scholarly journals Reliability of Mechanised UT Systems to Inspect Girth Welds During Pipeline Construction

1998 ◽  
Author(s):  
Jan A. de Raad
Keyword(s):  
High Speed ◽  
Ultrasonic Inspection ◽  
Probability Of Detection ◽  
Inspection System ◽  
Present System ◽  
Immediate Feedback ◽  
Long Distance ◽  
Acceptance Criteria ◽  
Actual Use ◽  
Girth Welds

As an alternative to radiography, a field-proven mechanized ultrasonic inspection system is discussed. Called Rotoscan, this system has been developed for inspection of girth welds during construction of long-distance pipelines, both on- and offshore. It is characterized by high inspection speed and instant recording of results. Unlike prevailing radiography, it provides immediate feedback to the welders. Recent technical improvements in flaw sizing and recording have allowed the application of rejection/acceptance criteria for weld defects based on fracture mechanics principles. The development and actual use of such modern acceptance criteria, particularly in Canada, supported the introduction of mechanised ultrasonic inspection. World wide applications proved that, contrary to expectations, ultrasonic inspection does not lead to higher weld repair rates than radiography does. Between early 1989 and now, over 5.000 km of pipeline (300.000 welds) were inspected with Rotoscan and its reliability proven. The introduction of colour enhanced transit distance “C-scan mapping”, producing a coherent picture based on the signal’s transit distance, enabled the system to cope with most existing ultrasonic procedures and acceptance criteria, because of its capability to detect and quantify volumetric defects. Moreover, the integrated simultaneous Time Of Flight Diffraction (TOFD) function enables through-thickness sizing of defect. The present system is capable of achieving a high Probability Of Detection (POD) together with a low False Call Rate (FCR). In the meantime, Rotoscan has been qualified in various countries, for different customers and for a variety of weld processes, pipe diameters and wall thicknesses. Because of its features, the now mature system has demonstrated its capabilities also for use on lay barges as an alternative to high-speed radiography.

Development of a 3D Ultrasonic Inspection Device for Pipeline Girth Welds

2006 ◽  
Author(s):  
Hiroshi Sato ◽  
Takayuki Hamajima ◽  
Masahiro Katayama ◽  
Yasuhisa Kanamaru
Keyword(s):  
High Speed ◽  
System Development ◽  
Ultrasonic Inspection ◽  
Three Dimensional ◽  
Synthetic Aperture ◽  
Quality Data ◽  
Inspection System ◽  
Wave Form ◽  
External Diameter ◽  
Girth Welds

Quality requirements for girth welded joints in gas pipelines necessitate adequate penetration to the inner surface and no harmful defects. Toho Gas has completed development of the world’s first inspection system applying the ultrasonic synthetic aperture method for welds in steel pipes used to carry gas (external diameter 200mm, pipe wall thickness 5.8mm). In recent years, ultrasonic phased-array technology and ultrasonic TOFD methods etc. have attracted attention. However, the ultrasonic synthetic aperture method is an imaging technology that is superior to these, as it can synthesize several thousands of wave form data at high speed, its image clarity is the best in the world. The four features of the system are (1) the ability to provide an image of the interior of a weld, (2) the ability to quantity incomplete root bead penetration, (3) automatic high speed collection of data, and (4) data base management capability. The ultrasonic synthetic aperture method simplifies defect judgments because it does not require that operators possess special qualifications and training. It can produce three-dimensional high picture quality data. It can be handled easily at work sites because it is portable. This report describes the ultrasonic inspection system development process and the results of trial inspections.

Automatic Ultrasonic Inspection Method of Railway Axle and its Remaining Life Prediction

2011 ◽  
Vol 213 ◽  
pp. 291-296 ◽  
Author(s):  
Hong Wei Hu ◽  
Xiong Bing Li ◽  
Xiang Hong Wang ◽  
Yi Min Shao
Keyword(s):  
High Speed ◽  
Fatigue Cracks ◽  
Ultrasonic Inspection ◽  
Inspection System ◽  
Remaining Life ◽  
High Speed Railway ◽  
Inspection Method ◽  
Spiral Trajectory ◽  
Image Element ◽  
The Matrix

With the high speed railway utilization, the probability of defects or fatigue cracks in railway axles is increased. An automatic ultrasonic inspection system for railway axles is presented. This system uses combined probes and inspects the defects with spiral trajectory along the axis of the axle. Through the matrix representation of C-scan image element, a defect edge extraction method is adopted, with which the defect parameters of crack are obtained automatically. Based on these defect parameters, the stress intensity factor is assessed by svm regression and the method to predict remaining life is proposed.

