Longitudinal seam weld characterization by focused ultrasonics

1996 ◽  
Author(s):  
Laney H. Bisbee ◽  
Lawrence Nottingham
Keyword(s):  
Seam Weld ◽  
Longitudinal Seam

Integrity Evaluation of an Older Vintage ERW Pipeline

2002 ◽  
Author(s):  
Geoff B. Rogers ◽  
Steve C. Rapp ◽  
Garry M. Matocha
Keyword(s):  
Planning Process ◽  
Ultrasonic Inspection ◽  
Mechanical Damage ◽  
Project Planning ◽  
Operating Pressure ◽  
Seam Weld ◽  
Weld Defects ◽  
Natural Gas Pipeline ◽  
Longitudinal Seam ◽  
Future Project

As part of a program to increase the operating pressure of a 20” (508.0mm) natural gas pipeline, a careful plan was developed and executed to ensure the integrity of the pipeline. The pipeline was built in 1943 using linepipe produced having a DC ERW longitudinal seam weld and travels along a densely populated route in the suburbs of Philadelphia. The work plan included ILI inspection methods to detect corrosion (MFL tool), mechanical damage (geometry tool), and ERW seam weld defects (TFI MFL tool). After the anomalies were identified and the necessary pipe replacements were completed, the pipeline was hydrostatically tested prior to being returned to service at the newly established operating pressure. The paper will describe the project planning process used to ensure the fitness and reliability of the pipeline and provide a review of the ILI results, excavations, pipe replacements, and hydrostatic test experiences. Of particular interest were the capabilities and limitations of the TFI tool to detect, discriminate, and size ERW seam weld defects. Seam weld defects were evaluated using ILI inspection methods and in many cases field prove-up ultrasonic inspection methods. When an ERW defect was confirmed by field NDT prove-up, the pipe section was removed and metallographic work was conducted to characterize the ERW flaw size and nature. A correlation was then possible between the sizing capability of the TFI tool, the ultrasonic prove-up method, and the actual defect size. All this information is useful to establish a level of confidence in defect sizing for future project needs. The final validation of the pipeline fitness at the higher operating pressure was established through the successful hydrostatic test. A short summary will be given on how the pipeline fitness was qualified and demonstrated.

Evaluation of Historical Longitudinal Seam Weld Failures in Grades 11, 12, and 22 Materials

2008 ◽  
Author(s):  
Marvin J. Cohn ◽  
Steve R. Paterson
Keyword(s):  
Hoop Stress ◽  
Seam Weld ◽  
Failure Data ◽  
Weld Failure ◽  
Curve Fit ◽  
Power Utilities ◽  
Term Creep ◽  
Longitudinal Seam ◽  
Grade 11

Since the catastrophic HEP seam weld failures of Mohave (1985) and Monroe (1986), electric power utilities have become more interested in developing and implementing examination and fitness-for-service evaluations of their HEP systems. At least 30 failures or substantial cracks in Grade 11 (1-1/4Cr – 1/2Mo), Grade 12 (1Cr – 1/2Mo) and Grade 22 (2-1/4 Cr – 1Mo) pipe longitudinal seam welds or clamshell welds have occurred from 1979 through 2000. This paper provides a statistical analysis of well-characterized Grade 11, Grade 12, and Grade 22 longitudinal seam weld failures or substantial cracks developed by long term creep rupture damage. Considering several applicable hoop stress parameters, linear regression analyses were performed to minimize scatter about a log stress versus Larson Miller Parameter (LMP) curve fit. Each of six applicable hoop stress equations was evaluated to determine the best fit stress space for the longitudinal seam weld failure data. These service experience industry data include pipe thicknesses ranging from 0.5 to 4.5 inches and failure times ranging from 71,000 to 278,000 hours.

scholarly journals Improvement of notch toughness and soundness in longitudinal seam weld of line pipe.

