Influence of structural relaxation and partial devitrification on the corrosion resistance of Fe78B13Si9 amorphous alloy

International Nuclear Information System (INIS)

Souza, C.A.C.; Politi, F.S.; Kiminami, C.S.

1998-01-01

Amorphous alloys obtained by rapid solidification from the melt exhibit a similar structure to those observed in the liquid state, i.e., without long range ordering, in such a way that the constituents of the alloy usually are randomly and homogeneously distributed. Amorphous alloys, depending on their composition, may exhibit interesting characteristics such as very soft magnetic properties and improved resistance to corrosion. The high corrosion resistance of these alloys is attributed mainly to a higher rate of dissolution of passivating elements in the amorphous state. In addition, amorphous alloys are chemically homogeneous and free of defects such as grain boundaries, precipitates and segregation, which are favorable sites for corrosion. The corrosion resistance of amorphous alloys also depends on their thermal history. Several authors have reported that structural changes, such as structural relaxation and devitrification caused by annealing, change significantly the corrosion properties of these alloys. The purpose of this paper is to study corrosion resistance of the amorphous FeBSi alloy and the effects of structural changes such as structural relaxation and partial crystallization caused by annealing

Water chemistry: cause and control of corrosion degradation in nuclear power plants

International Nuclear Information System (INIS)

Kain, Vivekanand

2008-01-01

The corrosion degradation of a material is directly determined by the water chemistry, material (composition, fabrication procedure and microstructure) and by the stress/strain in the material under operating conditions. Water chemistry plays an important role in both uniform corrosion and localized forms of corrosion of materials. Once we understand how water chemistry is contributing to corrosion of a material, it is logical to modify/change that water chemistry to control the corrosion degradation. In nuclear power plants, different water chemistries have been used in different components/systems. This paper will cover the origin of corrosion degradation in the Primary Heat Transport system of different reactor types, Steam Generator tubing, secondary circuit pipelines, service water pipelines and auxiliary systems and establish the role of water chemistry in causing corrosion degradation. The history of changes in water chemistry adopted in these systems to control corrosion degradation is also described. It is shown by examples that there is an obvious limitation in changing water chemistry to control corrosion degradation and in those cases, a change of material or change of the state of stresses/fabrication procedure becomes necessary. The role of water chemistry as a causative factor and also as a controlling parameter on particular types of corrosion degradation e.g. stress corrosion cracking, flow accelerated corrosion, pitting, crevice corrosion is illustrated. It will be shown that increase in dissolved oxygen content (due to radiolysis in nuclear reactors) is sufficient to make even the de-mineralized water to cause stress corrosion cracking in Boiling Water Reactors. Hydrogen Water Chemistry (by hydrogen injection) to control dissolved oxygen is shown to control the stress corrosion cracking. However, it is not possible to control dissolved oxygen at all parts of the Boiling Water Reactors. Therefore, a further refinement in terms of noble metal

Management of Reinforcement Corrosion

DEFF Research Database (Denmark)

Küter, André; Geiker, Mette Rica; Møller, Per

Reinforcement corrosion is the most important cause for deterioration of reinforced concrete structures, both with regard to costs and consequences. Thermodynamically consistent descriptions of corrosion mechanisms are expected to allow the development of innovative concepts for the management...... of reinforcement corrosion....

Image-based corrosion recognition for ship steel structures

Science.gov (United States)

Ma, Yucong; Yang, Yang; Yao, Yuan; Li, Shengyuan; Zhao, Xuefeng

2018-03-01

Ship structures are subjected to corrosion inevitably in service. Existed image-based methods are influenced by the noises in images because they recognize corrosion by extracting features. In this paper, a novel method of image-based corrosion recognition for ship steel structures is proposed. The method utilizes convolutional neural networks (CNN) and will not be affected by noises in images. A CNN used to recognize corrosion was designed through fine-turning an existing CNN architecture and trained by datasets built using lots of images. Combining the trained CNN classifier with a sliding window technique, the corrosion zone in an image can be recognized.

Corrosion of structural materials and electrochemistry in high temperature water of nuclear power systems

International Nuclear Information System (INIS)

Uchida, Shunsuke

2008-01-01

The latest experiences with corrosion in the cooling systems of nuclear power plants are reviewed. High temperature cooling water causes corrosion of structural materials, which often leads to adverse effects in the plants, e.g., increased shutdown radiation, generation of defects in materials of major components and fuel claddings, and increased volume of radwaste sources. Corrosion behavior is greatly affected by water quality and differs according to the water quality values and the materials themselves. In order to establish reliable operation, each plant requires its own unique optimal water chemistry control based on careful consideration of its system, materials and operational history. Electrochemistry is one of the key issues that determine corrosion-related problems, but it is not the only issue. Most corrosion-related phenomena, e.g., flow accelerated corrosion (FAC), intergranular stress corrosion cracking (IGSCC), primary water stress corrosion cracking (PWSCC) and thinning of fuel cladding materials, can be understood based on an electrochemical index, e.g., the electrochemical corrosion potential (ECP), conductivities and pH. The most important electrochemical index, the ECP, can be measured at elevated temperature and applied to in situ sensors of corrosion conditions to detect anomalous conditions of structural materials at their very early stages. (orig.)

Corrosion of Carbon Steel and Corrosion-Resistant Rebars in Concrete Structures Under Chloride Ion Attack

Science.gov (United States)

Mohamed, Nedal; Boulfiza, Mohamed; Evitts, Richard

2013-03-01

Corrosion of reinforced concrete is the most challenging durability problem that threatens reinforced concrete structures, especially structures that are subject to severe environmental conditions (i.e., highway bridges, marine structures, etc.). Corrosion of reinforcing steel leads to cracking and spalling of the concrete cover and billions of dollars are spent every year on repairing such damaged structures. New types of reinforcements have been developed to avoid these high-cost repairs. Thus, it is important to study the corrosion behavior of these new types of reinforcements and compare them to the traditional carbon steel reinforcements. This study aimed at characterizing the corrosion behavior of three competing reinforcing steels; conventional carbon steel, micro-composite steel (MMFX-2) and 316LN stainless steel, through experiments in carbonated and non-carbonated concrete exposed to chloride-laden environments. Synthetic pore water solutions have been used to simulate both cases of sound and carbonated concrete under chloride ions attack. A three-electrode corrosion cell is used for determining the corrosion characteristics and rates. Multiple electrochemical techniques were applied using a Gamry PC4™ potentiostat manufactured by Gamry Instruments (Warminster, PA). DC corrosion measurements were applied on samples subjected to fixed chloride concentration in the solution.

Corrosion of structural materials and electrochemistry in high temperature water of nuclear power systems

International Nuclear Information System (INIS)

Uchida, Shunsuke

2014-01-01

The latest experiences with corrosion in the cooling systems of nuclear power plants are reviewed. High temperature cooling water causes corrosion of structural materials, which often leads to adverse effects in the plants, e.g., generating defects in materials of major components and fuel claddings, increasing shutdown radiation and increasing the volume of radwaste sources. Corrosion behaviors are much affected by water qualities and differ according to the values of water qualities and the materials themselves. In order to establish reliable operation, each plant requires its own unique optimal water chemistry control based on careful consideration of its system, materials and operational history. Electrochemistry is one of key issues that determine corrosion related problems but it is not the only issue. Most phenomena for corrosion related problems, e.g., flow-accelerated corrosion (FAC), intergranular stress corrosion cracking (IGSCC), primary water stress corrosion cracking (PWSCC) and thinning of fuel cladding materials, can be understood based on an electrochemical index, e.g., electrochemical corrosion potential (ECP), conductivities and pH. The most important electrochemical index, ECP, can be measured at elevated temperature and applied to in situ sensors of corrosion conditions to detect anomalous conditions of structural materials at their very early stages. In the paper, theoretical models based on electrochemistry to estimate wall thinning rate of carbon steel piping due to flow-accelerated corrosion and corrosive conditions determining IGSCC crack initiation and growth rate are introduced. (author)

The anti corrosive design of structural metallic elements in buildings with large exploitation period

International Nuclear Information System (INIS)

Avila Ayon, V.; Rodriguez Quesada, A. L.

2009-01-01

The corrosion deterioration in metallic structural elements, with the consistent loss of his physical and mechanical properties, is cause by errors in the design or fabrication, that allows the accumulation of humidity and contaminants in the surfaces, or acceleration zones of the corrosion processes, as the bimetalics pairs. The aggressiveness of the environment and the productive processes that develop in industrial installations, causes the apparition of premature failures that engage the edification use. The identification of design errors is the first step in the conservation of these structures. the elimination and made a project adapted to the proper installations conditions, is essential procedures to prolong the edification useful life with an optimum and rational use of the resources that destined for this end. The investigation is about the results obtained in the diagnostic and the conservation of industrial installment, with large exploitation periods, in which existed evidences of failures by corrosion, specifically to the elimination of errors of design. (Author) 12 refs

The effect of corrosion on the structural reliability of steel offshore structures

International Nuclear Information System (INIS)

Melchers, Robert E.

2005-01-01

This paper considers essential theoretical concepts and data requirements for engineering structural reliability assessment suitable for the estimation of the safety and reliability of corroding ships, offshore structures and pipelines. Such infrastructure operates in a harsh environment. Allowance must be made for structural deterioration since protective measures such as paint coatings, galvanizing or cathodic protection may be ineffective. Reliability analysis requires accurate engineering models for the description and prediction of material corrosion loss and for the maximum depth of pitting. New probability-based models for both these forms of corrosion have been proposed recently and calibrated against a wide range of data. The effects of water velocity and of water pollution are reviewed and compared with recently reported field data for a corrosion at an offshore oil platform. The data interpreted according to the model show good correlation when allowance is made for the season of first immersion and the adverse effects of seawater velocity and of water pollution. An example is given to illustrate the application of reliability analysis to a pipeline subject to pitting corrosion. An important outcome is that good quality estimation of the longer-term probability of loss of structural integrity requires good modelling of the longer-term corrosion behaviour. This is usually associated with anaerobic corrosion. As a result, it cannot be extrapolated from data for short-term corrosion as this is associated with aerobic corrosion conditions

The effect of corrosion on the structural reliability of steel offshore structures

Energy Technology Data Exchange (ETDEWEB)

Melchers, Robert E. [Centre for Infrastructure Performance and Reliability, Department of Civil, Surveying and Environmental Engineering, School of Engineering, University of Newcastle, University Drive, Callaghan NSW 2300 (Australia)]. E-mail: rob.melchers@newcastle.edu.au

2005-10-01

This paper considers essential theoretical concepts and data requirements for engineering structural reliability assessment suitable for the estimation of the safety and reliability of corroding ships, offshore structures and pipelines. Such infrastructure operates in a harsh environment. Allowance must be made for structural deterioration since protective measures such as paint coatings, galvanizing or cathodic protection may be ineffective. Reliability analysis requires accurate engineering models for the description and prediction of material corrosion loss and for the maximum depth of pitting. New probability-based models for both these forms of corrosion have been proposed recently and calibrated against a wide range of data. The effects of water velocity and of water pollution are reviewed and compared with recently reported field data for a corrosion at an offshore oil platform. The data interpreted according to the model show good correlation when allowance is made for the season of first immersion and the adverse effects of seawater velocity and of water pollution. An example is given to illustrate the application of reliability analysis to a pipeline subject to pitting corrosion. An important outcome is that good quality estimation of the longer-term probability of loss of structural integrity requires good modelling of the longer-term corrosion behaviour. This is usually associated with anaerobic corrosion. As a result, it cannot be extrapolated from data for short-term corrosion as this is associated with aerobic corrosion conditions.

Corrosion-resistant multilayer structures with improved reflectivity

Science.gov (United States)

Soufli, Regina; Fernandez-Perea, Monica; Robinson, Jeff C.

2013-04-09

In one general embodiment, a thin film structure includes a substrate; a first corrosion barrier layer above the substrate; a reflective layer above the first corrosion barrier layer, wherein the reflective layer comprises at least one repeating set of sub-layers, wherein one of the sub-layers of each set of sub-layers being of a corrodible material; and a second corrosion barrier layer above the reflective layer. In another general embodiment, a system includes an optical element having a thin film structure as recited above; and an image capture or spectrometer device. In a further general embodiment, a laser according to one embodiment includes a light source and the thin film structure as recited above.

Analyses of containment structures with corrosion damage

International Nuclear Information System (INIS)

Cherry, J.L.

1997-01-01

Corrosion damage that has been found in a number of nuclear power plant containment structures can degrade the pressure capacity of the vessel. This has prompted concerns regarding the capacity of corroded containments to withstand accident loadings. To address these concerns, finite element analyses have been performed for a typical PWR Ice Condenser containment structure. Using ABAQUS, the pressure capacity was calculated for a typical vessel with no corrosion damage. Multiple analyses were then performed with the location of the corrosion and the amount of corrosion varied in each analysis. Using a strain-based failure criterion, a open-quotes lower boundclose quotes, open-quotes best estimateclose quotes, and open-quotes upper boundclose quotes failure level was predicted for each case. These limits were established by: determining the amount of variability that exists in material properties of typical containments, estimating the amount of uncertainty associated with the level of modeling detail and modeling assumptions, and estimating the effect of corrosion on the material properties

Review on stress corrosion and corrosion fatigue failure of centrifugal compressor impeller

Science.gov (United States)

Sun, Jiao; Chen, Songying; Qu, Yanpeng; Li, Jianfeng

2015-03-01

Corrosion failure, especially stress corrosion cracking and corrosion fatigue, is the main cause of centrifugal compressor impeller failure. And it is concealed and destructive. This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments, and it also points out that existing stress corrosion cracking theories can be reduced to the anodic dissolution (AD), the hydrogen-induced cracking (HIC), and the combined AD and HIC mechanisms. The corrosion behavior and the mechanism of corrosion fatigue in the crack propagation stage are similar to stress corrosion cracking. The effects of stress ratio, loading frequency, and corrosive medium on the corrosion fatigue crack propagation rate are analyzed and summarized. The corrosion behavior and the mechanism of stress corrosion cracking and corrosion fatigue in corrosive environments, which contain sulfide, chlorides, and carbonate, are analyzed. The working environments of the centrifugal compressor impeller show the behavior and the mechanism of stress corrosion cracking and corrosion fatigue in different corrosive environments. The current research methods for centrifugal compressor impeller corrosion failure are analyzed. Physical analysis, numerical simulation, and the fluid-structure interaction method play an increasingly important role in the research on impeller deformation and stress distribution caused by the joint action of aerodynamic load and centrifugal load.

Anaerobic Corrosion of 304 Stainless Steel Caused by the Pseudomonas aeruginosa Biofilm

Directory of Open Access Journals (Sweden)

Ru Jia

2017-11-01

Full Text Available Pseudomonas aeruginosa is a ubiquitous bacterium capable of forming problematic biofilms in many environments. They cause biocorrosion of medical implants and industrial equipment and infrastructure. Aerobic corrosion of P. aeruginosa against stainless steels has been reported by some researchers while there is a lack of reports on anaerobic P. aeruginosa corrosion in the literature. In this work, the corrosion by a wild-type P. aeruginosa (strain PAO1 biofilm against 304 stainless steel (304 SS was investigated under strictly anaerobic condition for up to 14 days. The anaerobic corrosion of 304 SS by P. aeruginosa was reported for the first time. Results showed that the average sessile cell counts on 304 SS coupons after 7- and 14-day incubations were 4.8 × 107 and 6.2 × 107 cells/cm2, respectively. Scanning electron microscopy and confocal laser scanning microscopy corroborated the sessile cell counts. The X-ray diffraction analysis identified the corrosion product as iron nitride, confirming that the corrosion was caused by the nitrate reducing biofilm. The largest pit depths on 304 SS surfaces after the 7- and 14-day incubations with P. aeruginosa were 3.9 and 7.4 μm, respectively. Electrochemical tests corroborated the pitting data.

Sensor Systems for Corrosion Monitoring in Concrete Structures

Directory of Open Access Journals (Sweden)

K.Kumar

2006-05-01

Full Text Available It is a need of permanently embedded corrosion monitoring devices to monitor the progress of corrosion problems on a new or existing reinforced concrete structures before embarking on repair or rehabilitation of the structures. Numerous devices are available for investigating corrosion problems, because no single technique exists which tells an engineer what he needs to know, namely how much damage there is on a structure now and how rapidly the damage will grow with time. In this investigation the studies on the sensors systems based on the measurements of half cell potential of rebars inside the concrete, resistivity of concrete, corrosion rate of rebars by eddy current measurements and sensing of chloride ions are reported. An integrated system consists of above sensors are fabricated and embedded into concrete. The response from each sensor was acquired and analyzed by NI hardware through LabVIEW software.

Full surface inspection methods regarding reinforcement corrosion of concrete structures

International Nuclear Information System (INIS)

Reichling, K.; Raupach, M.; Broomfield, J.; Gulikers, J.; L'Hostis, Valerie

2013-01-01

For reinforced concrete structures a localisation of all significant critical areas can only be done by a full surface inspection. The economic advantages are obvious: uncritical areas have not to be repaired expensively.The first step of the assessment should always be a visual inspection. The range of deterioration causes can be limited and the degree of deterioration may be estimated roughly. The inspection program can be adjusted to the requirements. By means of a full surface potential mapping areas with a high risk for chloride induced reinforcement corrosion can be localised, although no deteriorations are visually detectable at the concrete surface. In combination with concrete cover depth and resistivity measurements areas with corrosion promoting exposure conditions can be localised even if the reinforcement is not yet de-passivated. The following publication gives an overview about the essential full surface investigation methods to localise critical areas regarding corrosion of steel in concrete. The selection of methods is based on the inspection procedure given in reference 2. (authors)

Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures.

Science.gov (United States)

Angst, Ueli M; Boschmann, Carolina; Wagner, Matthias; Elsener, Bernhard

2017-08-31

The aging of reinforced concrete infrastructure in developed countries imposes an urgent need for methods to reliably assess the condition of these structures. Corrosion of the embedded reinforcing steel is the most frequent cause for degradation. While it is well known that the ability of a structure to withstand corrosion depends strongly on factors such as the materials used or the age, it is common practice to rely on threshold values stipulated in standards or textbooks. These threshold values for corrosion initiation (Ccrit) are independent of the actual properties of a certain structure, which clearly limits the accuracy of condition assessments and service life predictions. The practice of using tabulated values can be traced to the lack of reliable methods to determine Ccrit on-site and in the laboratory. Here, an experimental protocol to determine Ccrit for individual engineering structures or structural members is presented. A number of reinforced concrete samples are taken from structures and laboratory corrosion testing is performed. The main advantage of this method is that it ensures real conditions concerning parameters that are well known to greatly influence Ccrit, such as the steel-concrete interface, which cannot be representatively mimicked in laboratory-produced samples. At the same time, the accelerated corrosion test in the laboratory permits the reliable determination of Ccrit prior to corrosion initiation on the tested structure; this is a major advantage over all common condition assessment methods that only permit estimating the conditions for corrosion after initiation, i.e., when the structure is already damaged. The protocol yields the statistical distribution of Ccrit for the tested structure. This serves as a basis for probabilistic prediction models for the remaining time to corrosion, which is needed for maintenance planning. This method can potentially be used in material testing of civil infrastructures, similar to established

FEM Modelling of the Evolution of Corrosion Cracks in Reinforced Concrete Structures

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

Corrosion cracks are caused by the increasing volume of corrosion products during the corrosion of the reinforcement. After corrosion initiation the rust products from the corroded reinforcement will initially fill the porous zone near the reinforcement and the result in an expansion of the concr......Corrosion cracks are caused by the increasing volume of corrosion products during the corrosion of the reinforcement. After corrosion initiation the rust products from the corroded reinforcement will initially fill the porous zone near the reinforcement and the result in an expansion...... of the concrete near the reinforcement. Tensile stresses are then initiated in the concrete. With increasing corrosion, the tensile stresses will at a certain time reach a critical value and cracks will be developed. The increase of the crack with after formation of the initial crack is the subject of this paper...

Analytical model for time to cover cracking in RC structures due to rebar corrosion

International Nuclear Information System (INIS)

Bhargava, Kapilesh; Ghosh, A.K.; Mori, Yasuhiro; Ramanujam, S.

2006-01-01

The structural degradation of concrete structures due to reinforcement corrosion is a major worldwide problem. Reinforcement corrosion causes a volume increase due to the oxidation of metallic iron, which is mainly responsible for exerting the expansive radial pressure at the steel-concrete interface and development of hoop tensile stresses in the surrounding concrete. Cracking occurs, once the maximum hoop tensile stress exceeds the tensile strength of the concrete. The cracking begins at the steel-concrete interface and propagates outwards and eventually results in the thorough cracking of the cover concrete and this would indicate the loss of service life for the corrosion affected structures. An analytical model is proposed to predict the time required for cover cracking and the weight loss of reinforcing bar in corrosion affected reinforced concrete structures. The modelling aspects of the residual strength of cracked concrete and the stiffness contribution from the combination of reinforcement and expansive corrosion products have also been incorporated in the model. The problem is modeled as a boundary value problem and the governing equations are expressed in terms of the radial displacement. The analytical solutions are presented considering a simple two-zone model for the cover concrete, viz. cracked or uncracked. Reasonable estimation of the various parameters in the model related to the composition and properties of expansive corrosion products based on the available published experimental data has also been discussed. The performance of the proposed corrosion cracking model is then investigated through its ability to reproduce available experimental trends. Reasonably good agreement between experimental results and the analytical predictions has been obtained. It has also been found that tensile strength and initial tangent modulus of cover concrete, annual mean corrosion rate and modulus of elasticity of reinforcement plus corrosion products combined

Maintenance Planning for Chloride Initiated Corrosion in Concrete Structures

DEFF Research Database (Denmark)

Engelund, S.; Sørensen, John Dalsgaard

1998-01-01

Corrosion of the reinforcement in concrete structures can be initiated when the chloride concentration around the reinforcement exceeds a threshold value. In order to prevent the corrosion from reaching a stage where the load-bearing capacity of a given structure suffers a substantial decrease...

Research on corrosion detection for steel reinforced concrete structures using the fiber optical white light interferometer sensing technique

International Nuclear Information System (INIS)

Zhao, Xuefeng; Cui, Yanjun; Kong, Xianglong; Wei, Heming; Zhang, Pinglei; Sun, Changsen

2013-01-01

In this paper, a novel kind of steel rebar corrosion monitoring technique for steel reinforced concrete structures is proposed, designed, and tested. The technique is based on the fiber optical white light interferometer (WLI) sensing technique. Firstly, a feasibility test was carried out using an equal-strength beam for comparison of strain sensing ability between the WLI and a fiber Bragg grating (FBG). The comparison results showed that the sensitivity of the WLI is sufficient for corrosion expansion strain monitoring. Then, two WLI corrosion sensors (WLI-CSs) were designed, fabricated, and embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion. Their performance was studied in an accelerated electrochemical corrosion test. Experimental results show that expansion strain along the fiber optical coil winding area can be detected and measured accurately by the proposed sensor. The advantages of the proposed monitoring technique allow for quantitative corrosion expansion monitoring to be executed in real time for reinforced concrete structures and with low cost. (paper)

Smart Coatings for Corrosion Protection

Science.gov (United States)

Calle, Luz Marina; Li, Wendy; Buhrow, Jerry W.; Johnsey, Marissa N.

2016-01-01

Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it.

Ultrasonic assessment of service life of concrete structures subject to reinforcing steel corrosion

Science.gov (United States)

Udegbunam, Ogechukwu Christian

Over half of the bridges in the United States were built before 1970. Such bridges and the network of roads that they carry include the Inter State system, which was built as part of the great public works program, following the end of the Second World War. During that era, the emphasis was on strength design and economical construction of new structures, and not much premium was placed on durability and maintainability concerns. Since the end of this construction boom in the early 1970s, the concern for the durability of transportation infrastructure has steadily gained prominence among those agencies that must secure, program and administer funds for maintaining highway networks. The objective of this research was to develop a nondestructive method of assessing the durability of concrete bridge decks susceptible to damage from corrosion of embedded reinforcing steel. This was accomplished by formulating a holistic approach that accounts for the major factors that influence corrosion based deterioration of reinforced concrete. In this approach, the assessment of the durability of concrete bridge decks is based on a model that estimates the time it takes for the cover concrete to fail a result of stresses caused by expansion of reinforcing steel bars, due to corrosion activities. This time to failure is comprised of two distinct periods that must be evaluated before the problem can be solved. The research consisted of an experimental program and an analytical study. In the experimental program concrete specimens were cast and tested to determine their diffusivity and mechanical properties. The diffusivity was used to evaluate the period it takes for corrosion of the reinforcing bars to commence. In the analytical study, the resistance of the concrete structure against the internal forces caused by corrosion was evaluated with the finite element techniques. This resistance was used to evaluate the period defining the failure of the cover concrete. These two periods

Investigation of Stress Concentration and Casing Strength Degradation Caused by Corrosion Pits

Directory of Open Access Journals (Sweden)

Wei Yan

2016-01-01

Full Text Available Downhole casing and tubing are subjected to corrosion in many cases because of the exposure to corrosive environment. A more serious problem is that pitting corrosion occurs in the casing inner surface. Meanwhile, downhole strings are subjected to various forms of mechanical loads, for example, internal pressure load, external collapse load, or both. These loads acting on the corrosion pits will cause stress concentration and degrade the casing strength. Thus, it is essential to evaluate the stress concentration degree reasonably. The SCF (stress concentration factor is usually used to characterize the degree of stress concentration induced by corrosion pits. This paper presented a comparison on the SCFs regarding the analytical method for a single pit and experimental method for double pits. The results show that the SCF of a single pit depends mainly on the depth of the corrosion pit; however, the SCF of the double pits strongly depends on the pits distance. A correction factor of 1.3 was recommended in the double pits SCF prediction model.

Nuclear risk reduction study. The study of structure corrosion caused by sea salt aerosols

International Nuclear Information System (INIS)

Nakayasu, Fumio

2008-01-01

Present all nuclear power plants in Fukui prefecture are located at the bay side of Japan Sea coast. New facilities may be planed to be at ocean side. The sea salt corrosion at the ocean side should be larger than it at the bay side. We have the salt damage experimental yard at Awara sea coast and at Fukui city (about 15km from coast) for the corrosion comparison study between Japan Sea coast and inland. We confirm the amounts of sea salt aerosol vary among the season and year. The weight loss of specimen inside of shelter without filter is higher than both of sheltered with filter and inland specimen. The weight loss of specimen inside of shelter with filter is almost same as it of inland specimen. We confirmed the filter which we used is sufficient capability to prevent corrosion. We confirmed the corrosion rate of both opened specimen and sheltered specimen without filter increased after some periods. (author)

Pitting corrosion and structural reliability of corroding RC structures: Experimental data and probabilistic analysis

International Nuclear Information System (INIS)

Stewart, Mark G.; Al-Harthy, Ali

2008-01-01

A stochastic analysis is developed to assess the temporal and spatial variability of pitting corrosion on the reliability of corroding reinforced concrete (RC) structures. The structure considered herein is a singly reinforced RC beam with Y16 or Y27 reinforcing bars. Experimental data obtained from corrosion tests are used to characterise the probability distribution of pit depth. The RC beam is discretised into a series of small elements and maximum pit depths are generated for each reinforcing steel bar in each element. The loss of cross-sectional area, reduction in yield strength and reduction in flexural resistance are then inferred. The analysis considers various member spans, loading ratios, bar diameters and numbers of bars in a given cross-section, and moment diagrams. It was found that the maximum corrosion loss in a reinforcing bar conditional on beam collapse was no more than 16%. The probabilities of failure considering spatial variability of pitting corrosion were up to 200% higher than probabilities of failure obtained from a non-spatial analysis after 50 years of corrosion. This shows the importance of considering spatial variability in a structural reliability analysis for deteriorating structures, particularly for corroding RC beams in flexure

Corrosion Behavior of Brazed Zinc-Coated Structured Sheet Metal

Directory of Open Access Journals (Sweden)

A. Nikitin

2017-01-01

Full Text Available Arc brazing has, in comparison to arc welding, the advantage of less heat input while joining galvanized sheet metals. The evaporation of zinc is reduced in the areas adjacent to the joint and improved corrosion protection is achieved. In the automotive industry, lightweight design is a key technology against the background of the weight and environment protection. Structured sheet metals have higher stiffness compared to typical automobile sheet metals and therefore they can play an important role in lightweight structures. In the present paper, three arc brazing variants of galvanized structured sheet metals were validated in terms of the corrosion behavior. The standard gas metal arc brazing, the pulsed arc brazing, and the cold metal transfer (CMT® in combination with a pulsed cycle were investigated. In experimental climate change tests, the influence of the brazing processes on the corrosion behavior of galvanized structured sheet metals was investigated. After that, the corrosion behavior of brazed structured and flat sheet metals was compared. Because of the selected lap joint, the valuation of damage between sheet metals was conducted. The pulsed CMT brazing has been derived from the results as the best brazing method for the joining process of galvanized structured sheet metals.

Factors and mechanisms affecting corrosion of steel in concrete

International Nuclear Information System (INIS)

Dehqanian, Ch.

1986-01-01

Atomic power plants possess reinforced concrete structures which are exposed to sea water or sea atmosphere. Sea water or its surrounding environment contain very corrosive species which cause corrosion of metal in concrete. It should be mentioned that corrosion of steel in concrete is a complex problem that is not completely understood. Some of the factors which influence the corrosion mechanism and can be related to the pore solution composition is discussed. Chloride ion caused problems are the main source of the corrosion damage seen on the reinforced concrete structures. Corrosion rate in concrete varies and depends on the way chloride ion diffuses into concrete. In addition, the associated cations can influence diffusion of chloride into concrete. The type of portland cement and also the concrete mix design all affect the corrosion behaviour of steel in concrete

A corrosion monitoring system for existing reinforced concrete structures.

Science.gov (United States)

2015-05-01

This study evaluated a multi-parameter corrosion monitoring system for existing reinforced concrete structures in chloride-laden service environments. The system was fabricated based on a prototype concrete corrosion measurement system that : had bee...

Cause Analysis of Flow Accelerated Corrosion and Erosion-Corrosion Cases in Korea Nuclear Power Plants

Energy Technology Data Exchange (ETDEWEB)

Lee, Y. S.; Lee, S. H. [Korea Hydro and Nuclear Power Co., Ltd., Gyeongju (Korea, Republic of); Hwang, K. M. [KEPCO Engineering and Construction Company, Gimcheon (Korea, Republic of)

2016-08-15

Significant piping wall thinning caused by Flow-Accelerated Corrosion (FAC) and Erosion-Corrosion (EC) continues to occur, even after the Mihama Power Station unit 3 secondary pipe rupture in 2004, in which workers were seriously injured or died. Nuclear power plants in many countries have experienced FAC and EC-related cases in steam cycle piping systems. Korea has also experienced piping wall thinning cases including thinning in the downstream straight pipe of a check valve in a feedwater pump line, the downstream elbow of a control valve in a feedwater flow control line, and failure of the straight pipe downstream of an orifice in an auxiliary steam return line. Cause analyses were performed by reviewing thickness data using Ultrasonic Techniques (UT) and, Scanning Electron Microscope (SEM) images for the failed pipe, and numerical simulation results for FAC and EC cases in Korea Nuclear Power Plants. It was concluded that the main cause of wall thinning for the downstream pipe of a check valve is FAC caused by water vortex flow due to the internal flow shape of a check valve, the main cause of wall thinning for the downstream elbow of a control valve is FAC caused by a thickness difference with the upstream pipe, and the main cause of wall thinning for the downstream pipe of an orifice is FAC and EC caused by liquid droplets and vortex flow. In order to investigate more cases, additional analyses were performed with the review of a lot of thickness data for inspected pipes. The results showed that pipe wall thinning was also affected by the operating condition of upstream equipment. Management of FAC and EC based on these cases will focus on the downstream piping of abnormal or unusual operated equipment.

Non-destructive electrochemical techniques applied to the corrosion evaluation of the liner structures in nuclear power plants

International Nuclear Information System (INIS)

Martinez, I.; Castillo, A.; Andrade, C.

2008-01-01

The liner structure in nuclear power plants provides containment for the operation and therefore the study of its durability and integrity during its service life is an important issue. There are several causes for the deterioration of the liner, which in general involve corrosion due to its metallic nature. The present paper is aimed at describing the assessment of corrosion problems of two liners from two different nuclear power plants, which were evaluated using non-destructive electrochemical techniques. In spite of the testing difficulties arisen, from the results extracted it can be concluded that the electrochemical techniques applied are adequate for the corrosion evaluation. They provide important information about the integrity of the structure and allow for its evolution with time to be assessed

21PF overpacks: Phenolic-foam induced corrosion

International Nuclear Information System (INIS)

Kovac, F.M.

1994-01-01

The 21PF overpack was developed in the 1960s and approved for use in the 1970s by the US Department of Transportation (DOT). This package, used for the transport of uranium hexafluoride enriched >1%, has had a history of severe metal corrosion, water ingress, and subsequent leakage. Problems associated with corrosion and water leaking from 21PF overpacks caused the DOT to seek public comments and to undertake rulemaking action. As a result, the DOT required modifications and refurbishment of existing overpacks, and specification changes for the fabrication of new 21PF overpacks. Recent studies conducted by the roofing industry indicate that phenolic foam has caused severe corrosion in metal roofing structures, and its use is being curtailed. These findings need to be explored in order to determine if phenolic foam in 21PF overpacks causes corrosion and compromises the package integrity. Metallic corrosion induced by phenolic foam may affect the continued use of the 21PF overpack because damage to the structural integrity of the metal parts of the packaging will affect its ability to meet design specifications

Stress corrosion and corrosion fatigue crack growth monitoring in metals

International Nuclear Information System (INIS)

Senadheera, T.; Shipilov, S.A.

2003-01-01

Environmentally assisted cracking (including stress corrosion cracking and corrosion fatigue) is one of the major causes for materials failure in a wide variety of industries. It is extremely important to understand the mechanism(s) of environmentally assisted crack propagation in structural materials so as to choose correctly from among the various possibilities-alloying elements, heat treatment of steels, parameters of cathodic protection, and inhibitors-to prevent in-service failures due to stress corrosion cracking and corrosion fatigue. An important step towards understanding the mechanism of environmentally assisted crack propagation is designing a testing machine for crack growth monitoring and that simultaneously provides measurement of electrochemical parameters. In the present paper, a direct current (DC) potential drop method for monitoring crack propagation in metals and a testing machine that uses this method and allows for measuring electrochemical parameters during stress corrosion and corrosion fatigue crack growth are described. (author)

Exfoliation Corrosion and Pitting Corrosion and Their Role in Fatigue Predictive Modeling: State-of-the-Art Review

Directory of Open Access Journals (Sweden)

David W. Hoeppner

2012-01-01

Full Text Available Intergranular attack (IG and exfoliation corrosion (EC have a detrimental impact on the structural integrity of aircraft structures of all types. Understanding the mechanisms and methods for dealing with these processes and with corrosion in general has been and is critical to the safety of critical components of aircraft. Discussion of cases where IG attack and exfoliation caused issues in structural integrity in aircraft in operational fleets is presented herein along with a much more detailed presentation of the issues involved in dealing with corrosion of aircraft. Issues of corrosion and fatigue related to the structural integrity of aging aircraft are introduced herein. Mechanisms of pitting nucleation are discussed which include adsorption-induced, ion migration-penetration, and chemicomechanical film breakdown theories. In addition, pitting corrosion (PC fatigue models are presented as well as a critical assessment of their application to aircraft structures and materials. Finally environmental effects on short crack behavior of materials are discussed, and a compilation of definitions related to corrosion and fatigue are presented.

Corrosion Control in the Aerospace Industry

Science.gov (United States)

Calle, Luz Marina; Li, Wenyan; Buhrow, Jerry W.; Johnsey, Marissa N.

2016-01-01

Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it..

Monitoring of corrosion damage using high-frequency guided ultrasonic waves

OpenAIRE

Chew, D.; Fromme, P.

2014-01-01

Due to adverse environmental conditions corrosion can develop during the life cycle of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the integrity and load bearing capacity of the structure. Structural health monitoring of corrosion damage in difficult to access areas can in principle be achieved using high frequency guided waves propagating along...