An Automatic Flaw Identification Method for Defect Inspection of Pipeline Girth Weld

2008 ◽  
Author(s):  
Jian Li ◽  
Xianglin Zhan ◽  
Shili Chen ◽  
Jingchang Zhuge ◽  
Shijiu Jin ◽  
...  
Keyword(s):  
Phased Array ◽  
Flaw Detection ◽  
Inspection System ◽  
Energy Status ◽  
Long Distance ◽  
Feature Extraction Method ◽  
Identification Method ◽  
Ultrasonic Phased Array ◽  
Flaw Classification ◽  
Girth Welds

Various types of defect may be formed in girth welds of long-distance pipeline in the process of welding. They are hidden dangers to pipeline transportation safety. Currently, ultrasonic phased array instrument is commonly adopted for quick automatic positioning and quantitative analysis of flaws in the girth weld after welding. But as for qualitative analysis – flaw classification, traditional manual identification method is still used. By traditional method, human-made error is easily introduced and classification result is depended on the detection experiences of the inspecting person. To overcome these deficiencies, a new method combined second generation wavelet transform (SGWT) with Radial Basis Function neural network (RBFN) is proposed in this paper, realizing automatic flaw classification and reducing human factors impaction. SGWT is ideally matched local characteristics of the flaw signal, improving both the computational speed and flaw classification efficiency. Then, based on the “energy-status” feature extraction method and the above SGWT analysis, feature eigenvectors of the flaw signals are extracted, training the following RBFN. And then when the feature of any flaw is extracted, it can be recognized by the network. The output of the network is the type of the input flaw signal, realizing automatic flaw classification. Finally, an ultrasonic phased array inspection system is described. The system is integrated with automatic flaw detection and classification. Experiments are tested on a long-distance pipeline girth weld block with artificial defects in it. The results validate that the proposed method is efficient, which is helpful to increasing inspection speed and reliability of flaw inspection for long-distance pipeline girth welds.

Reliability of Fracture Mechanics Approach to Fatigue

2009 ◽  
Author(s):  
Mario L. Macia ◽  
Jaime Buitrago ◽  
Wan Kan ◽  
Barron Bichon ◽  
Jonathan Moody ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fracture Mechanics ◽  
Safety Factor ◽  
Important Variable ◽  
Probability Of Detection ◽  
Inspection System ◽  
Acceptance Criteria ◽  
Fatigue Design ◽  
Critical Components ◽  
Selection Of

Current fatigue design of fracture-critical components, such as tendons and risers, requires dual fatigue life criteria to be satisfied. The S-N approach includes a safety factor (SF) of 10 on the life of the component, while the fracture mechanics (FM) approach includes a safety factor of 5 on the life through-thickness of an acceptable initial flaw. FM provides critical initial flaw sizes such that suitability of the selected NDE methods and weld acceptance criteria can be established. This paper pertains to a comparative fatigue life reliability study between those two approaches. The objective is to develop a rationale for the selection of a safety factor on fatigue life to use in FM calculations. A reliability-based methodology is proposed and implemented. The SFs for FM are obtained by targeting the reliability obtained in fatigue designs based on historically proven S-N damage approach. Random variables entering both approaches were characterized and a number of weld design cases devised to obtain reliabilities. One important variable is the distribution of initial flaw sizes. For this study, flaw distributions were developed from actual inspection records, accounting for the effects of probability of detection and sizing accuracy of the inspection system, as well as the flaw acceptance criteria during fabrication. Comparisons of reliabilities obtained for designs by both approaches for various quality S-N curves, stress spectra, pipe sizes, and initial flaw sizes indicate that there is ample scope to modify downward the current FM safety factor. However, given the limited scope of this study, it is recommended to asses the FM SF using reliability analysis on a project-specific basis.

Inspection Considerations for Deepwater Thick-Walled Riser Systems

2008 ◽  
Author(s):  
Jonathan Bowman ◽  
Hugh Thompson ◽  
Donald Stevens ◽  
James Crane
Keyword(s):  
Fatigue Loading ◽  
Thick Wall ◽  
Inspection System ◽  
Acceptance Criteria ◽  
Adequate Knowledge ◽  
Inspection Process ◽  
Engineering Requirement ◽  
Weld Inspection ◽  
Girth Welds ◽  
The Impact

The fatigue loading on deepwater risers results in the need to impose very tight weld acceptance criteria for pipe alignment and flaw sizes. The production of high-pressure, high-temperature reservoirs calls for increasingly thick-walled riser systems. The combination of thicker wall pipe and the maintenance of tight flaw acceptance criteria challenges automated ultrasonic testing (AUT) which is the primary method of riser weld inspection. An understanding of the limitations of the weld inspection system must be determined and accommodated as part of the engineering process and in conjunction with adequate knowledge of the pipe end dimensions can help optimize the inspection process. This paper discusses the challenges associated with the preparation for and inspection of thick-walled riser system welds and the impact this can have on the system design and engineering requirement. In support of the discussion an overview of a recent study to determine the detect-ability and sizing accuracy of an AUT system with thick-wall pipe girth welds is presented. The qualification program is based upon the AUT inspection of seeded defect welds which are subsequently cut into weld rings, re-inspected with an immersion scan and sectioned to determine the size of the flaws present. All AUT inspections are performed under similar conditions to the inspection of the production welds (i.e., no prior knowledge of the nature of the seeded welds).

