bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Natural Gas Pipeline Explosion on Material Performance of X80 Steel Pipe Laid in One Ditch
Authors: Ling Jiatong , Dong Shaohua , Zhang Hang , Peng Donghua 
Published: January 2021

Abstract
Due to geographical restrictions, it is often necessary to lay two pipelines in the same ditch during pipeline construction. However, as developments in natural gas pipelines increasingly incorporate higher grades of steel, larger diameters, and higher pressures, the consequences of an accident caused by leakage, explosion, or ignition become progressively more severe. The explosion occurred in one pipe would affect the other pipe laid in the same ditch, resulting in subsequent explosion. In this study, a full-scale explosion test was conducted on two X80 steel pipes with diameters of 1422 mm and 1219 mm, laid in one ditch and set up in parallel arrangement, with a spacing of 36 m between one another, and a burying depth of 1.5 m. Some X80 steel samples were selected to assess materials performance in different areas of a given pipe in the same ditch by deploying selective explosions. The mechanical performance tests on a number of points including tensile strength, impact, and hardness were executed by the Mechanical Testing and Sensing (MTS) universal testing machine. Drop-Weight Tear Test (DWTT) of the selected samples were executed by the DWTT pendulum test machine. Metallography and microstructure analysis of the steel samples was performed by the MEF4M metallographic microscope and image analysis system. Results indicate that limited effects of jet fire on the macroscopic tensile properties and impact toughness of the pipelines, but a more obvious softening effect on the steel surface material. Drop-Weight Tear Test and microscopic observation revealed that jet fire can significantly reduce crack propagation resistance on the surface of the pipeline, pointing to deformation behavior and other concerns that could impact pipeline safety and efficacy. The results of this experimentation can help to improve pipeline construction, resulting in better safety.
Recent Progress in Development of Ductile Fracture Arrest Methodology Based on CTOA: Test Standard, Transferability and Methodology
Authors: Xu S. , Bassindale C. , Xue J. , Williams B. W. , Wang X. 
Published: January 2021

Abstract
Significant progress has been made in development of a new fracture arrest methodology based on a toughness parameter designed to characterize propagation — the crack-tip opening angle (CTOA). A CTOA test procedure using lab-scale DWTT-type specimens has been standardized by ASTM, and recently published experimental work has demonstrated transferability of CTOA from DWTT to full-scale pipe.
This paper will present the basic methodology for determination of CTOA using DWTT-type specimens (i.e., ASTM E3039) and other specimens such as modified double-cantilever-beam (MDCB). Recent numerical studies using cohesive zone models (CZM) and others based on damage mechanics will be discussed, including models of full-scale pipe fracture. The effects on CTOA of loading rate, specimen flattening and constraint (bending vs. tension) will be reviewed. The effect on CTOA of loading rate between quasi-static and impact (covering five orders of magnitude) is small or negligible, being within experimental scatter. Observed differences between surface and mid-thickness CTOA values will be discussed. Models of DWTT specimens using damage mechanics have shown that the CTOA for tensile loading is the same at the surface and mid-thickness and equal to the mid-thickness value for bend loading, but that the surface CTOA is significantly larger than the mid-thickness CTOA in bending. Model calculations have revealed the dependence of crack velocity on stress for a given CTOA, enabling construction of fracture resistance curves (pressure required to propagate fracture as a function of crack velocity). These first-principles curves based on CTOA can then be used in the Battelle two-curve model (BTCM) to replace empirical resistance curves based on Charpy absorbed energy (Cv). It has been known for some time that Cv over-represents the propagation resistance for high-strength high-toughness steels, requiring empirical “correction factors” to Cv in the BTCM. Experiments have shown that there is a non-linear correlation between Cv and CTOA, explaining the need for correction factors to Cv and supporting the use of CTOA as a more appropriate propagation toughness.
Analysis of the Mechanical Behaviors of Fiber Reinforced Unbonded Flexible Pipe Under Combined Load
Authors: Wang Baodong , Zhang Hong , Liu Xiaoben , Xu Lixin , Fu Yang 
Published: January 2021