1986 ◽  
Vol 26 (5) ◽  
pp. 379-386 ◽  
Author(s):  
Kazutaka AKAO ◽  
Toshio ISHIHARA ◽  
Toyofumi KITADA ◽  
Yukio NISHINO ◽  
Naoki OKUDA ◽  
...  
Keyword(s):  
Notch Toughness ◽  
Line Pipe ◽  
Seam Weld ◽  
Longitudinal Seam

Fitness-for-Service of Longitudinal Seam Welds

2010 ◽  
Author(s):  
Dwight D. Agan ◽  
Marvin J. Cohn ◽  
Henry D. Vaillancourt
Keyword(s):  
Operating Temperature ◽  
High Energy ◽  
Management Program ◽  
Piping System ◽  
Operating Pressure ◽  
Seam Weld ◽  
Piping Systems ◽  
Average Operating ◽  
Operating Temperatures ◽  
Longitudinal Seam

A high energy piping (HEP) asset integrity management program is important for the safety of power plant personnel and reliability of the generating units. Hot reheat (HRH) longitudinal seam weld failures have resulted in serious injuries, fatalities, extensive damage of components, and significant lost generation. The HRH piping system is one of the most critical HEP systems. Since high temperature creep is a typical failure mechanism for longitudinal seam welds, the probability of failure increases with unit operating hours. This paper concludes that some seam welded spools in this specific HRH piping system are more likely to fail earlier than other spools, depending on their actual wall thicknesses and operating temperatures. In this case study, the HRH piping system has operated over 200,000 hours and experienced about 400 starts since commercial operation. There are two separate HRH lines, Lines A and B, for this piping system. The 36-inch OD pipe has a specified minimum wall thickness (MWT) of 1.984 inches. Pipe wall thicknesses were measured in 57 spools. The measured spool MWT values varied from 1.981 to 2.122 inches. On average, Line A operated about 8°F higher than Line B. A comparative risk assessment was performed using the estimated average temperatures and pressures throughout the life of this HRH piping system. Data associated with the reported failures or near failures of seam welded Grade 22 piping systems were plotted as log σHoop versus the Larson Miller Parameter (LMP). The range of log σHoop and LMP values for this unique piping system was also plotted, based on the average operating pressure and the range in the average operating temperatures and the measured spool MWT values. The Line A (with a higher average operating temperature) seamed spool having the lowest measured MWT fell slightly above the threshold line of reported seam weld pipe failures. The Line B (with a lower average operating temperature) seamed spool having the lowest MWT is about 10 operating years from reaching the threshold of reported seam weld pipe failures. The Line A seamed spool having the highest measured MWT is about 8 operating years from reaching the threshold of reported seam weld pipe failures. The Line B seamed spool having the highest measured MWT is more than 18 operating years from reaching the threshold of historical seam weld pipe failures.

Potential Components of an Effective LSW Integrity Management Program

2012 ◽  
Author(s):  
Tara Podnar ◽  
Thomas A. Bubenik ◽  
Jim Andrew ◽  
Dyke Hicks
Keyword(s):  
Positive Impact ◽  
Management Program ◽  
Safety Measures ◽  
Integrity Assessment ◽  
Seam Weld ◽  
Integrity Management ◽  
Examination Techniques ◽  
Inspection Data ◽  
Non Destructive ◽  
Longitudinal Seam

Det Norske Veritas (U.S.A.), Inc. (DNV) has had the opportunity to observe and contribute to a significant number of longitudinal seam weld integrity management programs. DNV has used these opportunities to identify activities with a positive impact on the integrity management of the longitudinal seam welds for which they are implemented. The Integrity Assessment activities identified by DNV include those pertaining to hydrostatic pressure testing, in-line inspection data, and in-line inspection technology. The Anomaly Review and Prioritization activities include excavation prioritization, control excavations, and investigative excavations. The Excavation and Repair Program activities include non-destructive examination techniques, technologies and validation, repair methods, and safety measures. The Tool Validation activities include in-line inspection specification and vendor feedback. The Reassessment activities include those pertaining to in-line inspection validation, operations, and reassessment interval calculation methodologies. Not all longitudinal seam weld integrity management activities are appropriate for all pipelines. In these cases, the correct combination of integrity management activities will result in an effective longitudinal seam weld integrity management program.