Design of a Parallel Ultrasonic Inspection System for Wheels of High Speed Trains

2012 ◽  
Vol 562-564 ◽  
pp. 2007-2010
Author(s):  
Jin Wang ◽  
Zhi Ling Sun ◽  
Qi Chang Guo ◽  
Min Quan Huang
Keyword(s):  
Parallel Processing ◽  
High Speed ◽  
Ultrasonic Inspection ◽  
Processing Technology ◽  
Host Computer ◽  
Computer Application ◽  
Inspection System ◽  
Ultrasonic Technology ◽  
High Speed Trains ◽  
Inspection Data

This thesis proposes a new inspection system for wheels of high speed trains, using Piezoelectric ultrasonic technology and parallel processing technology. This system allows all the wheelsets mounted in a train to be inspected within a few minutes. When a train passes through the testing line at low speed(3-5Km/h), wheel tread contact with the probe arrays in turn, which are installed inside of a special rails. Meanwhile, ultrasonic controllers stimulate the probes , collect inspection data and transfer the data to the host computer. Application results in field are presented to verify the effectiveness of the proposed structure.

Integration of Welding, NDT, Mechanical Testing and Field Control When Using an ECA Flaw Acceptance Criteria in Pipeline Construction

2018 ◽  
Author(s):  
Junfang Lu ◽  
Bob Huntley ◽  
Luke Ludwig ◽  
Axel Aulin ◽  
Andy Duncan
Keyword(s):  
Mechanical Testing ◽  
Gas Metal Arc Welding ◽  
Probability Of Detection ◽  
Destructive Testing ◽  
Acceptance Criteria ◽  
Pipeline Construction ◽  
High Productivity ◽  
Metal Arc Welding ◽  
Field Control ◽  
Girth Welds

The fracture mechanics based engineering critical assessment (ECA) method has been accepted as a fitness for service (FFS) approach to defining weld flaw acceptance criteria for pipeline girth welds. Mechanized gas metal arc welding (GMAW) processes are commonly used in cross country pipeline girth weld welding because of the advantages in good quality and high productivity. With the technical advancements of non-destructive testing (NDT) techniques, automated ultrasonic testing (AUT) has greatly improved flaw characterization, sizing and probability of detection during weld inspection. Alternative weld flaw acceptance criteria are permitted in pipeline construction code to assess the acceptability of mechanized girth welds using an ECA. The use of an ECA based weld flaw acceptance criteria can significantly reduce the construction cost. Mechanized girth weld acceptance criteria have been progressively transitioned from workmanship standards into using fitness for service based ECAs. To successfully deliver an ECA on a pipeline project, a multidisciplinary approach must be taken during the welding design and construction stages. Welding, NDT, mechanical testing and field control are all integral elements of pipeline construction. All these four elements have to be fully integrated in order to implement the ECA and achieve the overall integrity of a pipeline. The purpose of this paper is to discuss the importance of the integration of these four elements necessary for proper implementation of the ECA weld flaw acceptance criteria.

Pipeline Girth Weld Inspection and Flaw Acceptance Criteria for Sour Service Applications

2017 ◽  
Author(s):  
Shashi Bhushan Kumar ◽  
Kapil Mohan ◽  
Shaodong Zhang ◽  
Jens P. Tronskar
Keyword(s):  
Best Practice ◽  
Oil And Gas ◽  
Probability Of Detection ◽  
Resistance Testing ◽  
Acceptance Criteria ◽  
Gas Field ◽  
Radiographic Inspection ◽  
Weld Inspection ◽  
Girth Welds ◽  
Sour Service

To establish flaw acceptance criteria for carbon steel pipeline girth welds that are intended to transport sour crude, wet sour gas and condensate it is important to assess the effect of operating environment and strain levels by performing the fracture toughness/ resistance testing as per DNV-OS-F101: 2013 in a representative simulated service environment or under more severe test conditions. None the less many oil and gas field operators still believe that using workmanship criteria and radiographic inspection will be adequate to ensure a safe future operation of the pipeline meeting the design life requirements under sour or severely sour operating environments. Unfortunately, experience shows that this is a dangerous practice as radiography tends to miss out in detecting the most severe planar defects such a lack of fusion, hydrogen induced cracking and weld root centerline cracks, this is specifically so for narrow J-bevel welds. Hence, DNV GL based on experience from many projects advocates inspection of all sour service pipelines using inspection methods such as AUT with a high probability of detection for planar flaws. Further, the AUT acceptance criteria shall be chosen appropriately with due considerations as workmanship type of acceptance criteria without proper verification may result in non-conservatism in the pipeline girth weld inspection and weld sentencing. This present paper presents some recent project experiences from typical sour service subsea pipeline projects and provide advices representing what is considered current best practice for testing and qualification of AUT systems for sour service projects.

High-Speed, Long-Distance Electric Traction

1905 ◽  
Vol 59 (1537supp) ◽  
pp. 24627-24628
Author(s):  
Charles A. Mudge
Keyword(s):  
High Speed ◽  
Long Distance ◽  
Electric Traction
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