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Picture for Experimental Study and Finite Element Modelling of the Cathodic Protection Influence on Parallel Pipelines During Maintenance Operations
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Experimental Study and Finite Element Modelling of the Cathodic Protection Influence on Parallel Pipelines During Maintenance Operations

Product Number: 51324-20713-SG
Author: Erwan Diler; Yves Zannier; Alexandre Billot; Flavien Vucko; Tiphaine Lutzler
Publication Date: 2024
$40.00
Dense buried pipelines network, such as in implemented in parallel, can be installed in different process and storage mills, such as geological gas and hydrocarbon storages. Their corrosion resistance is ensured by a combination of organic coating and cathodic protection (CP). For maintenance operation on a specific pipeline, the CP can be turned off for safety reasons. Thus, the operated pipeline can be affected by CP influence from other surrounding protected ones. This phenomenon is supported in the field by different pigging inspections, highlighting local corrosion induced by output stray current on coating defects. In the literature, many studies focused on CP influences by finite and/or boundary element modeling. However, usually the foreign structures considered (under influence) are limited to bare steel or fully coated pipeline. Moreover, most of these studies are not confronted with experimental works. To our knowledge, the actual influence between the different pipelines is not much documented in the literature and not quantified. In this study, an experiment consisting in 3.00 x 1.80 x 0.80 m sand tank, equipped with 4 full scale parallel pipelines, with 17 model defects were realized. The model defects reproduce uniformly degraded coating and local defects. The experimental work allows i) measuring the DC influence under different CP configurations, and ii) providing stray current data for finite element modelling (FEM). The FEM was performed in a two steps i) a CP distribution in terms of current demand and electric field on protected pipelines, and ii) application of this electric field to the foreign pipeline. The good agreement obtained allows a validation the proposed approach and globally assess the riskier scenario in terms of nature of the defect, applied CP and soil environment.
Picture for Field Data Collection for Cathodic Protection and Hydrogen Embrittlement of Super Duplex Stainless Steel for Deep Sea Application - Use of Low Voltage Anode
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Field Data Collection for Cathodic Protection and Hydrogen Embrittlement of Super Duplex Stainless Steel for Deep Sea Application - Use of Low Voltage Anode

Product Number: 51324-20693-SG
Author: Nicolas Larché; Jean Vittonato; Anne-Marie Grolleau; Erwan Diler; Dominique Festy
Publication Date: 2024
$40.00
Picture for Forensic Evaluation of Long-Term Galvanic Cathodic Protection of Bridge Pilings in a Marine Environment
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Forensic Evaluation of Long-Term Galvanic Cathodic Protection of Bridge Pilings in a Marine Environment

Product Number: 51320-14485-SG
Author: Douglas L. Leng, Matthew Duncan, Ivan R. Lasa
Publication Date: 2020
$20.00
Picture for High-strength Nickel Low Alloy Steels for Oil and Gas Equipment: ASTM A508 Grade 4N under cathodic protection and simulated sour environments.
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High-strength Nickel Low Alloy Steels for Oil and Gas Equipment: ASTM A508 Grade 4N under cathodic protection and simulated sour environments.

Product Number: 51320-14706-SG
Author: Andreas Viereckl, Esteban Rodoni, Zakaria Quadir, Garry Leadbeater and Mariano Iannuzzi, Yuta Honma
Publication Date: 2020
$20.00

Low alloy steels (LASs) combine relatively low cost with exceptional mechanical properties, making LASs commonplace in Oil and Gas equipment. However, the strength and hardness of LASs for sour environments and for applications that generate atomic hydrogen at the surface, e.g., cathodic protection, is limited to prevent different forms of hydrogen embrittlement (HE) such as hydrogen stress cracking (HSC) and sulfide stress cracking (SSC). As a result, the specified minimum yield strength (SMYS) of forged LASs for, e.g., subsea components, rarely exceeds 550 MPa (80 ksi), while the most common pipeline steels are API(1) X65 to X70, with a SMYS of 450 MPa (65 ksi) and 482 MPa (70 ksi), respectively. Moreover, ISO(2) 15156-2 restricts LASs to a maximum of 1.0 wt% Ni due to SSC concerns. The LASs that exceed the ISO 15156-2 limit have to be qualified for service, lowering their commercial appeal.  

In this work, the HSC resistance of the high-nickel (3.41 wt%), quenched and tempered (Q&T), nuclear-grade ASTM(3) A508 Gr.4N LAS was investigated using slow strain rate testing (SSRT) as a function of applied cathodic potential. Results showed that the yield strength (YS) and ultimate tensile strength (UTS) were unaffected by hydrogen, even at a high negative potential of -2.0 VAg/AgCl. HE effects were observed once the material started necking, manifested by a loss in ductility with increasing applied cathodic potentials. Indeed, A508 Gr.4N was less affected by H at high cathodic potentials than a low-strength (YS = 340 MPa) ferritic-pearlitic LAS of similar nickel content. SSRT results were linked to microstructure features, which were characterized by light optical microscopy (LOM), scanning electron microscopy (SEM) coupled to electron backscatter diffraction (EBSD).