Corrosion of steel structures in sea-bed sediment

Indian Academy of Sciences (India)

Seabed sediment (SBS) is a special soil that is covered by seawater. With the developments in marine oil exploitation and engineering, more and more steel structures have been buried in SBS. SBS corrosion has now become a serious problem in marine environment and an important issue in corrosion science. In this ...

Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

Directory of Open Access Journals (Sweden)

Xingjun Lv

2011-11-01

Full Text Available In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

Brillouin corrosion expansion sensors for steel reinforced concrete structures using a fiber optic coil winding method.

Science.gov (United States)

Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

2011-01-01

In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

Investigation into the cause of leak in the pipe of the corrosion test apparatus of IS process

International Nuclear Information System (INIS)

Tanaka, Nobuyuki; Furukawa, Tomohiro; Inagaki, Yoshiyuki; Suwa, Hirokazu

2008-12-01

The thermochemical water-splitting hydrogen production IS process utilizes corrosive chemicals such as sulfuric acid and hydriodic acid. Corrosion tests in IS process environments have been carried out to get the corrosion data of materials. In the corrosion test in 90wt% sulfuric acid at 400degC, the leak of sulfuric acid was observed in a pipe connected with a reflux condenser. The cause of the leakage is a significant knowledge for the operation of the test apparatus. Therefore the cause was investigated. A 1mm wide through hole was detected in the pipe around the welding bead. By visual observation after cutting the pipe, the wall thickness of the pipe became thin at the inside welding bead around the through hole. In addition, EMPA showed that the inhomogeneous distribution of the constituent elements of the pipe was observed around the through hole. For these reasons, it is estimated that the lowering of the corrosion resistance by the sensitization at the welding caused the leakage. (author)

NASA's Corrosion Technology Laboratory at the Kennedy Space Center: Anticipating, Managing, and Preventing Corrosion

Science.gov (United States)

Calle, Luz Marina

2015-01-01

The marine environment at NASAs Kennedy Space Center (KSC) has been documented by ASM International (formerly American Society for Metals) as the most corrosive in North America. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pads were rendered even more severe by the highly corrosive hydrochloric acid (HCl) generated by the solid rocket boosters (SRBs). Numerous failures at the launch pads are caused by corrosion. The structural integrity of ground infrastructure and flight hardware is critical to the success, safety, cost, and sustainability of space missions. NASA has over fifty years of experience dealing with unexpected failures caused by corrosion and has developed expertise in corrosion control in the launch and other environments. The Corrosion Technology Laboratory at KSC evolved, from what started as an atmospheric exposure test site near NASAs launch pads, into a capability that provides technical innovations and engineering services in all areas of corrosion for NASA, external partners, and customers.This paper provides a chronological overview of NASAs role in anticipating, managing, and preventing corrosion in highly corrosive environments. One important challenge in managing and preventing corrosion involves the detrimental impact on humans and the environment of what have been very effective corrosion control strategies. This challenge has motivated the development of new corrosion control technologies that are more effective and environmentally friendly. Strategies for improved corrosion protection and durability can have a huge impact on the economic sustainability of human spaceflight operations.

Corrosion of Steel in Concrete, Part I – Mechanisms

DEFF Research Database (Denmark)

Küter, André; Møller, Per; Geiker, Mette Rica

2006-01-01

prematurely. Reinforcement corrosion is identified to be the foremost cause of deterioration. Steel in concrete is normally protected by a passive layer due the high alkalinity of the concrete pore solution; corrosion is initiated by neutralization through atmospheric carbon dioxide and by ingress...... of depassivation ions, especially chloride ions. The background and consequences of deterioration of reinforced concrete structures caused by steel corrosion are summarized. Selected corrosion mechanisms postulated in the literature are briefly discussed and related to observations. The key factors controlling...... initiation and propagation of corrosion of steel in concrete are outlined....

Investigation on the thermographic detection of corrosion in RC structures

Science.gov (United States)

Tantele, Elia A.; Votsis, Renos A.; Kyriakides, Nicholas; Georgiou, Panagiota G.; Ioannou, Fotia G.

2017-09-01

Corrosion of the steel reinforcement is the main problem of reinforced concrete (RC) structures. Over the past decades, several methods have been developed aiming to detect the corrosion process early in order to minimise the structural damage and consequently the repairing costs. Emphasis was given in developing methods and techniques of non-destructive nature providing fast on-the-spot detection and covering large areas rather that concentrating on single locations. This study, investigates a non-destructive corrosion detection technique for reinforced concrete, which is based on infrared thermography and the difference in thermal characteristics of corroded and non-corroded steel rebars. The technique is based on the principle that corrosion products have poor heat conductivity, and they inhibit the diffusion of heat that is generated in the reinforcing bar due to heating. For the investigation RC specimens, have been constructed in the laboratory using embedded steel bars of different corrosion states. Afterward, one surface of the specimens was heated using an electric device while thermal images were captured at predefined time instants on the opposite surface with an IR camera. The test results showed a clear difference between the thermal characteristics of the corroded and the non-corroded samples, which demonstrates the potential of using thermography in corrosion detection in RC structures.

Corrosion of structural materials for Generation IV systems

International Nuclear Information System (INIS)

Balbaud-Celerier, F.; Cabet, C.; Courouau, J.L.; Martinelli, L.; Arnoux, P.

2009-01-01

The Generation IV International Forum aims at developing future generation nuclear energy systems. Six systems have been selected for further consideration: sodium-cooled fast reactor (SFR), gas-cooled fast reactor (GFR), lead-cooled fast reactor (LFR), molten salt reactor (MSR), supercritical water-cooled reactor (SCWR) and very high temperature reactor (VHTR). CEA, in the frame of a national program, of EC projects and of the GIF, contributes to the structural materials developments and research programs. Particularly, corrosion studies are being performed in the complex environments of the GEN IV systems. As a matter of fact, structural materials encounter very severe conditions regarding corrosion concerns: high temperatures and possibly aggressive chemical environments. Therefore, the multiple environments considered require also a large diversity of materials. On the other hand, the similar levels of working temperatures as well as neutron spectrum imply also similar families of materials for the various systems. In this paper, status of the research performed in CEA on the corrosion behavior of the structural material in the different environments is presented. The materials studied are either metallic materials as austenitic (or Y, La, Ce doped) and ferrito-martensitic steels, Ni base alloys, ODS steels, or ceramics and composites. In all the environments studied, the scientific approach is identical, the objective being in all cases the understanding of the corrosion processes to establish recommendations on the chemistry control of the coolant and to predict the long term behavior of the materials by the development of corrosion models. (author)

Electrochemical techniques to detect corrosion in concrete structures in nuclear installations - Technical note

International Nuclear Information System (INIS)

2002-01-01

The mechanism of corrosion in aqueous media is of electrochemical nature. This means that the oxidation of the metal is counterbalanced by the reduction of another substance in another region of the metallic surface. Therefore, zones (anodes and cathodes) with different electrochemical potential, develop. In the case of concrete the electrolyte is constituted by the pore solution, which is very alkaline. This pore solution is formed by mainly a mixture of KOH and NaOH presenting pH values ranging between 12.6-14. The solution is saturated in Ca(OH) 2 . Steel embedded in concrete is naturally protected by this high alkalinity and by the barrier effect of the cover itself. The two main causes of electrochemical corrosion are carbonation and the presence of chlorides. Carbonation usually induces a generalized corrosion while chloride will lead into pitting or localized attack. The corrosion can be easily recognized by the rust presence on the rebar and by the appearance of cracks running parallel to the rebars. The objective of this report is to describe the electrochemical non-destructive techniques that can be used in real size reinforced concrete structures to assess the corrosion condition of their reinforcement. These techniques can be used indistinctly in conventional civil engineering structures or in those of nuclear installations. Electrochemical techniques are used to detect electrochemical corrosion activity of metallic reinforcements. They cannot quantify stress corrosion cracking or hydrogen embrittlement although may give some qualitative information about them. The aims of their applications may be one of the following circumstances: 1. Quality control of new constructions; 2. Condition evaluation of existing structures for: - Identification of steel de-passivation, - Detecting corroding areas for rehabilitation purposes, - Calculation of residual load-bearing capacity of the structure, - Prediction of the damage evolution, - Determination of the

Data book of anti-corrosion method

International Nuclear Information System (INIS)

Lee, Ui Ho

1997-07-01

This book deals with cases, influence, cause, standard of corrosion of steel structure, which includes bridges, steel tower, corrosion data, the ocean, ports, and RC structure for civil engineering, exterior materials of construction, building equipment pipes, processing industries such as chemical equipment, oil device, pump and coolant, environment facility like trash incinerator, and sewage process, thermal power generation and nuclear energy generation, and energy industry.

Simple experiments studying the catastrophic corrosion of stainless steel caused by sodium leaks

International Nuclear Information System (INIS)

Mathison, J.; Trevalion, P.A.; Hamer, A.N.

1971-01-01

Under certain conditions, small quantities of soditum escaping through a small hole may cause extensive corrosion and cratering on the outside of the containment in the vicinity of the leak and there is a possibility that this might lead to a major rupture of the containment. It is difficult to estimate such a corrosion rate by conducting post mortems after an incident because of the lack of precise information about times and temperatures. Simple sodium burning experiments have therefore been carried out in an attempt to provide rough quantitative data on the size of these corrosion rates. These showed that the average rate of corrosion of specimens of 18.8.1 stainless steel beneath a burning pool of sodium was of the order of 0.05 cm/hr at 600 ° C and 0.005 cm/hr at 400 ° C. Enhanced corrosion occurs at the periphery of the burning sodium. The rate of penetration will depend on the shape of the corrosion profile which exists in the affected surface. The times needed to penetrate different wall thicknesses of stainless steel pipework have been calculated for various corrosion profiles similar to those which have been observed after incidents in REML. (author)

Corrosion behaviour of non-ferrous metals in sea water

Energy Technology Data Exchange (ETDEWEB)

Birn, Jerzy; Skalski, Igor [Ship Design and Research Centre, Al. Rzeczypospolitej 8, 80-369 Gdansk (Poland)

2004-07-01

The most typical kinds of corrosion of brasses are selective corrosion (dezincification) and stress corrosion. Prevention against these kinds of corrosion lies in application of arsenic alloy addition and appropriate heat treatment removing internal stresses as well as in maintaining the arsenic and phosphorus contents on a proper level. The most typical corrosion of cupronickels is the local corrosion. Selective corrosion occurs less often and corrosion cracking caused by stress corrosion in sea water does not usually occur. Crevice corrosion is found especially in places of an heterogeneous oxidation of the surface under inorganic deposits or under bio-film. Common corrosive phenomena for brasses and cupronickels are the effects caused by sea water flow and most often the impingement attack. Alloy additions improve resistance to the action of intensive sea water flow but situation in this field requires further improvement, especially if the cheaper kinds of alloys are concerned. Contaminants of sea water such as ammonia and hydrogen sulphide are also the cause of common corrosion processes for all copper alloys. Corrosion of copper alloys may be caused also by sulphate reducing bacteria (SRB). Galvanic corrosion caused by a contact with titanium alloys e.g. in plate heat exchangers may cause corrosion of both kinds copper alloys. Bronzes belong to copper alloys of the highest corrosion resistance. Failures that sometimes occur are caused most often by the cavitation erosion, by an incorrect chemical composition of alloys or at last by their inadequate structure. The main problems of aluminium alloys service in sea water are following phenomena: local corrosion (pitting and crevice corrosion), galvanic corrosion, exfoliation and corrosion in the presence of OH- ions. The cause of local corrosion are caused by presence of passive film on the alloy's surface and presence of chlorides in sea water which are able to damage the passive film. Galvanic corrosion is

Damage induced by continued corrosion in concrete repair systems

NARCIS (Netherlands)

Luckovic, M.; Savija, B.; Schlangen, E.

2014-01-01

Corrosion of steel reinforcement is the main cause of deterioration in reinforced concrete structures. After the repair, corrosion of the steel might continue and even accelerate. While the development of the corrosion cell depends on many parameters and is difficult to control, the occurrence of

Development of an Improved Crack Propagation Model for Corrosion-Induced Cover Cracking in RC Structures

Science.gov (United States)

Hilyati, S.; Nizam, Z. M.; Zurisman, M. A. A.; Azhar, A. T. S.

2017-06-01

During the last two decades, reinforced concrete (RC) has been extensively used in most of the world as one of the common construction material due to its advantages and durability. However, RC structures exposed to marine environments are subjected to chloride attack. Chlorides from seawater penetrate into RC structures are not only causing severe corrosion problems but also affect the durability and serviceability of such structures. This paper investigates the influence of transverse reinforcement and spacing of reinforcing bars on concrete cover cracking of two-way RC slab specimens using accelerated corrosion tests. The experimental program involved the testing of four RC slab specimens and was generally designed to observe the crack width and the time of crack to propagate. An improved model for predicting the timing of crack propagation based on the experimental data was then developed.

Modeling of Metal Structure Corrosion Damage: A State of the Art Report

Directory of Open Access Journals (Sweden)

Francesco Portioli

2010-07-01

Full Text Available The durability of metal structures is strongly influenced by damage due to atmospheric corrosion, whose control is a key aspect for design and maintenance of both new constructions and historical buildings. Nevertheless, only general provisions are given in European codes to prevent the effects of corrosion during the lifetime of metal structures. In particular, design guidelines such as Eurocode 3 do not provide models for the evaluation of corrosion depth that are able to predict the rate of thickness loss as a function of different influencing parameters. In this paper, the modeling approaches of atmospheric corrosion damage of metal structures, which are available in both ISO standards and the literature, are presented. A comparison among selected degradation models is shown in order to evaluate the possibility of developing a general approach to the evaluation of thickness loss due to corrosion.

Experimental and Empirical Time to Corrosion of Reinforced Concrete Structures under Different Curing Conditions

Directory of Open Access Journals (Sweden)

Ahmed A. Abouhussien

2014-01-01

Full Text Available Reinforced concrete structures, especially those in marine environments, are commonly subjected to high concentrations of chlorides, which eventually leads to corrosion of the embedded reinforcing steel. The total time to corrosion of such structures may be divided into three stages: corrosion initiation, cracking, and damage periods. This paper evaluates, both empirically and experimentally, the expected time to corrosion of reinforced concrete structures. The tested reinforced concrete samples were subjected to ten alternative curing techniques, including hot, cold, and normal temperatures, prior to testing. The corrosion initiation, cracking, and damage periods in this investigation were experimentally monitored by an accelerated corrosion test performed on reinforced concrete samples. Alternatively, the corrosion initiation time for counterpart samples was empirically predicted using Fick’s second law of diffusion for comparison. The results showed that the corrosion initiation periods obtained experimentally were comparable to those obtained empirically. The corrosion initiation was found to occur at the first jump of the current measurement in the accelerated corrosion test which matched the half-cell potential reading of around −350 mV.

High temperature corrosion of metals

International Nuclear Information System (INIS)

Quadakkers, W.J.; Schuster, H.; Ennis, P.J.

1988-08-01

This paper covers three main topics: 1. high temperature oxidation of metals and alloys, 2. corrosion in sulfur containing environments and 3. structural changes caused by corrosion. The following 21 subjects are discussed: Influence of implanted yttrium and lanthanum on the oxidation behaviour of beta-NiA1; influence of reactive elements on the adherence and protective properties of alumina scales; problems related to the application of very fine markers in studying the mechanism of thin scale formation; oxidation behaviour of chromia forming Co-Cr-Al alloys with or without reactive element additions; growth and properties of chromia-scales on high-temperature alloys; quantification of the depletion zone in high temperature alloys after oxidation in process gas; effects of HC1 and of N2 in the oxidation of Fe-20Cr; investigation under nuclear safety aspects of Zircaloy-4 oxidation kinetics at high temperatures in air; on the sulfide corrosion of metallic materials; high temperature sulfide corrosion of Mn, Nb and Nb-Si alloys; corrosion behaviour or NiCrAl-based alloys in air and air-SO2 gas mixtures; sulfidation of cobalt at high temperatures; preoxidation for sulfidation protection; fireside corrosion and application of additives in electric utility boilers; transport properties of scales with complex defect structures; observations of whiskers and pyramids during high temperature corrosion of iron in SO2; corrosion and creep of alloy 800H under simulated coal gasification conditions; microstructural changes of HK 40 cast alloy caused by exploitation in tubes in steam reformer installation; microstructural changes during exposure in corrosive environments and their effect on mechanical properties; coatings against carburization; mathematical modeling of carbon diffusion and carbide precipitation in Ni-Cr-based alloys. (MM)

Economic effects of full corrosion surveys for aging concrete structures

NARCIS (Netherlands)

Polder, R.B.; Peelen, W.H.A.; Raupach, M.; Reichling, K.

2013-01-01

This paper investigates the economic effects of full corrosion surveys of concrete structures. The background is that the existing concrete infrastructure is aging, while being exposed to aggressive influences, which increases the occurrence of corrosion and related concrete damage over time. The

Lead-Bismuth technology ; corrosion resistance of structural materials

Energy Technology Data Exchange (ETDEWEB)

Jeong, Ji Young; Park, Won Seok [Korea Atomic Energy Research Institute, Taejeon (Korea)

2000-02-01

Lead-Bismuth (Pb-Bi) eutectic alloy was determined as a coolant material for the HYPER system being studied by KAERI. The Pb-Bi alloy as a coolant, has a number of the favorable thermo-physical and technological properties, while it is comparatively corrosive to the structural materials. It is necessary to solve this problem for providing a long failure-proof operation of the facilities with Pb-Bi coolant. It seems to be possible to maintain corrosion resistance on structural material up to 600 deg C by using of various technologies, but it needs more studies for application to large-scale NPPs. 22 refs., 11 figs., 7 tabs. (Author)

Laboratory study of reinforcement protection with corrosion inhibitors

International Nuclear Information System (INIS)

Stefanescu, D.; Mihalache, M.; Mogosan, S.

2013-01-01

Concrete is a durable material and its performance as part of the containment function in NPPs has been good. However, experience shows that degradation of the reinforced concrete structures caused by the corrosion of the reinforcing steel represents more than 80% of all damages in the world. Much effort has been made to develop a corrosion inhibition process to prolong the life of existing structures and minimize corrosion damages in new structures. Migrating Corrosion Inhibitor technology was developed to protect the embedded steel rebar/concrete structure. These inhibitors can be incorporated as an admixture or can be surface impregnated on existing concrete structures. The effectiveness of two inhibitors (ethanolamine and diethanolamine) mixed in the reinforced concrete was evaluated by gravimetric measurements. The corrosion behavior of the steel rebar and the inhibiting effects of the amino alcohol chemistry in an aggressive environment were monitored using electrochemical measurements and scanning electron microscopy (SEM) investigations. (authors)

Corrosion monitoring using high-frequency guided ultrasonic waves

Science.gov (United States)

Fromme, Paul

2014-02-01

Corrosion develops due to adverse environmental conditions during the life cycle of a range of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the structural integrity. The nondestructive detection and monitoring of corrosion damage in difficult to access areas can be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic transducers with single sided access to the structure, guided wave modes were generated that penetrate through the complete thickness of the structure. The wave propagation and interference of the different guided wave modes depends on the thickness of the structure. Laboratory experiments were conducted and the wall thickness reduced by consecutive milling of the steel structure. Further measurements were conducted using accelerated corrosion in a salt water bath and the damage severity monitored. From the measured signal change due to the wave mode interference the wall thickness reduction was monitored. The high frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.

Failure Modes in Concrete Repair Systems due to Ongoing Corrosion

NARCIS (Netherlands)

Lukovic, M.; Šavija, B.; Ye, G.; Schlangen, H.E.J.G.; van Breugel, K.

2017-01-01

Corrosion of steel reinforcement is the main cause of deterioration in reinforced concrete structures. It can result in cracking and spalling of the concrete cover. After the damaged cover is repaired, reinforcement corrosion might continue and even accelerate. While the development of the corrosion

Copper Tube Pitting in Santa Fe Municipal Water Caused by Microbial Induced Corrosion.

Science.gov (United States)

Burleigh, Thomas D; Gierke, Casey G; Fredj, Narjes; Boston, Penelope J

2014-06-05

Many copper water lines for municipal drinking water in Santa Fe, New Mexico USA, have developed pinhole leaks. The pitting matches the description of Type I pitting of copper, which has historically been attributed to water chemistry and to contaminants on the copper tubing surface. However, more recent studies attribute copper pitting to microbial induced corrosion (MIC). In order to test for microbes, the copper tubing was fixed in hexamethyldisilazane (HMDS), then the tops of the corrosion mounds were broken open, and the interior of the corrosion pits were examined with scanning electron microscopy (SEM). The analysis found that microbes resembling actinobacteria were deep inside the pits and wedged between the crystallographic planes of the corroded copper grains. The presence of actinobacteria confirms the possibility that the cause of this pitting corrosion was MIC. This observation provides better understanding and new methods for preventing the pitting of copper tubing in municipal water.

Copper Tube Pitting in Santa Fe Municipal Water Caused by Microbial Induced Corrosion

Directory of Open Access Journals (Sweden)

Thomas D. Burleigh

2014-06-01

Full Text Available Many copper water lines for municipal drinking water in Santa Fe, New Mexico USA, have developed pinhole leaks. The pitting matches the description of Type I pitting of copper, which has historically been attributed to water chemistry and to contaminants on the copper tubing surface. However, more recent studies attribute copper pitting to microbial induced corrosion (MIC. In order to test for microbes, the copper tubing was fixed in hexamethyldisilazane (HMDS, then the tops of the corrosion mounds were broken open, and the interior of the corrosion pits were examined with scanning electron microscopy (SEM. The analysis found that microbes resembling actinobacteria were deep inside the pits and wedged between the crystallographic planes of the corroded copper grains. The presence of actinobacteria confirms the possibility that the cause of this pitting corrosion was MIC. This observation provides better understanding and new methods for preventing the pitting of copper tubing in municipal water.

Evaluation method of corrosive conditions in cooling systems of nuclear power plants by combined analyses of flow dynamics and corrosion

Energy Technology Data Exchange (ETDEWEB)

Uchida, Shunsuke [Nuclear Power Engineering Corporation (NUPEC), Tokyo (Japan); Atomic Energy Society of Japan (AESJ) (Japan). Research Committee on Water Chemistry Standard; Naitoh, Masanori [Nuclear Power Engineering Corporation (NUPEC), Tokyo (Japan); Atomic Energy Society of Japan (AESJ) (Japan). Computational Science and Engineering Div.; Uehara, Yasushi; Okada, Hidetoshi [Nuclear Power Engineering Corporation (NUPEC), Tokyo (Japan); Hotta, Koji [ITOCHU Techno-Solutions Corporation (Japan); Ichikawa, Ryoko [Mizuho Information and Research Inst., Inc. (Japan); Koshizuka, Seiichi [Tokyo Univ. (Japan)

2007-03-15

Problems in major components and structural materials in nuclear power plants have often been caused by flow induced vibration, corrosion and their overlapping effects. In order to establish safe and reliable plant operation, it is necessary to predict future problems for structural materials based on combined analyses of flow dynamics and corrosion and to mitigate them before they become serious issues for plant operation. The analysis models are divided into two types. 1. Prediction models for future problems with structural materials: Distributions of oxidant concentrations along flow paths are obtained by solving water radiolysis reactions in the boiling water reactor (BWR) primary cooling water and hydrazine-oxygen reactions in the pressurized water reactor (PWR) secondary cooling water. Then, the electrochemical corrosion potential (ECP) at the point of interest is also obtained by the mixed potential model using oxidant concentration. Higher ECP enhances the possibility of intergranular stress corrosion cracking (IGSCC) in the BWR primary system, while lower ECP enhances flow accelerated corrosion (FAC) in the PWR secondary system. 2. Evaluation models of wall thinning caused by flow accelerated corrosion: The degree of wall thinning is evaluated at a location with a higher possibility of FAC occurrence, and lifetime is estimated for preventive maintenance. General features of models are reviewed in this paper and the prediction models for oxidant concentrations are briefly introduced. (orig.)

Evaluation method of corrosive conditions in cooling systems of nuclear power plants by combined analyses of flow dynamics and corrosion

International Nuclear Information System (INIS)

Uchida, Shunsuke; Hotta, Koji; Ichikawa, Ryoko; Koshizuka, Seiichi

2007-01-01

Problems in major components and structural materials in nuclear power plants have often been caused by flow induced vibration, corrosion and their overlapping effects. In order to establish safe and reliable plant operation, it is necessary to predict future problems for structural materials based on combined analyses of flow dynamics and corrosion and to mitigate them before they become serious issues for plant operation. The analysis models are divided into two types. 1. Prediction models for future problems with structural materials: Distributions of oxidant concentrations along flow paths are obtained by solving water radiolysis reactions in the boiling water reactor (BWR) primary cooling water and hydrazine-oxygen reactions in the pressurized water reactor (PWR) secondary cooling water. Then, the electrochemical corrosion potential (ECP) at the point of interest is also obtained by the mixed potential model using oxidant concentration. Higher ECP enhances the possibility of intergranular stress corrosion cracking (IGSCC) in the BWR primary system, while lower ECP enhances flow accelerated corrosion (FAC) in the PWR secondary system. 2. Evaluation models of wall thinning caused by flow accelerated corrosion: The degree of wall thinning is evaluated at a location with a higher possibility of FAC occurrence, and lifetime is estimated for preventive maintenance. General features of models are reviewed in this paper and the prediction models for oxidant concentrations are briefly introduced. (orig.)

Measurement of reinforcement corrosion in concrete structures. Betonirakenteiden raudoituksen korroosion tutkiminen

Energy Technology Data Exchange (ETDEWEB)

Meuronen, A

1992-03-01

Ageing and aggressive enviromental conditions of concrete structures will result in deterioration of concrete and corrosion of steel in concrete. Corrosion of steel will in time result in the end of the service life or expensive renovations, unless corrosion of steel is noticed and renovated in time. Corrosion of steel in concrete can be found out by the present corrosion measurement methods, so that renovation can be started in right time. The report presents mainly on the basis of the literature references the following corrosion measurement methods: polarisation resistance, AC-impedance, electrical resistance probe, electrochemical noice and half-cell potential mapping. The half-cell potential mapping will be presented more precisely than the other corrosion measurement methods, for the potential mapping is the most used method. Concrete and Soils Laboratory of Imatran Voima Oy uses in the measurement of reinforcement corrosion the English, eight channel potential measuring equipment.

Measurement of reinforcement corrosion in concrete structures; Betonirakenteiden raudoituksen korroosion tutkiminen

Energy Technology Data Exchange (ETDEWEB)

Meuronen, A

1992-03-01

Ageing and aggressive enviromental conditions of concrete structures will result in deterioration of concrete and corrosion of steel in concrete. Corrosion of steel will in time result in the end of the service life or expensive renovations, unless corrosion of steel is noticed and renovated in time. Corrosion of steel in concrete can be found out by the present corrosion measurement methods, so that renovation can be started in right time. The report presents mainly on the basis of the literature references the following corrosion measurement methods: polarisation resistance, AC-impedance, electrical resistance probe, electrochemical noice and half-cell potential mapping. The half-cell potential mapping will be presented more precisely than the other corrosion measurement methods, for the potential mapping is the most used method. Concrete and Soils Laboratory of Imatran Voima Oy uses in the measurement of reinforcement corrosion the English, eight channel potential measuring equipment.

Evaluation methods for corrosion damage of components in cooling systems of nuclear power plants by coupling analysis of corrosion and flow dynamics (1). Major targets and development strategies of the evaluation methods

International Nuclear Information System (INIS)

Naitoh, Masanori; Uchida, Shunsuke; Koshizuka, Seiichi; Ninokata, Hisashi; Hiranuma, Naoki; Dosaki, Koji; Nishida, Koji; Akiyama, Minoru; Saitoh, Hiroaki

2008-01-01

Problems in major components and structural materials in nuclear power plants have often been caused by flow induced vibration and corrosion and their overlapping effects. In order to establish safe and reliable plant operation, future problems for structural materials should be predicted based on combined analyses of flow dynamics and corrosion and they should be mitigated before becoming serious issues for plant operation. Three approaches have been prepared for predicting future problems in structural materials: 1. Computer program packages for predicting future corrosion fatigue on structural materials, 2. Computer program packages for predicting future corrosion damage on structural materials, and 3. Computer program packages for predicting wall thinning caused by flow accelerated corrosion. General features of evaluation methods and their computer packages, technical innovations required for their development, and application plans for the developed approaches for plant operation are introduced in this paper. (author)

Corrosion monitoring using high-frequency guided waves

Science.gov (United States)

Fromme, P.

2016-04-01

Corrosion can develop due to adverse environmental conditions during the life cycle of a range of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Generalized corrosion leading to wall thickness loss can cause the reduction of the strength and thus degradation of the structural integrity. The monitoring of corrosion damage in difficult to access areas can be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic wedge transducers with single sided access to the structure, guided wave modes were selectively generated that penetrate through the complete thickness of the structure. The wave propagation and interference of the different guided wave modes depends on the thickness of the structure. Laboratory experiments were conducted for wall thickness reduction due to milling of the steel structure. From the measured signal changes due to the wave mode interference the reduced wall thickness was monitored. Good agreement with theoretical predictions was achieved. The high frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.

Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material

International Nuclear Information System (INIS)

Gordon, G.

2004-01-01

Stress corrosion cracking is one of the most common corrosion-related causes for premature breach of metal structural components. Stress corrosion cracking is the initiation and propagation of cracks in structural components due to three factors that must be present simultaneously: metallurgical susceptibility, critical environment, and static (or sustained) tensile stresses. This report was prepared according to ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The purpose of this report is to provide an evaluation of the potential for stress corrosion cracking of the engineered barrier system components (i.e., the drip shield, waste package outer barrier, and waste package stainless steel inner structural cylinder) under exposure conditions consistent with the repository during the regulatory period of 10,000 years after permanent closure. For the drip shield and waste package outer barrier, the critical environment is conservatively taken as any aqueous environment contacting the metal surfaces. Appendix B of this report describes the development of the SCC-relevant seismic crack density model (SCDM). The consequence of a stress corrosion cracking breach of the drip shield, the waste package outer barrier, or the stainless steel inner structural cylinder material is the initiation and propagation of tight, sometimes branching, cracks that might be induced by the combination of an aggressive environment and various tensile stresses that can develop in the drip shields or the waste packages. The Stainless Steel Type 316 inner structural cylinder of the waste package is excluded from the stress corrosion cracking evaluation because the Total System Performance Assessment for License Application (TSPA-LA) does not take credit for the inner cylinder. This document provides a detailed description of the process-level models that can be applied to assess the performance of Alloy 22

Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material

Energy Technology Data Exchange (ETDEWEB)

G. Gordon

2004-10-13

Stress corrosion cracking is one of the most common corrosion-related causes for premature breach of metal structural components. Stress corrosion cracking is the initiation and propagation of cracks in structural components due to three factors that must be present simultaneously: metallurgical susceptibility, critical environment, and static (or sustained) tensile stresses. This report was prepared according to ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The purpose of this report is to provide an evaluation of the potential for stress corrosion cracking of the engineered barrier system components (i.e., the drip shield, waste package outer barrier, and waste package stainless steel inner structural cylinder) under exposure conditions consistent with the repository during the regulatory period of 10,000 years after permanent closure. For the drip shield and waste package outer barrier, the critical environment is conservatively taken as any aqueous environment contacting the metal surfaces. Appendix B of this report describes the development of the SCC-relevant seismic crack density model (SCDM). The consequence of a stress corrosion cracking breach of the drip shield, the waste package outer barrier, or the stainless steel inner structural cylinder material is the initiation and propagation of tight, sometimes branching, cracks that might be induced by the combination of an aggressive environment and various tensile stresses that can develop in the drip shields or the waste packages. The Stainless Steel Type 316 inner structural cylinder of the waste package is excluded from the stress corrosion cracking evaluation because the Total System Performance Assessment for License Application (TSPA-LA) does not take credit for the inner cylinder. This document provides a detailed description of the process-level models that can be applied to assess the

Corrosion caused by elevator and spider marks on CRA pipe: Comparison of conventional inserts and a new gripping system

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-05-01

Corrosion-resistant alloys (CRA) are used to reduce corrosion damage to casing and tubing strings and prolong the life span of the well pipe. An analysis of various corrosion mechanisms shows that surface integrity is an important factor in corrosion prevention. Surface damage caused by inappropriate handling or conventional slip markings contribute directly to the development and propagation of corrosion. A newly developed gripping system distributes the load equally onto a large number of small peaks, minimizing the indentation of each single peak. The new gripping system does not damage the surface integrity of the pipe, virtually eliminating the corrosion potential.

Fatigue strength degradation of metals in corrosive environments

OpenAIRE

Adasooriya, Mudiyan Nirosha Damayanthi; Hemmingsen, Tor; Pavlou, Dimitrios

2017-01-01

Structures exposed to aggressive environmental conditions are often subjected to time-dependent loss of coating and loss of material due to corrosion; this causes reduction in the cross-sectional properties of the members, increased surface roughness, surface irregularities and corrosion pits, and degradation of material strengths. These effects have been identified and simulated in different research studies. However, time and corrosive media dependent fatigue strength curves for materials h...

Detrimental effect of Air pollution, Corrosion on Building Materials and Historical Structures

OpenAIRE

N. Venkat Rao; M. Rajasekhar; Dr. G. Chinna Rao

2016-01-01

The economy of any country would be drastically changed if there were no corrosion. The annual cost of corrosion world wise is over 3 % of the worlds GDP. As pet the sources available, India losses $ 45 billion every year on account of corrosion of infrastructure, Industrial machinery and other historical heritage. Keeping this critical and alarming situation in view, this paper focuses on how all these forms of corrosion affect building materials and historical structures. It als...

Evidence of the pitting corrosion induced embrittlement of the structural steel SAE 8620

International Nuclear Information System (INIS)

Atanazio Filho, Nelson do Nascimento; Mansur, Tanius Rodrigues; Rabello, Emerson Giovani

2007-01-01

The influence of an aggressive environment (NaCl 3.5% aerated solution) on fatigue crack initiation and crack growth behavior were studied. This study comprised corrosion fatigue tests using specimens of SAE 8620 steel. The decreasing cyclic frequency (60 Hz to 11.7 Hz) effect on corrosion fatigue crack initiation behavior was examined. The tests carried out under rotating-bending loading conditions at 11.7 Hz (700 rpm), showed that pitting corrosion caused by anodic attack was responsible for corrosion fatigue crack initiation (author)

Monitoring of corrosion damage using high-frequency guided ultrasonic waves

Science.gov (United States)

Chew, D.; Fromme, P.

2015-03-01

Due to adverse environmental conditions corrosion can develop during the life cycle of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the integrity and load bearing capacity of the structure. Structural health monitoring of corrosion damage in difficult to access areas can in principle be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic transducers with single sided access to the structure, high frequency guided wave modes were generated that penetrate through the complete thickness of the structure. Wall thickness reduction was induced using accelerated corrosion in a salt water bath. The corrosion damage was monitored based on the effect on the wave propagation and interference of the different modes. The change in the wave interference was quantified based on an analysis in the frequency domain (Fourier transform) and was found to match well with theoretical predictions for the wall thickness loss. High frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.

Integral diagnostic in the failure causes of external corrosion of a natural gas transport pipeline

Energy Technology Data Exchange (ETDEWEB)

Mora-Mendoza, J.L.; Saucedo-Robles, L.C.; Rodriguez-Clemente, H. [PEMEX Gas y Petroquimica Basica, Subdireccion de Ductos; Marina Nacional 329, Edificio B-1, Piso 8, Col. Huasteca, D.F., CP 11311 (Mexico); Gonzalez-Nunez, M.A. [Instituto de Investigaciones Electricas, Reforma 113, Col. Palmira, Cuernavaca, Morelos, CP 62490 (Mexico); Zavala-Olivares, G.; Hernandez-Gayosso, M.J. [Instituto Mexicano del Petroleo, Direccion de Exploracion y Produccion, Eje Central Lazaro Cardenas Norte 152, Col. San Bartolo Atepehuacan, D.F., CP 07730 (Mexico)

2011-08-15

The objective of this study consisted in investigating the possible causes which give rise to the presence of low wall pipe thicknesses on a 16'' natural gas transport pipeline, even though during the last 12-year period cathodic protection (CP) potentials were kept in the protection range at which external corrosion should not occur. Results from in-line inspection from a 16'' natural gas transport pipeline showed 46 indications with more than 80% wall thickness lost due to external corrosion in the second segment of the pipeline. Direct inspection at the indication locations, review of the CP system performance, pipeline maintenance programs and studies, allowed to make an integral diagnostic where it was found out that the main cause of external corrosion was an inappropriate coating application since the pipeline construction, this situation has originated the increase of CP shielding effects through time. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Corrosion and corrosion control

International Nuclear Information System (INIS)

Khanna, A.S.; Totlani, M.K.