Abstract
Unbonded flexible pipe is widely used in the oil and gas industry for its good flexibility, especially in deepwater oil and gas transportation. And the fiber reinforced unbonded flexible pipe has excellent corrosion resistance and wear resistance. However, they are subjected to internal pressure, external pressure and tensile loads during the service process, which are important factors affecting the integrity and security of the flexible pipe. In this paper, the mechanical behaviors of an 8-inchs fiber reinforced unbonded flexible pipe used in offshore gas development which consists of internal layer, internal pressure reinforcement layers, anti-wear layers, external pressure armor, tensile reinforcement layers and outer sheath is investigated by numerical methods. A rigorous three-dimensional solid finite element model of flexible pipe that considers the real material parameters, structural nonlinearity as well as the nonlinear contact behavior was created. ABAQUS/Explicit quasi-static simulation is adopted to study the mechanical behaviors of the flexible pipe under combined load. And the accuracy of the simulation method for the fiber reinforced layers such as internal pressure layer is verified by comparing with the small-scale internal pressure burst test of 1-inch flexible pipe. The mechanical behavior of flexible pipe subjected to internal pressure, external pressure and tensile load was investigated in detail. Based on the contrastive analysis, some practical conclusions have been obtained which may be used for the practical design and production of flexible pipe. This study can be referenced for the applications of unbonded flexible pipe in marine oil and gas production.
Concerted, Computing-Intense Novel MFL Approach Ensuring Reliability and Reducing the Need for Dig Verification
Authors: Palmer Johannes , Schartner Aaron , Danilov Andrey , Tse Vincent 
Published: January 2021

Abstract
Magnetic Flux Leakage (MFL) is a robust technology with high data coverage. Decades of continuous sizing improvement allowed for industry-accepted sizing reliability. The continuous optimization of sizing processes ensures accurate results in categorizing metal loss features. However, the identified selection of critical anomalies is not always optimal; sometimes anomalies are dug up too early or unnecessarily, this can be caused by the feature type in the field (true metal loss shape) being incorrectly identified which affects sizing and tolerance. In addition, there is the possibility for incorrectly identifying feature types causing false under-calls.
Today, complex empirical formulas together with multifaceted lookup tables fed by pull tests, synthetic data, dig verifications, machine learning, artificial intelligence and last but not least human expertise translate MFL signals into metal loss assessments with high levels of success. Nevertheless, two important principal elements are limiting the possible MFL sizing optimization. One is the empirical character of the signal interpretation. The other is the implicitly induced data and result simplification.
The reason to go this principal route for many years is simple: it is methodologically impossible to calculate the metal source geometry directly from the signals. In addition, the pure number of possible relevant geometries is so large that simplification is necessary and inevitable. Moreover, the second methodological reason is the ambiguity of the signal, which defines the target of metal loss sizing as the most probable solution. However, even under the best conditions, the most probable one is not necessarily the correct one.
This paper describes a novel, fundamentally different approach as a basic alternative to the common MFL-analysis approach described above. A calculation process is presented, which overcomes the empirical nature of traditional approaches by using a result optimization method that relies on intense computing and avoids any simplification. Additionally, the strategy to overcome MFL ambiguity will be shown. Together with the operator, detailed blind-test examples demonstrate the enormous level of detail, repeatability and accuracy of this groundbreaking technological method with the potential to reduce tool tolerance, increase sizing accuracy, increase growth rate accuracy, and help optimize the dig program to target critical features with greater confidence.
At the Forefront of In-Line Crack Inspection Services: A Highly Versatile Crack Inspection Platform for Complex Flaw Morphologies and Absolute Depth Sizing
Authors: Bott Steven , MacKenzie Rob , Hill Mike , Hennig Thomas 
Published: January 2021

