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Book Growth Behavior of Surface Cracks in Pipeline Steels Exposed to Near neutral PH Environments

Download or read book Growth Behavior of Surface Cracks in Pipeline Steels Exposed to Near neutral PH Environments written by Afolabi T. Egbewande and published by . This book was released on 2013 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study is part of a larger study designed to help a consortium of pipeline operators replace current (very expensive) approaches to managing stress corrosion cracking (SCC) concerns in near-neutral pH (NNPH) environments with mathematical models that predict SCC growth rates. This could significantly reduce the cost of pipeline integrity management programs. The goal was to help find ways to improve the accuracy of existing models. NNPHSCC cracks are surface-type flaws. However, NNPHSCC was typically modelled as through-thickness cracks in previous laboratory studies. This was identified as a major reason why current NNPHSCC models are inaccurate. Therefore, this study was designed to model NNPHSCC cracks as surface-type flaws rather than through-thickness cracks. Results showed contrary to popular opinion that surface-type flaws propagated less rapidly than through-thickness cracks in NNPHSCC environments. Also, inherent variations in the local environment under a disbondment produce hydrogen concentration gradients that result in very high propagation rates at the open mouth of a disbondment. The propagation rate declines very sharply non-linearly distance away from the open mouth inside the disbondment. It was determined the environmental factor used to account for the contribution of the environment to crack propagation, could be up to ten times higher at the open mouth compared to other locations under the disbondment. Identifying these issues helps to guide NNPHSCC modellers in selecting more appropriate growth rates for SCC programs. A series of propagation rate ranges under various environmental and mechanical loading conditions were determined. Contrary to popular opinions, increased CO2 concentration in groundwater decreased crack propagation rates by intensifying (environmental) crack tip blunting. This delayed crack re-initiation from a dormant state. Under benign loading conditions, this helps to reduce/stop iv crack growth by driving towards dormancy. Mechanically blunting a crack tip was found to produce the same effect. Hydrogen enhanced localized plasticity (also called hydrogen enhanced low temperature creep) was found to be responsible for this blunting effect. Means of manipulating the mechanical loading factors to produce this effect were identified.

Book Materials Characterization

Download or read book Materials Characterization written by Ramiro Pérez Campos and published by Springer. This book was released on 2015-04-27 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers novel research results for process and techniques of materials characterization for a wide range of materials. The authors provide a comprehensive overview of the aspects of structural and chemical characterization of these materials. The articles contained in this book covers state of the art and experimental techniques commonly used in modern materials characterization. The book includes theoretical models and numerous illustrations of structural and chemical characterization properties.

Book Stress Corrosion Cracking of Linepipe Steels in Near Neutral PH Environment

Download or read book Stress Corrosion Cracking of Linepipe Steels in Near Neutral PH Environment written by W. Zheng and published by . This book was released on 2000 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stress corrosion cracking (SCC), a form of environment-assisted cracking, has caused 24 major pipeline failures in the Canadian oil and gas pipeline system. The role of stress in the SCC of linepipe steels in near-neutral pH environment, as in other SCC systems, is complex. In this paper, the effects of stress on the development of both axial cracking and circumferential cracking are reviewed. The long-term beneficial effect of compressive stress introduced by hydrostatic testing is also discussed.

Book Advancement of Optical Methods and Fracture and Fatigue Volume 3

Download or read book Advancement of Optical Methods and Fracture and Fatigue Volume 3 written by Cosme Furlong and published by Springer Nature. This book was released on with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Quarterly Bulletin of the Canadian Mining Institute

Download or read book Quarterly Bulletin of the Canadian Mining Institute written by Canadian Institute of Mining, Metallurgy and Petroleum and published by . This book was released on 2005 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Stress Corrosion Cracking of Pipelines