1995-01-01

Corrosion has always been associated with structures, plants, installations and equipment exposed to aggressive environments. It effects economy, safety and product reliability. Monitoring of component corrosion has thus become an essential requirement for the plant health and safety. Protection methods such as appropriate coatings, cathodic protection and use of inhibitors have become essential design parameters. High temperature corrosion, especially hot corrosion, is still a difficult concept to accommodate in corrosion allowance; there is a lack of harmonized system of performance testing of materials at high temperatures. In order to discuss and deliberate on these aspects, National Association for Corrosion Engineers International organised a National Conference on Corrosion and its Control in Bombay during November 28-30, 1995. This volume contains papers presented at the symposium. Paper relevant to INIS is indexed separately. refs., figs., tabs

Boric Acid Corrosion of Concrete Rebar

Directory of Open Access Journals (Sweden)

Yang L.

2013-07-01

Full Text Available Borated water leakage through spent fuel pools (SFPs at pressurized water reactors is a concern because it could cause corrosion of reinforcement steel in the concrete structure and compromise the integrity of the structure. Because corrosion rate of carbon steel in concrete in the presence of boric acid is lacking in published literature and available data are equivocal on the effect of boric acid on rebar corrosion, corrosion rate measurements were conducted in this study using several test methods. Rebar corrosion rates were measured in (i borated water flowing in a simulated concrete crack, (ii borated water flowing over a concrete surface, (iii borated water that has reacted with concrete, and (iv 2,400 ppm boric acid solutions with pH adjusted to a range of 6.0 to 7.7. The corrosion rates were measured using coupled multielectrode array sensor (CMAS and linear polarization resistance (LPR probes, both made using carbon steel. The results indicate that rebar corrosion rates are low (~1 μm/yr or lesswhen the solution pH is ~7.1 or higher. Below pH ~7.1, the corrosion rate increases with decreasing pH and can reach ~100 μm/yr in solutions with pH less than ~6.7. The threshold pH for carbon steel corrosion in borated solution is between 6.8 and 7.3.

Evaluation of Corrosion Caused by the use of In Natura Biogas in Steam Generator Boilers of Carbon Steel Structural Elements

OpenAIRE

Fontenelle, Marcellus; Alves, Helton José; Monteiro, Marcos Roberto; Higa, Silvia Midori; Rovere, Carlos Alberto Della; Pellizzer, Eder Luis; Fontenelle, Isaddora

2017-01-01

This work evaluates the corrosion process caused by the presence of hydrogen sulfide in the biogas in natura, in steels commonly used in the construction of steam generator boilers, simulating conditions close to those found on the real application of these materials, exposing the test bodies directly to biogas in natura, flame of combustion and gases resulting from the combustion of this biofuel, in chimney. After 314 hours of exposure under the specified conditions, the corroded surfaces of...

Structural characteristics and corrosion behavior of biodegradable Mg-Zn, Mg-Zn-Gd alloys.

Science.gov (United States)

Kubásek, J; Vojtěch, D

2013-07-01

In this research, binary Mg-Zn (up to 3 wt% Zn) and ternary Mg-Zn-Gd (up to 3 wt% Gd, 3 wt% Zn) alloys were prepared by induction melting in an argon atmosphere. The structures of these alloys were characterized using light and scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction and X-ray fluorescence. In addition, Brinell hardness measurements were taken to supplement these studies. Corrosion behavior was evaluated by immersion tests and potentiodynamic measurements in a physiological solution (9 g/l NaCl). Depending on the composition, structures of the as-cast alloys contained α-Mg dendrites, MgZn, Mg5Gd and Mg3Gd2Zn3 phases. Compared to pure Mg, zinc improved the corrosion resistance of binary Mg-Zn. Gadolinium also improved the corrosion resistance in the case of Mg-1Zn-3Gd alloy. The highest corrosion rate was observed for Mg-3Zn-3Gd alloy. Our results improve the understanding of the relationships between the structure and corrosion behavior of our studied alloy systems.

Corrosion

Science.gov (United States)

Slabaugh, W. H.

1974-01-01

Presents some materials for use in demonstration and experimentation of corrosion processes, including corrosion stimulation and inhibition. Indicates that basic concepts of electrochemistry, crystal structure, and kinetics can be extended to practical chemistry through corrosion explanation. (CC)

Effect of layerwise structural inhomogeneity on stress- corrosion cracking of steel tubes

Science.gov (United States)

Perlovich, Yu A.; Krymskaya, O. A.; Isaenkova, M. G.; Morozov, N. S.; Fesenko, V. A.; Ryakhovskikh, I. V.; Esiev, T. S.

2016-04-01

Based on X-ray texture and structure analysis data of the material of main gas pipelines it was shown that the layerwise inhomogeneity of tubes is formed during their manufacturing. The degree of this inhomogeneity affects on the tendency of tubes to stress- corrosion cracking under exploitation. Samples of tubes were cut out from gas pipelines located under various operating conditions. Herewith the study was conducted both for sections with detected stress-corrosion defects and without them. Distributions along tube wall thickness for lattice parameters and half-width of X-ray lines were constructed. Crystallographic texture analysis of external and internal tube layers was also carried out. Obtained data testifies about considerable layerwise inhomogeneity of all samples. Despite the different nature of the texture inhomogeneity of gas pipeline tubes, the more inhomogeneous distribution of texture or structure features causes the increasing of resistance to stress- corrosion. The observed effect can be explained by saturation with interstitial impurities of the surface layer of the hot-rolled sheet and obtained therefrom tube. This results in rising of lattice parameters in the external layer of tube as compared to those in underlying metal. Thus, internal layers have a compressive effect on external layers in the rolling plane that prevents cracks opening at the tube surface. Moreover, the high mutual misorientation of grains within external and internal layers of tube results in the necessity to change the moving crack plane, so that the crack growth can be inhibited when reaching the layer with a modified texture.

Simulation of Corrosion Process for Structure with the Cellular Automata Method

Science.gov (United States)

Chen, M. C.; Wen, Q. Q.

2017-06-01

In this paper, from the mesoscopic point of view, under the assumption of metal corrosion damage evolution being a diffusive process, the cellular automata (CA) method was proposed to simulate numerically the uniform corrosion damage evolution of outer steel tube of concrete filled steel tubular columns subjected to corrosive environment, and the effects of corrosive agent concentration, dissolution probability and elapsed etching time on the corrosion damage evolution were also investigated. It was shown that corrosion damage increases nonlinearly with increasing elapsed etching time, and the longer the etching time, the more serious the corrosion damage; different concentration of corrosive agents had different impacts on the corrosion damage degree of the outer steel tube, but the difference between the impacts was very small; the heavier the concentration, the more serious the influence. The greater the dissolution probability, the more serious the corrosion damage of the outer steel tube, but with the increase of dissolution probability, the difference between its impacts on the corrosion damage became smaller and smaller. To validate present method, corrosion damage measurements for concrete filled square steel tubular columns (CFSSTCs) sealed at both their ends and immersed fully in a simulating acid rain solution were conducted, and Faraday’s law was used to predict their theoretical values. Meanwhile, the proposed CA mode was applied for the simulation of corrosion damage evolution of the CFSSTCs. It was shown by the comparisons of results from the three methods aforementioned that they were in good agreement, implying that the proposed method used for the simulation of corrosion damage evolution of concrete filled steel tubular columns is feasible and effective. It will open a new approach to study and evaluate further the corrosion damage, loading capacity and lifetime prediction of concrete filled steel tubular structures.

Standard guide for corrosion-related failure analysis

CERN Document Server

American Society for Testing and Materials. Philadelphia

2000-01-01

1.1 This guide covers key issues to be considered when examining metallic failures when corrosion is suspected as either a major or minor causative factor. 1.2 Corrosion-related failures could include one or more of the following: change in surface appearance (for example, tarnish, rust, color change), pin hole leak, catastrophic structural failure (for example, collapse, explosive rupture, implosive rupture, cracking), weld failure, loss of electrical continuity, and loss of functionality (for example, seizure, galling, spalling, swelling). 1.3 Issues covered include overall failure site conditions, operating conditions at the time of failure, history of equipment and its operation, corrosion product sampling, environmental sampling, metallurgical and electrochemical factors, morphology (mode) or failure, and by considering the preceding, deducing the cause(s) of corrosion failure. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibili...

A study on the corrosion characteristics of gear steel by shot peening

International Nuclear Information System (INIS)

Kang, Jin Shik; Kim, Tae Hyung; Cheong, Seong Kyun; Yoon, Jong Ku; Lee, Seung Ho

2001-01-01

The surface treatment technique to increase corrosion resistance is very important in mechanical components of structures. Therefore, this paper investigates the effects of shot peening on the corrosion resistance of SCM 420steel. The results show that the surface compressive residual stress largely increases, which cause the increase of corrosion resistance

On the application of thermodynamics of corrosion for service life design of concrete structures

DEFF Research Database (Denmark)

Küter, Andre; Geiker, Mette Rica; Møller, Per

2010-01-01

There are unexploited possibilities in the application of thermodynamics of corrosion for service life design (SLD) of concrete structures. Thermodynamics provides means for insightful descriptions of corrosion mechanisms and of corrosion protection mechanisms. Strategies for corrosion protection...... of the application of thermodynamics for SLD and gives examples of two applications: description of corrosion processes and design of countermeasures. Emphasis is set on chloride induced corrosion....... can be based on thermodynamically consistent corrosion mechanisms and evaluation of existing and design of new countermeasures can be performed using thermodynamics. Similarly, materials concepts for embedded electrodes can be designed using thermodynamics. The present paper provides a brief outline...

A Multifunctional Smart Coating for Autonomous Corrosion Control

Science.gov (United States)

Calle, Luz Marina; Buhrow, Jerry W.; Jolley, Scott T.

2012-01-01

Corrosion is a destructive process that often causes failure in metallic components and structures. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to control it. The multi-functionality of the coating is based on micro-encapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of other existing microcapsules designs, the corrosion controlled release function that allows the delivery of corrosion indicators and inhibitors on demand only when and where needed. Corrosion indicators as well as corrosion inhibitors have been incorporated into microcapsules, blended into several paint systems, and tested for corrosion detection and protection efficacy. This

Effect of boron control of environment on corrosion and resistance to low-cycle corrosion fatigue in structural steels

International Nuclear Information System (INIS)

Babej, Yu.I.; Zhitkov, V.V.; Zvezdin, Yu.I.; Liskevich, I.Yu.; Nazarov, A.A.

1982-01-01

Tests of the specimens on total, contact and crevice corrosion, corrosion cracking and low-cycle fatigue are conducted for determination of corrosion and corrosion-fatigue characteristics in the 15Kh3NMFA, 10N3MFA, 10Kh16N4B, 05Kh13N6M2 structural steels, used in energetics. The environment is subjected to boron control and contacting with atmosphere for simulation of stop and operation modes of the facility. The experiments are carried out in the distilled water with 12g/l H 3 BO 3 and 10 mg/l Cl' at 25, 60, 100 deg C under contacting with atmosphere. It is established, that the pearlitic steels 15Kh3NMFA, 10N3MFA, as well as transition and martensitic 05Kh13N6M2 and 10Kh16N4B steels are highly stable to total, crevice and contact corrosion at the high parameters of aqueous boron-containing medium. Steel resistance to low-cycle fracture decreases slightly under the conditions similar to the operation ones, in the water with 12 g/l H 3 BO 3 . Durability of the pearlitic steels at the simulation of stop conditions decreases more noticeably, crack formation as a rule, initiating from corrosion spots

An Influence of Ageing on the Structure, Corrosion Resistance and Hardness of High Aluminum ZnAl40Cu3 Alloy

Directory of Open Access Journals (Sweden)

Michalik R.

2016-03-01

Full Text Available Zn-Al-Cu alloys are used primarily because of their tribological properties as an alternative material for bronze, cast iron and aluminum alloy bearings and as a construction material. Particularly interesting are high aluminum zinc alloys. Monoeutectic zinc and aluminum alloys are characterized by the highest hardness, tensile strength and wear resistance of all of the zinc alloys. A significant problem with the use of the Zn-Al-Cu alloys is their insufficient resistance to electrochemical corrosion. Properties of Zn-Al-Cu alloys can be improved by heat treatment. The purpose of examination was to determine the effect of heat treatment (aging at various temperatures on the microstructure and corrosion resistance of the ZnAl40Cu3 alloy. The scope of the examination included: structural examinations, determination of hardness using Brinell’s method and corrosion resistance examinations. Ageing at higher temperatures causes a creation of areas where is an eutectoid mixture. The study showed that ageing causes a decrease in hardness of ZnAl40Cu3 alloy. This decrease is even greater, when the temperature of ageing is lower. The studies have shown a significant influence of ageing on the corrosion resistance of the alloy ZnAl40Cu3. Maximum corrosion resistance were characterized by the sample after ageing at higher temperatures.

Corrosion and indices of operating reliability of steam-water circuits of foreign NPP

International Nuclear Information System (INIS)

Martynova, O.I.

1983-01-01

Corrosion failures in circuits of foreign NPPs are considered. According to American statistics there are more corrosion failures in two-circuit NPPs than in NPPs with one circuit. Steam generators mostly suffer from ''corrosion denting''. Lately pitting corrosion becomes a potentially serious problem. Steam generator vertical tubes are maiply subjected to this corrosion type. Attention is drawn to intercrystalline corrosion. The causes of corrosion are described. The problem of optimization of structural materials is discussed to reduce corrosion failures as well as other methods of decreasing corrosion failures. Organization of nondestructive testing, increased requirements to water and steam purity are of great importance

An insight in spatial corrosion prediction

International Nuclear Information System (INIS)

Mustaffa, Zahiraniza; Gelder, Pieter van; Hashim, Ahmad Mustafa

2012-01-01

Recent discoveries on fluid–structure interactions between the external flows and circular cylinders placed close to the wall have added new values to the hydrodynamics of unburied offshore pipelines laid on a sea bed. The hydrodynamics of waves and/or currents introduced vortex flows surrounding the pipeline. External corrosions formed in the pipelines were assumed to be partly contributed by such fluid–structure interactions. The spatial consequences of such interactions were of interest of this study. This paper summarizes selected previous experimental and numerical works reported by literature on these discoveries. Actual field data were utilized in this study for further validation. The characteristics of corrosion orientations in the pipelines were studied comprehensively using simple statistics and results were discussed. Results adopted from the field data acknowledged well to the hypothesis from the reported literature. The updated knowledge from this fluid–structure interaction is hoped to benefit the industry and constructively incorporated into the current subsea pipeline designs. Highlights: ► We attempt to predict spatial corrosions in offshore pipelines. ► We validate the analysis using theories on fluid–structure interactions. ► Vortex flows are assumed to cause external corrosions on pipeline walls. ► More defects are expected for pipelines placed in areas governed by waves.

Corrosion and corrosion protection of support structures for offshore wind energy devices (OWEA)

Energy Technology Data Exchange (ETDEWEB)

Momber, A. [Muehlhan AG, Schlinckstrasse 3, D-21107 Hamburg (Germany)

2011-05-15

The paper provides a review about the corrosion and corrosion protection of offshore wind energy devices (OWEA). Firstly, special features resulting from location and operation of OWEA are being discussed. Secondly, types of corrosion and corrosion phenomena are summarized in a systematic way. Finally, practical solutions to the corrosion protection of OWEA, including steel allowances, cathodic protection and coatings and linings, are discussed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A probabilistic physics-of-failure model for prognostic health management of structures subject to pitting and corrosion-fatigue

International Nuclear Information System (INIS)

Chookah, M.; Nuhi, M.; Modarres, M.

2011-01-01

A combined probabilistic physics-of-failure-based model for pitting and corrosion-fatigue degradation mechanisms is proposed to estimate the reliability of structures and to perform prognosis and health management. A mechanistic superposition model for corrosion-fatigue mechanism was used as a benchmark model to propose the simple model. The proposed model describes the degradation of the structures as a function of physical and critical environmental stresses, such as amplitude and frequency of mechanical loads (for example caused by the internal piping pressure) and the concentration of corrosive chemical agents. The parameters of the proposed model are represented by the probability density functions and estimated through a Bayesian approach based on the data taken from the experiments performed as part of this research. For demonstrating applications, the proposed model provides prognostic information about the reliability of aging of structures and is helpful in developing inspection and replacement strategies. - Highlights: ► We model an inventory system under static–dynamic uncertainty strategy. ► The demand is stochastic and non-stationary. ► The optimal ordering policy is proven to be a base stock policy. ► A solution algorithm for finding an optimal solution is provided. ► Two heuristics developed produce high quality solutions and scale-up efficiently.

A Multifunctional Coating for Autonomous Corrosion Control

Science.gov (United States)

Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott t.

2011-01-01

Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of existing microcapsulation designs, the corrosion controlled release function that triggers the delivery of corrosion indicators and inhibitors on demand, only when and where needed. Microencapsulation of self-healing agents for autonomous repair of mechanical damage to the coating is also being pursued. Corrosion indicators, corrosion inhibitors, as well as self-healing agents, have been encapsulated and dispersed into several paint systems to test the corrosion detection, inhibition, and self-healing properties of the coating. Key words: Corrosion, coating, autonomous corrosion control, corrosion indication, corrosion inhibition, self-healing coating, smart coating, multifunctional coating, microencapsulation.

Smart Multifunctional Coatings for Corrosion Detection and Control in the Aerospace Industry

Science.gov (United States)

Calle, Luz Marina

2015-01-01

Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it.

NASA's Corrosion Technology Laboratory at the Kennedy Space Center: Anticipating, Managing, and Preventing Corrosion

Science.gov (United States)

Calle, Luz Marina

2014-01-01

Corrosion is the degradation of a material that results from its interaction with the environment. The marine environment at NASAs Kennedy Space Center (KSC) has been documented by ASM International (formerly American Society for Metals) as the most corrosive in the United States. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pads were rendered even more severe by the 70 tons of highly corrosive hydrochloric acid that were generated by the solid rocket boosters. Numerous failures at the launch pads are caused by corrosion.The structural integrity of ground infrastructure and flight hardware is critical to the success, safety, cost, and sustainability of space missions. As a result of fifty years of experience with launch and ground operations in a natural marine environment that is highly corrosive, NASAs Corrosion Technology Laboratory at KSC is a major source of corrosion control expertise in the launch and other environments. Throughout its history, the Laboratory has evolved from what started as an atmospheric exposure facility near NASAs launch pads into a world-wide recognized capability that provides technical innovations and engineering services in all areas of corrosion for NASA and external customers.This presentation will provide a historical overview of the role of NASAs Corrosion Technology in anticipating, managing, and preventing corrosion. One important challenge in managing and preventing corrosion involves the detrimental impact on humans and the environment of what have been very effective corrosion control strategies. This challenge has motivated the development of new corrosion control technologies that are more effective and environmentally friendly. Strategies for improved corrosion protection and durability can have a huge impact on the economic sustainability of human spaceflight operations.

Development of evaluation method on flow-induced vibration and corrosion of components in two-phase flow by coupled analysis. 2. Evaluation of corrosive conditions in cooling systems of nuclear power plants

International Nuclear Information System (INIS)

Uchida, Shunsuke; Naitoh, Masanori; Okada, Hidetoshi; Uehara, Yasushi; Katono, Kenichi; Ichikawa, Ryoko; Hotta, Koji

2007-01-01

In order to establish safety and reliable plant operation, it is required to forecast future troubles on structural materials based on combined analyses of flow dynamics and corrosion and to mitigate them before they become serious problems on plant operation. The models are divided into two parts, which are as follows. 1. Prediction model of future trouble on structural materials based on evaluation of corrosive conditions. 2. Evaluation model of wall thinning caused by flow accelerated corrosion. (author)

Eradication of the corrosion-causing bacterial strains Desulfovibrio vulgaris and Desulfovibrio desulfuricans using photodisinfection

Energy Technology Data Exchange (ETDEWEB)

Street, C.N.; Gibbs, A.J. [Biocorrosion Solutions Inc., Edmonton, AB (Canada)

2010-07-01

Microbiologically influenced corrosion (MIC) can cause oil and gas pipelines to fail prematurely. The free-floating bacteria collects on the inner pipeline surface to form complex adherent biofilms. This study evaluated the use of photodisinfection as a means of treating 2 sulfate-reducing bacterial strains known to contribute to MIC. The sulfate-reducing strains Desulfovibrio vulgaris and Desulfovibrio desulfuricans were studied experimentally to a concentration of 10{sup 7} colony-forming units per millimeter. Bacterial inocula was made to an optical density of 0.150 at 420 nm in order to assess biofilm growth. The study showed that photodisinfection was able to eradicate more than 99 per cent of the bacterial populations prepared in the study. The method was highly effective in removing the biofilms known to cause MIC in oil and gas pipelines. A close-loop dynamic flow system model will be prepared to evaluate the ability of photodisinfection to inhibit bacterially-influenced corrosion of steel coupons. 24 refs., 3 tabs., 1 fig.

DEVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

Energy Technology Data Exchange (ETDEWEB)

Bill W. Bogan; Brigid M. Lamb; John J. Kilbane II

2004-10-30

The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Previous testing indicated that the growth, and the metal corrosion caused by pure cultures of sulfate reducing bacteria were inhibited by hexane extracts of some pepper plants. This quarter tests were performed to determine if chemical compounds other than pepper extracts could inhibit the growth of corrosion-associated microbes and to determine if pepper extracts and other compounds can inhibit corrosion when mature biofilms are present. Several chemical compounds were shown to be capable of inhibiting the growth of corrosion-associated microorganisms, and all of these compounds limited the amount of corrosion caused by mature biofilms to a similar extent. It is difficult to control corrosion caused by mature biofilms, but any compound that disrupts the metabolism of any of the major microbial groups present in corrosion-associated biofilms shows promise in limiting the amount/rate of corrosion.

Stress state reassessment of Romanian offshore structures taking into account corrosion influence

Science.gov (United States)

Joavină, R.; Zăgan, S.; Zăgan, R.; Popa, M.

2017-08-01

Progressive degradation analysis for extraction or exploration offshore structure, with appraisal of failure potential and the causes that can be correlated with the service age, depends on the various sources of uncertainty that require particular attention in design, construction and exploitation phases. Romanian self erecting platforms are spatial lattice structures consist of tubular steel joints, forming a continuous system with an infinite number of dynamic degrees of freedom. Reassessment of a structure at fixed intervals of time, recorrelation of initial design elements with the actual situation encountered in location and with structural behaviour represents a major asset in lowering vulnerabilities of offshore structure. This paper proposes a comparative reassessment of the stress state for an offshore structure Gloria type, when leaving the shipyard and at the end of that interval corresponding to capital revision, taking into account sectional changes due to marine environment corrosion. The calculation was done using Newmark integration method on a 3D model, asses of the dynamic loads was made through probabilistic spectral method.

An AFM and XPS study of corrosion caused by micro-liquid of dilute sulfuric acid on stainless steel

International Nuclear Information System (INIS)

Wang Rongguang

2004-01-01

Micro-liquid of dilute sulfuric acid deposited on SUS304 steel surface were observed with the ac non-contact mode of an atomic force microscopy (AFM), and the detail of the corrosion process caused by them was investigated with the contact mode of the AFM, X-ray photoelectron spectroscopy (XPS) and wavelength dispersive X-ray spectroscopy (WDXS). As a result, even not applying bias voltages between the tip of the cantilever and the specimen, micro-liquid of sulfuric acid can be successfully imaged using the ac non-contact mode of AFM. Two shapes of micro-acid, i.e., micro-droplets and micro-films, were found to co-exist on the specimen surface. On areas covered by micro-films of acid, only small corrosion product particles appeared and no corrosion pits were found. Beneath micro-droplets, corrosion reaction continue to produce pits until they were all consumed to form a corrosion product (mainly iron oxides) with almost the same shape with the droplet. The total corrosion reaction time was speculated to be between 690 and 1500 ks. The corrosion product formed from micro-droplets was believed to be a process of accumulating small corrosion product particles from the liquid/substrate interface to the surface of the formerly produced corrosion product. The XPS and WDXS analysis also supports the above results

Corrosion resistance of structural material AlMg-2 in water following heat treatment and cooling

International Nuclear Information System (INIS)

Maman Kartaman A; Djoko Kisworo; Dedi Hariyadi; Sigit

2005-01-01

Corrosion tests of structural material AlMg-2 in water were carried out using autoclave in order to study the effects of heat treatment on the corrosion resistance of the material. Prior to the tests, the samples were heat-treated at temperatures of 90, 200, 300 and 500 °C and cooled in air, sand and water. The corrosion tests were conducted in water at temperature of 150 °C for 250 hours. The results showed that AlMg-2 samples were corroded although the increase of mass gain was relatively small. Heat treatment from 90 to 500 °C in sand cooling media resulted in an increase of mass gain despite that at 300 °C the increase was less than those at 200 °C and 500 °C. For water cooling media in the temperature range of 90 to 200 °C, the mass gain increased from 0.1854 g/cm 2 to 2.1204 g/cm 2 although after 200 °C it decreased to 1.8207 g/cm 2 and 1.6779 g/cm 2 respectively. For air cooling media, the mass gain was relatively constant. Based on the experiment results, it can be concluded that heat treatment and cooling did not significantly influence the corrosion resistance of material AlMg-2. The passive film Al 2 O 3 on the surface was able to protect the inner surface from further corrosion. Water media with pH range from 4 – 9 did not cause damage to passive layer formed. (author)

Structure Analysis Of Corrosion Resistant Thermal Sprayed Coatings On Low Alloy Steels

Science.gov (United States)

Chaliampalias, D.; Vourlias, G.; Pistofidis, N.; Pavlidou, E.; Stergiou, A.; Stergioudis, G.; Polychroniadis, E. K.

2007-04-01

Metallic coatings have been proved to reduce the rate of corrosion of steel in various atmospheres. In this work the structure of Al, Cu-Al and Zn thermal sprayed coatings is examined. The as formed coatings are extremely rough, and they are composed of several phases which increase corrosion resistance as it was determined Salt Spray Chamber tests.

Fatigue strength degradation of metals in corrosive environments

Science.gov (United States)

Adasooriya, N. D.; Hemmingsen, T.; Pavlou, D.

2017-12-01

Structures exposed to aggressive environmental conditions are often subjected to time-dependent loss of coating and loss of material due to corrosion; this causes reduction in the cross-sectional properties of the members, increased surface roughness, surface irregularities and corrosion pits, and degradation of material strengths. These effects have been identified and simulated in different research studies. However, time and corrosive media dependent fatigue strength curves for materials have not been discussed in the design or assessment guidelines for structures. This paper attempts to review the corrosion degradation process and available approaches/models used to determine the fatigue strength of corroded materials and to interpolate corrosion deterioration data. High cycle fatigue and full range fatigue life formulae for fatigue strength of corroded materials are proposed. The above formulae depend on the endurance limit of corroded material, in addition to the stress-life fatigue curve parameters of the uncorroded material. The endurance limit of corroded material can either be determined by a limited number of tests in the very high-cycle fatigue region or predicted by an analytical approach. Comparison with experimentally measured corrosion fatigue behavior of several materials is provided and discussed.

Achievments of corrosion science and corrosion protection technology

International Nuclear Information System (INIS)

Fontana, M.; Stehjl, R.

1985-01-01

Problems of corrosion-mechanical strength of metals, effect of corrosive media on creep characteristics are presented. New concepts of the mechanism of corrosion cracking and its relation to hydrogen embrittlement are described. Kinetics and mechanism of hydrogen embrittlement effect on the process of corrosion cracking of different steels and alloys are considered. The dependence of such types of failure on various structural factors is shown. Data on corrosion cracking of high-strength aluminium and titanium alloys, mechanism of the processes and protective methods are given

Corrosion on Mars: An Investigation of Corrosion Mechanisms Under Relevant Simulated Martian Environments

Science.gov (United States)

Calle, Luz M.; Li, Wenyan; Johansen, Michael R.; Buhrow, Jerry W.; Calle, Carlos I.

2017-01-01

This one-year project was selected by NASA's Science Innovation Fund in FY17 to address Corrosion on Mars which is a problem that has not been addressed before. Corrosion resistance is one of the most important properties in selecting materials for landed spacecraft and structures that will support surface operations for the human exploration of Mars. Currently, the selection of materials is done by assuming that the corrosion behavior of a material on Mars will be the same as that on Earth. This is understandable given that there is no data regarding the corrosion resistance of materials in the Mars environment. However, given that corrosion is defined as the degradation of a metal that results from its chemical interaction with the environment, it cannot be assumed that corrosion is going to be the same in both environments since they are significantly different. The goal of this research is to develop a systematic approach to understand corrosion of spacecraft materials on Mars by conducting a literature search of available data, relevant to corrosion in the Mars environment, and by performing preliminary laboratory experiments under relevant simulated Martian conditions. This project was motivated by the newly found evidence for the presence of transient liquid brines on Mars that coincided with the suggestion, by a team of researchers, that some of the structural degradation observed on Curiosity's wheels may be caused by corrosive interactions with the brines, while the most significant damage was attributed to rock scratching. An extensive literature search on data relevant to Mars corrosion confirmed the need for further investigation of the interaction between materials used for spacecraft and structures designed to support long-term surface operations on Mars. Simple preliminary experiments, designed to look at the interaction between an aerospace aluminum alloy (AA7075-T73) and the gases present in the Mars atmosphere, at 20degC and a pressure of 700 Pa

Non-Destructive Evaluation for Corrosion Monitoring in Concrete: A Review and Capability of Acoustic Emission Technique

Science.gov (United States)

Zaki, Ahmad; Chai, Hwa Kian; Aggelis, Dimitrios G.; Alver, Ninel

2015-01-01

Corrosion of reinforced concrete (RC) structures has been one of the major causes of structural failure. Early detection of the corrosion process could help limit the location and the extent of necessary repairs or replacement, as well as reduce the cost associated with rehabilitation work. Non-destructive testing (NDT) methods have been found to be useful for in-situ evaluation of steel corrosion in RC, where the effect of steel corrosion and the integrity of the concrete structure can be assessed effectively. A complementary study of NDT methods for the investigation of corrosion is presented here. In this paper, acoustic emission (AE) effectively detects the corrosion of concrete structures at an early stage. The capability of the AE technique to detect corrosion occurring in real-time makes it a strong candidate for serving as an efficient NDT method, giving it an advantage over other NDT methods. PMID:26251904

Non-Destructive Evaluation for Corrosion Monitoring in Concrete: A Review and Capability of Acoustic Emission Technique

Directory of Open Access Journals (Sweden)

Ahmad Zaki

2015-08-01

Full Text Available Corrosion of reinforced concrete (RC structures has been one of the major causes of structural failure. Early detection of the corrosion process could help limit the location and the extent of necessary repairs or replacement, as well as reduce the cost associated with rehabilitation work. Non-destructive testing (NDT methods have been found to be useful for in-situ evaluation of steel corrosion in RC, where the effect of steel corrosion and the integrity of the concrete structure can be assessed effectively. A complementary study of NDT methods for the investigation of corrosion is presented here. In this paper, acoustic emission (AE effectively detects the corrosion of concrete structures at an early stage. The capability of the AE technique to detect corrosion occurring in real-time makes it a strong candidate for serving as an efficient NDT method, giving it an advantage over other NDT methods.

Corrosion induced failure analysis of subsea pipelines

International Nuclear Information System (INIS)

Yang, Yongsheng; Khan, Faisal; Thodi, Premkumar; Abbassi, Rouzbeh

2017-01-01

Pipeline corrosion is one of the main causes of subsea pipeline failure. It is necessary to monitor and analyze pipeline condition to effectively predict likely failure. This paper presents an approach to analyze the observed abnormal events to assess the condition of subsea pipelines. First, it focuses on establishing a systematic corrosion failure model by Bow-Tie (BT) analysis, and subsequently the BT model is mapped into a Bayesian Network (BN) model. The BN model facilitates the modelling of interdependency of identified corrosion causes, as well as the updating of failure probabilities depending on the arrival of new information. Furthermore, an Object-Oriented Bayesian Network (OOBN) has been developed to better structure the network and to provide an efficient updating algorithm. Based on this OOBN model, probability updating and probability adaptation are performed at regular intervals to estimate the failure probabilities due to corrosion and potential consequences. This results in an interval-based condition assessment of subsea pipeline subjected to corrosion. The estimated failure probabilities would help prioritize action to prevent and control failures. Practical application of the developed model is demonstrated using a case study. - Highlights: • A Bow-Tie (BT) based corrosion failure model linking causation with the potential losses. • A novel Object-Oriented Bayesian Network (OOBN) based corrosion failure risk model. • Probability of failure updating and adaptation with respect to time using OOBN model. • Application of the proposed model to develop and test strategies to minimize failure risk.

Boundary element inverse analysis for rebar corrosion detection: Study on the 2004 tsunami-affected structure in Aceh

Directory of Open Access Journals (Sweden)

S. Fonna

2018-06-01

Full Text Available Evaluation of rebar/reinforcing-steel corrosion for the 2004 tsunami-affected reinforced concrete (RC buildings in Aceh was conducted using half-cell potential mapping technique. However, the results only show qualitative meaning as corrosion risk rather than the corrosion itself, such as the size and location of corrosion. In this study, boundary element inverse analysis was proposed to be performed to detect rebar corrosion of the 2004 tsunami-affected structure in Aceh, using several electrical potential measurement data on the concrete surface. One RC structure in Peukan Bada, an area heavily damaged by the tsunami, was selected for the study. In 2004 the structure was submerged more than 5 m by the tsunami. Boundary element inverse analysis was developed by combining the boundary element method (BEM and particle swarm optimization (PSO. The corrosion was detected by evaluating measured and calculated electrical potential data. The measured and calculated electrical potential on the concrete surface was obtained by using a half-cell potential meter and by performing BEM, respectively. The solution candidates were evaluated by employing PSO. Simulation results show that boundary element inverse analysis successfully detected the size and location of corrosion for the case study. Compared with the actual corrosion, the error of simulation result was less than 5%. Hence, it shows that boundary element inverse analysis is very promising for further development to detect rebar corrosion. Keywords: Inverse analysis, Boundary element method, PSO, Corrosion, Reinforced concrete

Corrosion cracking

International Nuclear Information System (INIS)

Goel, V.S.

1985-01-01

This book presents the papers given at a conference on alloy corrosion cracking. Topics considered at the conference included the effect of niobium addition on intergranular stress corrosion cracking, corrosion-fatigue cracking in fossil-fueled-boilers, fracture toughness, fracture modes, hydrogen-induced thresholds, electrochemical and hydrogen permeation studies, the effect of seawater on fatigue crack propagation of wells for offshore structures, the corrosion fatigue of carbon steels in seawater, and stress corrosion cracking and the mechanical strength of alloy 600

Corrosion Risk of Reinforced Concrete Structure Arising from Internal and External Chloride

Directory of Open Access Journals (Sweden)

M. J. Kim

2018-01-01

Full Text Available The corrosion risk of internal chloride and external chloride from three different exposure conditions was evaluated. The initiation of corrosion was detected by monitoring the galvanic current between cathode metal and embedded steel. The chloride threshold was determined by measuring the corrosion rate of steel by the polarization technique for internal chloride and the chloride profiling test for external chloride. As the result, the initiation of corrosion was accelerated with a cyclic wet/dry condition, compared to the totally wet condition. In addition, it was found that an increase of the drying ratio in the exposure condition resulted in an increase of corrosion rate after initiation. The threshold level of external chloride ranged from 0.2 to 0.3% weight by cement and internal chloride shows higher range, equated to 1.59–3.10%. Based on these data, the chloride penetration with exposure condition was predicted to determine the service life of reinforced concrete structure.