Refurbishment of a 230 KM Oil Pipeline With Longitudinal Seam Weld Fatigue Cracking Problem

2002 ◽  
Author(s):  
Marianela Ledezma ◽  
Jose´ G. Aranguren ◽  
Fabrizio Paletta
Keyword(s):  
Fatigue Cracking ◽  
Management Plan ◽  
Maintenance Cost ◽  
Defect Tolerance ◽  
Critical Crack ◽  
Oil Pipeline ◽  
Seam Weld ◽  
Weld Fatigue ◽  
Pressure Changes ◽  
Longitudinal Seam

Recently, a Petro´leos de Venezuela S. A. (PDVSA) oil pipeline, 230 Km (143 miles) in length and 660 mm (26 in.) in diameter, had a leak in the longitudinal seam weld of one of its sections. The analysis of this failure revealed that the leakage was originated in a fatigue crack which nucleated at a stress concentrator associated to a weld defect, and it propagated due to the cyclic stresses induced by the internal pressure changes. Partial external inspection of the pipeline revealed that the problem was extended to other sections. This paper summarizes the actions taken for the refurbishment of the oil pipeline which included: 1- the management plan set to face the problem; 2- the inspection of the pipeline, externally and internally; 3- the analysis of the inspection results; 4- the defect tolerance assessment / fitness-for-purpose study, to estimate both, the critical crack sizes as well as the crack propagation rates; 5- the development of repair procedures, and, 6- the determination of future inspection and maintenance recommended programs. All of it, with the main purpose of maintaining the operation of this line with complete guarantee of its integrity. Thanks to these actions, it has been possible to prevent additional failures in the same pipeline as well as to reduce in about MM$ 25 the maintenance cost associated with it.

An Improved Methodology for Prioritizing Pipelines With Respect to Fatigue Cracking of Seam Weld Flaws

2020 ◽  
Author(s):  
Michael Turnquist ◽  
Nader A. Al-Otaibi ◽  
Nauman Teshin ◽  
Mohammed A. Al-Rabeeah
Keyword(s):  
Additional Data ◽  
Fatigue Cracking ◽  
Primary Concern ◽  
Operating Pressure ◽  
Electric Resistance ◽  
Seam Weld ◽  
Pressure Cycle ◽  
Weld Fatigue ◽  
Longitudinal Seam ◽  
Submerged Arc

Abstract The threat of pressure cycle induced fatigue cracking of flaws associated with the longitudinal seam weld continues to be a primary concern for pipeline operators. Cyclic pressure loading can cause initial manufacturing flaws in a seam weld to sharpen and grow over time. While this behavior is most prevalent in pre-1979 electric resistance welds (ERW) and electric flash welds (EFW), historical data also shows that submerged arc welds (SAW) have been observed to develop cracks at the toe of the weld, and those cracks have exhibited fatigue growth from transit fatigue, operating pressure cycles, or both. When managing a large pipeline network, it is important to understand which pipelines exhibit higher priority with respect to seam weld fatigue cracking. While there are industry-accepted methodologies used to prioritize pipelines with respect to seam weld integrity (TTO-5 [1] and API RP 1176 [2] being the most well-known), these methodologies can be improved upon when specifically considering fatigue. Saudi Aramco and Quest Integrity developed a detailed methodology to determine a prioritization for a group of pipelines specifically with respect to seam weld fatigue cracking. This improved methodology was specially tailored to consider additional data available in Saudi Aramco’s records to rank the likelihood for a fatigue failure to occur. This initial prioritization will be used to implement a more rigorous program to manage their assets. Additional data gathered in subsequent assessments can be included to refine the prioritization. The primary metrics used to determine the prioritization are pressure cycle aggressiveness, predicted remaining life with respect to recent hydrostatic testing, and the API 1176 Annex B prioritization classification.

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.

Friction Stir Welding of Elements Made of Cast Aluminium Alloys

2014 ◽  
Vol 59 (1) ◽  
pp. 385-392
Author(s):  
B. Rams ◽  
A. Pietras ◽  
K. Mroczka
Keyword(s):  
Friction Stir Welding ◽  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Welding Parameters ◽  
Process Conditions ◽  
Friction Stir ◽  
Seam Weld ◽  
Cast Aluminium ◽  
Weld Structure ◽  
Welding Stability

Abstract The article presents application of FSW method for joining elements made of cast aluminium alloys which are hardly weldable with other known welding techniques. Research’s results of plasticizing process of aluminium and moulding of seam weld during different FSW process’ conditions were also presented. Influence of welding parameters, shape and dimensions of tool on weld structure, welding stability and quality was examined. Application of FSW method was exemplified on welding of hemispheres for valves made of cast aluminium alloy EN AC-43200.

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