Abstract
In 2014, Enbridge published a request for proposals to develop and provide a solution on a specific type of long seam cracks in a 26” pipeline. In-line inspection technologies available at the time were not able to consistently and accurately characterize the crack threat, although the line was successfully hydrostatically tested in 2015. During the early stages of the project, NDT Global analyzed in detail Enbridge’s requirements, including the specific challenges, spool type, seam weld characteristics etc. and provided different proposals to Enbridge. In 2016, both parties signed a development contract to develop and build a 26” Next Generation Crack Inspection Platform (Proton). The project was divided into various stages to support a successful project that met performance requirements based both on pump tests and a field trial supported by investigative digs and coupon cutouts.
The robot developed is a highly versatile crack inspection platform: it allows to be set up in a configuration optimized for the given threat, pipeline conditions, inspection speed and medium characteristics. This optimization of the configuration allows choosing the optimum measurement modes for flaws in the base material and in the seam weld independently. Additionally, the local wall thickness even in the seam weld is measured accurately. These capabilities allow the operator to collect the best data for each situation. Feeding the information into the crack management program allows Enbridge to maintain the target reliability of the asset.
The robot was utilized successfully in the 26” pipeline. Processing, data analysis and reporting were performed within pre-agreed periods. Initial field findings and lab tests show high correlation of ILI and real flaws and proof the stated accuracy of the new service.
The authors will present in detail some of the specific challenges of the pipeline system and limitations of available crack inspection technologies. Validation results from in-the-ditch non-destructive examination and destructive freeze breaks including cross sections from flaws with complex morphologies will be shown. Performance statistics and comparison to previous inspection results will be used to demonstrate that the new robot can be used as part of an effective crack management program.
Pipeline Steel Fracture Toughness and the Need for a Toughness Database of API 5L Line Pipe
Authors: Lamborn Lyndon , Zhang Shenwei , Limón Sergio , Lai Roger 
Published: January 2021

Abstract
In order for the pipeline industry to usher in the next-level fracture mechanics engineering analysis, reasonable and prudent fracture toughness characterizations are needed to improve burst pressure predictions and fatigue crack growth analysis of pipelines with planar cracks. Converting Charpy V-Notch (CVN) value to fracture toughness via different empirical correlation models derived throughout the years, while laudable, have inherent shortcomings. The main issues being that the Charpy toughness test is not a fracture mechanics-based measurement and the transferability of sub-scale fracture toughness testing is often not completely understood nor is correctly applied. This paper expands on these shortcomings and presents solutions which are supported by fracture toughness data obtained from the pipe boy and seam weld of API 5L line pipe steels. In this manner, best available toughness derivations for mean toughness in base metal and long seam welds are presented. Suggestions for standard fracture mechanics sub-scale coupon testing, such as ASTM E1820, on pipeline steel samples are delineated with rationale for each test type. The transferability of fracture toughness from sub-scale coupon testing results to that exhibits in full-scale pipe failure are demonstrated in the paper. This fracture toughness test database and other similar data sets can be combined and serve as the basis for establishing an industry wide Pipeline Material Database which would mirror established material databases in the aerospace industry such as NASGRO and AFMAT. It is envisioned that a centralized and validated Pipeline Material Database will be expanded to include fatigue crack growth rate data and other pipeline material characterization data sets. These data will support minimizing material assumptions and increase the accuracy of structural integrity predictions to improve the overall pipeline performance. This combined database would be accessible to engineers, analysts, and researchers and updated at regular intervals as more data becomes available.
Establishment and Application of the Pipeline Monitoring System in Permafrost Regions in China
Authors: Liu Jianping , Chen Pengchao , Zhang Hong , Wang Baodong , Liu Xiaoben 
Published: January 2021