Download or read book Stress Corrosion Cracking of Pipelines written by Y. Frank Cheng and published by John Wiley & Sons. This book was released on 2013-02-19 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explains why pipeline stress corrosion cracking happens and how it can be prevented Pipelines sit at the heart of the global economy. When they are in good working order, they deliver fuel to meet the ever-growing demand for energy around the world. When they fail due to stress corrosion cracking, they can wreak environmental havoc. This book skillfully explains the fundamental science and engineering of pipeline stress corrosion cracking based on the latest research findings and actual case histories. The author explains how and why pipelines fall prey to stress corrosion cracking and then offers tested and proven strategies for preventing, detecting, and monitoring it in order to prevent pipeline failure. Stress Corrosion Cracking of Pipelines begins with a brief introduction and then explores general principals of stress corrosion cracking, including two detailed case studies of pipeline failure. Next, the author covers: Near-neutral pH stress corrosion cracking of pipelines High pH stress corrosion cracking of pipelines Stress corrosion cracking of pipelines in acidic soil environments Stress corrosion cracking at pipeline welds Stress corrosion cracking of high-strength pipeline steels The final chapter is dedicated to effective management and mitigation of pipeline stress corrosion cracking. Throughout the book, the author develops a number of theoretical models and concepts based on advanced microscopic electrochemical measurements to help readers better understand the occurrence of stress corrosion cracking. By examining all aspects of pipeline stress corrosion cracking—the causes, mechanisms, and management strategies—this book enables engineers to construct better pipelines and then maintain and monitor them to ensure safe, reliable energy supplies for the world.

Book Stress Corrosion Cracking

Download or read book Stress Corrosion Cracking written by V S Raja and published by Elsevier. This book was released on 2011-09-22 with total page 817 pages. Available in PDF, EPUB and Kindle. Book excerpt: The problem of stress corrosion cracking (SCC), which causes sudden failure of metals and other materials subjected to stress in corrosive environment(s), has a significant impact on a number of sectors including the oil and gas industries and nuclear power production. Stress corrosion cracking reviews the fundamentals of the phenomenon as well as examining stress corrosion behaviour in specific materials and particular industries.The book is divided into four parts. Part one covers the mechanisms of SCC and hydrogen embrittlement, while the focus of part two is on methods of testing for SCC in metals. Chapters in part three each review the phenomenon with reference to a specific material, with a variety of metals, alloys and composites discussed, including steels, titanium alloys and polymer composites. In part four, the effect of SCC in various industries is examined, with chapters covering subjects such as aerospace engineering, nuclear reactors, utilities and pipelines.With its distinguished editors and international team of contributors, Stress corrosion cracking is an essential reference for engineers and designers working with metals, alloys and polymers, and will be an invaluable tool for any industries in which metallic components are exposed to tension, corrosive environments at ambient and high temperatures. - Examines the mechanisms of stress corrosion cracking (SCC) presenting recognising testing methods and materials resistant to SCC - Assesses the effect of SCC on particular metals featuring steel, stainless steel, nickel-based alloys, magnesium alloys, copper-based alloys and welds in steels - Reviews the monitoring and management of SCC and the affect of SCC in different industries such as petrochemical and aerospace

Book Stress Corrosion Cracking of X65 Pipeline Steel in Fuel Grade Ethanol Environments