Radiation corrosion in aluminum alloy bellows

International Nuclear Information System (INIS)

Konno, Osamu

1987-01-01

Testing was carried out in which materials for vacuum devices (Al, Ti, Cu, SUS) are exposed to electron beams (50 MeV, average current 80 μA) to determine the changes in the quantity, partial pressure and composition of the gases released from the materials. The test appratus used are made of Al alloys alone. During the test, vacuum leak is found in the Al alloy bellows used in the drive device. The leak is found to result from corrosion caused by water. The surface structure is analyzed by SEM, EPMA, ESCA and IMA. It is confirmed that the Al alloy used as material for the bellows if highly resistant to corrosion. It is concluded that it is necessary to use high purity cooling water to prevent the cooling water from causing corrosion. It has been reported that high purity aluminum is very high in resistance to corrosion. Based on these measurements and considerations, it is suggested that when aluminum is to be used as material for vacuum devices in an accelerator, it is required to provide protection film on its surface to prevent corrosion or to use cooling water pipes cladded with pure aluminum and an aluminum alloy. In addition, the temperature of the cooling water should be set after adequately considering the environmental conditions in the room. (Nogami, K.)

Enamel coated steel reinforcement for improved durability and life-cycle performance of concrete structures: microstructure, corrosion, and deterioration

Science.gov (United States)

Tang, Fujian

This study is aimed (a) to statistically characterize the corrosion-induced deterioration process of reinforced concrete structures (concrete cracking, steel mass loss, and rebar-concrete bond degradation), and (b) to develop and apply three types of enamel-coated steel bars for improved corrosion resistance of the structures. Commercially available pure enamel, mixed enamel with 50% calcium silicate, and double enamel with an inner layer of pure enamel and an outer layer of mixed enamel were considered as various steel coatings. Electrochemical tests were respectively conducted on steel plates, smooth bars embedded in concrete, and deformed bars with/without concrete cover in 3.5 wt.% NaCl or saturated Ca(OH)2 solution. The effects of enamel microstructure, coating thickness variation, potential damage, mortar protection, and corrosion environment on corrosion resistance of the steel members were investigated. Extensive test results indicated that corrosion-induced concrete cracking can be divided into four stages that gradually become less correlated with corrosion process over time. The coefficient of variation of crack width increases with the increasing level of corrosion. Corrosion changed the cross section area instead of mechanical properties of steel bars. The bond-slip behavior between the corroded bars and concrete depends on the corrosion level and distribution of corrosion pits. Although it can improve the chemical bond with concrete and steel, the mixed enamel coating is the least corrosion resistant. The double enamel coating provides the most consistent corrosion performance and is thus recommended to coat reinforcing steel bars for concrete structures applied in corrosive environments. Corrosion pits in enamel-coated bars are limited around damage locations.

Study of ion plating parameters, coating structure, and corrosion protection for aluminum coatings on uranium

International Nuclear Information System (INIS)

Egert, C.M.; Scott, D.G.

1987-01-01

A study of ion-plating parameters (primarily deposition rate and substrate bias voltage), coating structure, and the corrosion protection provided by aluminum coatings on uranium is presented. Ion plating at low temperatures yields a variety of aluminum coating structures on uranium. For example, aluminum coatings produced at high deposition rates and low substrate bias voltages are columnar with voids between columns, as expected for high-rate vapor deposition at low temperatures. On the other hand, low deposition rate and high bias voltage produce a modified coating with a dense, noncolumnar structure. These results are not in agreement with other studies that have found no relationship between deposition rate and coating structure in ion plating. This discrepancy is probably due to the high deposition rates used in these studies. An accelerated, water vapor corrosion test indicates that the columnar aluminum coatings provide some corrosion protection despite their porous nature; however, the dense noncolumnar coatings provide significantly greater protection. These results indicate that ion-plated aluminum coatings produced at low deposition rates and high substrate bias voltages creates dense coating structures that are most effective in protecting uranium from corrosion

The anti corrosive design of structural metallic elements in buildings with large exploitation period; El diseno anticorrovio de elementos estructurales metalicos en edificaciones con periodos prolongados de explotacion

Energy Technology Data Exchange (ETDEWEB)

Avila Ayon, V.; Rodriguez Quesada, A. L.

2009-07-01

The corrosion deterioration in metallic structural elements, with the consistent loss of his physical and mechanical properties, is cause by errors in the design or fabrication, that allows the accumulation of humidity and contaminants in the surfaces, or acceleration zones of the corrosion processes, as the bimetalics pairs. The aggressiveness of the environment and the productive processes that develop in industrial installations, causes the apparition of premature failures that engage the edification use. The identification of design errors is the first step in the conservation of these structures. the elimination and made a project adapted to the proper installations conditions, is essential procedures to prolong the edification useful life with an optimum and rational use of the resources that destined for this end. The investigation is about the results obtained in the diagnostic and the conservation of industrial installment, with large exploitation periods, in which existed evidences of failures by corrosion, specifically to the elimination of errors of design. (Author) 12 refs.

Underground Corrosion by Microorganisms Part II : Role of Anaerobic Sulphate Reducing Bacteria-Desulfotomaculum SP

OpenAIRE

H. M. Dayal; K. C. Tiwari; Kamlesh Mehta; Mr. Chandrashekhar

1988-01-01

During the course of studies on the corrosion causing soil microflora from different geoclimatic regions of India, several strains of anaerobic sulphate reducing bacteria belonging to genus Desulfotomaculum were isolated and characterised. Their corrosive action on mild steel, galvanised iron and structural aluminium, the three main metals of construction of underground structures, have been studied under laboratory conditions.

Erosion corrosion in water-steam systems: Causes and countermeasures

International Nuclear Information System (INIS)

Heitmann, H.G.; Kastner, W.

1985-01-01

For the purpose of a better understanding of erosion corrosion, the physical and chemical principles will be summarized briefly. Then results obtained at KWU in the BENSON test section in tests on test specimens in single-phase flow of fully demineralized water will be presented. The experimental studies provide information about the most important influencing parameters. These include flow rate, fluid temperature and water quality (pH value and oxygen content). In addition, the resistance of various materials is compared, and the resistance of magnetite coatings to erosion corrosion is investigated. Furthermore, tests are presented that will show the extent to which erosion corrosion in power plants can be influenced by chemical measures

Corrosion of lead shielding in a radiology department

International Nuclear Information System (INIS)

Schick, D.K.; CAsey, R.N.; Sim, L.H.; Siddle, K.J.

1999-01-01

Corrosion of lead sheet used for structural radiation protection in the Princess Alexandra Hospital Radiology Department has been identified. The corrosion is thought to have been caused by organic acid vapours released from oregon timber wall panelling. Non-destructive testing (NDT) and X-ray transmission measurements were used to define the extent and severity of damage, and subsequently to provide the data necessary for estimation of staff and public radiation doses. Although radiation dose limits have not been exceeded, corrective actions including structural modifications and staff information sessions have been undertaken. Copyright (1999) Blackwell Science Pty Ltd

Monitoring dc stray current corrosion at sheet pile structures

NARCIS (Netherlands)

Peelen, W.H.A.; Neeft, E.A.C.; Leegwater, G.; Kanten-Roos, W. van; Courage, W.M.G.

2012-01-01

Steel is discarded by railway owners as a material for underground structures near railway lines, due to uncertainty over increased corrosion by DC stray currents stemming from the traction power system. This paper presents a large scale field test in which stray currents interference of a sheet

Effect of temperature on structure and corrosion resistance for ...

Indian Academy of Sciences (India)

The effect of plating temperatures between 60 and 90◦C on structure and corrosion resistance for elec- troless NiWP coatings ..... which helps to form fine grain. At 80 .... [23] Zhang W X, Jiang Z H, Li G Y and Jiang Q 2008 Surf. Coat. Technol.

Structure, mechanical and corrosion properties of powdered stainless steel Kh13

International Nuclear Information System (INIS)

Radomysel'skij, I.D.; Napara-Volgina, S.G.; Orlova, L.N.; Apininskaya, L.M.

1982-01-01

Structure, mechanical and corrosion properties are studied for compact powdered stainless steel, Grade Kh13, produced from prealloyed powder and a mixture of chromium and iron powders by hot vacuum pressing (HVP) following four schemes: HVP of unsintered billets; HVP of presintered billets; HVP of unsintered billets followed by diffusion annealing; HVP of sintered billets followed by diffusion annealing. Analysis of the structure, mechanical and corrosion properties of Kh13 steel produced according to the four schemes confirmed that production of this steel by the HVP method without presintering of porous billets and diffusion annealing of compact stampings is possible only when prealloyed powder of particular composition is used as a starting material

Microstructural characterisation and corrosion performance of old railway girder bridge steel and modern weathering structural steel

International Nuclear Information System (INIS)

Tewary, N.K.; Kundu, A.; Nandi, R.; Saha, J.K.; Ghosh, S.K.

2016-01-01

Highlights: • Microstructure and corrosion performance are compared for two structural steels. • Microstructure evolution shows primarily ferrite-pearlite in both the steels. • Steels show higher corrosion rate in 1% HCl solution than in 3.5% NaCl solution. • The corrosion products show the presence of oxide, hydroxide and oxy-hydroxides. • The corroded surface reveals morphologies like flowery, cotton balls and rosette. - Abstract: A comparison on microstructure and corrosion performance has been made between the two structural steels used in old railway girder bridge (Sample A) and modern grades of weathering structural steel (Sample B). The microstructures, viewed under optical microscope and scanning electron microscope (SEM), show mainly ferrite-pearlite phase constituents in both the steels, A and B. The phase fraction analysis shows higher amount of pearlite in steel A compared to that of steel B. The grain size of steel A is larger than that of steel B under identical processing condition. The immersion corrosion test in 3.5% NaCl shows that the corrosion rate of steel A increases with time, while the same for steel B decreases with time. On the other hand, corrosion test in 1% HCl shows that the corrosion rate of both steel A and B is higher as compared to that of NaCl which always decreases with time. The XRD analysis of corrosion products show the presence of many oxides, hydroxide and oxy-hydroxide like Lepidocrocite (γ-FeOOH), Goethite (α-FeOOH), Akaganeite (β-FeOOH), Magnetite (Fe_3O_4) and Maghemite (γ-Fe_2O_3) in both the steels. The SEM images of corroded surfaces reveal different morphologies like flowery, cotton balls and rosette etc. which indicate that the corrosion products primarily contain Lepidocrocite (γ-FeOOH), Goethite (α-FeOOH) and Akaganeite (β-FeOOH).

Development of evaluation method on flow-induced vibration and corrosion of components in two-phase flow by coupled analysis. 1. Evaluation of effects of flow-induced vibration on structural material integrity

International Nuclear Information System (INIS)

Naitoh, Masanori; Uchida, Shunsuke; Koshizuka, Seiichi; Ninokata, Hisashi; Anahara, Naoki; Dosaki, Koji; Katono, Kenichi; Akiyama, Minoru; Saitoh, Hiroaki

2007-01-01

Problems in major components and structural materials in nuclear power plants have often been caused by flow induced vibration, corrosion and their overlapping effects. In order to establish safe and reliable plant operation, it is necessary to predict future problems for structural materials based on combined analyses of flow dynamics and corrosion and to mitigate them before they become serious issues for plant operation. An innovative method for flow induced vibration of structures in two phase flow by combined analyses of three dimensional flow dynamics and structures is to be introduced. (author)

Internal corrosion control of northern pipelines

Energy Technology Data Exchange (ETDEWEB)

Papavinasam, S.

2005-02-01

The general causes of internal corrosion in pipelines were discussed along with the methods to control them. Efficient methods are needed to determine chemical efficiency for mitigating internal corrosion in transmission pipelines, particularly those used in environmentally sensitive regions in the Arctic where harsh environmental conditions prevail. According to the Office of Pipeline Safety, 15 per cent of pipeline failures in the United States from 1994 to 2000 were caused by internal corrosion. Since pipelines in the United States are slightly older than Canadian pipelines, internal corrosion is a significant issue from a Canadian perspective. There are 306,618 km of energy-related pipelines in western Canada. Between April 2001 and March 2002 there were 808 failures, of which 425 failures resulted from internal corrosion. The approach to control internal corrosion comprises of dehydrating the gases at production facilities; controlling the quality of corrosive gases such as carbon dioxide and hydrogen sulphide; and, using internal coatings. The approaches to control internal corrosion are appropriate, when supplemented by adequate integrity management program to ensure that corrosive liquids do not collect, over the operational lifetime of the pipelines, at localized areas. It was suggested that modeling of pipeline operations may need improvement. This paper described the causes, prediction and control of internal pitting corrosion. It was concluded that carbon steel equipment can continue to be used reliably and safely as pipeline materials for northern pipelines if the causes that lead to internal corrosion are scientifically and accurately predicted, and if corrosion inhibitors are properly evaluated and applied. 5 figs.

Modelling reinforcement corrosion in concrete

DEFF Research Database (Denmark)

Michel, Alexander; Geiker, Mette Rica; Stang, Henrik

2012-01-01

A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold......, a numerical example is pre-sented, that illustrates the formation of corrosion cells as well as propagation of corrosion in a reinforced concrete structure....

Electrochemical methods for the inspection of reinforcement corrosion in concrete structures - field experience

International Nuclear Information System (INIS)

Elsener, B.; Boehni, H.

1992-01-01

Maintenance and planning of the restoration work on reinforced concrete structures need a rapid, non-destructive inspection technique that detects corrosion at an early stage. In this paper the field experience with electrochemical techniques are reported. The results of potential surveys on bridge decks of the Swiss highways, realized with a new computer controlled eight-wheel measurement system, clearly show that a fixed potential value (as proposed in ASTM C 876-87) for the identification and location of active corrosion of steel in concrete does not exist. A statistical elaboration of the potential data allows to identify the potential value for corroding and passive rebar for each structure individually. A rapid new technique using galvanostatic pulse measurements was tested successfully on site. It gives clear, unambiguous results on the corrosion state of the rebars when half-cell potentials are uncertain. In addition, the ohmic resistance and the apparent polarization resistance are determined from the evaluation of the transients. From these values the concrete resistivity and the actual corrosion rate of the rebars may be estimated

Development of stress corrosion techniques for structural integrity evaluation and life extension of PWR facilities

International Nuclear Information System (INIS)

Moreira, Pedro A.L.D.L. Pinheiro; Vilela, Jeferson J.; Lorenzo, Roberto F. Di; Lopes, Jadir A.M.

2000-01-01

The stress corrosion is a mechanism of degradation present in the nuclear plants. To extend the life of the plants components, this corrosion type it should be known. An evaluation for the implantation of methodologies of stress corrosion study in CDTN/CNEN, shows that the technique of slow deformation can be used in the evaluation of integrity structural nuclear power stations. This technique consists of straining a sample slowly, usually, in strain rate between 10 -4 and 10- 8 s -1 and in conditions that simulate the reactivity of the metal in environment (pressure, temperature, chemical composition of the water and etc) similar to the found at the nuclear power power stations. This simulation allows evaluating susceptibility the stress corrosion of components mechanical and structure that operate in central nuclear. (author)

Prognostic investigation of galvanic corrosion precursors in aircraft structures and their detection strategy

Science.gov (United States)

James, Robin; Kim, Tae Hee; Narayanan, Ram M.

2017-04-01

Aluminum alloys have been the dominant materials for aerospace construction in the past fifty years due to their light weight, forming and alloying, and relative low cost in comparison to titanium and composites. However, in recent years, carbon fiber reinforced polymers (CFRPs) and honeycomb materials have been used in aircrafts in the quest to attain lower weight, high temperature resistance, and better fuel efficiency. When these two materials are coupled together, the structural strength of the aircraft is unparalleled, but this comes at a price, namely galvanic corrosion. Previous experimental results have shown that when CFRP composite materials are joined with high strength aluminum alloys (AA7075-T6 or AA2024-T3), galvanic corrosion occurs at the material interfaces, and the aluminum is in greater danger of corroding, particularly since carbon and aluminum are on the opposite ends of the galvanic series. In this paper, we explore the occurrence of the recognizable precursors of galvanic corrosion when CFRP plate is coupled to an aluminum alloy using SS-304 bolts and exposed to environmental degradation, which creates significant concerns for aircraft structural reliability. The galvanic corrosion software package, BEASY, is used to simulate the growth of corrosion in the designed specimen after which a microwave non-destructive testing (NDT) technique is explored to detect corrosion defects that appear at the interface of this galvanic couple. This paper also explores a loaded waveguide technique to determine the dielectric constant of the final corrosion product at the Q-band millimeter-wave frequency range (33-50 GHz), as this can be an invaluable asset in developing early detection strategies.

The corrosion and corrosion mechanical properties evaluation for the LBB concept in VVERs

Energy Technology Data Exchange (ETDEWEB)

Ruscak, M.; Chvatal, P.; Karnik, D.

1997-04-01

One of the conditions required for Leak Before Break application is the verification that the influence of corrosion environment on the material of the component can be neglected. Both the general corrosion and/or the initiation and, growth of corrosion-mechanical cracks must not cause the degradation. The primary piping in the VVER nuclear power plant is made from austenitic steels (VVER 440) and low alloy steels protected with the austenitic cladding (VVER 1000). Inspection of the base metal and heterogeneous weldments from the VVER 440 showed that the crack growth rates are below 10 m/s if a low oxygen level is kept in the primary environment. No intergranular cracking was observed in low and high oxygen water after any type of testing, with constant or periodic loading. In the framework of the LBB assessment of the VVER 1000, the corrosion and corrosion mechanical properties were also evaluated. The corrosion and corrosion mechanical testing was oriented predominantly to three types of tests: stress corrosion cracking tests corrosion fatigue tests evaluation of the resistance against corrosion damage. In this paper, the methods used for these tests are described and the materials are compared from the point of view of response on static and periodic mechanical stress on the low alloyed steel 10GN2WA and weld metal exposed in the primary circuit environment. The slow strain rate tests and static loading of both C-rings and CT specimens were performed in order to assess the stress corrosion cracking characteristics. Cyclic loading of CT specimens was done to evaluate the kinetics of the crack growth under periodical loading. Results are shown to illustrate the approaches used. The data obtained were evaluated also from the point of view of comparison of the influence of different structure on the stress corrosion cracking appearance. The results obtained for the base metal and weld metal of the piping are presented here.

Launch Pad Coatings for Smart Corrosion Control

Science.gov (United States)

Calle, Luz M.; Hintze, Paul E.; Bucherl, Cori N.; Li, Wenyan; Buhrow, Jerry W.; Curran, Jerome P.; Whitten, Mary C.

2010-01-01

Corrosion is the degradation of a material as a result of its interaction with the environment. The environment at the KSC launch pads has been documented by ASM International (formerly American Society for Metals) as the most corrosive in the US. The 70 tons of highly corrosive hydrochloric acid that are generated by the solid rocket boosters during a launch exacerbate the corrosiveness of the environment at the pads. Numerous failures at the pads are caused by the pitting of stainless steels, rebar corrosion, and the degradation of concrete. Corrosion control of launch pad structures relies on the use of coatings selected from the qualified products list (QPL) of the NASA Standard 5008A for Protective Coating of Carbon Steel, Stainless Steel, and Aluminum on Launch Structures, Facilities, and Ground Support Equipment. This standard was developed to establish uniform engineering practices and methods and to ensure the inclusion of essential criteria in the coating of ground support equipment (GSE) and facilities used by or for NASA. This standard is applicable to GSE and facilities that support space vehicle or payload programs or projects and to critical facilities at all NASA locations worldwide. Environmental regulation changes have dramatically reduced the production, handling, use, and availability of conventional protective coatings for application to KSC launch structures and ground support equipment. Current attrition rate of qualified KSC coatings will drastically limit the number of commercial off the shelf (COTS) products available for the Constellation Program (CxP) ground operations (GO). CxP GO identified corrosion detection and control technologies as a critical, initial capability technology need for ground processing of Ares I and Ares V to meet Constellation Architecture Requirements Document (CARD) CxP 70000 operability requirements for reduced ground processing complexity, streamlined integrated testing, and operations phase affordability

Corrosion of beryllium

International Nuclear Information System (INIS)

Mueller, J.J.; Adolphson, D.R.

1987-01-01

The corrosion behavior of beryllium in aqueous and elevated-temperature oxidizing environments has been extensively studied for early-intended use of beryllium in nuclear reactors and in jet and rocket propulsion systems. Since that time, beryllium has been used as a structural material in les corrosive environments. Its primary applications include gyro systems, mirror and reentry vehicle structures, and aircraft brakes. Only a small amount of information has been published that is directly related to the evaluation of beryllium for service in the less severe or normal atmospheric environments associated with these applications. Despite the lack of published data on the corrosion of beryllium in atmospheric environments, much can be deduced about its corrosion behavior from studies of aqueous corrosion and the experiences of fabricators and users in applying, handling, processing, storing, and shipping beryllium components. The methods of corrosion protection implemented to resist water and high-temperature gaseous environments provide useful information on methods that can be applied to protect beryllium for service in future long-term structural applications

A Probabilistic Model for Chloride-Ingress and Initation of Corrosion in Reinforced Concrete Structures

DEFF Research Database (Denmark)

Engelund, S.; Sørensen, John Dalsgaard

1998-01-01

Corrosion of the reinforcement is a major problem for a large number of reinforced concrete structures because it can lead to a substantial decrease of the load-bearing capacity. One mode of corrosion initiation is that the chloride content around the reinforcement exceeds a critical threshold va...

Modelling of Corrosion Cracks

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed.......Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed....

Oesophageal strictures caused by the ingestion of corrosive agents: effectiveness of balloon dilatation in children

Energy Technology Data Exchange (ETDEWEB)

Doo, E.-Y. [Department of Radiology, Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center (Korea, Republic of); Shin, J.H. [Department of Radiology, Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center (Korea, Republic of)], E-mail: jhshin@amc.seoul.kr; Kim, J.H.; Song, H.-Y. [Department of Radiology, Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center (Korea, Republic of)

2009-03-15

Aim: To evaluate the safety and clinical effectiveness of balloon dilatation in children for oesophageal strictures caused by the ingestion of corrosive agents. Materials and methods: The study comprised 11 children (median age 6 years; range 1-14 years) with oesophageal strictures caused by corrosive agents, who underwent a total of 36 balloon dilatation sessions. The technical and clinical success, recurrence of dysphagia, complications, and primary and secondary patency rates were retrospectively evaluated. Results: Technical success was achieved in 91% of patients and in 97% of balloon dilatation sessions. Clinical success (defined as improved food intake and reduced dysphagia within 1 month of the first balloon dilatation session) was achieved in 64% of patients (7/11). During the mean 35-month follow-up period (range 1-89 months), 10 (91%) patients experienced recurrence. Oesophageal rupture (types 1 or 2) occurred in 45% of patients and in 31% of balloon dilatation sessions. Primary patency rates at 6 months and 1, 2, 3, 4, and 5 years were 36, 27, 14, 14, 14, and 14%, respectively. Secondary patency rates at 6 months and 1, 2, 3, 4, and 5 years were 82, 82, 82, 56, 42, and 42%, respectively. The secondary patency rate was higher than the primary patency rate (p < 0.05). Conclusion: The present study examined oesophageal balloon dilatation for paediatric oesophageal strictures caused by the ingestion of corrosive agents. Although the technical success rate was high and there were no deaths, the clinical success rate was low owing to a high recurrence rate. However, repeated balloon dilatations resulted in an acceptable secondary patency rate.

The corrosion behaviour and structure of amorphous and thermally treated Fe-B-Si alloys

International Nuclear Information System (INIS)

Raicheff, R.; Zaprianova, V.; Petrova, E.

2003-01-01

The corrosion behaviour of magnetic amorphous alloys Fe 78 B 13 Si 9 , Fe 81 B 13 Si 4 C 2 and Fe 67 Co 18 Bi 4 S 1 obtained by rapid quenching from the melts are investigated in a model corrosive environment of 1N H 2 SO 4 . The structure of the alloys, is, characterized by DTA, SEM, TEM, X-ray and electron diffraction techniques. The dissolution kinetics of the,alloys is studied using gravimetric and electrochemical polarization measurements. It is established that the corrosion rate of the amorphous Fe 67 Co 18 Bt 4 S 1 alloy is up to 50 times lower than that of Fe 78 Bi 3 Si 9 alloy and the addition of cobalt leads to a considerable reduction of the rates of both partial corrosion reactions, while the addition of carbon results only in a moderate decrease (2-3 times) of the corrosion rate. It is also shown that the crystallization of the amorphous Fe 78 B 13 Si 9 alloy (at 700 o C for 3 h) leads to formation of multiphase structure consisting of crystalline phases α-Fe and Fe 3 (B,Si). After crystallization an increase of the rate of both hydrogen evolution and anodic dissolution reactions is observed which results in a considerable (an order of magnitude) increase of the corrosion rate of the alloy. (Original)

Numerical simulation of the detection of crack in reinforced concrete structures of NPP due to expansion of reinforcing corrosive products using Impact-Echo method

Directory of Open Access Journals (Sweden)

Morávka Š.

2008-12-01

Full Text Available Nuclear energy boom is starting nowadays. But also current nuclear power plants (NPP are duty to certify their security for regular renewal of their operating licenses. NPP security can be significantly affected by defects of large amount of ageing reinforced concrete structures. Advanced Impact-Echo method seams to be very hopeful to cooperate at performing in-service inspections such structures. Just these in-service inspections are included in the first priority group of specific technical issues according to the recommendations of OECD-Nuclear Energy Agency, Commission on Safety of Nuclear Installation in the field of ageing management.This paper continues of extensive project dealing with Impact-Echo method application. It will present method description and main results of numerical modeling of detection and localization of crack caused by corrosive product expansion. Steel reinforcing rods are subjected to corrosion due to diffusion of corrosive agents from structure surface. Corrosive products have up to 7-times larger volume than pure steel. Raised strain can cad lead up to concrete failure and crack development. We investigate whether it is possible to detect these growing cracks by Impact-Echo method in time.Experimental verification of our numerical predictions is prepared on Civil Faculty in Brno.

Corrosion performance of some titanium-based hard coatings

International Nuclear Information System (INIS)

Matthes, B.; Broszeit, E.; Aromaa, J.; Ronkainen, H.; Hannula, S.P.; Leyland, A.; Matthews, A.

1991-01-01

Tools and machine parts which could benefit from wear-resistant titanium-based hard films are often subject to corrosive environments. Physically vapour-deposited coatings frequently exhibit porosity and even small defects, which can cause rapid local corrosion of the substrate material; there is therefore a requirement for dense and chemically inert coatings. This paper presents corrosion data for titanium-based hard coatings such as TiN, (Ti, Al)N, Ti(B, N) and TiB 2 and also for multilayered structures where additional aluminium-based insulating surface layers (AlN and Al 2 O 3 ) were deposited. The corrosion resistance and porosity of the films were analysed by electrochemical techniques. The degree of metallic bonding can play a significant role in influencing the corrosion resistance of refractory transition-metal-based ceramic coatings. Here we demonstrate that, under potentiodynamic corrosion test conditions, resistance to corrosive attack was relatively poor for TiB 2 , better for (Ti, Al)N and Ti(B, N) and best for TiN. It is also shown that applying the additional protective aluminium-based insulating surface layers on the coating can further improve corrosion resistance. (orig.)

Steel fibre corrosion in cracks:durability of sprayed concrete

OpenAIRE

Nordström, Erik

2000-01-01

Steel fibre reinforced sprayed concrete is common practice for permanent linings in underground construction. Today there is a demand on "expected technical service life" of 120 years. Thin steel fibres could be expected to discontinue carrying load fast with a decrease of fibre diameter caused by corrosion, especially in cracks. The thesis contains results from inspections on existing sprayed concrete structures and a literature review on corrosion of steel fibres in cracked concrete. To stu...

Chromium-modified a-C films with advanced structural, mechanical and corrosive-resistant characteristics

Energy Technology Data Exchange (ETDEWEB)

Ming, Miao Yi [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Jiang, Xiaohong, E-mail: jxh0668@sina.com [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Piliptsou, D.G., E-mail: pdg_@mail.ru [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Zhuang, Yuzhao; Rogachev, A.V.; Rudenkov, A.S. [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Balmakou, A. [Faculty of Material Science and Technology, Slovak University of Technology, Trnava 91724 (Slovakia)

2016-08-30

Highlights: • Influence of the chromium interlayer on the structure and mechanical properties of a-C:Cr films. • Residual stress and wear of a-C:Cr and Cr/a-C varies due to their phase and surface morphology. • Chromium-modified a-C films with advanced structural, mechanical and corrosive-resistant characteristics. - Abstract: To improve structural, mechanical and chemical properties of diamond-like carbon films, we developed amorphous carbon chromium-modified composite films fabricated by means of cathode magnetic filtered arc deposition. The properties were analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy for the purpose of the structure characterization, elemental analysis and topology examination. Moreover, we also assessed residual stress, the coefficient of friction, hardness, the elastic modulus and corrosion parameters through X-ray double-crystal surface profilometry, tribo-testing, nanoindenter-testing, as well as contact angle measurements and potentiodynamic polarization analysis. As a result of a comparative analysis, we revealed a substantial improvement in the characteristics of developed composite films in comparison with amorphous carbon films. For example, Cr-modification is resulted, in greater integrated performance, toughness and corrosion resistance; the residual stress was reduced substantially.

Recognition and Analysis of Corrosion Failure Mechanisms

Directory of Open Access Journals (Sweden)

Steven Suess

2006-02-01

Full Text Available Corrosion has a vast impact on the global and domestic economy, and currently incurs losses of nearly $300 billion annually to the U.S. economy alone. Because of the huge impact of corrosion, it is imperative to have a systematic approach to recognizing and mitigating corrosion problems as soon as possible after they become apparent. A proper failure analysis includes collection of pertinent background data and service history, followed by visual inspection, photographic documentation, material evaluation, data review and conclusion procurement. In analyzing corrosion failures, one must recognize the wide range of common corrosion mechanisms. The features of any corrosion failure give strong clues as to the most likely cause of the corrosion. This article details a proven approach to properly determining the root cause of a failure, and includes pictographic illustrations of the most common corrosion mechanisms, including general corrosion, pitting, galvanic corrosion, dealloying, crevice corrosion, microbiologically-influenced corrosion (MIC, corrosion fatigue, stress corrosion cracking (SCC, intergranular corrosion, fretting, erosion corrosion and hydrogen damage.

Corrosion of steel structures in sea-bed sediment

Indian Academy of Sciences (India)

Unknown

corrosion mechanism, measurement of metal corrosion rate, corrosion ... cables, steel rigs, pipelines and other marine facilities, is ..... make high strength steel material to crack with stress ... of SBS has yet been very limited, and selection of.

Structural integrity assessment of steam generator tubes deteriorated through primary water stress corrosion cracking in transition region of tube expansion

International Nuclear Information System (INIS)

Silveira, Helvecio Carlos Klinke da

2002-01-01

In PWR plants, steam generator tube degradation has been one of the most important economical concerns, besides causing operational safety problems. In this work, a survey of steam generator tube degradation modes is done. Degradation mechanisms and influence factors are introduced and discussed. The importance of stress corrosion cracking, especially in transition region of tube expansion zone, is underlined. The actual steam generator tube plugging criteria are conservative. Proposed alternative criteria are introduced and discussed. Distinction is done to structural integrity assessment of defective tubes. Real data of tube defect indications of axial cracks in expansion transition zone due to primary water stress corrosion cracking are used in analysis. Results allow discussing application aspects of deterministic and probabilistic criteria on structural integrity assessment of tubes with defect indications. Applied models are specifics, but the application of concept may be extended to other steam generator tube degradation modes. (author)

Assessment of corrosion and fatigue damage to light water reactor metal containments

International Nuclear Information System (INIS)

Sinha, U.P.; Shah, V.N.; Smith, S.K.

1991-01-01

This paper presents a generic procedure for estimating aging damage, evaluating structural integrity, and identifying mitigation activities for safe operation of boiling water reactor (BWR) Mark I metal containments and ice-condenser type pressurized water reactor (PWR) cylindrical metal containments. The mechanisms of concern that can cause aging damage to these two types of containments are corrosion and fatigue. Assessment of fatigue damage to bellows is also described. Assessment of corrosion and fatigue damage described in this paper include: containment design features that are relevant to aging assessment, several corrosion and fatigue mechanisms, inspection of corrosion and fatigue damage, and mitigation of damage caused by these mechanisms. In addition, synergistic interaction between corrosion and fatigue is considered. Possible actions for mitigating aging include enhanced inspection methods, maintenance activities based on operating experience, and supplementary surveillance programs. Field experience related to aging of metal containments is reviewed. Finally, conclusions and recommendations are presented

Lamb-Wave-Based Tomographic Imaging Techniques for Hole-Edge Corrosion Monitoring in Plate Structures

Directory of Open Access Journals (Sweden)

Dengjiang Wang

2016-11-01

Full Text Available This study presents a novel monitoring method for hole-edge corrosion damage in plate structures based on Lamb wave tomographic imaging techniques. An experimental procedure with a cross-hole layout using 16 piezoelectric transducers (PZTs was designed. The A0 mode of the Lamb wave was selected, which is sensitive to thickness-loss damage. The iterative algebraic reconstruction technique (ART method was used to locate and quantify the corrosion damage at the edge of the hole. Hydrofluoric acid with a concentration of 20% was used to corrode the specimen artificially. To estimate the effectiveness of the proposed method, the real corrosion damage was compared with the predicted corrosion damage based on the tomographic method. The results show that the Lamb-wave-based tomographic method can be used to monitor the hole-edge corrosion damage accurately.

Formation of the self-assembled structures by the ultrasonic cavitation erosion-corrosion effect on carbon steel

Directory of Open Access Journals (Sweden)

Dayun Yan

2015-11-01

Full Text Available The cavitation erosion-corrosion effect on the metal surface always forms irregular oxide structures. In this study, we reported the formation of regular self-assembled structures of amorphous nanoparticles around the cavitation erosion pits on carbon steel upon the ultrasonic cavitation in methylene blue solution. Each self-assembled structure was composed of linearly aligned nanoparticles of about 100 nm. The formation of self-assembled structures might be due to the combined effect of corrosion, specific sonochemical reaction in methylene blue solution, and the magnetic domain structures on the carbon steel.

Corrosion behavior of Ni-based structural materials for electrolytic reduction in lithium molten salt

International Nuclear Information System (INIS)

Cho, Soo Haeng; Park, Sung Bin; Lee, Jong Hyeon; Hur, Jin Mok; Lee, Han Soo

2011-01-01

In this study, the corrosion behavior of new Ni-based structural materials was studied for electrolytic reduction after exposure to LiCl-Li 2 O molten salt at 650 deg. C for 24-216 h under an oxidizing atmosphere. The new alloys with Ni, Cr, Al, Si, and Nb as the major components were melted at 1700 deg. C under an inert atmosphere. The melt was poured into a preheated metallic mold to prepare an as-cast alloy. The corrosion products and fine structures of the corroded specimens were characterized by scanning electron microscope (SEM), Energy Dispersive X-ray Spectroscope (EDS), and X-ray diffraction (XRD). The corrosion products of as cast and heat treated low Si/high Ti alloys were Cr 2 O 3 , NiCr 2 O 4 , Ni, NiO, and (Al,Nb,Ti)O 2 ; those of as cast and heat treated high Si/low Ti alloys were Cr 2 O 3 , NiCr 2 O 4 , Ni, and NiO. The corrosion layers of as cast and heat treated low Si/high Ti alloys were continuous and dense. However, those of as cast and heat treated high Si/low Ti alloys were discontinuous and cracked. Heat treated low Si/high Ti alloy showed the highest corrosion resistance among the examined alloys. The superior corrosion resistance of the heat treated low Si/high Ti alloy was attributed to the addition of an appropriate amount of Si, and the metallurgical evaluations were performed systematically.

