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.

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.

Overview of a Comprehensive Study to Understand Longitudinal ERW Seam Failures

2014 ◽  
Author(s):  
Bruce A. Young ◽  
Steve Nanney ◽  
Brian Leis ◽  
Jennifer M. Smith
Keyword(s):  
Phase I ◽  
Management Practices ◽  
Structural Integrity ◽  
Experimental Studies ◽  
Current Approach ◽  
Transportation Safety ◽  
Seam Weld ◽  
Integrity Management ◽  
Weld Corrosion ◽  
Comprehensive Study

In response to the National Transportation Safety Board (NTSB) Recommendation P-09-1, the Department of Transportation (DOT) Pipeline and Hazardous Material Safety Administration (PHMSA) initiated a comprehensive study to identify actions that could be implemented by pipeline operators to eliminate longitudinal seam failures in electric resistance weld (ERW) pipe. This study was contracted with Battelle, working with Kiefner and Associates (KAI) and Det Norske Veritas (DNV) as subcontractors. The purpose of this paper is to provide an overview of the project with focus on the study objectives, results, and on-going work. Phase I of the project consisted of four major tasks aimed at understanding the current state of the issues. Task 1 analyzed the databases gathered and qualified in five interim reports that dealt with 1) the failure history of vintage ERW seams, including flash-weld (FW) pipe and selective seam-weld corrosion (SSWC); documented in two subtask 1.4 reports, 2) the effectiveness of in-line inspection (ILI) and hydrotesting, and experience with predictive modeling, documented in subtask reports 1.2 and 1.3 and 3) literature concerning SSWC documented in subtask 1.5 report. Task 2 addressed experimental studies designed to better characterize the failure of ERW/FW seams and quantify the resistance of such seams (Subtask 2.1–2.3 and 2.6 reports) and their response to pressure (Subtask 2.4 and 2.5 reports). Task 3 considered aspects related to SSWC with four separate reports from subtask 3.1–3.4. Task 4 focused on integration of the other tasks, trending, and analysis. Phase II has been initiated and consists of five tasks with the following objectives relevant to the ERW and FW process: 1) develop and optimize viable hydrotest protocols for ERW/FW seam defects 2) improve the sensors, interpretive algorithms, and tool platforms in regard to ILI and In-the-Ditch-Methods (ITDM) to better ensure structural integrity with optimized detection and sizing, 3) bridge gaps in defect characterization in regard to types, sizes, shapes, and idealizations. The goal of this subtask is to increase pipeline safety through improvements in the tools needed to implement both ILI and hydrotesting, 4) validate existing models and, where gaps preclude validation, refine or develop models needed to assess and quantify defect severity for cold welds, hook cracks, and selective seam weld corrosion (SSWC) (the primary threats) for failure subject to loadings that develop both during hydrotests and in service, and 5) develop a digitally based framework to support integrity management of seam welds with enough flexibility to benefit from the experience embedded in the stopgap protocol. To date, this study has led to seventeen (17) reports. These publically available reports are located on the PHMSA website: http://primis.phmsa.dot.gov/matrix/PrjHome.rdm?prj=390. Based on the work completed during Phase I, gaps identified in the context of the NTSB Recommendation P-09-1 were supported by the historic records. Additionally, recent improvements in related technologies and integrity management practices point to the practical utility and viability of PHMSA’s current approach to manage the integrity of the U.S. pipeline.

Review of Phase II for the Comprehensive Study to Understand Longitudinal ERW Seam Failures

2016 ◽  
Author(s):  
Bruce A. Young ◽  
Jennifer M. O’Brian ◽  
Steve Nanney
Keyword(s):  
Phase Ii ◽  
Structural Integrity ◽  
Prediction Models ◽  
Transportation Safety ◽  
Develop Software ◽  
Integrity Management ◽  
Resistance Weld ◽  
Weld Corrosion ◽  
Pipeline Safety ◽  
Comprehensive Study

In response to the National Transportation Safety Board (NTSB) Recommendation P-09-1, the Department of Transportation (DOT) Pipeline and Hazardous Material Safety Administration (PHMSA) initiated a comprehensive study to identify actions that could be implemented by pipeline operators to significantly reduce longitudinal seam failures in electric resistance weld (ERW) pipe. The purpose of this paper is to provide a review of Phase II of the project with focus on the study objectives and results. Phase II of the project consisted of five tasks with the following objectives relevant to the ERW and flash weld (FW) process: 1) develop and optimize viable hydrotest protocols for ERW/FW seam defects 2) improve the sensors, interpretive algorithms, and tool platforms in regard to In-Line-Inspection (ILI) and In-the-Ditch-Methods (ITDM) to better ensure structural integrity by developing and optimizing concepts to address problems in detecting and sizing, 3) bridge gaps in defect characterization in regard to types, sizes, geometries, and idealizations, to increase pipeline safety through improvements needed to implement both ILI and hydrotesting, 4) validate existing failure prediction models and, where gaps preclude validation, refine or develop these models needed to assess and quantify defect severity for cold welds, hook cracks, and selective seam weld corrosion (SSWC) (the primary ERW/FW seam threats) for failure subject to loadings that develop both during hydrotests and in service, and 5) develop software to support integrity management of seam welds with enough flexibility to benefit from the experience gained during this project. The reports generated during the course of the project are publically available and are located on following PHMSA website: http://primis.phmsa.dot.gov/matrix/PrjHome.rdm?prj=390.

Sign in / Sign up

Export Citation Format

Share Document