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PRCI PR-243-9518
- Detection of Stress Corrosion Induced Toe Cracks
- Report / Survey by Pipeline Research Council International, 03/01/1996
- Publisher: PRCI
$148.00$295.00
L51748e
Ginzel & Associates Ltd
(e-book version)Need: In the past few years an ongoing problem has existed with stress corrosion cracking (SCC) in pipelines around the world. Several member companies of the Pipeline Research Council International, Inc. have experienced multiple incidents as a result of ERW defects and SCC. TCPL is running a series of hydrostatic tests and trial digs to identify the most severely affected areas. These excavations and failure studies have ascertained that most of the SCC causing failure has been on the outside diameter of long seam welded pipe at the edge of the weld. Defects at that location are known as "Toe-Cracks".
Benefit: Ginzel has developed an ultrasonic inspection technique that will detect both SCC colonies and toe cracks in long seam pipe. The main design objective for this research project was the selection and placement of ultrasonic transducers to combine weld, plate thickness and lamination inspection, along with SCC detection and sizing. Examination of sample pipe sections to demonstrate its success is reported in detail below. The primary stages for this research project are as follows:
1. Assemble test equipment
2. Establish test procedure
3. System trials and data collection
4. Evaluation of system performance and collected data
5. Correlation of test data - Results
Result: The use of a time domain ultrasonic inspection technique has successfully demonstrated the ability to reliably detect and size stress corrosion cracking defects in dual sub-arc long seam welds. The technique utilizes a multimode transducer technology for both the detection and the sizing transducers. The interaction of four pulse combinations with the crack provides three potential sizing methods. The technique is independent of amplitude responses and pattern recognition is used to qualify indications.
The design and testing of the transducer configuration have established fundamental requirements for implementing the developed technique into a scanning system. Current system design permits inspection of the weld and 60mm (2.36") of the adjacent parent material from the inside diameter of the pipe. With the design of a carrier to deliver the transducer tray, pipe in designate high risk areas, such as dwelling locations or creek and road crossings may be examined. The excavation required for the new inspection device could be limited to a single bell hole for entry and removal.
Ginzel & Associates Ltd
(e-book version)Need: In the past few years an ongoing problem has existed with stress corrosion cracking (SCC) in pipelines around the world. Several member companies of the Pipeline Research Council International, Inc. have experienced multiple incidents as a result of ERW defects and SCC. TCPL is running a series of hydrostatic tests and trial digs to identify the most severely affected areas. These excavations and failure studies have ascertained that most of the SCC causing failure has been on the outside diameter of long seam welded pipe at the edge of the weld. Defects at that location are known as "Toe-Cracks".
Benefit: Ginzel has developed an ultrasonic inspection technique that will detect both SCC colonies and toe cracks in long seam pipe. The main design objective for this research project was the selection and placement of ultrasonic transducers to combine weld, plate thickness and lamination inspection, along with SCC detection and sizing. Examination of sample pipe sections to demonstrate its success is reported in detail below. The primary stages for this research project are as follows:
1. Assemble test equipment
2. Establish test procedure
3. System trials and data collection
4. Evaluation of system performance and collected data
5. Correlation of test data - Results
Result: The use of a time domain ultrasonic inspection technique has successfully demonstrated the ability to reliably detect and size stress corrosion cracking defects in dual sub-arc long seam welds. The technique utilizes a multimode transducer technology for both the detection and the sizing transducers. The interaction of four pulse combinations with the crack provides three potential sizing methods. The technique is independent of amplitude responses and pattern recognition is used to qualify indications.
The design and testing of the transducer configuration have established fundamental requirements for implementing the developed technique into a scanning system. Current system design permits inspection of the weld and 60mm (2.36") of the adjacent parent material from the inside diameter of the pipe. With the design of a carrier to deliver the transducer tray, pipe in designate high risk areas, such as dwelling locations or creek and road crossings may be examined. The excavation required for the new inspection device could be limited to a single bell hole for entry and removal.
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