Abstract
Buried pipelines in permafrost regions are inevitably subjected to some typical geohazards, such as frost heave, thaw settlement and thaw slumping. The bending or/and longitudinal strains will be induced in pipe under these types ground movement, which is the potential cause of weld joint rupture. Thus, in order to prevent pipe failure, a comprehensive monitoring system was designed and used in the Mohe-Daqing oil pipeline in the permafrost region in northeast China. The Mohe-Daqing oil pipeline is built for importing oil from Russia and its north part of 440km lays in permafrost. The monitoring system includes soil temperature field monitoring system, ground displacement monitoring system and pipe strain monitoring system. The soil temperature field monitoring system, which uses fiber brag grating sensors, can monitor the distribution of surrounding soil temperature in radial direction of pipe in order to detect the change of active ring of permafrost. The ground displacement monitoring system, which is based on a total station, can discover any subsidence or heave of the pipe itself and the embankment along the pipeline. The pipe strain monitoring system, which includes pipe stress monitoring system based on fiber brag grating sensors and inertial measurement unit (IMU) mapping, can inspect the real-time change of pipe stress and the bending strain periodically respectively. Using the comprehensive monitoring system, the important parameters that affect pipeline integrity such as pipeline temperature, stress, strain and displacement of Mohe-Daqing oil pipeline can be supervised timely and effectively. And the accuracy and reliability of the monitoring system have been verified in practical application. In this paper, detail about how these systems are designed and installed on the Mohe-Daqing oil pipeline is elucidated and the monitoring data is analyzed. Through these data, the present mechanical situation of Mohe-Daqing oil pipeline is safe, but the long-term change is critical because of the soaring oil temperature that is far high than the design temperature. The monitoring system is of great significance to ensure the safe operation of Mohe-Daqing pipeline and can provide reference for the pipeline operation in permafrost areas.
Hydrostatic Collapse Tests of Full-Scale Pipeline Specimens With Thickness Metal Loss
Authors: Cunha Divino J. S. , Ferraz Caroline , Netto Theodoro A. , Diniz J. C. , Rosa Diego G. G. , Freire José L. F. 
Published: January 2021

Abstract
The present paper deals with the subject of failure of deep-sea pipelines that have thickness metal-loss areas caused by corrosion and are subjected to high external hydrostatic pressure. An extensive research program was launched to observe failure modes, to examine existing and to develop prediction collapse equations, and to determine their accuracy. The program uses finite element modeling and external hydrostatic collapse tests of full-scale specimens. This paper presents and discusses the results of the first 20 collapse tests, which were performed in a new 103 MPa (15 ksi) hyperbaric chamber (760 mm internal diameter and 7200 mm length). The test results obtained with full scale specimens (324 mm external diameter and 23 mm thickness) made of low carbon steel API 5L X60 with external machined metal loss defects are used to verify the level of accuracy and conservatism of four analytical simple equations used to predict collapse of pipes with corrosion subjected to high external pressure.
Improved Inspection Through Full Matrix Capture Technology
Authors: Bellistri Domenico , Vinyard Jeff , Seward Cameron 
Published: January 2021

Abstract
The ideal Non Destructive Evaluation/Examination process should be carried out using a fully automated system: planning, execution, evaluation and reporting would be all tasks performed by automated technologies and artificial intelligence that don’t need human intervention, thus taking the Human Factor out of the equation. Not yet reaching this level of automation, it is still possible to improve the overall quality of the NDE process to increase both speed and quality, while maintaining safety.
Ultrasonic Testing NDE is considered a safe, portable and reliable inspection method. Detection and characterization depends upon factors like technician’s experience and skills, especially for shear wave UT, where an amplitude vs time signal, the A-Scan, is the only given information from the specimen to be examined. With this technique there is very little digital data saved, often in the form of screenshots.
The evolution of shear wave UT was represented by the use of an array probe with the Phased Array technique: the new capabilities of simultaneously steering the beam in multiple directions and combining all the A-Scans in images together, has made it easier to interpret any anomalies found during inspection.
However, skill and experience are still very important factors to avoid false positive and false negative results. For example, focusing distance from the array probe and false signals from mode conversion may lead to the wrong conclusions.
Ultrasonic imaging technology based on full matrix capture has the intrinsic ability to improve interpretation over more conventional techniques such as PA UT or shear wave UT since it provides information not only about the size of flaws, but also on their geometry in terms of horizontal and vertical extent.
Characterization of Crystallographic Texture of ERW Welded and Heat-Treated API X70 Pipeline Steel
Authors: Sharma Nitin , Wang Yiyu , Li Leijun , Anderson Neil , Rashid Muhammad 
Published: January 2021