Corrosion in the oil industry

Energy Technology Data Exchange (ETDEWEB)

Brondel, D [Sedco Forex, Montrouge (France); Edwards, R [Schlumberger Well Services, Columbus, OH (United States); Hayman, A [Etudes et Productions Schlumberger, Clamart (France); Hill, D [Schlumberger Dowell, Tulsa, OK (United States); Mehta, S [Schlumberger Dowell, St. Austell (United Kingdom); Semerad, T [Mobil Oil Indonesia, Inc., Sumatra (Indonesia)

1994-04-01

Corrosion costs the oil industry billions of dollars a year, a fact that makes the role of the corrosion engineer an increasingly important one. Attention is paid to how corrosion affects every aspect of exploration and production, from offshore rigs to casing. Also the role of corrosion agents such as drilling and production fluids is reviewed. Methods of control and techniques to monitor corrosion are discussed, along with an explanation of the chemical causes of corrosion. 21 figs., 32 refs.

Structural strength deterioration of coastal bridge piers considering non-uniform corrosion in marine environments

Science.gov (United States)

Guo, Anxin; Yuan, Wenting; Li, Haitao; Li, Hui

2018-04-01

In the aggressive marine environment over a long-term service period, coastal bridges inevitably sustain corrosion-induced damage due to high sea salt and humidity. This paper investigates the strength reduction of coastal bridges, especially focusing on the effects of non-uniform corrosion along the height of bridge piers. First, the corrosion initiation time and the degradation of reinforcement and concrete are analyzed for bridge piers in marine environments. To investigate the various damage modes of the concrete cover, a discretization method with fiber cells is used for calculating time-dependent interaction diagrams of cross-sections of the bridge piers at the atmospheric zone and the splash and tidal zone under a combination of axial force and bending moment. Second, the shear strength of these aging structures is analyzed. Numerical simulation indicates that the strength of a concrete pier experiences dramatic reduction from corrosion initiation to the spalling of the concrete cover. Strength loss in the splash and tidal zone is more significant than in the atmospheric zone when structures' service time is assumed to be the same.

Corrosion processes of physical vapor deposition-coated metallic implants.

Science.gov (United States)

Antunes, Renato Altobelli; de Oliveira, Mara Cristina Lopes

2009-01-01

Protecting metallic implants from the harsh environment of physiological fluids is essential to guaranteeing successful long-term use in a patient's body. Chemical degradation may lead to the failure of an implant device in two different ways. First, metal ions may cause inflammatory reactions in the tissues surrounding the implant and, in extreme cases, these reactions may inflict acute pain on the patient and lead to loosening of the device. Therefore, increasing wear strength is beneficial to the performance of the metallic implant. Second, localized corrosion processes contribute to the nucleation of fatigue cracks, and corrosion fatigue is the main reason for the mechanical failure of metallic implants. Common biomedical alloys such as stainless steel, cobalt-chrome alloys, and titanium alloys are prone to at least one of these problems. Vapor-deposited hard coatings act directly to improve corrosion, wear, and fatigue resistances of metallic materials. The effectiveness of the corrosion protection is strongly related to the structure of the physical vapor deposition layer. The aim of this paper is to present a comprehensive review of the correlation between the structure of physical vapor deposition layers and the corrosion properties of metallic implants.

Investigation of parameters governing the corrosion protection efficacy of fusion bonded epoxy coatings

OpenAIRE

Ramniceanu, Andrei

2007-01-01

The primary cause of corrosion in transportation structures is due to chlorides which are applied to bridge decks as deicing salts. The direct cost of corrosion damage to the countryâ s infrastructure is approximately $8.3 billion per year. One of the most common corrosion abatement methods in the United States is the barrier protection implemented through the application of fusion bonded epoxy coatings. The purpose of this study was to investigate various coating and exposure param...

Fuel element failures caused by iodine stress corrosion

International Nuclear Information System (INIS)

Videm, K.; Lunde, L.

1976-01-01

Sections of unirradiated cladding tubes were plugged in both ends by mechanical seals and internally pressurized with argon containing iodine. The time to failure and the strain at failure as a function of stress was determined for tubing with different heat treatments. Fully annealed tubes suffer cracking at the lowest stress but exhibit the largest strains at failure. Elementary iodine is not necessary for stress corrosion: small amounts of iodides of zirconium, iron and aluminium can also give cracking. Moisture, however, was found to act as an inhibitor. A deformation threshold exists below which stress corrosion failure does not occur regardless of the exposure time. This deformation limit is lower the harder the tube. The deformation at failure is dependent on the deformation rate and has a minimum at 0.1%/hr. At higher deformation rates the failure deformation increases, but only slightly for hard tubes. Fuel was over-power tested at ramp rates varying between 0.26 to 30 W/cm min. For one series of fuel pins the failure deformations of 0.8% at high ramp rates were in good agreement with predictions based on stress corrosion experiments. For another series of experiments the failure deformation was surprisingly low, about 0.2%. (author)

Quantifying movements of corrosion products in reinforced concrete using x-ray attenuation measurements

DEFF Research Database (Denmark)

Pease, Bradley Justin; Michel, Alexander; Stang, Henrik

2011-01-01

Corrosion of steel reinforcement, embedded in concrete, may substantially degrade concrete structures due to the expansive nature of corrosion products. Expansion of corrosion products cause tensile stresses to develop and cracks to form in concrete. Extensive research has focused on corrosion...... of corrosion products move into the concrete without generating tensile stresses and cracks in the concrete. Typically, corrosion products are thought to occupy pores, interfacial defects, and/or air voids located near the concrete-steel interface and stresses develop only after filling of these pores. Further....... X-ray attenuation measurements are also capable of detecting cracks. Therefore, this approach provides a direct measurement of the amount and location of reinforcement corrosion products required to induce cracking. Results of a parametric investigation on the impact of water-to-cement ratio (0...

Analysis of Gamma Dose Rate Caused by Corrosion Products inside the Containment Building of Yonngwang Nuclear Power Plant Unit 3 During Shutdown Period

Energy Technology Data Exchange (ETDEWEB)

Ha, Wi Ho; Kim, Jae Cheon; Kim, Soon Young; Kim, Jong Kyung [Hanyang Univ., Seoul (Korea, Republic of)

2005-07-01

Occupational radiation exposure(ORE) of nuclear power plant(NPP) workers mainly occurs during the shutdown period. Major radioactive sources are the corrosion products released from the reactor coolant system(RCS). The corrosion products consist of circulating crud and deposited crud. Major radioactive corrosion products, {sup 58}Co and {sup 60}Co, are known to contribute approximately more than 70% of the total ORE. In this study, the corrosion products regarding cobalt were evaluated during the shutdown period, and gamma dose rates caused by them were calculated at the main working area inside the containment building of the Yonggwang NPP Unit 3.

Corrosion behavior of Ni-based structural materials for electrolytic reduction in lithium molten salt

Energy Technology Data Exchange (ETDEWEB)

Cho, Soo Haeng, E-mail: nshcho1@kaeri.re.kr [Korea Atomic Energy Research Institute, 1045 Daedeokdaero Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Park, Sung Bin [Korea Atomic Energy Research Institute, 1045 Daedeokdaero Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Lee, Jong Hyeon, E-mail: jonglee@cnu.ac.kr [Graduate School of Green Energy Technology, Chungnam National University, 79 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Hur, Jin Mok; Lee, Han Soo [Korea Atomic Energy Research Institute, 1045 Daedeokdaero Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

2011-05-01

In this study, the corrosion behavior of new Ni-based structural materials was studied for electrolytic reduction after exposure to LiCl-Li{sub 2}O molten salt at 650 deg. C for 24-216 h under an oxidizing atmosphere. The new alloys with Ni, Cr, Al, Si, and Nb as the major components were melted at 1700 deg. C under an inert atmosphere. The melt was poured into a preheated metallic mold to prepare an as-cast alloy. The corrosion products and fine structures of the corroded specimens were characterized by scanning electron microscope (SEM), Energy Dispersive X-ray Spectroscope (EDS), and X-ray diffraction (XRD). The corrosion products of as cast and heat treated low Si/high Ti alloys were Cr{sub 2}O{sub 3}, NiCr{sub 2}O{sub 4}, Ni, NiO, and (Al,Nb,Ti)O{sub 2}; those of as cast and heat treated high Si/low Ti alloys were Cr{sub 2}O{sub 3}, NiCr{sub 2}O{sub 4}, Ni, and NiO. The corrosion layers of as cast and heat treated low Si/high Ti alloys were continuous and dense. However, those of as cast and heat treated high Si/low Ti alloys were discontinuous and cracked. Heat treated low Si/high Ti alloy showed the highest corrosion resistance among the examined alloys. The superior corrosion resistance of the heat treated low Si/high Ti alloy was attributed to the addition of an appropriate amount of Si, and the metallurgical evaluations were performed systematically.

In Vitro Corrosion Assessment of Additively Manufactured Porous NiTi Structures for Bone Fixation Applications

Directory of Open Access Journals (Sweden)

Hamdy Ibrahim

2018-03-01

Full Text Available NiTi alloys possess distinct functional properties (i.e., shape memory effect and superelasticity and biocompatibility, making them appealing for bone fixation applications. Additive manufacturing offers an alternative method for fabricating NiTi parts, which are known to be very difficult to machine using conventional manufacturing methods. However, poor surface quality, and the presence of impurities and defects, are some of the major concerns associated with NiTi structures manufactured using additive manufacturing. The aim of this study is to assess the in vitro corrosion properties of additively manufactured NiTi structures. NiTi samples (bulk and porous were produced using selective laser melting (SLM, and their electrochemical corrosion characteristics and Ni ion release levels were measured and compared with conventionally fabricated NiTi parts. The additively manufactured NiTi structures were found to have electrochemical corrosion characteristics similar to those found for the conventionally fabricated NiTi alloy samples. The highest Ni ion release level was found in the case of 50% porous structures, which can be attributed to their significantly higher exposed surface area. However, the Ni ion release levels reported in this work for all the fabricated structures remain within the range of most of values for conventionally fabricated NiTi alloys reported in the literature. The results of this study suggest that the proposed SLM fabrication process does not result in a significant deterioration in the corrosion resistance of NiTi parts, making them suitable for bone fixation applications.

The Effect of Heat Treatment on the Sensitized Corrosion of the 5383-H116 Al-Mg Alloy

Directory of Open Access Journals (Sweden)

Ying-Kai Lin

2017-03-01

Full Text Available In this study, the effects of heat treatment and sensitized corrosion on the 5383-H116 Al-Mg alloy were investigated for temperatures ranging from 100 to 450 °C. The results show that the heat treatment temperature is the main factor that causes changes to the microstructure and mechanical strength of the 5383-H116 Al-Mg alloy, inducing β-phase (Al3Mg2 precipitation in the form of a continuous layer along the grain boundaries. Intergranular corrosion was caused by the β-phase of the grain boundary precipitation, and the corrosion susceptibility of the recrystallized structure was significantly higher than the corrosion susceptibility of the recovered structure. According to the conductivity values detected, β-phase precipitation can enhance the 5383-H116 Al-Mg alloy conductivity, with the response due to structural dislocation density being higher than that due to the recrystallized structure. As such, the β-phase precipitation after sensitization is more significant than the β-phase precipitation prior to the sensitization, such that after sensitization, the conductivity rises to a significantly higher level than that exhibited by the recrystallization structure.

Corrosion of candidate iron-base waste package structural barrier materials in moist salt environments

International Nuclear Information System (INIS)

Westerman, R.E.; Pitman, S.G.

1984-11-01

Mild steels are considered to be strong candidates for waste package structural barrier (e.g., overpack) applications in salt repositories. Corrosion rates of these materials determined in autoclave tests utilizing a simulated intrusion brine based on Permian Basin core samples are low, generally <25 μm (1 mil) per year. When the steels are exposed to moist salts containing simulated inclusion brines, the corrosion rates are found to increase significantly. The magnesium in the inclusion brine component of the environment is believed to be responsible for the increased corrosion rates. 1 reference, 4 figures, 2 tables

Radiometric investigation of effect of decontamination agents on corrosion behavior of structural materials for nuclear power engineering

International Nuclear Information System (INIS)

Silber, R.; Ecksteinova, A.

1987-01-01

The tracer technique is used in monitoring corrosion behaviour of high-alloy steels used as structural materials in nuclear power engineering. Radioisotopes 59 Fe, 51 Cr, 58 Co and 60 Co produced by neutron irradiation of steel are mainly used for labelling steel components. The actual corrosion test proceeds in a facility whose description is given. The facility allows automatic sampling of corrosion medium fractions in preset intervals. The fractions are evaluated using a multi-channel analyzer with a Ge(Li) detector. The method can be applied in, e.g., monitoring extraction corrosion, the effect of decontamination agents on the corrosion of alloy steels and the effect of heat treatment of steels of their corrosion resistance in a model corrosion environment. (Z.M.). 2 fig., 1 tab., 5 refs

Stress corrosion in high-strength aluminum alloys

Science.gov (United States)

Dorward, R. C.; Hasse, K. R.

1980-01-01

Report describes results of stress-corrosion tests on aluminum alloys 7075, 7475, 7050, and 7049. Tests compare performance of original stress-corrosion-resistant (SCR) aluminum, 7075, with newer, higher-strength SCR alloys. Alloys 7050 and 7049 are found superior in short-transverse cross-corrosion resistance to older 7075 alloy; all alloys are subject to self-loading effect caused by wedging of corrosion products in cracks. Effect causes cracks to continue to grow, even at very-low externally applied loads.

Evaluation of corrosion attack of chimney liners

Directory of Open Access Journals (Sweden)

Blahetová M.

2016-06-01

Full Text Available The case study of chimney liner corrosion addresses three specific cases of damage of chimney systems from of stainless steels. These systems were used for flue of gas arising from the combustion of brown coal in small automatic boilers, which are used for heating. Detailed analyzes implied that the cause of devastating corrosion of the steel AISI 316 and 304 steel (CSN 17349, 17241 was particularly high content of halides (chlorides and fluorides, which caused a severe pitting corrosion, which led up to the perforation of the liner material. Simultaneous reduction of the thickness of the used sheets was due to by the general corrosion, which was caused by the sulfur in the solid fuel. The condensation then led to acid environment and therefore the corrosion below the dew point of the sulfuric acid has occurred. All is documented by metallographic analysis and microanalysis of the corrosion products.

Corrosion fatigue in LP steam turbine blading - experiences, causes and appropriate measures; Korrosionsutmattning i aangturbinskovlar - Erfarenheter, inverkande faktorer och moejliga aatgaerder

Energy Technology Data Exchange (ETDEWEB)

Tavast, J [ABB STAL AB, Finspaang (Sweden)

1996-12-01

Corrosion fatigue in LP steam turbine blading was reviewed together with result of tests performed in order to find blade materials with improved resistance against this. According to international experience, corrosion fatigue of 12Cr steam turbine blades in the transition zone between dry and wet steam, is one of the major causes, if not the major cause, for unavailability of steam turbines. Corrosion fatigue in LP blading is a frequent problem also in Swedish and Finnish nuclear power plants, especially in turbines of type D54 in BWR-plants. Corrosion fatigue has also been discovered in at least one type of nuclear turbine. Initiation times have been very long and the varying experiences in different types of turbines may simply reflect differing initiation times. Corrosion fatigue may therefore become more frequent in other types of turbines in the future. The type of water treatment (BWR/PWR) and possibly temperature after reheating seem to influence the risk for corrosion fatigue. Influence of inleakage of cooling water is less clear for these nuclear plants. The long initiation times together with the fact that very few of the cracked blades have actually failed, indicate that the cracks initiate and/or propagate during transients. Extensive laboratory tests show that there are alternative blade materials available with improved resistance against corrosion fatigue, with the most promising being 15/5 PH and A905, together with Ti6Al4V. The Ti alloy shows the best resistance against corrosion fatigue in most environments and is already used in some turbines. Disadvantage is a higher cost and possible need for redesign of the blades. The alternative materials are recommended for use for blades in the transition zone between dry and wet steam in LP turbines. The main disadvantage is a lack of references, even if 15%5 PH has been used to a very limited extent. 40 refs, 24 figs, 12 tabs, 9 appendices

Effect of Plastic Deformation on the Corrosion Behavior of a Super-Duplex Stainless Steel

Science.gov (United States)

Renton, Neill C.; Elhoud, Abdu M.; Deans, William F.

2011-04-01

The role of plastic deformation on the corrosion behavior of a 25Cr-7Ni super-duplex stainless steel (SDSS) in a 3.5 wt.% sodium chloride solution at 90 °C was investigated. Different levels of plastic strain between 4 and 16% were applied to solution annealed tensile specimens and the effect on the pitting potential measured using potentiodynamic electrochemical techniques. A nonlinear relationship between the pitting potential and the plastic strain was recorded, with 8 and 16% causing a significant reduction in average E p, but 4 and 12% causing no significant change when compared with the solution-annealed specimens. The corrosion morphology revealed galvanic interaction between the anodic ferrite and the cathodic austenite causing preferential dissolution of the ferrite. Mixed potential theory and the changing surface areas of the two phases caused by the plastic deformation structures explain the reductions in pitting potential at certain critical plastic strain levels. End-users and manufacturers should evaluate the corrosion behavior of specific cold-worked duplex and SDSSs using their as-produced surface finishes assessing in-service corrosion performance.

Corrosion characteristics of an aqueous self-cooled fusion blanket

International Nuclear Information System (INIS)

Bogaerts, W.F.; Embrechts, M.J.; Steiner, D.; Deutsch, L.; Jackson, D.

1986-01-01

A novel aqueous self-cooled blanket concept (ASCB) has recently been proposed. This blanket concept, as applied to a MARS-like tandem mirror reactor, consists of disks of spiraling tubes of Zircaloy-4 housed in a structural container of vanadium alloy (V-15 Ti-5 Cr). The Zircaloy tubes are cooled by a mixture of light and heavy water with 9 g of LiOH per 100 cm 3 of water dissolved in the coolant. A major issue for the feasibility of the integrated blanket coil concept is the chemical compatibility of the coolant and Zircaloy. Initial corrosion tests have been undertaken in order to resolve this question. Results clearly show that successful alloy heats can be prepared, for which corrosion problems will probably not be the limiting factor of the ASCB design concept. As is quite well known from fission engineering studies, small variations in the alloy compositions or in the metallurgical structure may, however, be able to cause significant alterations in the oxidation or corrosion rates. Further tests will be necessary to resolve the remaining uncertainties and to determine the behavior of successful alloy heats in the presence of trace impurities in order to address the sensitivity to localized corrosion phenomena such as pitting, stress corrosion cracking, and intergranular attack

CORROSION RATE OF STEELS DX51D AND S220GD IN DIFFERENT CORROSION ENVIRONMENT

Directory of Open Access Journals (Sweden)

Alina Crina CIUBOTARIU

2016-06-01

Full Text Available Corrosion in the marine environment is an important issue because the costs causes by marine corrosion increased year upon year. It is necessary a correctly approach to materials selection, protection and corrosion control to reduce this burden of wasted materials, wasted energy and wasted money. Many different types of corrosion attack can be observed to structures, ships and other equipment used in sea water service. Shipping containers are exposed to various corrosive mediums like as airborne salt, industrial pollutants, rain and saltwater. Transport damage during loading onto and unloading off trucks, train beds and ships breaches the paint coating which further contributes to corrosion. The result is shortened container life and high costs for container repair or replacement. The paper intends to evaluate, by gravimetric method, the corrosion rate and corrosion penetration rate of two types of carbon steel DX51D and S220GD. Carbon steel DX51D and hot-dip galvanized steel S220GD are used in marine and industrial applications for buildings cargo vessels, container ships and oil tankers. For testing it was used different corrosive environments: 5% NaOH solution; 5% HCL solution and 0.5M NaCl solution. The samples were immersed in 400mL of testing solution for exposure period of 28 days. Periodically at 3 days, 7 days, 14 days, 21 days and 28 days was measured de mass loss and evaluate the corrosion rate and corrosion stability coefficient. The steel DX51D was stable in 5% NaOH solution for 28 days, the values of corrosion stability coefficient was 7 after 3 days and 6 after 28 days of immersion in corrosive medium. In 5% HCL solution steels DX51D and S220GD was completely corroded in 21 days with a corrosion stability coefficient equal with 9 for 7 days and 8 for 21 days of immersion in corrosive solution. It was observed a good resistance for 3 days in 0.5M NaCl solution with a corrosion stability coefficient equal with 5, but after that

Influence of Portland Cement Class on the Corrosion Rate of Steel Reinforcement in Cement Mortar Caused by Penetrating Chloride and Sulfate from the Environment

Directory of Open Access Journals (Sweden)

Bikić, F.

2013-01-01

Full Text Available The influence of portland cement class on the corrosion rate of steel reinforcement in cement mortar caused by penetrating chloride or sulfate from the environment in already hardened cement mortar is investigated in this paper. Three classes of portland cement have been used for the tests, PC 35, PC 45 and PC 55. Cylindrical samples of cement mortar with steel reinfor- cement in the middle were treated 6 months at room temperature in the following solutions: w(SO42- = 2.1 % and w(Cl- = 5 %. Two techniques have been used for testing corrosion rate of steel reinforcement in cement mortar: Tafel extrapolation technique and potentiodynamic polarization technique. Investigations were conducted by potentiostat/galvanostat Princeton Applied Research 263A-2 with the software PowerCORR®. The results of both techniques indi-cate the most active corrosion of steel reinforcement in the samples prepared from cement PC 35 in both treated solutions, while the lowest corrosion of the steel reinforcement was observed in cement samples prepared from cement PC 55. This conclusion was drawn by analyzing the results shown in Figs. 1–4. Comparing corrosion current density of samples, working electrodes, Figs. 1 and 2, Table 2, the results show the most stable corrosion of steel reinforcement in samples prepared from cement PC 55, and the most active corrosion in samples prepared from ce- ment PC 35. The most active corrosion in samples prepared from cement PC 35 is evident from the positions of the open circuit potentials whose values are less for samples prepared from cement PC 35 in both the treated solution, Figs. 1 and 2, Table 2. Comparison of the anodic polarization curves of the working electrodes in both the treated solutions, Figs. 3 and 4, also shows that the intensity of corrosion is the largest for the working electrodes prepared from cement PC 35 and the smallest for the working electrodes prepared from cement PC 55. Investigation results should be

General Corrosion and Localized Corrosion of Waste Package Outer Barrier

Energy Technology Data Exchange (ETDEWEB)

K.G. Mon

2004-10-01

The waste package design for the License Application is a double-wall waste package underneath a protective drip shield (BSC 2004 [DIRS 168489]; BSC 2004 [DIRS 169480]). The purpose and scope of this model report is to document models for general and localized corrosion of the waste package outer barrier (WPOB) to be used in evaluating waste package performance. The WPOB is constructed of Alloy 22 (UNS N06022), a highly corrosion-resistant nickel-based alloy. The inner vessel of the waste package is constructed of Stainless Steel Type 316 (UNS S31600). Before it fails, the Alloy 22 WPOB protects the Stainless Steel Type 316 inner vessel from exposure to the external environment and any significant degradation. The Stainless Steel Type 316 inner vessel provides structural stability to the thinner Alloy 22 WPOB. Although the waste package inner vessel would also provide some performance for waste containment and potentially decrease the rate of radionuclide transport after WPOB breach before it fails, the potential performance of the inner vessel is far less than that of the more corrosion-resistant Alloy 22 WPOB. For this reason, the corrosion performance of the waste package inner vessel is conservatively ignored in this report and the total system performance assessment for the license application (TSPA-LA). Treatment of seismic and igneous events and their consequences on waste package outer barrier performance are not specifically discussed in this report, although the general and localized corrosion models developed in this report are suitable for use in these scenarios. The localized corrosion processes considered in this report are pitting corrosion and crevice corrosion. Stress corrosion cracking is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]).

Microscopic analysis of effect of shot peening on corrosion fatigue behavior of aluminum alloy

International Nuclear Information System (INIS)

Kim, Jong Cheon; Cheong, Seong Kyun

2012-01-01

The object of this study considers corrosion fatigue improvement of 7075-T6 aluminum by using shot peening treatment on 3.5% NaCl solution at room temperature. Aluminum alloy is generally used in aerospace structural components because of the light weight and high strength characteristics. Many studies have shown that an aluminum alloy can be approximately 50% lighter than other materials. Mostly, corrosion leads to earlier fatigue crack propagation under tensile conditions and severely reduces the life of structures. Therefore, the technique to improve material resistance to corrosion fatigue is required. Shot peening technology is widely used to improve fatigue life and other mechanical properties by induced compressive residual stress. Even the roughness of treated surface causes pitting corrosion, the compressive residual stress, which is induced under the surface layer of material by shot peening, suppersses the corrosion and increases the corrosion resistance. The experimental results for shot peened specimens were compared with previous work for non treated aluminum alloy. The results show that the shot peening treatment affects the corrosion fatigue improvement of aluminum alloys and the induced compressive residual stress by shot peening treatment improves the resistance to corrosion fatigue

Microscopic analysis of effect of shot peening on corrosion fatigue behavior of aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Cheon; Cheong, Seong Kyun [Seoul Nat' l Univ. of Science and Technology, Seoul (Korea, Republic of)

2012-11-15

The object of this study considers corrosion fatigue improvement of 7075-T6 aluminum by using shot peening treatment on 3.5% NaCl solution at room temperature. Aluminum alloy is generally used in aerospace structural components because of the light weight and high strength characteristics. Many studies have shown that an aluminum alloy can be approximately 50% lighter than other materials. Mostly, corrosion leads to earlier fatigue crack propagation under tensile conditions and severely reduces the life of structures. Therefore, the technique to improve material resistance to corrosion fatigue is required. Shot peening technology is widely used to improve fatigue life and other mechanical properties by induced compressive residual stress. Even the roughness of treated surface causes pitting corrosion, the compressive residual stress, which is induced under the surface layer of material by shot peening, suppersses the corrosion and increases the corrosion resistance. The experimental results for shot peened specimens were compared with previous work for non treated aluminum alloy. The results show that the shot peening treatment affects the corrosion fatigue improvement of aluminum alloys and the induced compressive residual stress by shot peening treatment improves the resistance to corrosion fatigue.

Degradation of aged plants by corrosion: 'Long cell action' in unresolved corrosion issues

International Nuclear Information System (INIS)

Saji, Genn

2009-01-01

In a series of previously published papers the author has identified that 'long cell action' corrosion plays a pivotal role in practically all unresolved corrosion issues for all types of nuclear power plants (e.g. PWR/VVER, BWR/RBMK and CANDU). Some of these unresolved issues are IGSCC, PWSCC, AOA and FAC (erosion-corrosion). In conventional corrosion science it is well established that 'long cell action' can seriously accelerate or suppress the local cell corrosion activities. Although long cell action is another fundamental mechanism of corrosion, especially in a 'soil corrosion' arena, potential involvement of this corrosion process has never been studied in nuclear and fossil power plants as far as the author has been able to establish. The author believes that the omission of this basic corrosion mechanism is the root cause of practically all un-resolved corrosion issues. In this paper, the author further elaborated on his assessment to other key corrosion issues, e.g. steam generator and turbine corrosion issues, while briefly summarizing previous discussions for completeness purposes, as well as introducing additional experimental and theoretical evidence of this basic corrosion mechanism. Due to the importance of this potential mechanism the author is calling for institutional review activities and further verification experiments in the form of a joint international project.

Prevention of superheater corrosion caused by chlorine; Tulistimien kloorikorroosion estaeminen

Energy Technology Data Exchange (ETDEWEB)

Roppo, J. [Kvaerner Power Oy, Tampere (Finland)

2006-12-19

Combustion of CO{sub 2}-neutral fuels is becoming more attractive and common method to decrease CO2 emissions of energy production. Also well managed and controlled combustion of waste fractions compared to their landfilling produces much less greenhouse gas emissions. In combustion of these fuels in high efficiency power plants notably increased superheater corrosion risk is prevailing, mainly caused by chlorine. Typical such fuels are forest, agricultural and household residues, biological sludge's of pulp and paper industry and RDF made from separated municipal and industrial solid waste. The goal of the project is to develop clearly cheaper and more effective method to protect superheaters, which enables combustion of biomass and waste fuels with higher energy shares. Tests in pilot and full scale power plants will reveal the potential and applicability of the developed method for commercial use. (orig.)

Effects of gaseous nitriding AISI4140 alloy steel on corrosion and hardness properties

Science.gov (United States)

Tamil Moli, L.; Wahab, N.; Gopinathan, M.; Karmegam, K.; Maniyarasi, M.

2016-10-01

Corrosion is one of the major problems in the industry especially on machinery since it weakens the structure of the machinery part and causes the mechanical failure. This will stop the production and increase the maintenance cost. In this study, the corrosion behaviour of gas nitriding on a screw press machine shaft made from AISI 4140 steel was investigated. Pitting corrosion was identified as a major cause of the shaft failure and this study was conducted to improve the corrosion resistance on the AISI 4140 alloy steel shaft by gas nitriding as a surface hardening treatment. Gas nitriding was performed with composition of 15% ammonia and 85% nitrogen at temperatures of 525 °C, 550 °C and 575 °C and with the soaking time of 30, 45 and 60 minutes, respectively. The samples were prepared as rectangular sized of 30mm x 12mm x 3mm for immersion testing. The results showed that corrosion rate of untreated samples was 77% higher compared to the nitrided samples. It was also found that hardness of the nitrided samples was higher than untreated sample. All in all, it can be concluded that gaseous nitriding can significantly improve the surface hardness and the corrosion resistance of the shaft made of AISI 4140 alloy steel, hence reduces the pitting that is the root cause of failure.

Corrosion inhibitors

International Nuclear Information System (INIS)

El Ashry, El Sayed H.; El Nemr, Ahmed; Esawy, Sami A.; Ragab, Safaa

2006-01-01

The corrosion inhibition efficiencies of some triazole, oxadiazole and thiadiazole derivatives for steel in presence of acidic medium have been studied by using AM1, PM3, MINDO/3 and MNDO semi-empirical SCF molecular orbital methods. Geometric structures, total negative charge on the molecule (TNC), highest occupied molecular energy level (E HOMO ), lowest unoccupied molecular energy level (E LUMO ), core-core repulsion (CCR), dipole moment (μ) and linear solvation energy terms, molecular volume (V i ) and dipolar-polarization (π *), were correlated to corrosion inhibition efficiency. Four equations were proposed to calculate corrosion inhibition efficiency. The agreement with the experimental data was found to be satisfactory; the standard deviations between the calculated and experimental results ranged between ±0.03 and ±4.18. The inhibition efficiency was closely related to orbital energies (E HOMO and E LUMO ) and μ. The correlation between quantum parameters and experimental inhibition efficiency has been validated by single point calculations for the semi-empirical AM1 structures using B3LYP/6-31G** as a higher level of theory. The proposed equations were applied to predict the corrosion inhibition efficiency of some related structures to select molecules of possible activity from a presumable library of compounds

Studies of corrosion resistance of Japanese steels in liquid lead-bismuth

International Nuclear Information System (INIS)

Kamata, Kin-ya; Ono, Hiroshi; Kitano, Teruaki; Ono, Mikinori

2003-01-01

Liquid lead-bismuth has attractive characteristics as a coolant in future fast reactors and Accelerator Driven Sub-critical Systems (ADS) applications. The corrosion behavior of structural materials in lead-bismuth eutectic is one of key problems in developing nuclear power plants and installations using lead-bismuth coolant. Our experiences with heat exchangers using liquid lead-bismuth and the results of corrosion tests of Japanese steels are reported in this paper. A series of corrosion tests was carried out in collaboration with the Institute of Physics and Power Engineering (IPPE). Test specimens of various Japanese steels were exposed in a non-isothermal forced circulation loop. The influence of maximum temperature and oxygen content in lead bismuth were chosen for study as the primary causes of corrosion in Japanese steels. After the corrosion tests, corrosion behavior was analyzed by visual inspection, measurement of weight loss and metallurgical examination of the microstructure of the corroded zone. The corrosion mechanism in liquid lead bismuth is discussed on the basis of the metallurgical examination of the corroded zone. (author)

Structural Response to Blast Loading: The Effects of Corrosion on Reinforced Concrete Structures

Directory of Open Access Journals (Sweden)

Hakan Yalciner

2014-01-01

Full Text Available Structural blast design has become a necessary part of the design with increasing terrorist attacks. Terrorist attacks are not the one to make the structures important against blast loading where other explosions such as high gas explosions also take an important place in structural safety. The main objective of this study was to verify the structural performance levels under the impact of different blast loading scenarios. The blast loads were represented by using triangular pulse for single degree of freedom system. The effect of blast load on both corroded and uncorroded reinforced concrete buildings was examined for different explosion distances. Modified plastic hinge properties were used to ensure the effects of corrosion. The results indicated that explosion distance and concrete strength were key parameters to define the performance of the structures against blast loading.

Coal-fired power plants and the causes of high temperature corrosion

Energy Technology Data Exchange (ETDEWEB)

Oakey, J E; Simms, N J [British Coal Corporation, Coal Technology Development Div., Cheltenham, Glos (United Kingdom); Tomkings, A B [ERA Technology Ltd., Leatherhead, Surrey (United Kingdom)

1996-12-01

The heat exchangers in all types of coal-fired power plant operate in aggressive, high temperature environments where high temperature corrosion can severely limit their service lives. The extent of this corrosion is governed by the combined effects of the operating conditions of the heat exchanger and the presence of corrosive species released from the coal during operation. This paper reviews the coal-related factors, such as ash deposition, which influence the operating environments of heat exchangers in three types of coal-fired power plant - conventional pulverized coal boilers, fluidized bed boilers and coal gasification systems. The effects on the performance of the materials used for these heat exchangers are then compared. (au) 35 refs.

Corrosion monitoring for underground and submerged concrete structures - examples and interpretation issues

NARCIS (Netherlands)

Polder, R.B.; Peelen, W.H.A.; Leegwater, G.

2008-01-01

Since about 1980 Corrosion Monitoring Systems have been used in many concrete structures in aggressive environmentworldwide. While these systemswork properly in aboveground environment, some questions have arisen for submerged conditions, e.g. the outer sides of tunnels, piers in seawater or

Emerging Corrosion Inhibitors for Interfacial Coating

Directory of Open Access Journals (Sweden)

Mona Taghavikish

2017-12-01

Full Text Available Corrosion is a deterioration of a metal due to reaction with environment. The use of corrosion inhibitors is one of the most effective ways of protecting metal surfaces against corrosion. Their effectiveness is related to the chemical composition, their molecular structures and affinities for adsorption on the metal surface. This review focuses on the potential of ionic liquid, polyionic liquid (PIL and graphene as promising corrosion inhibitors in emerging coatings due to their remarkable properties and various embedment or fabrication strategies. The review begins with a precise description of the synthesis, characterization and structure-property-performance relationship of such inhibitors for anti-corrosion coatings. It establishes a platform for the formation of new generation of PIL based coatings and shows that PIL corrosion inhibitors with various heteroatoms in different form can be employed for corrosion protection with higher barrier properties and protection of metal surface. However, such study is still in its infancy and there is significant scope to further develop new structures of PIL based corrosion inhibitors and coatings and study their behaviour in protection of metals. Besides, it is identified that the combination of ionic liquid, PIL and graphene could possibly contribute to the development of the ultimate corrosion inhibitor based coating.

Hidden corrosion detection in aircraft aluminum structures using laser ultrasonics and wavelet transform signal analysis.

Science.gov (United States)

Silva, M Z; Gouyon, R; Lepoutre, F

2003-06-01

Preliminary results of hidden corrosion detection in aircraft aluminum structures using a noncontact laser based ultrasonic technique are presented. A short laser pulse focused to a line spot is used as a broadband source of ultrasonic guided waves in an aluminum 2024 sample cut from an aircraft structure and prepared with artificially corroded circular areas on its back surface. The out of plane surface displacements produced by the propagating ultrasonic waves were detected with a heterodyne Mach-Zehnder interferometer. Time-frequency analysis of the signals using a continuous wavelet transform allowed the identification of the generated Lamb modes by comparison with the calculated dispersion curves. The presence of back surface corrosion was detected by noting the loss of the S(1) mode near its cutoff frequency. This method is applicable to fast scanning inspection techniques and it is particularly suited for early corrosion detection.

Effect of temperature, of oxygen content and the downstream effect on corrosion rate of structural materials in liquid sodium

International Nuclear Information System (INIS)

Ilincev, G.

1988-01-01

The effects were experimentally tested of temperature and of oxygen content on the corrosion rate of structural materials in liquid sodium and on reducing the corrosion rate down the sodium stream. The results of the experiments are shown in graphs and tables and are discussed in detail. The duration of all tests was standard 1,000 hours. The test parameters were set such as to determine the effect of temperature on corrosion of a quantity of various materials in sodium with a low oxygen content (1.2 to 2 ppm) at temperatures of 500 to 800 degC and in sodium with a high oxygen content (345 ppm) at temperatures of 500 to 700 degC. More experiments served the determination of the effect of a different oxygen content varying between 1.2 and 2 ppm at a constant temperature of 600 degC. The materials being tested included main structural materials used for fast reactor construction and materials allowing to establish the effect of main alloying elements on their corrosion in liquid sodium of different temperatures and purity grades. The relationships showing the effects of temperature and oxygen content in sodium on the rate of corrosion of various structural materials in hot parts of the installation and on the reduction in the rate of corrosion downstream due to sodium saturation with corrosion products were constructed using the experimental results. (Z.M.). 15 figs., 2 tabs., 7 refs

The dual role of microbes in corrosion.

Science.gov (United States)

Kip, Nardy; van Veen, Johannes A

2015-03-01

Corrosion is the result of a series of chemical, physical and (micro) biological processes leading to the deterioration of materials such as steel and stone. It is a world-wide problem with great societal and economic consequences. Current corrosion control strategies based on chemically produced products are under increasing pressure of stringent environmental regulations. Furthermore, they are rather inefficient. Therefore, there is an urgent need for environmentally friendly and sustainable corrosion control strategies. The mechanisms of microbially influenced corrosion and microbially influenced corrosion inhibition are not completely understood, because they cannot be linked to a single biochemical reaction or specific microbial species or groups. Corrosion is influenced by the complex processes of different microorganisms performing different electrochemical reactions and secreting proteins and metabolites that can have secondary effects. Information on the identity and role of microbial communities that are related to corrosion and corrosion inhibition in different materials and in different environments is scarce. As some microorganisms are able to both cause and inhibit corrosion, we pay particular interest to their potential role as corrosion-controlling agents. We show interesting interfaces in which scientists from different disciplines such as microbiology, engineering and art conservation can collaborate to find solutions to the problems caused by corrosion.

The dual role of microbes in corrosion

Science.gov (United States)

Kip, Nardy; van Veen, Johannes A

2015-01-01

Corrosion is the result of a series of chemical, physical and (micro) biological processes leading to the deterioration of materials such as steel and stone. It is a world-wide problem with great societal and economic consequences. Current corrosion control strategies based on chemically produced products are under increasing pressure of stringent environmental regulations. Furthermore, they are rather inefficient. Therefore, there is an urgent need for environmentally friendly and sustainable corrosion control strategies. The mechanisms of microbially influenced corrosion and microbially influenced corrosion inhibition are not completely understood, because they cannot be linked to a single biochemical reaction or specific microbial species or groups. Corrosion is influenced by the complex processes of different microorganisms performing different electrochemical reactions and secreting proteins and metabolites that can have secondary effects. Information on the identity and role of microbial communities that are related to corrosion and corrosion inhibition in different materials and in different environments is scarce. As some microorganisms are able to both cause and inhibit corrosion, we pay particular interest to their potential role as corrosion-controlling agents. We show interesting interfaces in which scientists from different disciplines such as microbiology, engineering and art conservation can collaborate to find solutions to the problems caused by corrosion. PMID:25259571

Fighting corrosion in India

Energy Technology Data Exchange (ETDEWEB)

Rajagopalan, K S; Rangaswamy, N S

1979-03-01

A survey covers the cost of corrosion in India; methods of preventing corrosion in industrial plants; some case histories, including the prevention of corrosion in pipes through which fuels are pumped to storage and the stress-corrosion cracking of evaporators in fertilizer plants; estimates of the increase in demand in 1979-89 for anticorrosion products and processes developed by the Central Electrochemical Research Institute (CECRI) at Karaikudi, India; industries that may face corrosion problems requiring assistance from CECRI, including the light and heavy engineering structural, and transport industries and the chemical industry; and some areas identified for major efforts, including the establishment of a Corrosion Advisory Board with regional centers and the expansion of the Tropical Corrosion Testing Station at Mandapam Camp, Tamil Nadu.

Corrosion of materials for heat exchangers and the countermeasures

International Nuclear Information System (INIS)

Kawamoto, Teruaki

1978-01-01

When the materials for heat exchangers are selected, the heat transfer performance, mechanical strength, workability, cost, corrosion resistance and so on are taken in consideration. Most of the failure of heat exchangers is due to corrosion, and the corrosion failure on cooling water side occurs frequently, to which attention is not paid much usually. The rate of occurrence of corrosion failure is overwhelmingly high in heating tubes, and the failure owing to cooling water exceeds that owing to process fluid. The material of heating tubes is mostly aluminum brass, and local failure such as pitting corrosion or stress corrosion cracking holds a majority. The cause of corrosion failure due to cooling water is mostly the poor water quality. The mechanism of corrosion of metals can be explained by the electrochemical reaction between the metals and solutions. As for the factors affecting corrosion, dissolved oxygen, pH, Cl - ions, temperature, flow velocity, and foreign matters are enumerated. Copper alloys are sensitive to the effect of polluted sea water. Erosion corrosion is caused by eddies and bubbles owing to high flow velocity, and impingement attack is caused by scratching foreign matters. The quality of fresh water affects corrosion more than sea water in case of copper alloys. The preliminary examination of water quality is essential. (Kako, I.)

Role of hydrogen in stress corrosion cracking

International Nuclear Information System (INIS)

Mehta, M.L.

1981-01-01

Electrochemical basis for differentiation between hydrogen embrittlement and active path corrosion or anodic dissolution crack growth mechanisms is examined. The consequences of recently demonstrated acidification in crack tip region irrespective of electrochemical conditions at the bulk surface of the sample are that the hydrogen can evolve within the crack and may be involved in the cracking process. There are basically three aspects of hydrogen involvement in stress corrosion cracking. In dissolution models crack propagation is assumed to be caused by anodic dissolution on the crack tip sustained by cathodic reduction of hydrogen from electrolyte within the crack. In hydrogen induced structural transformation models it is postulated that hydrogen is absorbed locally at the crack tip producing structural changes which facilitate crack propagation. In hydrogen embrittlement models hydrogen is absorbed by stressed metal from proton reduction from the electrolyte within the crack and there is interaction between lattice and hydrogen resulting in embrittlement of material at crack tip facilitating crack propagation. In the present paper, the role of hydrogen in stress corrosion crack growth in high strength steels, austenitic stainless steels, titanium alloys and high strength aluminium alloys is discussed. (author)

Plastics for corrosion inhibition

CERN Document Server

Goldade, Victor A; Makarevich, Anna V; Kestelman, Vladimir N

2005-01-01

The development of polymer composites containing inhibitors of metal corrosion is an important endeavour in modern materials science and technology. Corrosion inhibitors can be located in a polymer matrix in the solid, liquid or gaseous phase. This book details the thermodynamic principles for selecting these components, their compatibility and their effectiveness. The various mechanisms of metal protection – barrier, inhibiting and electromechanical – are considered, as are the conflicting requirements placed on the structure of the combined material. Two main classes of inhibited materials (structural and films/coatings) are described in detail. Examples are given of structural plastics used in friction units subjected to mechano-chemical wear and of polymer films/coatings for protecting metal objects against corrosion.

Effects of Chemical Treatments on Microbiologically Influenced Corrosion

Science.gov (United States)

Friedman, E. S.; Strom, M.; Dexter, S. C.

2008-12-01

Biofilms are known to have an effect on galvanic corrosion of alloys in seawater systems. In the Delaware Bay, biofilm formation on surface of cathodes has been shown to cause galvanic corrosion to occur up to 100 times more rapidly. Given the impacts that corrosion can have on structures, it is important to study how we can affect corrosion rates. One way of doing this is the application of chemical treatments to biofilms on metal samples. To investigate this, natural marine biofilms were grown on alloy 6XN stainless steel samples, and various chemical treatments were applied to discover their effects on open circuit potentials and corrosion currents. Another objective of this study was to determine if there was a threshold molecular weight above which molecules were unable to penetrate the biofilm. It was discovered that chemicals with molecular weights as high as 741.6 g/mol were able to penetrate at least some parts of the heterogeneous biofilm and reach the metal surface. No upper threshold value was found in this study. It was found that the reducing agents sodium L-ascorbate and NADH as well as the chelate ferizene caused a drop in open circuit potential of biofilmed 6XN samples. Also, glutaraldahyde, which is used as a fixative for bacteria, shifted the open circuit potential of biofilm samples in the noble direction but had no effect on the corrosion current. Sodium L- ascorbate was found to reach the metal surface, but in concentrations lower than those present in the bulk fluid. It was not determined in this study whether this was due to physical or chemical processes within the biofilm. A synergistic effect was observed when applying a mixture of ferizene and glutaraldahyde. It is thought that this was due to the death of the bacteria as well as the disruption of iron cycling in the biofilm. Finally, it was observed that NADH caused a reduction in current at potentials associated with iron reduction, leading us to believe that the iron was being reduced

Improvement of PWR reliability by corrosion prevention

International Nuclear Information System (INIS)

Takamatsu, Hiroshi

1999-01-01

Since first PWR in Japan started commercial operation in 1970, we have encountered the various modes of corrosion on primary and secondary side components. We have paid much efforts for resolving these corrosion problems, that is, investigating the causes of corrosion and establishing the countermeasures for these corrosion. We summarize these efforts in this article. (author)

Control of molten salt corrosion of fusion structural materials by metallic beryllium

International Nuclear Information System (INIS)

Calderoni, P.; Sharpe, P.; Nishimura, H.; Terai, T.

2009-01-01

A series of tests have been performed between 2001 and 2006 at the Safety and Tritium Applied Research facility of the Idaho National Laboratory to demonstrate chemical compatibility between the molten salt flibe (2LiF + BeF 2 in moles) and fusion structural materials once suitable fluoride potential control methods are established. The tests adopted metallic beryllium contact as main fluoride potential control, and the results have been published in recent years. A further step was to expose two specimens of low activation ferritic/martensitic steel 9Cr-2W to static corrosion tests that include an active corrosion agent (hydrofluoric gas) in controlled conditions at 530 deg. C, and the results of the tests are presented in this paper. The results confirmed the expected correlation of the HF recovery with the concentration of metallic impurities dissolved in the salt because of specimen corrosion. The metals concentration dropped to levels close to the detectable limit when the beryllium rod was inserted and increased once the content of excess beryllium in the system had been consumed by HF reduction and specimen corrosion progressed. Metallographic analysis of the samples after 500 h exposure in reactive conditions showed evidence of the formation of unstable chromium oxide layers on the specimen's surface.

Integrated modelling of corrosion-induced deterioration in rein-forced concrete structures

DEFF Research Database (Denmark)

Michel, Alexander; Geiker, M.R.; Stang, Henrik

2013-01-01

at the reinforcement surface, a FEM based me-chanical model was used to simulate corrosion-induced concrete damage. Both FEM models were fully coupled, i.e. information, such as corrosion current density, dam-age state of concrete cover, etc., were constantly exchanged between the models. To demonstrate the potential......An integrated finite element based modelling approach is presented, which allows for fully coupled simulation of reinforcement corrosion and corrosion-induced concrete damage. While a finite element method (FEM) based corrosion model was used to describe electrochemical processes...... use of the modelling approach, a numerical example is presented which illustrates full coupling of formation of corrosion cells, propagation of corrosion, and subsequent development of corrosion-induced concrete damage....

Structural design guidelines for concrete bridge decks reinforced with corrosion-resistant reinforcing bars.

Science.gov (United States)

2014-10-01

This research program develops and validates structural design guidelines and details for concrete bridge decks with : corrosion-resistant reinforcing (CRR) bars. A two-phase experimental program was conducted where a control test set consistent : wi...

Sensitivity Analysis of Corrosion Rate Prediction Models Utilized for Reinforced Concrete Affected by Chloride

Science.gov (United States)

Siamphukdee, Kanjana; Collins, Frank; Zou, Roger

2013-06-01

Chloride-induced reinforcement corrosion is one of the major causes of premature deterioration in reinforced concrete (RC) structures. Given the high maintenance and replacement costs, accurate modeling of RC deterioration is indispensable for ensuring the optimal allocation of limited economic resources. Since corrosion rate is one of the major factors influencing the rate of deterioration, many predictive models exist. However, because the existing models use very different sets of input parameters, the choice of model for RC deterioration is made difficult. Although the factors affecting corrosion rate are frequently reported in the literature, there is no published quantitative study on the sensitivity of predicted corrosion rate to the various input parameters. This paper presents the results of the sensitivity analysis of the input parameters for nine selected corrosion rate prediction models. Three different methods of analysis are used to determine and compare the sensitivity of corrosion rate to various input parameters: (i) univariate regression analysis, (ii) multivariate regression analysis, and (iii) sensitivity index. The results from the analysis have quantitatively verified that the corrosion rate of steel reinforcement bars in RC structures is highly sensitive to corrosion duration time, concrete resistivity, and concrete chloride content. These important findings establish that future empirical models for predicting corrosion rate of RC should carefully consider and incorporate these input parameters.

Corrosion/94 conference papers

International Nuclear Information System (INIS)

Anon.

1994-01-01

The approximately 500 papers from this conference are divided into the following sections: Rail transit systems--stray current corrosion problems and control; Total quality in the coatings industry; Deterioration mechanisms of alloys at high temperatures--prevention and remediation; Research needs and new developments in oxygen scavengers; Computers in corrosion control--knowledge based system; Corrosion and corrosivity sensors; Corrosion and corrosion control of steel reinforced concrete structures; Microbiologically influenced corrosion; Practical applications in mitigating CO 2 corrosion; Mineral scale deposit control in oilfield-related operations; Corrosion of materials in nuclear systems; Testing nonmetallics for life prediction; Refinery industry corrosion; Underground corrosion control; Mechanisms and applications of deposit and scale control additives; Corrosion in power transmission and distribution systems; Corrosion inhibitor testing and field application in oil and gas systems; Decontamination technology; Ozone in cooling water applications, testing, and mechanisms; Corrosion of water and sewage treatment, collection, and distribution systems; Environmental cracking of materials; Metallurgy of oil and gas field equipment; Corrosion measurement technology; Duplex stainless steels in the chemical process industries; Corrosion in the pulp and paper industry; Advances in cooling water treatment; Marine corrosion; Performance of materials in environments applicable to fossil energy systems; Environmental degradation of and methods of protection for military and aerospace materials; Rail equipment corrosion; Cathodic protection in natural waters; Characterization of air pollution control system environments; and Deposit-related problems in industrial boilers. Papers have been processed separately for inclusion on the data base

Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life

Science.gov (United States)

Okafor, A. C.; Natarajan, S.

2007-03-01

Aging aircraft are prone to corrosion damage and fatigue cracks in riveted lap joints of fuselage skin panels. This can cause catastrophic failure if not detected and repaired. Hence detection of corrosion damage and monitoring its effect on structural integrity are essential. This paper presents multifrequency eddy current (EC) inspection of corrosion damage and machined material loss defect in clad A1 2024-T3 riveted lap joints and its effect on fatigue life. Results of eddy current inspection, corrosion product removal and fatigue testing are presented.

Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life

International Nuclear Information System (INIS)

Okafor, A. C.; Natarajan, S.

2007-01-01

Aging aircraft are prone to corrosion damage and fatigue cracks in riveted lap joints of fuselage skin panels. This can cause catastrophic failure if not detected and repaired. Hence detection of corrosion damage and monitoring its effect on structural integrity are essential. This paper presents multifrequency eddy current (EC) inspection of corrosion damage and machined material loss defect in clad A1 2024-T3 riveted lap joints and its effect on fatigue life. Results of eddy current inspection, corrosion product removal and fatigue testing are presented

Marine corrosion of mild steel at Lumut, Perak

Science.gov (United States)

Ting, Ong Shiou; Potty, Narayanan Sambu; Liew, Mohd. Shahir

2012-09-01

The corrosion rate of structural steels in the adverse marine and offshore environments affects the economic interest of offshore structures since the loss of steel may have significant impact on structural safety and performance. With more emphasis to maintain existing structures in service for longer time and hence to defer replacement costs, there is increasing interest in predicting corrosion rate at a given location for a given period of exposure once the protection coating or cathodic protection is lost. The immersion depth, salinity, steel composition and water pollution will be taken into account. Various corrosion allowances are prescribed for structural members by different standards. There are no studies to determine the appropriate corrosion allowance for steel structures in marine environment in Malaysia. The objectives of the research are to determine the nature and rate of corrosion in mm/year for steel structures in marine environment. It also tries to identify whether the corrosion rate is affected by differences in the chemical composition of the steels, and microalgae. Two sets of corrosion coupons of Type 3 Steel consisting of mild steel were fabricated and immersed in seawater using steel frames. The corrosion rate of the coupon in mm/ per year is estimated based on the material weight loss with time in service. The results are compared with recommendations of the code.

Using half-cell potential measurement to access the severity of corrosion in reinforced concrete structures in Gentilly-2 reactor building

International Nuclear Information System (INIS)

Picard, S.; Kadoum, N.; Poirier, F.

2009-01-01

The half-cell potential technique has been used to assess the corrosion in the reactor's building ring beam of the Gentilly-2 nuclear power plant. It is a non-destructive technique based on the ASTM C 876 Standard. Corrosion is the result of a difference of potential between anodic and cathodic zones within the re-bars network and these potential differences are measured in the half-cell potential technique. Time exposure is the leading factor and we recommend the installation of permanent electrodes of reference in strategic areas. The results show a low corrosion activity level on 98% of the investigated surface and no severe corrosion potential reading has been registered. Furthermore the exercise shows that the repair technique has no influence on the corrosion activity of the steel network. Since most of the readings are located in the low corrosion activity level (from 0 to -100 mV), it illustrates that there is heterogeneity of the corrosion activity within the ring beam. We recommend a system to monitor the evolution of the corrosion phenomena in real time. The installation of reference electrodes positioned in some ring beam strategic areas is a simple and accurate way of monitoring the corrosion activity of the steel in the structure. In the case where an evolution in higher level is noted in the corrosion activity, it would be possible to act and prevent any further degradation of the structure

The formation, composition and structure of corrosion products in CANDU nuclear power reactors

International Nuclear Information System (INIS)

Rummery, T.E.

1978-01-01

To gain a better understanding of the formation and transport of corrosion products in CANDU-PHW power reactors, and the role played by these products in the generation and subsequent fixation of radioactive species, we have examined in detail several surfaces removed from the Douglas Point Generating Station (Douglas Point, Ontario). Results are given for the surface of the primary-side of a Monel-400 boiler tube, and surfaces of carbon steel piping at the inlet and outlet of the boiler. The experimental techniques that were used included sequential acid stripping, X-ray diffractometry, scanning electron microscopy and energy dispersive X-ray spectrometry. The corrosion products on the Monel-400 were mainly nickel, copper, nickel oxide and nickel-deficient nickel ferrite and varied in composition and quantity as a function of both distance from the boiler inlet, and depth in the corrosion layer. The radioactive cobalt ( 60 Co) content was localized in 'streaks' deposited in the straight sections of the boiler tube, but distributed uniformly over the whole surface in the downstream bend section. The material covering the carbon steel surface comprised three phases: magnetite, aluminosilicate particles at the outermost surface, and a mixed cation spinel phase uniformly distributed over the surface at the corrosion film-water interface. The formation, composition and structure of the corrosion products are discussed. (author)

Evolutionary Computation Techniques for Predicting Atmospheric Corrosion

Directory of Open Access Journals (Sweden)

Amine Marref

2013-01-01

Full Text Available Corrosion occurs in many engineering structures such as bridges, pipelines, and refineries and leads to the destruction of materials in a gradual manner and thus shortening their lifespan. It is therefore crucial to assess the structural integrity of engineering structures which are approaching or exceeding their designed lifespan in order to ensure their correct functioning, for example, carrying ability and safety. An understanding of corrosion and an ability to predict corrosion rate of a material in a particular environment plays a vital role in evaluating the residual life of the material. In this paper we investigate the use of genetic programming and genetic algorithms in the derivation of corrosion-rate expressions for steel and zinc. Genetic programming is used to automatically evolve corrosion-rate expressions while a genetic algorithm is used to evolve the parameters of an already engineered corrosion-rate expression. We show that both evolutionary techniques yield corrosion-rate expressions that have good accuracy.

Corrosion in Electronics

DEFF Research Database (Denmark)

Ambat, Rajan; Gudla, Helene Virginie Conseil; Verdingovas, Vadimas

2017-01-01

Electronic control units, power modules, and consumer electronics are used today in a wide variety of varying climatic conditions. Varying external climatic conditions of temperature and humidity can cause an uncontrolled local climate inside the device enclosure. Uncontrolled humidity together...... and high density packing combined with the use of several materials, which can undergo electrochemical corrosion in the presence of water film formed due to humidity exposure and bias conditions on the PCBA surface. This article provides a short review of the corrosion reliability issues of electronics due...... to the use of electronics under varying humidity conditions. Important PCBA aspects, which are fundamental to the corrosion cell formation under humid conditions, are discussed. Effect of hygroscopic residues from the process and service and their role in assisting water film build up and corrosion...

Chemical and structural effects of phosphorus on the corrosion behavior of ion beam mixed Fe-Cr-P alloys

International Nuclear Information System (INIS)

Demaree, J.D.; Was, G.S.; Sorensen, N.R.

1992-01-01

An experimental program was conducted to determine the mechanisms by which phosphorus affects the corrosion and passivation behavior of Fe-Cr-P alloys. To identify separately the effects of structure and chemistry on the corrosion behavior, thin films of Fe-10Cr-xP (0≤x≤35 at.%) were prepared by ion beam mixing. Films with a phosphorus content greater than approximately 20at.% were found to be entirely amorphous. Devitrification of the amorphous phase was accomplished by heating the samples to 450degC in an inert environment. Standard polarization tests of the sulfuric acid (with and without Cl - ) indicated that the films containing phosphorus were more corrosion resistant than Fe-10Cr, at both active and passive potentials. There was a monotonic relationship between the amount of phosphorus in the alloy and the corrosion resistance, with the open-circuit corrosion rate of Fe-10Cr-35P nearly four orders of magnitude lower than that of Fe-10Cr. Devitrification of the alloys had no significant effect on the corrosion rate, indicating that the primary effect of phosphorus is chemical in nature, and not structural. The passive oxides were depth-profiled using X-ray photoelectron spectroscopy, which indicated that phosphorus was a primary constituent, as phosphate. The presence of phosphate in the passive oxides reduced the overall corrosion rate directly, by suppressing anodic dissolution. The presence of phosphorus did enhance chromium enrichment in the oxide, but that was not thought to be the primary mechanism by which phosphorus increased the corrosion resistance. (orig.)

Determination of the environmental effect for the sea salt aerosols corrosion (3)

International Nuclear Information System (INIS)

Nakayasu, Fumio; Umehara, Toshihiro; Kato, Akitoshi; Taniguchi, Akihide

2009-01-01

Fukui Prefecture presently hosts 15 reactor units, including PWRs, BWR, FBR (Monjyu) and Japanese ATR (Fugen), all of which are located along the Japan Sea. Under such a circumstange, corrosion due to sea salt aerosols is one of the major factors causing ageing degradation of nuclear power plants facilities. Many scientists have been engaged in research on the corrosion of structures due to sea salt aerosols. In pursuing sea salt aerosol-induced corrosion research, it was necessary to perform corrosion tests under a certain set of environmental conditions since corrosion of structures is highly sensitive to environmental factors. In this respect, we installed the outdoor exposure test facilities along the sea coast in Awara-city and inland in Fukui-city, Fukui Prefecture of Japan. The amounts of sea salt aerosol tend to be lower in the summer season and higher in the winter season. The difference between seasons is expected to relate to the wind speed, the sunshine time, the rain amount and others. We tried to use the multivariate analysis for finding some relations between sea salt aerosol amounts and environment factor. We found the clear relations. (author)

High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings

International Nuclear Information System (INIS)

Farmer, J C; Haslam, J J; Wong, F; Ji, X; Day, S D; Branagan, D J; Marshall, M C; Meacham, B E; Buffa, E J; Blue, C A; Rivard, J K; Beardsley, M B; Weaver, D T; Aprigliano, L F; Kohler, L; Bayles, R; Lemieux, E J; Wolejsza, T M; Martin, F J; Yang, N; Lucadamo, G; Perepezko, J H; Hildal, K; Kaufman, L; Heuer, A H; Ernst, F; Michal, G M; Kahn, H; Lavernia, E J

2004-01-01

The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an ''integral drip shield'' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent

Causes and effects of the corrosion of a plumbing galvanised steel

Directory of Open Access Journals (Sweden)

Alejandre Sánchez, F. J.

2002-06-01

Full Text Available Hot dip galvanising life as a corrosion protective coatings on steel depends basically on three factors: coatings quality (thickness, correct installation of the galvanised article, and weathering effects. The aim of this research it is to study the decaying causes and effects of a plumbing installation made with hot dip galvanised steel tubes. The mentioned installation was of use during 30 years in the water supply system of the Parque Alcosa market (Sevilla, Spain. The research was divided in three parts: in the first one, shape analysis and XDR of internal decayed products was carried out: in the second one, physical properties were determined according to UNE 37- 505-89, corrosion morphology was conducted by metalographic microscopy, and it was evaluated also water quality: and finally, in the third one, diameter, section, and internal volume decrease was calculated in order to evaluate friction increase and pressure decrease in the installation. The results obtained show the correct plumbing installation according to quality requirements (UNE 37-509-89, so corrosion causes are mainly attributed to an aggressive environment for the hot dip galvanising.

La durabilidad de los galvanizados en caliente como recubrimientos protectores de la corrosión del acero dependen básicamente de tres factores: la calidad del recubrimiento (espesor, la correcta instalación del elemento galvanizado, y la agresividad del medio al que se encuentren expuestos. En este trabajo se estudian las causas y consecuencias del deterioro sufrido por una tubería de acero galvanizado, destinada durante unos 30 años a la conducción de agua potable de la red en el mercado del Parque Al cosa (Sevilla. La investigación se ha dividido en tres etapas: en la primera, se ha realizado el análisis formal y la caracterización mediante DRX de los productos de alteración generados en el interior del tubo: en la segunda, se han determinado las características f

Corrosion of reinforcement induced by environment containing ...

Indian Academy of Sciences (India)

Unknown

carbonation and chlorides causing corrosion of steel reinforcement. ... interesting and important when the evaluation of the service life of the ... preferably in the areas of industrial and transport activities. ... For controlling the embedded corrosion sensors, elec- .... danger of corrosion of reinforcement seems to be more.

Corrosion/96 conference papers

International Nuclear Information System (INIS)

Anon.

1996-01-01

Topics covered by this conference include: cathodic protection in natural waters; cleaning and repassivation of building HVAC systems; worldwide opportunities in flue gas desulfurization; advancements in materials technology for use in oil and gas service; fossil fuel combustion and conversion; technology of corrosion inhibitors; computers in corrosion control--modeling and information processing; recent experiences and advances of austenitic alloys; managing corrosion with plastics; corrosion measurement technology; corrosion inhibitors for concrete; refining industry; advances in corrosion control for rail and tank trailer equipment; CO 2 corrosion--mechanisms and control; microbiologically influenced corrosion; corrosion in nuclear systems; role of corrosion in boiler failures; effects of water reuse on monitoring and control technology in cooling water applications; methods and mechanisms of scale and deposit control; corrosion detection in petroleum production lines; underground corrosion control; environmental cracking--relating laboratory results and field behavior; corrosion control in reinforced concrete structures; corrosion and its control in aerospace and military hardware; injection and process addition facilities; progress reports on the results of reinspection of deaerators inspected or repaired per RP0590 criteria; near 100% volume solids coating technology and application methods; materials performance in high temperature environments containing halides; impact of toxicity studies on use of corrosion/scale inhibitors; mineral scale deposit control in oilfield related operations; corrosion in gas treating; marine corrosion; cold climate corrosion; corrosion in the pulp and paper industry; gaseous chlorine alternatives in cooling water systems; practical applications of ozone in recirculating cooling water systems; and water reuse in industry. Over 400 papers from this conference have been processed separately for inclusion on the data base

Corrosion evaluation technology

International Nuclear Information System (INIS)

Kim, Uh Chul; Han, Jeong Ho; Nho, Kye Ho; Lee, Eun Hee; Kim, Hong Pyo; Hwang, Seong Sik; Lee, Deok Hyun; Hur, Do Haeng; Kim, Kyung Mo.

1997-09-01

A multifrequency ACPD system was assembled which can measure very small crack. Stress corrosion cracking test system with SSRT operating high temperature was installed. Stress corrosion cracking test of newly developed alloy 600 and existing alloy 600 was carried out in steam atmosphere of 400 deg C. No crack was observed in both materials within a test period of 2,000 hrs. Corrosion fatigue test system operating at high temperature was installed in which fatigue crack was measured by CDPD. Lead enhanced the SCC of the Alloy 600 in high temperature water, had a tendency to modify a cracking morphology from intergranular to transgranular. Pit initiation preferentially occurred at Ti-rich carbide. Resistance to pit initiation decreased with increasing temperature up to 300 deg C. Test loop for erosion corrosion was designed and fabricated. Thin layer activation technique was very effective in measuring erosion corrosion. Erosion corrosion of a part of secondary side pipe was evaluated by the Check Family Codes of EPRI. Calculated values of pipe thickness by Check Family Codes coincided with the pipe thickness measured by UT with an error of ± 20%. Literature review on turbine failure showed that failure usually occurred in low pressure turbine rotor disc and causes of failure are stress corrosion cracking and corrosion fatigue. (author). 12 refs., 20 tabs., 77 figs

Dynamic corrosion investigations in the eutectic lead-lithium melt Pb-17Li

International Nuclear Information System (INIS)

Frees, G.; Drechsler, G.; Peric, Z.

1989-01-01

The Pb-17Li circuit 'PICOLO' was constructed and commissioned in the Institute for Material and Solid State Research II of the Kernforschungszentrum Karlsruhe. This circuit serves for corrosion tests with the martensitic steel 1.4914, which is under discussion for the application as structural material for a fusion reactor blanket. The design and the functions of the circuit are described. The experience which has been gained so far is principally favorable. A temperature of 500deg C seems, however, to be the upper limit for the operation with the structural materials of the circuit. The corrosion of specimens and materials of the components becomes considerably high at higher temperatures; this has been seen to cause the plugging due to the precipitation of corrosion products. The results of the first test series are presented and discussed. (orig.) [de

Methodology for assessing the probability of corrosion in concrete structures on the basis of half-cell potential and concrete resistivity measurements.

Science.gov (United States)

Sadowski, Lukasz

2013-01-01

In recent years, the corrosion of steel reinforcement has become a major problem in the construction industry. Therefore, much attention has been given to developing methods of predicting the service life of reinforced concrete structures. The progress of corrosion cannot be visually assessed until a crack or a delamination appears. The corrosion process can be tracked using several electrochemical techniques. Most commonly the half-cell potential measurement technique is used for this purpose. However, it is generally accepted that it should be supplemented with other techniques. Hence, a methodology for assessing the probability of corrosion in concrete slabs by means of a combination of two methods, that is, the half-cell potential method and the concrete resistivity method, is proposed. An assessment of the probability of corrosion in reinforced concrete structures carried out using the proposed methodology is presented. 200 mm thick 750 mm  ×  750 mm reinforced concrete slab specimens were investigated. Potential E corr and concrete resistivity ρ in each point of the applied grid were measured. The experimental results indicate that the proposed methodology can be successfully used to assess the probability of corrosion in concrete structures.

Methodology for Assessing the Probability of Corrosion in Concrete Structures on the Basis of Half-Cell Potential and Concrete Resistivity Measurements

Directory of Open Access Journals (Sweden)

Lukasz Sadowski

2013-01-01

Full Text Available In recent years, the corrosion of steel reinforcement has become a major problem in the construction industry. Therefore, much attention has been given to developing methods of predicting the service life of reinforced concrete structures. The progress of corrosion cannot be visually assessed until a crack or a delamination appears. The corrosion process can be tracked using several electrochemical techniques. Most commonly the half-cell potential measurement technique is used for this purpose. However, it is generally accepted that it should be supplemented with other techniques. Hence, a methodology for assessing the probability of corrosion in concrete slabs by means of a combination of two methods, that is, the half-cell potential method and the concrete resistivity method, is proposed. An assessment of the probability of corrosion in reinforced concrete structures carried out using the proposed methodology is presented. 200 mm thick 750 mm  ×  750 mm reinforced concrete slab specimens were investigated. Potential Ecorr and concrete resistivity ρ in each point of the applied grid were measured. The experimental results indicate that the proposed methodology can be successfully used to assess the probability of corrosion in concrete structures.

Statistical characterization of pitting corrosion process and life prediction

International Nuclear Information System (INIS)

Sheikh, A.K.; Younas, M.

1995-01-01

In order to prevent corrosion failures of machines and structures, it is desirable to know in advance when the corrosion damage will take place, and appropriate measures are needed to mitigate the damage. The corrosion predictions are needed both at development as well as operational stage of machines and structures. There are several forms of corrosion process through which varying degrees of damage can occur. Under certain conditions these corrosion processes at alone and in other set of conditions, several of these processes may occur simultaneously. For a certain type of machine elements and structures, such as gears, bearing, tubes, pipelines, containers, storage tanks etc., are particularly prone to pitting corrosion which is an insidious form of corrosion. The corrosion predictions are usually based on experimental results obtained from test coupons and/or field experiences of similar machines or parts of a structure. Considerable scatter is observed in corrosion processes. The probabilities nature and kinetics of pitting process makes in necessary to use statistical method to forecast the residual life of machine of structures. The focus of this paper is to characterization pitting as a time-dependent random process, and using this characterization the prediction of life to reach a critical level of pitting damage can be made. Using several data sets from literature on pitting corrosion, the extreme value modeling of pitting corrosion process, the evolution of the extreme value distribution in time, and their relationship to the reliability of machines and structure are explained. (author)

Structural performance evaluation on aging underground reinforced concrete structures. Part 6. An estimation method of threshold value in performance verification taking reinforcing steel corrosion

International Nuclear Information System (INIS)

Matsuo, Toyofumi; Matsumura, Takuro; Miyagawa, Yoshinori

2009-01-01

This paper discusses applicability of material degradation model due to reinforcing steel corrosion for RC box-culverts with corroded reinforcement and an estimation method for threshold value in performance verification reflecting reinforcing steel corrosion. First, in FEM analyses, loss of reinforcement section area and initial tension strain arising from reinforcing steel corrosion, and deteriorated bond characteristics between reinforcement and concrete were considered. The full-scale loading tests using corroded RC box-culverts were numerically analyzed. As a result, the analyzed crack patterns and load-strain relationships were in close agreement with the experimental results within the maximum corrosion ratio 15% of primary reinforcement. Then, we showed that this modeling could estimate the load carrying capacity of corroded RC box-culverts. Second, a parametric study was carried out for corroded RC box culverts with various sizes, reinforcement ratios and levels of steel corrosion, etc. Furthermore, as an application of analytical results and various experimental investigations, we suggested allowable degradation ratios for a modification of the threshold value, which corresponds to the chloride induced deterioration progress that is widely accepted in maintenance practice for civil engineering reinforced concrete structures. Finally, based on these findings, we developed two estimation methods for threshold value in performance verification: 1) a structural analysis method using nonlinear FEM included modeling of material degradation, 2) a practical method using a threshold value, which is determined by structural analyses of RC box-culverts in sound condition, is multiplied by the allowable degradation ratio. (author)

Reliability and corrosion induced degradation of electronic system

International Nuclear Information System (INIS)

Tapas, V.K.; Varde, P.V.

2014-01-01

This paper describe the corrosion induced degradation of electronic system failures due to environmental conditions such as humidity, temperature, ionic or organic contaminants, residuals; etc. which can accelerates as electrochemical reaction and causes corrosion of electronic components, Corrosive gases and water vapours from humid condition come into contact with the base metal results in buildup of various chemical reaction products. Ionic contamination responsible for electrochemical reaction, forms soluble complexes with metals, it can degrade the protective oxide film that forms on the positively biased metallization and/or lead to change in the local pH. Deterioration of metal components or electronic circuitry due to electrochemical migration needs to be controlled in order to reduce the corrosion. With explosive increase in demand and miniaturization in electronic system resulted in smaller components, closer spacing and thinner metallic path, it is expected that the corrosion and deterioration of electronic components may become cause or concern. This paper summarises the current understanding of chemistry behind possible causes of corrosion of electronic devices and its failure mechanism. (author)

The Corrosion Inhibition Characteristics of Sodium Nitrite Using an On-line Corrosion Rate Measurement System

International Nuclear Information System (INIS)

Park, Mal-Yong; Kang, Dae-Jin; Moon, Jeon-Soo

2015-01-01

An on-line corrosion rate measurement system was developed using a personal computer, a data acquisition board and program, and a 2-electrode corrosion probe. Reliability of the developed system was confirmed with through comparison test. With this system, the effect of sodium nitrite (NaNO 2 ) as a corrosion inhibitor were studied on iron and aluminum brass that were immersed in sodium chloride (NaCl) solution. Corrosion rate was measured based on the linear polarization resistance method. The corrosion rates of aluminum brass and iron in 1% NaCl solutions were measured to be 0.290 mm per year (mmpy) and 0.2134 mmpy, respectively. With the addition of 200 ppm of NO 2 - , the corrosion rates decreased to 0.0470 mmpy and 0.0254 mmpy. The addition of NO 2 - caused a decrease in corrosion rates of both aluminum brass and iron, yet the NO 2 - acted as a more effective corrosion inhibitor for iron. than aluminum brass

General corrosion, irradiation-corrosion, and environmental-mechanical evaluation of nuclear-waste-package structural-barrier materials. Progress report

International Nuclear Information System (INIS)

Westerman, R.E.; Pitman, S.G.; Nelson, J.L.

1982-09-01

Pacific Northwest Laboratory is studying the general corrosion, irradiation-corrosion, and environmentally enhanced crack propagation of five candidate materials in high-temperature aqueous environments simulating those expected in basalt and tuff repositories. The materials include three cast ferrous materials (ductile cast iron and two low-alloy Cr-Mo cast steels) and two titanium alloys, titanium Grade 2 (commercial purity) and Grade 12 (a Ti-Ni-Mo alloy). The general corrosion results are being obtained by autoclave exposure of specimens to slowly replenished simulated ground water flowing upward through a bed of the appropriate crushed rock (basalt or tuff), which is maintained at the desired test temperature (usually 250 0 C). In addition, tests are being performed in deionized water. Metal penetration rates of iron-base alloys are being derived by stripping off the corrosion product film and weighing the specimen after the appropriate exposure time. The corrosion of titanium alloy specimens is being determined by weight gain methods. The irradiation-corrosion studies are similar to the general corrosion tests, except that the specimen-bearing autoclaves are held in a 60 Co gamma radiation field at dose rates up to 2 x 10 6 rad/h. For evaluating the resistance of the candidate materials to environmentally enhanced crack propagation, three methods are being used: U-bend and fracture toughness specimens exposed in autoclaves; slow strain rate studies in repository-relevant environments to 300 0 C; and fatigue crack growth rate studies at ambient pressure and 90 0 C. The preliminary data suggest a 1-in. corrosion allowance for iron-base barrier elements intended for 1000-yr service in basalt or tuff repositories. No evidence has yet been found that titanium Grade 2 or Grade 12 is susceptible to environmentally induced crack propagation or, by extension, to stress corrosion cracking

Analysis and countermeasures for the corrosion on the shaft of seawater pump

International Nuclear Information System (INIS)

Lu Hongtao; Chen Haiming

2010-01-01

The corrosion resistance of the shaft material-3Cr13 was studied through immersion test and electrochemistry test. The results indicated that 3Cr13 and the chromium plating on the shaft had poor resistance against local corrosion in seawater. And the free corrosion potential of 3Cr13 in seawater was lower than other components of the pump, this could accelerate the corrosion rate of the shaft due to galvanic corrosion. A comprehensive analysis showed that the root cause of the corrosion on the No.4 shaft was that 3Cr13 had poor resistance against local corrosion in seawater. Because of the exist of fit-up gap, galvanic corrosion effect and corrosive wear caused by sand, crevice corrosion, galvanic corrosion and wear occurred. All of these accelerated the corrosion rate of the shaft and finally caused its failure. It is suggested that the sealant should be improved and the current material 3Cr13 should be replaced by a kind of materials with better corrosion resistance. (authors)

The Leakage determination on corrosion fretting machine

International Nuclear Information System (INIS)

Sriyono; Satmoko, Ari; Hafid, Abdul; Febrianto; Prasetio, Joko; Abtokhi; Sumarno, Edy; Handoyo, Ismu; Hidayati, Nur Rahmah; Histori

1998-01-01

Fretting machine is an experimental loop to learn fretting corrosion phenomena wich is caused by loading and vibration. On the steam generator, one of the corrosion process that's occurred, it can be caused by vibration between tubes and bending material. Because of high flow rate inside the tube, the high frequency vibration will appeared so it can make the corrosion on bending material more faster. This process can be simulate by fretting machine. This machine has already damage because of leakage. So it will be repaired by dismantling, radiography testing and redrawing. from the result of radiography, the leakage is caused by cracking on bellows seals of the dynamic main support

Dictionary corrosion and corrosion control

International Nuclear Information System (INIS)

1985-01-01

This dictionary has 13000 entries in both languages. Keywords and extensive accompanying information simplify the choice of word for the user. The following topics are covered: Theoretical principles of corrosion; Corrosion of the metals and alloys most frequently used in engineering. Types of corrosion - (chemical-, electro-chemical, biological corrosion); forms of corrosion (superficial, pitting, selective, intercrystalline and stress corrosion; vibrational corrosion cracking); erosion and cavitation. Methods of corrosion control (material selection, temporary corrosion protection media, paint and plastics coatings, electro-chemical coatings, corrosion prevention by treatment of the corrosive media); Corrosion testing methods. (orig./HP) [de

Some problems on the aqueous corrosion of structural materials in nuclear engineering; Problemes de corrosion aqueuse de materiaux de structure dans les constructions nucleaires

Energy Technology Data Exchange (ETDEWEB)

Coriou, H; Grall, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

The purpose of this report is to give a comprehensive view of some aqueous corrosion studies which have been carried out with various materials for utilization either in nuclear reactors or in irradiated fuel treatment plants. The various subjects are listed below. Austenitic Fe-Ni-Cr alloys: the behaviour of austenitic Fe-Ni-Cr alloys in nitric medium and in the presence of hexavalent chromium; the stress corrosion of austenitic alloys in alkaline media at high temperatures; the stress corrosion of austenitic Fe-Ni-Cr alloys in 650 C steam. Ferritic steels: corrosion of low alloy steels in water at 25 and 360 C; zirconium alloys; the behaviour of ultrapure zirconium in water and steam at high temperature. (authors) [French] On presente un ensemble d'etudes de corrosion en milieu aqueux effectuees sur des materiaux utilises, soit dans la construction des reacteurs soit pour la realisation des usines de traitement des combustibles irradies. Les differents sujets etudies sont les suivants. Les alliages austenitiques Fer-Nickel-Chrome: comportement d'alliages austenitiques fer-nickel-chrome en milieu nitrique en presence de chrome hexavalent; Corrosion sous contrainte d'alliages austenitiques dans les milieux alcalins a haute temperature; Corrosion sous contrainte dans la vapeur a 650 C d'alliages austenitiques fer-nickel-chrome. Les aciers ferritiques; Corrosion d'aciers faiblement allies dans l'eau a 25 et 360 C; le zirconium et ses alliages; Comportement du zirconium tres pur dans l'eau et la vapeur a haute temperature. (auteurs)

Corrosion of target and structural materials in water irradiated by an 800 MeV proton beam

International Nuclear Information System (INIS)

Butt, D.P.; Kanner, G.S.; Lillard, R.S.

1996-01-01

Radiation enhanced, aqueous corrosion of solid neutron-targets such as tungsten or tantalum, or target cladding or structural materials such as superalloys and stainless steels, is a significant concern in accelerator-driven transmutation technologies. In this paper we briefly describe our current methods for control and in situ monitoring of corrosion in accelerator cooling water loops. Using floating, electrochemical impedance spectroscopy (EIS), we have measured the corrosion rates of aluminum 6061, copper, Inconel 718, and 304L stainless steel in the flow loop of a water target irradiated by a μamp, 800 MeV proton beam. Impedance spectroscopy allows us to model the corrosion process of a material as an equivalent electrical circuit. Thus the polarization resistance, which is inversely proportional to the corrosion rate, can be extracted from the frequency response of a metal specimen. During a three month period, without the use of corrosion mitigation techniques, we observed increases of several orders of magnitude in the water conductivity and the corrosion rates. The increase in corrosion is at least partially attributed to a build up of peroxide in our pseudo-closed loop system. In this paper we also briefly describe our second generation experiments, scheduled to begin in late 1996. In these experiments we plan to measure the corrosion rates of tungsten, tantalum, Inconel 718, 316L and 304L stainless steel, HT-9 austenitic stainless steel, and aluminum 5053. Two or three electrode probes of each material are being placed directly in the proton beam, in a high neutron flux region, or a significant distance from the high radiation area. We will be measuring corrosion rates, changes in pH and conductivity, and we will be establishing parameters for filtration and mitigation of corrosion. We will also discuss our ideas for making in situ measurements of water radiolysis using optical and laser diagnostic techniques

Structural performance evaluation on aging underground reinforced concrete structures. Part 5

International Nuclear Information System (INIS)

Matsumura, Takuro; Matsuo, Toyofumi; Miyagawa, Yoshinori

2009-01-01

When we evaluate the soundness of reinforced concrete structures, it is important to assess the chloride induced deterioration. We conducted the reinforcing steel corrosion tests of reinforced concrete specimens under simulated tidal environment of sea. Parameters of the tests were water cement ratio, cement type and crack width of concrete. Periods of the tests were eighty month. The obtained results were summarized at follows: (a) The chloride ion concentration at the initiation of reinforcing steel corrosion was about 3.0 kg/m 3 in case of reinforcing steel in non-crack concrete used ordinary cement. (b) The corrosion rate of reinforcing steels was almost constant at any cement type specimens after causing crack by reinforcing steel corrosion. (c) The corrosion rate of reinforcing steels in specimens, which caused cracks by bending load, increased as crack width. In the same type specimens, the corrosion rate of reinforcing steels in fly ash cement specimens was larger than that of ordinary cement specimens. In this case, the corrosion rate of reinforcing steels was evaluated about 0.18 mm/year. (author)

Corrosion and Corrosion-Fatigue Behavior of 7075 Aluminum Alloys Studied by In Situ X-Ray Tomography

Science.gov (United States)

Stannard, Tyler

7XXX Aluminum alloys have high strength to weight ratio and low cost. They are used in many critical structural applications including automotive and aerospace components. These applications frequently subject the alloys to static and cyclic loading in service. Additionally, the alloys are often subjected to aggressive corrosive environments such as saltwater spray. These chemical and mechanical exposures have been known to cause premature failure in critical applications. Hence, the microstructural behavior of the alloys under combined chemical attack and mechanical loading must be characterized further. Most studies to date have analyzed the microstructure of the 7XXX alloys using two dimensional (2D) techniques. While 2D studies yield valuable insights about the properties of the alloys, they do not provide sufficiently accurate results because the microstructure is three dimensional and hence its response to external stimuli is also three dimensional (3D). Relevant features of the alloys include the grains, subgrains, intermetallic inclusion particles, and intermetallic precipitate particles. The effects of microstructural features on corrosion pitting and corrosion fatigue of aluminum alloys has primarily been studied using 2D techniques such as scanning electron microscopy (SEM) surface analysis along with post-mortem SEM fracture surface analysis to estimate the corrosion pit size and fatigue crack initiation site. These studies often limited the corrosion-fatigue testing to samples in air or specialized solutions, because samples tested in NaCl solution typically have fracture surfaces covered in corrosion product. Recent technological advancements allow observation of the microstructure, corrosion and crack behavior of aluminum alloys in solution in three dimensions over time (4D). In situ synchrotron X-Ray microtomography was used to analyze the corrosion and cracking behavior of the alloy in four dimensions to elucidate crack initiation at corrosion pits

A study on structural analysis of highly corrosive melts at high temperature

CERN Document Server

Ohtori, N

2002-01-01

When sodium is burned at high temperature in the atmosphere, it reacts simultaneously with H sub 2 O in the atmosphere so that it can produce high temperature melt of sodium hydroxide as a solvent. If this melt includes peroxide ion (O sub 2 sup 2 sup -), it will be a considerably active and corrosive for iron so that several sodium iron double oxides will be produced as corrosion products after the reaction with steel structures. The present study was carried out in order to investigate the ability of presence of peroxide ion in sodium hydroxide solvent at high temperature and that of identification of the several corrosion products using laser Raman spectroscopy. The measurement system with ultraviolet laser was developed simultaneously in the present work to improve the ability of the measurement at high temperature. As results from the measurements, the possibility of the presence of peroxide ion was shown up to 823K in sodium peroxide and 823K in the melt of sodium hydroxide mixed with sodium peroxide. A...

Ultimate strength performance of tankers associated with industry corrosion addition practices

Directory of Open Access Journals (Sweden)

Kim Do Kyun

2014-09-01

Full Text Available In the ship and offshore structure design, age-related problems such as corrosion damage, local denting, and fatigue damage are important factors to be considered in building a reliable structure as they have a significant influence on the residual structural capacity. In shipping, corrosion addition methods are widely adopted in structural design to prevent structural capacity degradation. The present study focuses on the historical trend of corrosion addition rules for ship structural design and investigates their effects on the ultimate strength performance such as hull girder and stiffened panel of double hull oil tankers. Three types of rules based on corrosion addition models, namely historic corrosion rules (pre-CSR, Common Structural Rules (CSR, and harmonised Common Structural Rules (CSRH are considered and compared with two other corrosion models namely UGS model, suggested by the Union of Greek Shipowners (UGS, and Time-Dependent Corrosion Wastage Model (TDCWM. To identify the general trend in the effects of corrosion damage on the ultimate longitudinal strength performance, the corrosion addition rules are applied to four representative sizes of double hull oil tankers namely Panamax, Aframax, Suezmax, and VLCC. The results are helpful in understanding the trend of corrosion additions for tanker structures

Ultimate strength performance of tankers associated with industry corrosion addition practices

Directory of Open Access Journals (Sweden)

Do Kyun Kim

2014-09-01

Full Text Available In the ship and offshore structure design, age-related problems such as corrosion damage, local denting, and fatigue damage are important factors to be considered in building a reliable structure as they have a significant influence on the residual structural capacity. In shipping, corrosion addition methods are widely adopted in structural design to prevent structural capacity degradation. The present study focuses on the historical trend of corrosion addition rules for ship structural design and investigates their effects on the ultimate strength performance such as hull girder and stiffened panel of double hull oil tankers. Three types of rules based on corrosion addition models, namely historic corrosion rules (pre-CSR, Common Structural Rules (CSR, and harmonised Common Structural Rules (CSRH are considered and compared with two other corrosion models namely UGS model, suggested by the Union of Greek Shipowners (UGS, and Time-Dependent Corrosion Wastage Model (TDCWM. To identify the general trend in the effects of corrosion damage on the ultimate longitudinal strength performance, the corrosion addition rules are applied to four representative sizes of double hull oil tankers namely Panamax, Aframax, Suezmax, and VLCC. The results are helpful in understanding the trend of corrosion additions for tanker structures.

A degradation model for stray current induced corrosion in underground reinforced concrete structures

NARCIS (Netherlands)

Polder, R.B.; Peelen, W.H.A.

2003-01-01

This paper describes the effects of stray currents on durability and reinforcement corrosion of underground concrete structures. Cathodic protection of underground pipelines are stationary sources of stray current interference with concrete, and rail traction systems are non-stationary sources. The

Corrosion detection of steel reinforced concrete using combined carbon fiber and fiber Bragg grating active thermal probe

International Nuclear Information System (INIS)

Li, Weijie; Ho, Siu Chun Michael; Song, Gangbing

2016-01-01

Steel reinforcement corrosion is one of the dominant causes for structural deterioration for reinforced concrete structures. This paper presents a novel corrosion detection technique using an active thermal probe. The technique takes advantage of the fact that corrosion products have poor thermal conductivity, which will impede heat propagation generated from the active thermal probe. At the same time, the active thermal probe records the temperature response. The presence of corrosion products can thus be detected by analyzing the temperature response after the injection of heat at the reinforcement-concrete interface. The feasibility of the proposed technique was firstly analyzed through analytical modeling and finite element simulation. The active thermal probe consisted of carbon fiber strands to generate heat and a fiber optic Bragg grating (FBG) temperature sensor. Carbon fiber strands are used due to their corrosion resistance. Wet-dry cycle accelerated corrosion experiments were performed to study the effect of corrosion products on the temperature response of the reinforced concrete sample. Results suggest a high correlation between corrosion severity and magnitude of the temperature response. The technique has the merits of high accuracy, high efficiency in measurement and excellent embeddability. (paper)

Accelerated Test Method for Corrosion Protective Coatings Project

Science.gov (United States)

Falker, John; Zeitlin, Nancy; Calle, Luz

2015-01-01

This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as accurately and reliably as current long-term atmospheric exposure tests. This new accelerated test method will shorten the time needed to evaluate the corrosion protection performance of coatings for NASA's critical ground support structures. Lifetime prediction for spaceport structure coatings has a 5-year qualification cycle using atmospheric exposure. Current accelerated corrosion tests often provide false positives and negatives for coating performance, do not correlate to atmospheric corrosion exposure results, and do not correlate with atmospheric exposure timescales for lifetime prediction.

Influence of grain structure on quench sensitivity relative to localized corrosion of high strength aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Liu, ShengDan, E-mail: csuliusd@163.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha 410083 (China); Li, ChengBo [Light Alloy Research Institute, Central South University, Changsha 410083 (China); Deng, YunLai; Zhang, XinMing [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha 410083 (China)

2015-11-01

The influence of grain structure on quench sensitivity relative to localized corrosion of high strength aluminum alloy 7055 was investigated by electrochemical test, accelerated exfoliation corrosion test, optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The decrease of quench rate led to lower corrosion resistance of both the homogenized and solution heat treated (HS) alloy with equiaxed grains and the hot-rolled and solution heat treated (HRS) alloy with elongated grains, but there was a higher increment in corrosion depth and corrosion current density and a higher decrement in corrosion potential for the latter alloy, which therefore exhibited higher quench sensitivity. It is because in this alloy the larger amount of (sub) grain boundaries led to a higher increment in the amount of quench-induced η phase and precipitates free zone at (sub) grain boundaries with the decrease of quench rate, and there was a larger increment in the content of Zn, Mg and Cu in the η phase at grain boundaries due to slow quenching. The presence of subgrain boundaries in the HRS alloy tended to increase corrosion resistance at high quench rates higher than about 630 °C/min but decrease it at lower quench rates. - Highlights: • (Sub)Grain boundaries increase quench sensitivity relative to localized corrosion. • Subgrain boundaries decrease corrosion resistance below quench rate of 630 °C/min. • More (sub) grain boundaries leads to more GBPs and PFZ with decreasing quench rate.

Monitoring and modeling stress corrosion and corrosion fatigue damage in nuclear reactors

International Nuclear Information System (INIS)

Andresen, P.L.; Ford, F.P.; Solomon, H.D.; Taylor, D.F.

1990-01-01

Stress corrosion and corrosion fatigue are significant problems in many industries, causing economic penalties from decreased plant availability and component repair or replacement. In nuclear power reactors, environmental cracking occurs in a wide variety of components, including reactor piping and steam generator tubing, bolting materials and pressure vessels. Life assessment for these components is complicated by the belief that cracking is quite irreproducible. Indeed, for conditions which were once viewed as nominally similar, orders of magnitude variability in crack growth rates are observed for stress corrosion and corrosion fatigue of stainless steels and low-alloy steels in 288 degrees C water. This paper shows that design and life prediction approaches are destined to be overly conservative or to risk environmental failure if life is predicted by quantifying only the effects of mechanical parameters and/or simply ignoring or aggregating environmental and material variabilities. Examples include the Nuclear Regulatory Commission (NRC) disposition line for stress-corrosion cracking of stainless steel in boiling water reactor (BWR) water and the American Society of Mechanical Engineers' Section XI lines for corrosion fatigue

Nano structure Formations and Improvement in Corrosion Resistance of Steels by Means of Pulsed Electron Beam Surface Treatment

International Nuclear Information System (INIS)

Zhang, K.M.; Zou, J.X.; Zou, J.X.; Grosdidier, T.; Zou, J.X.; Grosdidier, T.; Grosdidier, T.

2013-01-01

The corrosion of steels has long been the topic for materials scientists. It is established that surface treatment is an efficient way to improve the corrosion resistance of steels without changing the bulk properties and with low costs. In the present paper, different kinds of surface treatment techniques for steels are briefly reviewed. In particular, the surface modification involving nano structure formations of steels by using a low energy high pulsed electron beam (LEHCPEB) treatment is lightened in the case of an AISI 316L stainless steel and D2 steel. The overall results demonstrate the high potential of the LEHCPEB technique for improving the corrosion performance of steels The corrosion of steels has long been the topic for materials scientists. It is established that surface treatment is an efficient way to improve the corrosion resistance of steels without changing the bulk properties and with low costs. In the present paper, different kinds of surface treatment techniques for steels are briefly reviewed. In particular, the surface modification involving nano structure formations of steels by using a low energy high pulsed electron beam (LEHCPEB) treatment is lightened in the case of an AISI 316L stainless steel and D2 steel. The overall results demonstrate the high potential of the LEHCPEB technique for improving the corrosion performance of steels

Corrosion Detection of Reinforcement of Building Materials with Piezoelectric Sensors

Directory of Open Access Journals (Sweden)

Jia Peng

2017-06-01

Full Text Available The extensive use of reinforced materials in the construction industry has raised increased concerns about their safety and durability, while corrosion detection of steel materials is becoming increasingly important. For the scientific management, timely repair and health monitoring of construction materials, as well as to ensure construction safety and prevent accidents, this paper investigates corrosion detection on construction materials based on piezoelectric sensors. At present, the commonly used corrosion detection methods include physical and electrochemical methods, but there are shortcomings such as large equipment area, low detection frequency, and complex operation. In this study an improved piezoelectric ultrasonic sensor was designed, which could not only detect the internal defects of buildings while not causing structural damage, but also realize continuous detection and enable qualitative and quantitative assessment. Corrosion detection of reinforced building materials with piezoelectric sensors is quick and accurate, which can find hidden dangers and provide a reliable basis for the safety of the buildings.

Corrosion of Aluminum Alloys in the Presence of Fire-Retardant Aircraft Interior Materials

Science.gov (United States)

1995-10-01

This research project was to evaluate the potential for fire-retardant materials used in aircraft interiors to cause corrosion of aluminum structural alloys. Service Difficulty Reports (SDR's) were reviewed for several aircraft types, and the most fr...

In situ corrosion monitoring of PC structures with distributed hybrid carbon fiber reinforced polymer sensors

Science.gov (United States)

Yang, C. Q.; Wu, Z. S.

2007-08-01

Firstly, the fabrication and sensing properties of hybrid carbon fiber reinforced polymer (HCFRP) composite sensors are addressed. In order to provide a distributed sensing manner, the HCFRP sensors were divided into multi-zones with electrodes, and each zone was regarded as a separate sensor. Secondly, their application is studied to monitor the steel corrosion of prestressed concrete (PC) beams. The HCFRP sensors with different gauge lengths were mounted on a PC tendon, steel bar and embedded in tensile and compressive sides of the PC beam. The experiment was carried out under an electric accelerated corrosion and a constant load of about 54 kN. The results reveal that the corrosion of the PC tendon can be monitored through measuring the electrical resistance (ER) change of the HCFRP sensors. For the sensors embedded in tensile side of the PC beam, their ER increases as the corrosion progresses, whereas for the sensors embedded in compressive side, their ER decreases with corrosion time. Moreover, the strains due to the corrosion can be obtained based on the ER change and calibration curves of HCFRP sensors. The strains measured with traditional strain gauges agree with the strains calculated from the ER changes of HCFRP sensors. The electrical behavior of the zones where the corrosion was performed is much different from those of the other zones. In these zones, either there exist jumps in ER, or the ER increases with a much larger rate than those of the other zones. Distributed corrosion monitoring for PC structures is thus demonstrated with the application of HCFRP sensors through a proper installation of multi-electrodes.

Prediction of Corrosion Resistance of Concrete Containing Natural Pozzolan from Compressive Strength

Science.gov (United States)

al-Swaidani, A. M.; Ismat, R.; Diyab, M. E.; Aliyan, S. D.

2015-11-01

A lot of Reinforced Concrete (RC) structures in Syria have suffered from reinforcement corrosion which shortened significantly their service lives. Probably, one of the most effective approaches to make concrete structures more durable and concrete industry on the whole - more sustainable is to substitute pozzolan for a portion of Portland cement (PC). Syria is relatively rich in natural pozzolan. In the study, in order to predict the corrosion resistance from compressive strength, concrete specimens were produced with seven cement types: one plain Portland cement (control) and six natural pozzolan-based cements with replacement levels ranging from 10 to 35%. The development of the compressive strengths of concrete cube specimens with curing time has been investigated. Chloride penetrability has also been evaluated for all concrete mixes after three curing times of 7, 28 and 90 days. The effect on resistance of concrete against damage caused by corrosion of the embedded reinforcing steel has been investigated using an accelerated corrosion test by impressing a constant anodic potential for 7, 28 and 90 days curing. Test results have been statistically analysed and correlation equations relating compressive strength and corrosion performance have been developed. Significant correlations have been noted between the compressive strength and both rapid chloride penetrability and corrosion initiation times. So, this prediction could be reliable in concrete mix design when using natural pozzolan as cement replacement.

Evaluation of the Corrosion Protection Coating in Accordance with Burn Damage

International Nuclear Information System (INIS)

Seo, ChangHo; Park, JinHwan

2016-01-01

This study was conducted in order to examine the effect of burn damage and the resultant anti-corrosion performance. The breakdown and defect of the paint film caused by burn damage are considered to affect not only the macroscopic appearance but also the adhesive force and the anti-corrosion performance of the paint film. The material of the paint film was epoxy paint that is used most widely for heavy-duty coating, and in order to induce burn damage, heat treatment with a torch was applied to the other side of the paint film. Surface and chemical structure changes according to aging were analyzed using FE-SEM and infrared absorption spectroscopy, and variation in the anti-corrosion performance was analyzed through the AC impedance test.

A New Corrosion Sensor to Determine the Start and Development of Embedded Rebar Corrosion Process at Coastal Concrete

OpenAIRE

Xu, Chen; Li, Zhiyuan; Jin, Weiliang

2013-01-01

The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete u...

Corrosion Cost and Corrosion Map of Korea - Based on the Data from 2005 to 2010

International Nuclear Information System (INIS)

Kim, Y. S.; Lim, H. K.; Kim, J. J.; Hwang, W. S.; Park, Y. S.

2011-01-01

Corrosion of metallic materials occurs by the reaction with corrosive environment such as atmosphere, marine, soil, urban, high temperature etc. In general, reduction of thickness and cracking and degradation are resulted from corrosion. Corrosion in all industrial facilities and infrastructure causes large economic losses as well as a large number of accidents. Economic loss by corrosion has been reported to be nearly 1-6% of GNP or GDP. In order to reduce corrosion damage of industrial facilities, corrosion map as well as a systematic investigation of the loss of corrosion in each industrial sector is needed. The Corrosion Science Society of Korea in collaboration with 15 universities and institutes has started to survey on the cost of corrosion and corrosion map of Korea since 2005. This work presents the results of the survey on cost of corrosion by Uhlig, Hoar, and input-output methods, and the evaluation of atmospheric corrosion rate of carbon steel, weathering steel, galvanized steel, copper, and aluminum in Korea. The total corrosion cost was estimated in terms of the percentage of the GDP of industry sectors and the total GDP of Korea. According to the result of Input/output method, corrosion cost of Korea was calculated as 2.9% to GDP (2005). Time of wetness was shown to be categories 3 to 4 in all exposure areas. A definite seasonal difference was observed in Korea. In summer and fall, time of wetness was higher than in other seasons. Because of short exposure period (12 months), significant corrosion trends depending upon materials and exposure corrosion environments were not revealed even though increased mass loss and decreased corrosion rate by exposure time

Structure and corrosion properties of PVD Cr-N coatings

International Nuclear Information System (INIS)

Liu, C.; Bi, Q.; Ziegele, H.; Leyland, A.; Matthews, A.

2002-01-01

PVD Cr-N coatings produced by physical vapor deposition (PVD) are increasingly used for mechanical and tribological applications in various industrial sectors. These coatings are particularly attractive for their excellent corrosion resistance, which further enhances the lifetime and service quality of coated components. PVD Cr-N coated steels in an aqueous solution are usually corroded by galvanic attack via through-coating 'permeable' defects (e.g., pores). Therefore, the corrosion performance of Cr-N coated steel is determined by a number of variables of the coating properties and corrosive environment. These variables include: (i) surface continuity and uniformity; (ii) through-coating porosity; (iii) film density and chemical stability; (iv) growth stresses; (v) interfacial and intermediate layers; (vi) coating thickness; (vii) coating composition; and (viii) substrate properties. In this article, PVD Cr-N coatings were prepared, by electron-beam PVD and sputter deposition, with different compositions, thicknesses, and surface roughnesses, by changing the N 2 flow rate, applying multilayering techniques and changing the substrate finish prior to coating. The microstructure of such coatings is investigated by various analytical techniques such as glancing angle x-ray diffraction and scanning electron microscopy, which are also correlated with the corrosion performance of the coated steel. Both dc polarization and ac impedance spectroscopy were employed to investigate the corrosion resistance of Cr-N coated steel in a 0.5N NaCl solution. It has been found that the N 2 flow rate during reactive deposition strongly determines the microstructure of Cr-N coatings (due to the changing nitrogen content in the film) and can thus affect the corrosion resistance of coated systems. The surface finish of the steel substrate also affects the uniformity and coverage of PVD coatings; grooves and inclusions on the original substrate can raise the susceptibility of coated

Stress corrosion cracking prevention using solar electricity

International Nuclear Information System (INIS)

Harijan, K.; Uqaaili, M.A; Mirani, M.

2004-01-01

Metallic structures exposed to soil and water naturally experience corrosion due to electrolytic action. These structures are also subjected to sustained tensile stresses. The combined effects of corrosion and stress results stress corrosion cracking (SCC). Removal of either of these i.e. stress or corrosion prevents SCC. The cathodic protection (CP) prevents corrosion, and hence prevents stress corrosion. Solar Photo voltaic (PV) generated electricity can be best external power source for CP systems especially in remote areas. This paper presents CP system using solar PV generated electricity as an external power source for prevention of SCC of metallic structures. The paper also compares CP systems using solar electricity with those of CP systems using conventional electricity. The paper concludes that a solar electricity power system provides a reliable solution for powering CP stations especially in remote areas, enables the placing of CP units in any location, and thus ensures optimal current distribution for the exact protection requirements. The paper also concludes that solar electricity CP systems are well suited for SCC protection of metallic structures especially in remote areas of an energy deficit country like Pakistan. (author)

Molten salt corrosion behavior of structural materials in LiCl-KCl-UCl3 by thermogravimetric study

Science.gov (United States)

Rao, Ch Jagadeeswara; Ningshen, S.; Mallika, C.; Mudali, U. Kamachi

2018-04-01

The corrosion resistance of structural materials has been recognized as a key issue in the various unit operations such as salt purification, electrorefining, cathode processing and injection casting in the pyrochemical reprocessing of spent metallic nuclear fuels. In the present work, the corrosion behavior of the candidate materials of stainless steel (SS) 410, 2.25Cr-1Mo and 9Cr-1Mo steels was investigated in molten LiCl-KCl-UCl3 salt by thermogravimetric analysis under inert and reactive atmospheres at 500 and 600 °C, for 6 h duration. Insignificant weight gain (less than 1 mg/cm2) in the inert atmosphere and marginal weight gain (maximum 5 mg/cm2) in the reactive atmosphere were observed at both the temperatures. Chromium depletion rates and formation of Cr-rich corrosion products increased with increasing temperature of exposure in both inert and reactive atmospheres as evidenced by SEM and EDS analysis. The corrosion attack by LiCl-KCl-UCl3 molten salt, under reactive atmosphere for 6 h duration was more in the case of SS410 than 9Cr-1Mo steel followed by 2.25Cr-1Mo steel at 500 °C and the corrosion attack at 600 °C followed the order: 9Cr-1Mo steel >2.25Cr-1Mo steel > SS410. Outward diffusion of the minor alloying element, Mo was observed in 9Cr-1Mo and 2.25Cr-1Mo steels at both temperatures under reactive atmosphere. Laser Raman spectral analysis of the molten salt corrosion tested alloys under a reactive atmosphere at 500 and 600 °C for 6 h revealed the formation of unprotected Fe3O4 and α-as well as γ-Fe2O3. The results of the present study facilitate the selection of structural materials for applications in the corrosive molten salt environment at high temperatures.

Long-term atmospheric corrosion of mild steel

International Nuclear Information System (INIS)

Fuente, D. de la; Diaz, I.; Simancas, J.; Chico, B.; Morcillo, M.

2011-01-01

Research highlights: → Atmospheric corrosion rate stabilises after the first 4-6 years of exposure. → Great compaction of the rust layers in rural and urban atmospheres. → Corrosion (in rural and urban) deviates from common behaviour of bilogarithmic law. → Typical structures of lepidocrocite, goethite and akaganeite are identified. → Formation of hematite (industrial atmosphere) and ferrihydrite (marine atmosphere). - Abstract: A great deal of information is available on the atmospheric corrosion of mild steel in the short, mid and even long term, but studies of the structure and morphology of corrosion layers are less abundant and generally deal with those formed in just a few years. The present study assesses the structure and morphology of corrosion product layers formed on mild steel after 13 years of exposure in five Spanish atmospheres of different types: rural, urban, industrial and marine (mild and severe). The corrosion layers have been characterised by X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Long-term corrosion is seen to be more severe in the industrial and marine atmospheres, and less so in the rural and urban atmospheres. In all cases the corrosion rate is seen to decrease with exposure time, stabilising after the first 4-6 years of exposure. The most relevant aspects to be noted are (a) the great compaction of the rust layers formed in the rural and urban atmospheres, (b) the formation of hematite and ferrihydrite phases (not commonly found) in the industrial and marine atmospheres, respectively and (c) identification of the typical morphological structures of lepidocrocite (sandy crystals and flowery plates), goethite (cotton balls structures) and akaganeite (cotton balls structures and cigar-shaped crystals).

Fractures in high-strength bolts due to hydrogen induced stress corrosion. Causes and corrective actions

International Nuclear Information System (INIS)

Hoche, Holger; Oechsner, Matthias

2017-01-01

Delayed brittle fractures of high-strength bolts of the strength class 10.9 are presented, taking the example of three damage cases. The respective damage mechanisms could be attributed to hydrogen induced stress corrosion which was caused, in turn, by hydrogen absorption during operation. The examples were chosen with a particular focus on the material condition's susceptibility which explains the cause for the occurrence of the damage mechanism. However, in only one of the three cases the susceptibility was evident and could be explained by violations of normative specifications and an unfavorable material choice. Whereas in the two other examples, only slight or no deviations from the standards and/or regulations could be found. The influencing parameters that caused the damage, those that further promoted the damage, as well as possible corrective actions are discussed taking into account the three exemplary damage cases.

Corrosion of reinforcement bars in steel ibre reinforced concrete structures

DEFF Research Database (Denmark)

Solgaard, Anders Ole Stubbe

and the influence of steel fibres on initiation and propagation of cracks in concrete. Moreover, the impact of fibres on corrosion-induced cover cracking was covered. The impact of steel fibres on propagation of reinforcement corrosion was investigated through studies of their impact on the electrical resistivity...... of concrete, which is known to affect the corrosion process of embedded reinforcement. The work concerning the impact of steel fibres on initiation and propagation of cracks was linked to corrosion initiation and propagation of embedded reinforcement bars via additional studies. Cracks in the concrete cover...... are known to alter the ingress rate of depassivating substances and thereby influence the corrosion process. The Ph.D. study covered numerical as well as experimental studies. Electrochemically passive steel fibres are electrically isolating thus not changing the electrical resistivity of concrete, whereas...

