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Book Crack Growth Behavior of Pipeline Steels in Near neutral PH Environment

Download or read book Crack Growth Behavior of Pipeline Steels in Near neutral PH Environment written by Mohammad Hassan Marvasti and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Crack Growth Behavior of Pipeline Steels Under Variable Pressure Fluctuations in a Near neutral PH Environment

Download or read book Crack Growth Behavior of Pipeline Steels Under Variable Pressure Fluctuations in a Near neutral PH Environment written by Mengshan Yu and published by . This book was released on 2015 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research aims at understanding the crack propagation behavior of pipeline steels under variable pressure fluctuations in a near-neutral pH environment. Although pressure fluctuations have been recognized as the driving force for crack growth for more than two decades, the mechanisms governing their effects on crack growth have yet to be determined. Existing crack growth models that consider the effect of pressure fluctuations are established primarily by assuming a fatigue loading with constant stress amplitudes. This often yields a predicted life that well exceeds the service lifetime observed in the field. We believe that the significant discrepancies between laboratory findings and field observations could be bridged by modeling crack growth through a consideration of variable amplitude fatigue loadings, which are the conditions in the field. This investigation has focused on the evaluation of a variable amplitude fatigue waveform consisting of cycles with higher R ratios (minimum stress/maximum stress), termed as minor cycles, and periodic underload cycles with lower R ratios. Such a waveform is typical for the pressure fluctuations in pipeline discharge sections, which was performed both in air and in near-neutral pH solution. Compared with the corresponding constant amplitude loadings, the variable amplitude waveform significantly enhanced fatigue crack growth. The waveform was varied to study the effects of various contributing factors, including loading frequency, maximum stress intensity factor, number of minor cycles, and amplitudes of underload and minor cycles. By comparing results in near-neutral pH solution with that in air, the role of hydrogen and corrosion in crack growth was characterized and clearly defined. The obtained results agree with various failure scenarios found in the field, including the high frequency of failures found at the discharge sections of pipelines, and the different crack growth characteristics between oil pipelines and gas pipelines. Based on these findings, practical strategies were proposed for avoiding accelerated crack growth.

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 Trends in Oil and Gas Corrosion Research and Technologies

Download or read book Trends in Oil and Gas Corrosion Research and Technologies written by A. M. El-Sherik and published by Woodhead Publishing. This book was released on 2017-06-09 with total page 928 pages. Available in PDF, EPUB and Kindle. Book excerpt: Trends in Oil and Gas Corrosion Research and Technologies: Production and Transmission delivers the most up-to-date and highly multidisciplinary reference available to identify emerging developments, fundamental mechanisms and the technologies necessary in one unified source. Starting with a brief explanation on corrosion management that also addresses today's most challenging issues for oil and gas production and transmission operations, the book dives into the latest advances in microbiology-influenced corrosion and other corrosion threats, such as stress corrosion cracking and hydrogen damage just to name a few. In addition, it covers testing and monitoring techniques, such as molecular microbiology and online monitoring for surface and subsurface facilities, mitigation tools, including coatings, nano-packaged biocides, modeling and prediction, cathodic protection and new steels and non-metallics. Rounding out with an extensive glossary and list of abbreviations, the book equips upstream and midstream corrosion professionals in the oil and gas industry with the most advanced collection of topics and solutions to responsibly help solve today's oil and gas corrosion challenges. - Covers the latest in corrosion mitigation techniques, such as corrosion inhibitors, biocides, non-metallics, coatings, and modeling and prediction - Solves knowledge gaps with the most current technology and discoveries on specific corrosion mechanisms, highlighting where future research and industry efforts should be concentrated - Achieves practical and balanced understanding with a full spectrum of subjects presented from multiple academic and world-renowned contributors in the industry

Book Effects of the Environment on the Initiation of Crack Growth

Download or read book Effects of the Environment on the Initiation of Crack Growth written by William Alan Van der Sluys and published by ASTM International. This book was released on 1997 with total page 304 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 Fatigue Crack Growth Rates in Pipeline Steels Using Curved M T Specimens

Download or read book Fatigue Crack Growth Rates in Pipeline Steels Using Curved M T Specimens written by Ph. P. Darcis and published by . This book was released on 2009 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study presents fatigue data for two different ferrite-pearlite pipeline steels. A fatigue crack growth test for full-thickness curved pipeline samples was developed using a middle tension (M(T)) specimen. Also, finite element analyses (FEAs) were carried out to show the M(T) curvature effects on the fatigue crack growth results. The two steels showed similar fatigue crack growth rate (da/dN) behavior. However, the ferrite-pearlite steel without banding had slightly better fatigue properties than the ferrite-pearlite banded steel. Uncertainty in the fatigue crack growth rates was analyzed by attributing all the fatigue scatter to the Paris law parameter C. The FEA based simulations, based on curved geometries, of the compliance relationship more accurately predicted both fatigue crack growth data and true crack lengths. Nevertheless, the ASTM E647-05 compliance relationship accurately predicted the crack length for the M(T) geometry, although its use leads to slightly conservative fatigue crack growth trends and a slight overestimation of the true final crack length.

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 2013-02-13 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 Comparison of Environmentally influenced Near threshold Fatigue crack growth Behavior in High and Lower strength Steels at Conventional Frequencies

Download or read book Comparison of Environmentally influenced Near threshold Fatigue crack growth Behavior in High and Lower strength Steels at Conventional Frequencies written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent studies in a wide variety of steels, of yield strengths ranging from 290 to 1740 MPa, have indicated that environmental influences on corrosion fatigue crack propagation at near-threshold levels (growth rates below approx. 10/sup -6/ mm/cycle), may be markedly different from those at higher growth rates. In this paper, the effect of such environments, specifically dry gaseous hydrogen and moist room air, on near-threshold cyclic crack growth is reviewed and comparisons made between behavior in high and lower strength steels. It is shown that, in lower strength steels (yield strength less than or equal to 700 MPa), near-threshold growth rates in dry hydrogen exceed those in moist air by up to two orders of magnitude at low load ratios only, whereas for steels of strength levels above approx. 700 MPa, the presence of hydrogen results in lower near-threshold growth rates compared to moist air regardless of load ratio. Such behavior is rationalized in terms of the competing effects of hydrogen embrittlement and oxide-induced crack closure mechanisms.

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.