some of the issues involved in pressure load characterization and is based upon work sponsored by the Pipeline Research Council International (PRCI). A series of sensitivity studies using fatigue crack growth calculations have been carried out to evaluate several factors that can influence crack stability and growth predictions that are often employed in pipeline integrity planning and repair programs. The results presented will highlight the issues related to performing integrity management based upon pump/compressor discharge or suction SCADA data to characterize the potential severity of pressure fluctuation or peak pressure dependent defects, illustrate the differences in fatigue crack growth rates along a pipeline segment and demonstrate the complexity of pressure cycle severity characterization, based upon distance from discharge, elevation, hydraulic gradient, for different sites along the pipeline route.

Regulatory Next Steps in Addressing Pipeline Seam Weld Challenges

2014 ◽  
Author(s):  
Steve Nanney
Keyword(s):  
Crack Detection ◽  
Growth Models ◽  
Phase 1 ◽  
Mitigation Measures ◽  
Phase 2 ◽  
Ongoing Research ◽  
Integrity Assessment ◽  
Integrity Management ◽  
Integrity Assurance ◽  
Comprehensive Study

Since the beginning of pipeline transportation operations, pipe seam integrity and mitigation measures to prevent pipe seam leaks and failures have been a challenge for the industry and government regulators. The Pipeline and Hazardous Materials Safety Administration’s (PHMSA) Office of Pipeline Safety (OPS) has investigated leaks and failures, issued advisory bulletins, funded research projects, and developed regulations for integrity assurance of pipe seams during pipeline design, construction, and operations and maintenance (including integrity management). This report will discuss PHMSA’s pipe seam efforts to date, framing leak and failure history, past advisory bulletins, United States (U.S.) Legislative and Executive actions (statutory actions), recent U.S. National Transportation Safety Board (NTSB) findings, accident investigation findings, and ongoing research for pipe long seam welds. PHMSA will review challenges and summarize past and possible future regulatory considerations based on the research findings to date and pipe seam incidents. In 2011 PHMSA initiated a long seam research project titled “Comprehensive Study to Understand Longitudinal ERW Seam Failures.” The program goals are to assist PHMSA in favorably closing U.S. NTSB Recommendations P-09-01 [1] and P-09-02 [1], which were issued after the Carmichael, Mississippi pipeline electric resistance welded (ERW) seam rupture, and recommended that PHMSA conduct a comprehensive study of ERW pipe properties and implement measures to assure that they do not fail in service. The research objectives for Phase 1 were to review current ERW seam integrity assessment methods (hydrostatic testing and in-line inspection using a crack-detection tool) to understand measures needed to consistently identify subcritical seam defects in order to act in time to prevent ERW seam ruptures. Phase 2 objectives are to develop hydrotest protocols, improve anomaly characterization criteria, develop seam defect growth models, and develop seam integrity management techniques. Phase 1 was completed in early January 2014, and Phase 2 is scheduled to be completed in late fall 2014. To date, this study has led to 17 technical reports. These reports are publically available on the following PHMSA website: http://primis.phmsa.dot.gov/matrix/PrjHome.rdm?prj=390.

Pipeline Operator Perspective in Use of Hydrostatic Testing as an Integrity Management Tool

2016 ◽  
Author(s):  
M. M. Hilger ◽  
B. C. Mittelstadt ◽  
M. Piazza ◽  
P. H. Vieth
Keyword(s):  
Assessment Tool ◽  
The United States ◽  
The Body ◽  
Management Tool ◽  
Test Program ◽  
Integrity Assessment ◽  
Pressure Testing ◽  
Industry Standards ◽  
Asme Code ◽  
Integrity Management

Regulation in the United States mandating the use of pressure testing as an assessment tool for the construction and commissioning of pipelines was initiated in 1970. Prior to regulation, however, pressure testing was being applied within the pipeline industry to provide confidence in the operational integrity of pipeline systems. Additional assessment technologies and processes including high resolution in-line inspection continue to be developed and further enhanced; however pressure testing remains a valuable and acceptable tool in the management of pipeline integrity. Current applications include quality verification of original construction practices, integrity assessment of existing pipelines, and verification of material yield strength when key records may be missing or incomplete. It is recognized that extensive hydrostatic testing knowledge exists today in the form of API Recommended Practices, ASME code documents, the body of work of industry consultants, regulatory language and other resources. A key element to implementing the current industry standards is a pipeline operator perspective in practical application on selection of hydrostatic testing as an assessment tool and the subsequent technical design of a hydrostatic test program in order to achieve integrity management goals. This paper discusses hydrostatic testing in the context of selection as an integrity management tool, development of risk-balanced objectives for a hydrostatic test program, and understanding the limitations and potential detrimental effects of hydrostatic testing. This paper summarizes key considerations in guidelines published in 2016 that were developed through a Pipeline Research Council International (PRCI) project. While written to be applicable to all hydrostatic testing, this work is a key element of the multi-year PRCI Electric Resistance Welded (ERW) and Longitudinal Seam Pipe Program which began in 2011 and was formed to comprehensively study and develop strategies for management of factors that contribute to seam failures.

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