Download or read book Stress Corrosion Cracking of X65 Pipeline Steel in Fuel Grade Ethanol Environments written by Lindsey R. Goodman and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, the demand for alternatives to fossil fuels has risen dramatically, and ethanol fuel has become an important liquid fuel alternative globally. The most efficient mode of transportation of petroleum-based fuel is via pipelines, and due to the 300% increase in ethanol use in the U.S. in the past decade, a similar method of conveyance must be adopted for ethanol. Low-carbon, low-alloy pipeline steels like X52, X60, and X65 comprise the existing fuel transmission pipeline infrastructure. However, similar carbon steels, used in the ethanol processing and production industry, were found to exhibit stress corrosion cracking (SCC) in ethanol service. Prior work has shown that contaminants absorbed by the ethanol during distillation, processing or transport could be the possible determinants of SCC susceptibility; 200 proof ethanol alone was shown not to cause SCC in laboratory studies. To ensure the safety and integrity of the pipeline system, it was necessary to perform a mechanistic study of SCC of pipeline steel in fuel grade ethanol (FGE).\r : The objective of this work was to determine the environmental factors relating to SCC of X65 steel in fuel grade ethanol (FGE) environments. To accomplish this, a systematic study was done to test effects of FGE feedstock and common contaminants and constituents such as water, chloride, dissolved oxygen, and organic acids on SCC behavior of an X65 pipeline steel. Slow strain rate tests (SSRT) were employed to evaluate and compare specific constituents' effects on crack density, morphology, and severity of SCC of X65 in FGE. SCC did not occur in commercial FGE environments, regardless of the ethanol feedstock. In both FGE and simulated fuel grade ethanol (SFGE), SCC of carbon steel was found to occur at low water contents (below 5 vol%) when chloride was present above a specific threshold quantity. Cl- threshold for SCC varied from 10ppm in FGE to approximately 1 ppm in SFGE. SCC of carbon steel was inhibited when oxygen was removed from solution via N2 purge or pHe was increased by addition of NaOH. During SSRT, in-situƠ electrochemical measurements showed a significant role of film rupture in the SCC mechanism. Analysis of repassivation kinetics in mechanical scratch tests revealed a large initial anodic dissolution current spike in SCC-causing environments, followed by repassivation indicated by current transient decay. In the deaerated environments, repassivation did not occur, while in alkaline SFGE repassivation was significantly more rapid than in SCC-inducing SFGE. Composition and morphology of the passive film on X65 during static exposure tests was studied using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Results showed stability of an air-formed native oxide under static immersion in neutral (pHe = 5.4) SFGE, and dissolution of the film when pHe was decreased to 4.3. XPS spectra indicated changes in film composition at high pHe (near 13) and in environments lacking sufficient water. In light of all results, a film-rupture anodic-dissolution mechanism is proposed in which local plastic strains facilitates local breakdown of the air-formed oxide film, causing iron to dissolve anodically. During crack propagation anodic dissolution occurs at the crack tip while crack walls repassivate preserving crack geometry and local stress concentration at the tip. It is also proposed that SCC can be mitigated by use of alkaline inhibitors that speed repassivation and promotes formation of a more protective Fe(OH)3 film.

Book Stress Corrosion Cracking Susceptibility of API X 52 Pipeline Steel in Aqueous Solutions

Download or read book Stress Corrosion Cracking Susceptibility of API X 52 Pipeline Steel in Aqueous Solutions written by Rahmat Safruddin and published by . This book was released on 1995 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Stress corrosion Cracking

Download or read book Stress corrosion Cracking written by Warren E. Berry and published by . This book was released on 1961 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Investigation of Corrosion and Crack Morphology Behavior Under Disbonded Coatings on Pipelines

Download or read book Investigation of Corrosion and Crack Morphology Behavior Under Disbonded Coatings on Pipelines written by Karina Chevil and published by . This book was released on 2015 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coating disbondment on pipelines is a common phenomenon that leads to exposure of the pipeline metal to the surrounding soil and ground water solutions. The exposure of pipelines to those corrosive environments is associated with development of corrosion and Stress Corrosion Cracking (SCC) on the pipeline steel. Despite the wide study of the electrochemical conditions underneath disbonded coatings, little information has been provided regarding the correlation between the coating disbondment gap size, the corrosion rate of the steel, and the SCC shallow crack morphology at the disbondment location. This research aims to understand the effect of the pipeline coating conditions on corrosion and near-neutral pH SCC of the underlying pipeline steel. The corrosion behavior and rate of pipeline steel under coating disbondment gaps of varying sizes was investigated through field data and experimental studies. The experimental studies were performed on X-65 pipeline steel coupons in anaerobic conditions, with various CO2 concentrations (2%, 5%, and 20% CO2), without Cathodic Protection (CP). The steel coupons were placed into a vertical coupon holder simulating a coating disbondment on a pipeline. The findings showed that a metal ion concentration cell may develop under narrower coating disbondments. In the analysis of the field data, dig reports provided by a Canadian gas transportation company were analyzed for cases of anaerobic corrosion under tape and asphalt coatings. The results obtained through field data analysis correlated with the experimental findings, suggesting that concentration cells under narrow coating disbondments may be responsible for enhanced corrosion on pipelines in the field. The effect of the coating disbondment gap size on the morphology of shallow cracks was analyzed in X-60 pipeline steel, in 5% CO2 under triangular tensile loading under coating disbondment gaps of various sizes. The results showed that the coating disbondment gap size affects the morphology of the shallow cracks under the disbondment.

Book Stress Corrosion Cracking

Download or read book Stress Corrosion Cracking written by G. M. Ugiansky and published by ASTM International. This book was released on 1979 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: