scholarly journals Corrosion Resistance of Steel Pipelines under Various Thermal Insulation Materials

2021 ◽  
Vol 2(50) ◽  
Author(s):  
Anatoly Zemlyanko ◽  
◽  
Vyacheslav Semenov ◽  
Aleksey Zhukov ◽  
Elena Shuvalova ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Open Porosity ◽  
Residual Life ◽  
Experimental Studies ◽  
Corrosion Damage ◽  
Corrosion Process ◽  
Water Soluble ◽  
Insulating Materials ◽  
Remaining Service Life ◽  
Insulation Systems

The durability of insulation systems for pipelines is determined by the operational resistance of the pipeline material and the design of the insulation system. The issue of studying the corrosion processes of steel pipelines under various heat-insulating materials is relevant. The aim of the work was to study the process of corrosion of steel pipelines under insulating materials of vari-ous nature and porosity. The object of research is pipeline insulation systems. The subject of research is the corrosion processes in various insulation systems. This goal was achieved by car-rying out a set of experimental studies aimed at studying the rate of the corrosion process of the metal of the pipeline, insulated with various materials, with the subsequent calculation of the remaining service life of the pipeline. The most significant results are: the dependence of the corrosion rate and the area of damage of carbon steel on the structure (porosity) of the heat-insulating material, the residual number of ions of water-soluble chlorides. It was found that the maximum corrosion rate of steel under materials with open porosity is 0.29-0.41 mm/year. The increase in the rate of the corrosion process is directly proportional to the increase in the number of chlorine anions in the structure of the material. The smallest area of corrosion damage to the steel surface is observed under materials with open porosity. The significance of the results ob-tained consists in determining the residual life of the pipeline under a heat-insulating layer of various materials.

scholarly journals In-situ study of the corrosion process of biodegradable magnesium alloys

2021 ◽  
pp. 18-25
Author(s):  
P. N. Myagkikh ◽  
◽  
E. D. Merson ◽  
V. A. Poluyanov ◽  
D. L. Merson ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Magnesium Alloys ◽  
Human Body ◽  
Corrosion Damage ◽  
Az31 Alloy ◽  
Corrosion Process ◽  
Ex Situ ◽  
Zk60 Alloy ◽  
In Situ Methods

The interest in magnesium and its alloys considerably increases in recent years. These materials have a unique complex of properties: light-weight and strength make magnesium alloys promising structural materials for the aircraft industry and space application, and ability to reabsorb in vivo conditions and good biocompatibility allow producing biodegradable surgical implants of magnesium alloys, which can resorb in a human body without detriment to health. The materials for such demanding applications require detailed investigation of their properties, such as corrosion, including the kinetics of corrosion rate and staging of corrosion damage on the surface. To obtain a full view of the corrosion process, in addition to common ex-situ methods such as the corrosion rate evaluating using the weight loss method and the morphology corrosion damage investigation by optical or confocal laser scanning microscopy (CLSM), it is important to use modern in-situ methods. In-situ methods allow obtaining data immediately during the experiment and not after its completion. The authors carried out a comprehensive study of the corrosion process of the commercial ZK60 and AZ31 magnesium alloys in the simulated human-body environment (temperature, corrosion media composition, circulation of corrosion media) using in-situ methods, including hydrogen evolution corrosion rate evaluating and video-observation of a sample surface. The results show that AZ31 alloy is more corrosion-resistant than ZK60 alloy. Moreover, AZ31 alloy is prone to filiform surface corrosion, and ZK60 alloy exhibits severe pitting corrosion. Based on the comparison of the data obtained by in-situ and ex-situ methods, the authors concluded on their main differences and features.

scholarly journals Degradation Monitoring in Reinforced Concrete with 3D Localization of Rebar Corrosion and Related Concrete Cracking

2021 ◽  
Vol 11 (15) ◽  
pp. 6772
Author(s):  
Charlotte Van Steen ◽  
Els Verstrynge
Keyword(s):  
Reinforced Concrete ◽  
Degradation Mechanism ◽  
Heterogeneous Material ◽  
Corrosion Damage ◽  
Corrosion Process ◽  
Internal Damage ◽  
Rc Structures ◽  
Degradation Monitoring ◽  
Rebar Corrosion ◽  
Width Measurements

Corrosion of the reinforcement is a major degradation mechanism affecting durability and safety of reinforced concrete (RC) structures. As the corrosion process starts internally, it can take years before visual damage can be noticed on the surface, resulting in an overall degraded condition and leading to large financial costs for maintenance and repair. The acoustic emission (AE) technique enables the continuous monitoring of the progress of internal cracking in a non-invasive way. However, as RC is a heterogeneous material, reliable damage detection and localization remains challenging. This paper presents extensive experimental research aiming at localizing internal damage in RC during the corrosion process. Results of corrosion damage monitoring with AE are presented and validated on three sample scales: small mortar samples (scale 1), RC prisms (scale 2), and RC beams (scale 3). For each scale, the corrosion process was accelerated by imposing a direct current. It is found that the AE technique can detect damage earlier than visual inspection. However, dedicated filtering is necessary to reliably localize AE events. Therefore, AE signals were filtered by a newly developed post-processing protocol which significantly improves the localization results. On the smallest scale, results were confirmed with 3D micro-CT imaging, whereas on scales 2 and 3, results were compared with surface crack width measurements and resulting rebar corrosion levels.

scholarly journals Biodegradable Iron-Based Materials—What Was Done and What More Can Be Done?

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3381
Author(s):  
Gabriela Gąsior ◽  
Jonasz Szczepański ◽  
Aleksandra Radtke
Keyword(s):  
Corrosion Rate ◽  
Iron Metabolism ◽  
Elastic Moduli ◽  
High Strength ◽  
Corrosion Process ◽  
Basic Data ◽  
Metal Stents ◽  
Biodegradable Metal ◽  
Iron Based

Iron, while attracting less attention than magnesium and zinc, is still one of the best candidates for biodegradable metal stents thanks its biocompatibility, great elastic moduli and high strength. Due to the low corrosion rate, and thus slow biodegradation, iron stents have still not been put into use. While these problems have still not been fully resolved, many studies have been published that propose different approaches to the issues. This brief overview report summarises the latest developments in the field of biodegradable iron-based stents and presents some techniques that can accelerate their biocorrosion rate. Basic data related to iron metabolism and its biocompatibility, the mechanism of the corrosion process, as well as a critical look at the rate of degradation of iron-based systems obtained by several different methods are included. All this illustrates as the title says, what was done within the topic of biodegradable iron-based materials and what more can be done.

Accurate Thickness Inversion of Corrosion Using A1 Lamb Wave

2021 ◽  
Author(s):  
Min Lin ◽  
Yang Liu
Keyword(s):  
High Resolution ◽  
Oil And Gas ◽  
Residual Life ◽  
Early Stage ◽  
Corrosion Damage ◽  
Oil And Gas Industry ◽  
Forward Modeling ◽  
Guided Wave ◽  
Velocity Inversion ◽  
Wave Tomography

Abstract Corrosion is one of the most critical issues in the oil and gas industry, leading to severe environmental and economic problems. Due to the high cost and serious safety risk of corrosion, it is essential to improve current corrosion testing techniques to detect corrosion damages at an early stage. Guided wave tomography (GWT) demonstrates its great potential to inspect and quantify the corrosion damage. GWT is capable of determining the residual life of corrosion structures by quantifying the remaining wall thickness. In this paper, an accurate guided wave tomography technique incorporating full waveform inversion (FWI) and higher-order Lamb waves (A1 mode) is presented for plate-like structures, which is able to get high-resolution reconstruction results. The technique consists of three steps: forward modeling, velocity inversion and thickness reconstruction. The forward modeling is computed by solving the elastic full-wave equations in 2-D time domain by using the finite difference method. High-resolution phase velocity inversion can then be obtained by minimizing the waveform misfit function between simulated and recorded data using a second order optimization method, which updates the velocity model from low to high frequencies iteratively. Finally, the velocity variations can be transformed into depth profiles by using the dispersive characteristics of ultrasonic guided waves; therefore, the thickness reconstruction can be obtained. The numerical simulations are performed on an aluminum plate with a complicated corrosion defect. By comparing the thickness reconstruction maps using both A1 and A0 modes, the results demonstrate that FWI with A1 mode can achieve significantly better resolution of corrosion imaging than that with A0 mode.

scholarly journals TWO-STEP CROSSLINKING OF PVP/GEL NANOFIBERS

2021 ◽  
Vol 2021 ◽  
pp. 164-170
Author(s):  
H.K. Güler ◽  
F.C. Çallıoğlu
Keyword(s):  
Fiber Diameter ◽  
Experimental Studies ◽  
Water Soluble ◽  
Diameter Distribution ◽  
Sem Images ◽  
Crosslinking Process ◽  
Different Temperatures ◽  
Ft Ir ◽  
Ir Analysis ◽  
Gel Polymers

In this study, it was achieved that crosslinking of PVP/GEL nanofibers with two-steps. Crosslinking is a process highly important for water-soluble polymers in terms of application areas and mechanical properties. Firstly, crosslinking of PVP polymers experimental studies were carried out via heat treatment at different temperatures and times. Then, GEL polymers were crosslinked with GTA vapour at different times. Morphological analysis was carried out via SEM images and chemical characteristics were determined via FT-IR analysis. Moreover, after the crosslinking process, SD and WL values were calculated. All results showed that before crosslinking of SEM images, nanofibers were smooth, fine and without beads. The average fiber diameter is 196 nm and the fiber diameter distribution is quite uniform. After crosslinking of SEM images, it is expected that all nanowebs will turn from fibrous surfaces to membranous. Generally, SD and WL values decrease with crosslinking time increase. According to all of the SEM images, SD and WL values, optimum conditions were determined for PVP as 4 hours at 180oC and for GEL as 24 hours. Lastly, the presence of PVP and GEL polymers in the nanofiber structure was verified chemically with FT-IR analysis.

scholarly journals Investigation of the structure of cement conglomerates

2021 ◽  
Vol 266 ◽  
pp. 03005
Author(s):  
D. N. Shabanov ◽  
E. Trambitsky ◽  
E. Borovkova
Keyword(s):  
Strain State ◽  
Residual Life ◽  
Experimental Studies ◽  
Cement Stone ◽  
Virtual Model ◽  
Structural Studies ◽  
Acoustic Sensors ◽  
Cement Pastes ◽  
The Moment ◽  
Physical And Chemical

This article describes the structural studies of a cement conglomerate, its evolution from the moment of formation to the loss of operational properties. Physical and chemical phenomena and interactions of various elements of cement stone are considered. The study of its rheology includes creating a virtual model and monitoring the formation of the structure of cement pastes by acoustic emission (AE). The results of combined experimental studies to determine the residual life of cement stone samples using AE and tensometry methods are presented. The authors created a complex for monitoring the stress-strain state of artificial conglomerates, which includes both internal and acoustic sensors.

scholarly journals Evaluation of possible corrosion enhancement due to telluric currents: case study of the Bolivia–Brazil pipeline

2020 ◽  
Vol 38 (4) ◽  
pp. 881-888
Author(s):  
Joyrles Fernandes de Moraes ◽  
Igo Paulino ◽  
Lívia R. Alves ◽  
Clezio Marcos Denardini
Keyword(s):  
Corrosion Rate ◽  
Space Weather ◽  
Geomagnetic Storms ◽  
Corrosion Process ◽  
Fluxgate Magnetometer ◽  
Weather Events ◽  
Source Line ◽  
Geomagnetic Data ◽  
Telluric Currents

Abstract. The electric field induced in the Bolivia–Brazil gas pipeline (GASBOL) was calculated by using the distributed source line transmission (DSLT) theory during several space weather events. We used geomagnetic data collected by a fluxgate magnetometer located at São José dos Campos (23.2∘ S, 45.9∘ W). The total corrosion rate was calculated by using the Gummow (2002) methodology and was based on the assumption of a 1 cm hole in the coating of the pipeline. The calculations were performed at the ends of pipeline where the largest “out-of-phase” pipe-to-soil potential (PSP) variations were obtained. The variations in PSP during the 17 March 2015 geomagnetic storm have led to the greatest corrosion rate of the analyzed events. All the space weather events evaluated with high terminating impedance may have contributed to increases in the corrosion process. The applied technique can be used to evaluate the corrosion rate due to the high telluric activity associated with the geomagnetic storms at specific locations.

scholarly journals Research of Supporting Ability and Prediction of Residual Life of Casing Pipes at General Corrosion Damage of Inner Surface

2021 ◽  
Vol 225 ◽  
pp. 02002
Author(s):  
Natalia Fedorova ◽  
Yulianna Dimitriadi ◽  
Nikita Ryapolov
Keyword(s):  
Residual Life ◽  
Corrosion Damage ◽  
General Corrosion ◽  
Corrosion Depth ◽  
Inner Pressure ◽  
Nominal Thickness ◽  
Inner Surface ◽  
To Receive

The detection and the measuring of the developing damages must be accompanied by evaluation of the supporting ability of the design in terms of the increasing size of a defect. If the type of damage is dominant one on the further period of the operation, so the received functional dependences can be used to predict a residual life of the designs. As illustrated by the casing pipes of 168.3 mm diameter, where the dominant damage is the general corrosion of the inner surface, the algorithm to receive the expression for the calculation of coefficients of the lowering of the supporting ability to the excessive inner pressure in the function of the nominal thickness of pipes wall and corrosion depth is shown. The algorithm of the application of the received expression to calculate the residual life of the damaged casing pipes is given.

Corrosion of pipe steels 20 and 17G1S-U in ground electrolytes with a hydrogen indicator close to neutral

2021 ◽  
Vol 1 (108) ◽  
pp. 16-23
Author(s):  
M. Polutrenko ◽  
P. Maruschak ◽  
A. Babii ◽  
O. Prentkovskis
Keyword(s):  
Corrosion Rate ◽  
Protective Effect ◽  
Residual Life ◽  
Aggressive Medium ◽  
Borate Buffer ◽  
Soil Conditions ◽  
Process Conditions ◽  
Pipe Steels ◽  
Gas Pipelines ◽  
Protective Properties

Purpose: of this paper is to analyse the mechanism of near-neutral pH corrosion of main gas pipelines. The stages of main gas pipelines in model environments that meet the soil conditions of Ukraine have been studied. Design/methodology/approach: The corrosion rate of steel specimens from steels 17G1S-U and 20 and the influence of borate buffers on their protective properties were evaluated. The influence of corrosion time on changes in pH of model media is shown. Morphological features of surface damages of pipe steels are established. The defect analysis of specimens from steels 17G1S-U and 20 by electron scanning microscopy is carried out. Findings: The effect of borate buffers on the protective properties of the steel grades studied was revealed, and changes in the pH of the model media during corrosion processes were described. The main regularities in corrosion, as well as the surface morphology of damaged specimens, were studied by scanning electron microscopy. Research limitations/implications: Detailed investigation of localised corrosion phenomena induced by inclusions that are present in steels 17G1S-U and 20 is extremely critical. In particular, there is still ambiguity as to whether the localised corrosion initiation induced by non-metallic inclusions is an electrochemical process or a chemical process. Practical implications: The research findings will be used when testing specimens from pipe steels under cyclic loading in the model media studied, as well as for predicting the residual life of gas pipelines with corrosion defects. Their generalization will make it possible to develop the effective methods of ground diagnostics and prediction of SCC of main pipelines. Originality/value: It was found that the corrosion rate is determined by internal (nature and properties of the metal) and external (properties of the aggressive medium and the corrosion process conditions) factors. The protective effect for steel 17G1S in medium NS4 + borate buffer (1: 1) was 61.5%. Steel 20 had the greatest protective effect in medium NS4 + borate buffer (1: 3), which was 87.05%.

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