Abstract
The impact toughness of high frequency electric resistance welded (ERW) line pipe depends on the steel chemical composition, welding procedure, and post-welding heat treatment. Among several microstructural factors that may influence the impact toughness of high frequency electric resistance welded bond line, the crystallographic texture factor is often assumed, but not sufficiently studied. The evolution of texture during high frequency electric resistance welding and simulated post-welding heat treatments (PWHT) of API X70 pipeline steel was characterized using X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). Results of a texture factor calculated using the θ/2θ XRD scans indicated that following the post-weld normalizing treatment, the texture factor of {100} planes for the weld bond line appeared to have increased with the increase in post-weld normalizing temperature. The texture factor results obtained from θ/2θ XRD scans were further verified by using the EBSD on the CVN tested samples in the regions near the fracture path. The XRD texture factor was also used to correlate the evolution of crystallographic texture and Charpy toughness for the PWHT samples. Based on the observations from both XRD and EBSD, the {100} crystallographic orientation of planes in the notched direction correlates well with the cleavage fracture planes of the Charpy impact tested samples. Therefore, the post-weld heat treatment should be designed to minimize any preferred crystallographic texture with {100} planes in the bond line, to promote ductile fracture and improved bond line impact toughness at low temperatures.
Austenite Grain Size Model for the Coarse Grain Heat Affected Zone in Line Pipe Steels
Authors: Romualdi Nicolas , Militzer Matthias , Poole Warren , Collins Laurie , Lazor Robert 
Published: January 2021

Abstract
Pipelines are the safest and most cost-effective method of oil and gas transportation to storage and processing facilities. Large diameter welded pipes fabricated by submerged arc welding (SAW) are the preferred product in many cases for pipeline construction. Furthermore, pipelines are constructed by welding segments of pipe, typically by single or dual torch Gas Metal Arc Welding (GMAW). During welding, both during pipe fabrication and girth welding, the Heat Affected Zone (HAZ) experiences rapid thermal cycles with peak temperatures up to the melting temperature of the base metal. Controlling the microstructure evolution in the HAZ during welding of line pipe steels is critical to ensure that these products meet the Charpy impact testing and CTOD requirements imposed by clients and specifications.
In particular, the Coarse Grain Heat Affected Zone (CGHAZ) is of concern. Here, austenite grain growth occurs readily due to the combination of high temperature and precipitate dissolution. Controlling the CGHAZ austenite grain size is critical to obtain final microstructures with acceptable impact properties. In this study, austenite grain growth has been measured and modeled for thermal conditions relevant for the CGHAZ in 27 steels, including industrial as well as laboratory steels with systematic variations of alloying element content.
Austenite grain size was measured using a Laser Ultrasonics for Metallurgy (LUMet) sensor attached to a Gleeble 3500 Thermomechanical Simulator, which enables high-throughput in-situ monitoring of austenite grain growth. A classical grain growth model has been developed based on a standard test. The grain growth kinetics are described by combining curvature driven grain growth with pinning due to TiN precipitates. A phenomenological relationship has been developed for the grain boundary mobility that decreases with C, Nb and Mo alloying which is consistent with their expected grain boundary segregation. The pinning parameter is rationalized in terms of volume fraction and size of TiN particles. The proposed model has been validated for CGHAZ heat treatment cycles including an industrial welding trial.
The results of this study provide a model to predict the austenite grain size in the CGHAZ as a function of steel chemistries and heat treatment paths, i.e. welding parameters. Austenite grain size maps have been constructed as a function of peak local temperature and line pipe steel chemistry. The model can be used both for steel chemistry design and for optimizing welding of steels with known chemical composition to minimize the CGHAZ austenite grain size both during pipe fabrication and girth welding.