BWR steel containment corrosion

Energy Technology Data Exchange (ETDEWEB)

Tan, C.P.; Bagchi, G.

1996-04-01

The report describes regulatory actions taken after corrosion was discovered in the drywell at the Oyster Creek Plant and in the torus at the Nine Mile Point 1 Plant. The report describes the causes of corrosion, requirements for monitoring corrosion, and measures to mitigate the corrosive environment for the two plants. The report describes the issuances of generic letters and information notices either to collect information to determine whether the problem is generic or to alert the licensees of similar plants about the existence of such a problem. Implementation of measures to enhance the containment performance under severe accident conditions is discussed. A study by Brookhaven National Laboratory (BNL) of the performance of a degraded containment under severe accident conditions is summarized. The details of the BNL study are in the appendix to the report.

Enhancing corrosion resistance of reinforced concrete structures with hybrid fiber reinforced concrete

International Nuclear Information System (INIS)

Blunt, J.; Jen, G.; Ostertag, C.P.

2015-01-01

Highlights: • Reinforced concrete beams were subjected to cyclic flexural loading. • Hybrid fiber reinforced composites were effective in reducing corrosion rates. • Crack resistance due to fibers increased corrosion resistance of steel rebar. • Galvanic corrosion measurements underestimated corrosion rates. • Polarization resistance measurements predicted mass loss more accurately. - Abstract: Service loads well below the yield strength of steel reinforcing bars lead to cracking of reinforced concrete. This paper investigates whether the crack resistance of Hybrid Fiber Reinforced Concrete (HyFRC) reduces the corrosion rate of steel reinforcing bars in concrete after cyclic flexural loading. The reinforcing bars were extracted to examine their surface for corrosion and compare microcell and macrocell corrosion mass loss estimates against direct gravimetric measurements. A delay in corrosion initiation and lower active corrosion rates were observed in the HyFRC beam specimens when compared to reinforced specimens containing plain concrete matrices cycled at the same flexural load

Failure Modes in Concrete Repair Systems due to Ongoing Corrosion

Directory of Open Access Journals (Sweden)

Mladena Luković

2017-01-01

Full Text Available Corrosion of steel reinforcement is the main cause of deterioration in reinforced concrete structures. It can result in cracking and spalling of the concrete cover. After the damaged cover is repaired, reinforcement corrosion might continue and even accelerate. While the development of the corrosion cell is difficult to control, the damage can be possibly delayed and controlled by use of a suitable repair material. The lattice fracture model is used in this paper to investigate the performance of strain hardening cementitious composite (SHCC in concrete repair systems exposed to ongoing corrosion. Numerical results were verified by experimental tests when SHCC, nonreinforced material (repair mortar, and commercial repair mortar are used as repair materials. In experiments, reinforcement bars (surrounded by a repair material were exposed to accelerated corrosion tests. The influence of the substrate surface preparation, the type of repair material, the interface, and the substrate strength on the resulting damage and failure mode of repair systems are discussed. In general, SHCC repair enables distributed cracking with small crack widths, up to several times smaller compared to repair mortar. Furthermore, more warning signs prior to the final failure are present in the SHCC repair system.

Fluid-structure-interaction analysis for welded pipes with flow-accelerated corrosion wall thinning

Energy Technology Data Exchange (ETDEWEB)

Sun, L.; Ding, Y., E-mail: lan.sun@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

2016-06-15

The flow-accelerated corrosion (FAC) entrance effect results in enhanced wall thinning immediately downstream of a weld if the weld connects an upstream FAC-resistant material with a downstream less resistant material. The weld regions, especially those with local repairs, are susceptible to cracking due to the high residual stresses induced by fabrication. The combined effects of the FAC entrance effect and high stresses at a weld might compromise the structural integrity of the piping and lead to a failure. Weld degradation by FAC entrance effect has been observed at nuclear and fossil power plants. This paper describes an application using fluid-structure-interaction (FSI) modelling to study the combined effects of FAC wall thinning, weld residual stresses, and in-service loads on welded structures. Simplified cases analyzed were based on CANDU outlet feeder conditions. The analysis includes the flow and mass transfer modelling of the FAC entrance effect using computational fluid dynamics (CFD) and nonlinear structural analyses of the welded structures with wall thinning and an assumed weld residual stress and strain distribution. The FSI analyses were performed using ANSYS Workbench, an integrated platform that enables the coupling of CFD and structural analysis solutions. The obtained results show that the combination of FAC, weld residual stresses, in-service loads (including the internal pressure) and (or) extreme loads could cause high stresses and affect the integrity of the welded pipes. The present work demonstrated that the FSI modelling can be used as an effective approach to assess the integrity of welded structures. (author)

Effect of Thermal Fields on the Structure of Corrosion-Resistant Steels Under Different Modes of Laser Treatment

Science.gov (United States)

Tarasova, T. V.; Gusarov, A. V.; Protasov, K. E.; Filatova, A. A.

2017-11-01

The influence of temperature fields on the structure and properties of corrosion-resistant chromium steels under different modes of laser treatment is investigated. A model of heat transfer under laser impact on target is used to plot thermal fields and cycles and cooling rates. It is shown that the model used for computing thermal fields gives tentative geometric sizes of the fusion zones under laser treatment and selective laser fusion. The cooling rate is shown to have decisive influence on the structure of corrosion-resistant steels after laser treatment with surface fusion in devices for pulsed, continuous, and selective laser melting.

Assessment of Corrosion Characteristics and Development of Remedial Technologies in Nuclear Materials

Energy Technology Data Exchange (ETDEWEB)

Kim, Hong Pyo; Kim, J. S.; Lim, Y. S. (and others)

2007-04-15

In general, materials having superior resistance to corrosion are used for main components and structures in nuclear power plants (NPPs) to improve their safety. During long-term operations in the high temperature and pressure environment, however, localized-corrosion related degradations occur frequently in those materials, leading to unexpected shutdown of the plants. The unexpected shutdowns may lower the operating efficiency of the power generation and expand the repair period, which results in a huge economical loss. Moreover, since the damages may cause a leakage of the primary coolant that brings about a contamination by radioactive substances, the corrosion related degradations of structural materials have become a menace to the safety of NPPs. The steam generator tubes forming a boundary between the primary and secondary sides of NPPs are one of the main components that are most damaged by corrosion. Therefore, it is strongly required to verify the degradation mechanisms of Alloy 182 and Alloy 600 materials used in the steam generator tubes and primary systems, to establish remedial techniques for the degradations, to manage the damages, and to develop techniques for the extension of the plant's life. In this study, (1) the assessment techniques of corrosion damages were improved and the database of the obtained results were established. (2) The basic technologies of the management of corrosion damages were developed for the practical use. (3) The fundamental technologies for inhibition and repair of corrosion damages were also developed. The results of this project are applicable to the assessment, failure analysis and life estimation of the materials against corrosion damages. The assessment data obtained in this work are available for the technical references of the corrosion failures of components in NPPs during operation. Furthermore, it is applicable to establish materials design requirements, to establish the optimum operation condition and to

Corrosion performance of epoxy-coated reinforcement in aggressive environments

Science.gov (United States)

Vaca Cortes, Enrique

The objective of this research was to investigate the integrity and corrosion performance of epoxy-coated reinforcement in aggressive environments. A series of experimental studies were conducted: (a) hot water immersion and knife adhesion testing for assessment of coating adhesion; (b) materials and procedures for repairing coating damage; (c) degree of mechanical damage caused during concrete placement when using metal head and rubber head vibrators; (d) accelerated corrosion of coated bars embedded in macrocell and beam specimens placed in a corrosive environment for more than four years. The effects of coating condition and amount of damage, repaired vs. unrepaired damage, bar fabrication, and concrete cracking were studied. Regardless of coating condition, the performance of epoxy-coated bars was better than that of uncoated bars. Unlike black bars, coated bars did not exhibit deep pitting or substantial loss of cross section at crack locations. Damage to epoxy coating was the most significant factor affecting corrosion performance. Bars with coating in good condition, without any visible damage, performed best. The greater the size and frequency of damage, the more severe and extensive the amount of corrosion. The performance of bars that were fabricated or bent after coating was worse than that of coated straight bars. Mixing coated and uncoated bars in the same concrete member led to undesirable performance. Patching damaged coating reduced but did not prevent corrosion, particularly at bar ends. The most important factor in coating repair was the type and properties of the patching material. Surface preparation prior to coating had little effect. The absence of cracks in the concrete delayed, but did not prevent the onset of corrosion of coated bars. During consolidation of concrete, rubber head vibrators caused less damage to epoxy-coated reinforcement than did comparable metal heads. Hot water and adhesion tests were useful and practical for evaluating

Corrosion products in the primary circuits of PWRs

International Nuclear Information System (INIS)

Darras, R.

1983-01-01

The characteristics of PWR primary circuits are recalled, particularly the chemical specifications of the medium and the various materials used (austenitic steel, nickel alloys, cobalt-based alloys and zirconium alloys). The behaviour of these materials as regards general corrosion in nominal and transient conditions is then outlined briefly, special emphasis being laid on the effect of the determining parameters on the quantity of corrosion products formed. The release of the latter into the primary coolant is caused by two main processes: solubilization and erosion. Particular attention was given therefore to the laws governing the solubility of the oxides involved, especially as a function of temperature and pH. Erosion, or release in the form of solid particles, is relatively severe during transient events. As these corrosion products are then carried through all circuits, they cause deposits to form in favourable places on the walls as a result either of precipitation of soluble species or of sedimentation followed by consolidation of suspended particles. The presence of corrosion products in the primary circuits creates a particular impact since they become radioactive as they pass through the core and especially when they remain in it in the form of deposits; as a result, the products are capable of contaminating the entire system. Finally, although long-term reliability is obviously an essential condition for materials developed, attention must also be given to problems associated with a build-up of corrosion products in the cooling circuits and efforts made to minimize them. To that end, a number of precautions are recommended, and various remedies can be applied: selecting materials which are not readily activated, keeping structures clean, purifying fluids properly, restricting solubilization and precipitation, and perhaps, periodic decontamination. (author)

GCR dismantling: corrosion of vessel internals during decay storage

International Nuclear Information System (INIS)

Gras, J.M.

1991-06-01

Gas-cooled reactor decommissioning confronts EDF with the problem of the corrosion resistance of vessel internals over a decay storage period fixed at 50 years. The layer of magnetite previously formed in the C0 2 should protect structural steelwork from atmospheric corrosion. In any case, estimated steel corrosion after 50 years may be put at below or equal to 0.1 mm and the corresponding swelling induced by corrosion products at 0.2 mm. There should be no risk of hydrogen embrittlement or stress corrosion cracking of threaded fasteners. Corrosion tests aimed at providing further insight into the effects of the magnetite layer and a program for the surveillance of post-decommissioning structural corrosion should nevertheless be envisaged

Corrosion kinetics of alloy Ni-22Cr-13Mo-3W as structural material in high level nuclear waste containers

International Nuclear Information System (INIS)

Rodriguez, Martin A.

2004-01-01

was detected in the solutions containing fluoride ions. It was attributed to a change in the oxidation state of molybdenum and/or nickel in the passive film. Current densities in the trans passive range were higher in the solutions containing fluoride ions, especially at ph 6. Crevice corrosion was detected at potentials higher than the corrosion potential, only in presence of chloride ions at 90 C degrees. Pitting corrosion was not detected in any case. Chloride plus fluoride mixtures were more aggressive to localized corrosion resistance than pure chloride solutions. It was attributed to the weakening of the film caused by fluoride ions and the interference in the self-repairing process caused by chloride ions. There were no differences in behavior between of mill annealed and thermal aged alloys neither in the passive and trans passive states, nor in the localized corrosion susceptibility. (author) [es

Protecting solar collector systems from corrosion

Energy Technology Data Exchange (ETDEWEB)

1978-01-01

The main cause of the reduced life of a solar heating system is corrosion of the exterior parts and the internal components. This report outlines ways of reducing the cost of solar heating by reducing the corrosion in solar heating systems, and hence increasing the system's service life. Mechanisms for corrosion are discussed: these include galvanic corrosion and crevice corrosion. Means of minimizing corrosion at the design stage are then described. Such methods, when designing the solar collector, involve ensuring proper drainage of exterior water; eliminating situations where moisture, dirt and pollutants may collect; preventing condensation inside the collector; using proper gaskets and sealants at appropriate places; and selecting optimum materials and coatings. Interior corrosion can be minimized at the design stage by choosing a good heat transfer fluid and corrosion inhibitor, in the case of systems where liquids are used; ensuring a low enough flow rate to avoid erosion; designing the system to avoid crevices; and avoiding situations where galvanic corrosion could occur. Other procedures are given for minimizing corrosion in the construction and operation of solar heating systems. 7 figs., 7 tabs.

Influence of bovine serum albumin in Hanks' solution on the corrosion and stress corrosion cracking of a magnesium alloy.

Science.gov (United States)

Harandi, Shervin Eslami; Banerjee, Parama Chakraborty; Easton, Christopher D; Singh Raman, R K

2017-11-01

It is essential for any temporary implant to possess adequate strength to maintain their mechanical integrity under the synergistic effects of mechanical loading characteristics of human body and the corrosive physiological environment. Such synergistic effects can cause stress corrosion cracking (SCC). The aim of the present study is to investigate the effect of the addition of bovine serum albumin (BSA) to Hanks' solution in corrosion and SCC susceptibility of AZ91D magnesium alloy. The electrochemical impedance spectroscopy (EIS) results indicated that the addition of BSA increased corrosion resistance of the alloy during the first 48h of immersion and then decreased it rapidly. The energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses indicated adsorption of BSA on the alloy surface during initial hours of immersion. However, with the increasing immersion time, BSA chelated with the corrosion products causing disruption of the protective film; thus, it accelerated the corrosion of the alloy. Both the mechanical data and fractographic evidence have confirmed susceptibility of the alloy to SCC. However, in the presence of BSA, the alloy suffered greater SCC which was attributed to its increased susceptibility towards localized corrosion. Copyright © 2017. Published by Elsevier B.V.

Highly corrosion resistant zirconium based alloy for reactor structural material

International Nuclear Information System (INIS)

Ito, Yoichi.

1996-01-01

The alloy of the present invention is a zirconium based alloy comprising tin (Sn), chromium (Cr), nickel (Ni) and iron (Fe) in zirconium (Zr). The amount of silicon (Si) as an impurity is not more than 60ppm. It is preferred that Sn is from 0.9 to 1.5wt%, that of Cr is from 0.05 to 0.15wt%, and (Fe + Ni) is from 0.17 to 0.5wt%. If not less than 0.12wt% of Fe is added, resistance against nodular corrosion is improved. The upper limit of Fe is preferably 0.40wt% from a view point of uniform suppression for the corrosion. The nodular corrosion can be suppressed by reducing the amount of Si-rich deposition product in the zirconium based alloy. Accordingly, a highly corrosion resistant zirconium based alloy improved for the corrosion resistance of zircaloy-2 and usable for a fuel cladding tube of a BWR type reactor can be obtained. (I.N.)

Reinforcement Corrosion: Numerical Simulation and Service Life Prediction

DEFF Research Database (Denmark)

Michel, Alexander

defects and b) define the end of service life once reinforcement corrosion is initiated neglecting corrosion processes during the propagation stage. The goal of this work was to develop a framework for the service life prediction of reinforced concrete covering initiation and propagation of chloride......Modelling of deterioration processes in concrete structures plays an increasing role in the design of reinforced concrete structures. Large sums are spent every year to ensure the durability of concrete structures, especially towards reinforcement corrosion. Improved durability provides increased...... structural reliability, economical improvements in form of less need for maintenance and repair as well as increased sustainability due to an increased energy and resource efficiency. Several service life prediction models dealing with reinforcement corrosion in concrete structurescan be found...

Marine sulfate-reducing bacteria cause serious corrosion of iron under electroconductive biogenic mineral crust

Science.gov (United States)

Enning, Dennis; Venzlaff, Hendrik; Garrelfs, Julia; Dinh, Hang T; Meyer, Volker; Mayrhofer, Karl; Hassel, Achim W; Stratmann, Martin; Widdel, Friedrich

2012-01-01

Iron (Fe0) corrosion in anoxic environments (e.g. inside pipelines), a process entailing considerable economic costs, is largely influenced by microorganisms, in particular sulfate-reducing bacteria (SRB). The process is characterized by formation of black crusts and metal pitting. The mechanism is usually explained by the corrosiveness of formed H2S, and scavenge of ‘cathodic’ H2 from chemical reaction of Fe0 with H2O. Here we studied peculiar marine SRB that grew lithotrophically with metallic iron as the only electron donor. They degraded up to 72% of iron coupons (10 mm × 10 mm × 1 mm) within five months, which is a technologically highly relevant corrosion rate (0.7 mm Fe0 year−1), while conventional H2-scavenging control strains were not corrosive. The black, hard mineral crust (FeS, FeCO3, Mg/CaCO3) deposited on the corroding metal exhibited electrical conductivity (50 S m−1). This was sufficient to explain the corrosion rate by electron flow from the metal (4Fe0 → 4Fe2+ + 8e−) through semiconductive sulfides to the crust-colonizing cells reducing sulfate (8e− + SO42− + 9H+ → HS− + 4H2O). Hence, anaerobic microbial iron corrosion obviously bypasses H2 rather than depends on it. SRB with such corrosive potential were revealed at naturally high numbers at a coastal marine sediment site. Iron coupons buried there were corroded and covered by the characteristic mineral crust. It is speculated that anaerobic biocorrosion is due to the promiscuous use of an ecophysiologically relevant catabolic trait for uptake of external electrons from abiotic or biotic sources in sediments. PMID:22616633

An overview of erosion corrosion models and reliability assessment for corrosion defects in piping system

International Nuclear Information System (INIS)

Srividya, A.; Suresh, H.N.; Verma, A.K.; Gopika, V.; Santosh

2006-01-01

Piping systems are part of passive structural elements in power plants. The analysis of the piping systems and their quantification in terms of failure probability is of utmost importance. The piping systems may fail due to various degradation mechanisms like thermal fatigue, erosion-corrosion, stress corrosion cracking and vibration fatigue. On examination of previous results, erosion corrosion was more prevalent and wall thinning is a time dependent phenomenon. The paper is intended to consolidate the work done by various investigators on erosion corrosion in estimating the erosion corrosion rate and reliability predictions. A comparison of various erosion corrosion models is made. The reliability predictions based on remaining strength of corroded pipelines by wall thinning is also attempted. Variables in the limit state functions are modelled using normal distributions and Reliability assessment is carried out using some of the existing failure pressure models. A steady state corrosion rate is assumed to estimate the corrosion defect and First Order Reliability Method (FORM) is used to find the probability of failure associated with corrosion defects over time using the software for Component Reliability evaluation (COMREL). (author)

Exploration and Modeling of Structural changes in Waste Glass Under Corrosion

Energy Technology Data Exchange (ETDEWEB)

Pantano, Carlos; Ryan, Joseph; Strachan, Denis

2013-11-10

Vitrification is currently the world-wide treatment of choice for the disposition of high-level nuclear wastes. In glasses, radionuclides are atomistically bonded into the solid, resulting in a highly durable product, with borosilicate glasses exhibiting particularly excellent durability in water. Considering that waste glass is designed to retain the radionuclides within the waste form for long periods, it is important to understand the long-term stability of these materials when they react in the environment, especially in the presence of water. Based on a number of previous studies, there is general consensus regarding the mechanisms controlling the initial rate of nuclear waste glass dissolution. Agreement regarding the cause of the observed decrease in dissolution rate at extended times, however, has been elusive. Two general models have been proposed to explain this behavior, and it has been concluded that both concepts are valid and must be taken into account when considering the decrease in dissolution rate. Furthermore, other processes such as water diffusion, ion exchange, and precipitation of mineral phases onto the glass surface may occur in parallel with dissolution of the glass and can influence long-term performance. Our proposed research will address these issues through a combination of aqueous-phase dissolution/reaction experiments and probing of the resulting surface layers with state-of-the-art analytical methods. These methods include solid-state nuclear magnetic resonance (SSNMR) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). The resulting datasets will then be coupled with computational chemistry and reaction-rate modeling to address the most persistent uncertainties in the understanding of glass corrosion, which indeed have limited the performance of the best corrosion models to date. With an improved understanding of corrosion mechanisms, models can be developed and improved that, while still conservative, take advantage of

Organic compounds as corrosion inhibitors for mild steel in acidic media: correlation between inhibition efficiency and chemical structure

Energy Technology Data Exchange (ETDEWEB)

Elias, Elizandra C.S.; Chrisman, Erika C.A.N. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Escola de Quimica

2009-12-19

The use of inhibitors for mild steels corrosion control which are in contact with aggressive environment is an accepted practice in acid treatment of oil-wells. Organic compounds have been studied to evaluate their corrosion inhibition potential. Film-forming corrosion inhibitors, commonly used to protect oil-field equipment, can be absorbed on the steel surface to give structurally ordered layers. Therefore, the electrons should act as an important role for this adsorption. Studies reveal that organic compounds show significant inhibition efficiency. For this purpose, their molecules should contain N, O and S heteroatoms in various functional groups, long hydrocarbon linear or branched radical and anion and cation active components. However, most of these compounds are not only expensive but also toxic to living beings. According to the 'Green Chemistry' rules, corrosion inhibitors based on organic compounds should be cheap, with low toxicity and have high inhibition efficiency. In this study, the effects of some organic compounds with different groups such as amide, ether, phenyldiamine, anime and aminophenol on the corrosion behavior of mild steel in acidic media have been investigated. The experimental data were obtained by gravimetric measurements. The results show that these compounds reveal a promising corrosion inhibition where phenyldiamine is the most efficient. The effect of molecular structure on the corrosion inhibition efficiency was investigated by semi-empirical quantum chemical calculations. The electronic properties such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels, and LUMO-HOMO energy gap orbital density were calculated. The relations between the inhibition efficiency and some quantum parameters are discussed and correlations are proposed. The highest values for the HOMO densities were found in the vicinity nitrogen atom, indicating that it is the most probable adsorption center

The corrosion effect on the conduit systems

International Nuclear Information System (INIS)

Laaidi, Naouar; Belattar, Sougratti

2009-01-01

The conduits in the buildings require a regular and permanent control, in order to avoid the risks of deterioration caused by the corrosion or the escape of water. In this work, we present a thermal nondestructive testing method of concrete structures containing water conduits, based on numerical modeling in three dimensions. The goal is to study the detectability of these conduits in different situations and to give a thermal characterization of the rust behaviour in the steel conduits. (author)

Corrosion Resistant Coatings for High Temperature Applications

Energy Technology Data Exchange (ETDEWEB)

Besman, T.M.; Cooley, K.M.; Haynes, J.A.; Lee, W.Y.; Vaubert, V.M.

1998-12-01

Efforts to increase efficiency of energy conversion devices have required their operation at ever higher temperatures. This will force the substitution of higher-temperature structural ceramics for lower temperature materials, largely metals. Yet, many of these ceramics will require protection from high temperature corrosion caused by combustion gases, atmospheric contaminants, or the operating medium. This paper discusses examples of the initial development of such coatings and materials for potential application in combustion, aluminum smelting, and other harsh environments.

Corrosion engineering in nuclear power industry

International Nuclear Information System (INIS)

Prazak, M.; Tlamsa, J.; Jirousova, D.; Silber, K.

1990-01-01

Corrosion problems in nuclear power industry are discussed from the point of view of anticorrosion measures, whose aim is not only increasing the lifetime of the equipment but, first of all, securing ecological safety. A brief description is given of causes of corrosion damage that occurred at Czechoslovak nuclear power plants and which could have been prevented. These involve the corrosion of large-volume radioactive waste tanks made of the CSN 17247 steel and of waste piping of an ion exchange station made of the same material, a crack in a steam generator collector, contamination of primary circuit water with iron, and corrosion of CrNi corrosion-resistant steel in a spent fuel store. It is concluded that if a sufficient insight into the corrosion relationships exists and a reasonable volume of data is available concerning the corrosion state during the nuclear facility performance, the required safety can be achieved without adopting extremely costly anticorrosion measures. (Z.M.)

Improvement of Corrosion Inhibitors of Primary and Secondary Closed Cooling Water System

International Nuclear Information System (INIS)

Choi, Byung Seon; Kim, K. M.; Kim, K. H.

2010-08-01

In nuclear power plants, the Closed Cooling Water (CCW) system provide cooling to both safety-related and non-safety-related heat exchange equipment. Various chemicals are used to mitigate corrosion, fouling, and microbiological growth in the CCW systems. In nuclear plants, these inhibitors have included chromates, nitrites, molybdates, hydrazine, and silicate. In the case of the CCW of some domestic nuclear power plants, there is during the overhaul period, a saturation of ion exchange resin caused by an inhibitor which has high conductivity for an increase in radiation exposure and radioactive waste. The objective of this study is to evaluate the corrosion behavior of structural materials with various corrosion inhibitors. In the present study, more than 50 ppm hydrazine concentration is needed to reduce the corrosion rate of carbon steel to satisfy the CCW operational guidelines. However, if hydrazine is continuously injected into the CCW system, the critical concentration of hydrazine will be lower. Hydrazine might be an alternative corrosion inhibitor for nitrite in the CCW system of nuclear power plant

Case histories of microbial induced corrosion

Energy Technology Data Exchange (ETDEWEB)

Birketveit, Oe.; Liengen, T.

2006-03-15

Recent years bacterial activity has caused process problems and corrosion on several of Hydro s installations in the North Sea. The process problems are related to iron sulphide formed in process equipment and increased oil in discharge water. The corrosion problem is seen in downstream pipelines made of carbon steel, where deposits and formation of biofilm cause the corrosion inhibitor to be ineffective. In most cases the bacteria reproduce in the topside system and especially in the reclaimed oil sump tank. The problems observed, related to bacterial activity, are often a result of how the content from the reclaimed oil sump tank is re-circulated to the process system. Process modifications, changes in biocide treatment strategy, sulphide measurements, cleaning strategy and bio monitoring are presented. (author) (tk)

Relationship between Corrosion Level of Rebar Embedded in Concrete, Corrosion Potential and Current Density Measured by Non-destructive Test Method

International Nuclear Information System (INIS)

Chung, Lan; Cho, Seung Ho; Roh, Young Sook; Kim, Joong Koo

2004-01-01

The purpose of this study is to identify corrosion mechanism and develop qualitative measurement method of corrosion level. Fist of all, structural behavior of each different level of corrosion states have been evaluated. And mathematical models that can predict corrosion level in terms of electric potential and corrosion intensity are proposed. Corrosion rate in reinforcing bar was investigated in this study using accelerated corrosion method due to electric potential differences based on Faradays law. Total 288 measurement spots were designed in terms of corrosion rates, diameter of reinforcing bars, and concrete cover thickness. Corrosion current densities and corrosion potentials of concrete were measured on these specimens using Gecor device. This study suggested the relationship between corrosion levels, and measured electric current density as follows

Protecting with nature (PwN) PwN concept (bio-) corrosion prevention

NARCIS (Netherlands)

Mijle Meijer, van der H.; Foekema, E.M.; Leon, F.

2014-01-01

Harbour infrastructures, civil engineering structures and offshore structures are exposed to a very aggressive maritime environment. The local corrosion mechanism bio-corrosion or microbial influenced corrosion (MIC) seems to be the life determining failure mechanism for these structures. There is a

Events as Power Source: Wireless Sustainable Corrosion Monitoring

OpenAIRE

Sun, Guodong; Qiao, Guofu; Zhao, Lin; Chen, Zhibo

2013-01-01

This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source), which monitors the corrosion events in reinforced concrete (RC) structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event) releases electric energy; this is ...

Research on corrosion mechanism of suspension insulator steel foot of direct current system and measures for corrosion inhibition

Science.gov (United States)

Chen, He; Yang, Yueguang; Su, Guolei; Wang, Xiaoqing; Zhang, Hourong; Sun, Xiaoyu; Fan, Youping

2017-09-01

There are increasingly serious electrocorrosion phenomena on insulator hardware caused by direct current transmission due to the wide-range popularization of extra high voltage direct current transmission engineering in our country. Steel foot corrosion is the main corrosion for insulators on positive polarity side of transmission lines. On one hand, the corrosion leads to the tapering off of steel foot diameter, having a direct influence on mechanical property of insulators; on the other hand, in condition of corrosion on steel foot wrapped in porcelain ware, the volume of the corrosion product is at least 50% more than that of the original steel foot, leading to bursting of porcelain ware, threatening safe operation of transmission lines. Therefore, it is necessary to conduct research on the phenomenon and propose feasible measures for corrosion inhibition. Starting with the corrosion mechanism, this article proposes two measures for corrosion inhibition, and verifies the inhibition effect in laboratory conditions, providing reference for application in engineering.

A study of microbial population dynamics associated with corrosion rates influenced by corrosion control materials

NARCIS (Netherlands)

Chang, Yu Jie; Hung, Chun Hsiung; Lee, Jyh Wei; Chang, Yi Tang; Lin, Fen Yu; Chuang, Chun Jie

2015-01-01

This research aims to analyze the variations of microbial community structure under anaerobic corrosive conditions, using molecular fingerprinting method. The effect of adding various materials to the environment on the corrosion mechanism has been discussed. In the initial experiment,

Electrochemical Characterisation of Filiform Corrosion on Aluminium Rolled Products

NARCIS (Netherlands)

Huisert, M.

2001-01-01

When aluminium is protected by an organic coating a special form of corrosion can occur underneath the organic coating; filiform corrosion. This form of corrosion manifests itself as threadlike filaments under the coating, it causes local delamination of the coating and the coating cannot protect

Finite element model for expansive stress due to corrosion of reinforced concrete structures; Analisis con elemento finito de los esfuerzos expansivos por corrosion en las estructuras de concreto reforzado

Energy Technology Data Exchange (ETDEWEB)

Castorena Gonzalez, J.H.; Calderon Guillen, J.A. [Universidad Autonoma de Sinaloa, Los Mochis, Sinaloa (Mexico)]. E-mail: kstor28@yahoo.com.mx; cajoel_99@yahoo.com; Almeraya Calderon, F.; Gaona Tiburcio, C. [Centro de Investigacion en Materiales Avanzados, S.C., Chihuahua, Chihuahua (Mexico)]. E-mail: facundo.almeraya@cimav.edu.mx; citlalli.gaona@cimav.edu.mx; Almaral Sanchez, J.L. [Universidad Autonoma de Sinaloa, Los Mochis, Sinaloa (Mexico)]. E-mail: jalmaral@gmail.com; Martinez Villafane, A. [Centro de Investigacion en Materiales Avanzados, S.C., Chihuahua, Chihuahua (Mexico)]. E-mail: martinez.villafane@cimav.edu.mx

2011-01-15

The corrosion in the reinforcement steel is a problem that diminishes the useful life of reinforced concrete structures, reside committing its structural security. In the available models to estimate the mechanical effect of the corrosion, it is assumed that the corroded steel, through the oxides that grow to its surroundings, exercises a pressure on the surrounding concrete supposing a problem of plane stress or plane strain. In this work, the problem is modeled with three-dimensional finite element starting from an experiment on a subjected cylinder to accelerated corrosion, with strain gage to measure the pressure indirectly in the interface steel-concrete. From the results obtained it can be concluded that the effect of the length of corroded steel, anodic length, has a significant effect on the magnitude of the pressure in the interface steel-concrete, fact that can be used to improve the existing models. [Spanish] La corrosion en el acero de refuerzo es un problema que disminuye la vida util en las estructuras de concreto reforzado, ademas de comprometer su seguridad estructural. En los modelos disponibles para estimar el efecto mecanico de la corrosion, se supone que el acero corroido, a traves de los oxidos que crecen a su alrededor, ejercen una presion sobre el concreto circundante suponiendo un problema de esfuerzos o deformaciones planas, En el presente trabajo, se modela el problema con elemento finito tridimensional a partir de un experimento sobre un cilindro de concreto reforzado sometido a corrosion acelerada, instrumentado para medir indirectamente la presion en la interfase acero-concreto. De los resultados obtenidos se concluye que el efecto de la longitud de acero corroido, longitud anodica, tiene un efecto significativo sobre la magnitud de la presion en la interfase acero-concreto, hecho que puede ser utilizado para mejorar los modelos existentes.

Effect Of Age And Concrete Cover Thickness On Steel Reinforcement Corrosion At Splash Zone In Reinforced Concrete Hydraulic Structures

Directory of Open Access Journals (Sweden)

Nada M. Al- Galawi

2015-08-01

Full Text Available Corrosion of reinforcing steel bars in reinforced concrete is considered as one of the biggest problems that face countries overlooking to the Arabian Gulf including Iraq. The research aims to study the effect of the corrosion of steel bars in concrete structures that are exposed to wetting and drying via waves. Reinforced concrete samples were exposed to marine simulated environment for 90 days using prepared system for this purpose. At the end of exposure period polarization test was implemented to measure the actual corrosion rate in each sample. After that the corrosion process was accelerated using impressed current technique by applying a constant electric current DC to the reinforcing bars. Depending on the corrosion current in natural conditions which was measured in polarization test periods of exposing samples to accelerated corrosion current so as to maintain virtual exposure ages of 5 and 25 years of exposure to natural corrosion were calculated. The results showed a remarkable increase in the corrosion current of steel bars in samples that had lower concrete cover thickness. The increase in the cover thickness from 20mm to 40 and 65 mm had a significant effect on reducing the corrosion current at the age of 90 days to about 70 of its original value in both cases. At the virtual exposure age of 5 years the reduction percentage in the corrosion current resulted from increasing cover thickness from 20mm to 40 and 65 mm were 43 and 79 respectively.

Influence of heat treatment on corrosive resistance of concrete steels

International Nuclear Information System (INIS)

Woldan, A.; Suliga, I.; Kusinski, J.; Jazowy, R.

1998-01-01

The reinforcing bars are essential elements of ferro-concrete structures. During the building structure service the reinforcing bars should co-operate with surrounding concrete. Any bonding defects as well as corrosion induced strength reduction may result in construction failure. The reinforcing steel working environment is determined by concrete chemical and phase composition and surrounding environmental properties. The aggressive corrosive activity of the letter implies necessity of effective ways development to protect elements against corrosion. The effect of heat treatment, increased Si content in steel on corrosion resistance of reinforcing steel in concrete was studied in the current work. Corrosion tests and metallographic examinations proved a positive influence of hardening and Si enrichment on corrosion resistance of reinforcing bars in ferro-concrete structures. (author)

Corrosion of Structural Materials for Advanced Supercritical Carbon- Dioxide Brayton Cycle

Energy Technology Data Exchange (ETDEWEB)

Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States)

2017-05-13

for simultaneous occurrence of carburization during oxidation of the material. Carburization can potentially lead to embrittlement of structural alloys in SC-CO₂ Brayton cycle. An important consideration in regards to corrosion is that the temperatures can vary widely across the various sections of the SC-CO₂ Brayton cycle, from room temperature to 750°C, with even higher temperatures being desirable for higher efficiencies. Thus the extent of corrosion and corrosion mechanisms in various components and SC-CO₂ Brayton cycle will be different, requiring a judicious selection of materials for different sections of the cycle. The goal of this project was to address materials corrosion-related challenges, identify appropriate materials, and advance the body of scientific knowledge in the area of high temperature SC-CO₂ corrosion. The focus was on corrosion of materials in SC-CO₂ environment in the temperature range of 450°C to 750°C at a pressure of 2900 psi for exposure duration for up to 1000 hours. The Table below lists the materials tested in the project. The materials were selected based on their high temperature strength, their code certification status, commercial availabilities, and their prior or current usage in the nuclear reactor industry. Additionally, pure Fe, Fe-12%Cr, and Ni-22%Cr were investigated as simple model materials to more clearly understand corrosion mechanisms. This first phase of the project involved testing in research grade SC-CO₂ (99.999% purity). Specially designed autoclaves with high fidelity temperature, pressure, and flow control capabilities were built or modified for this project.

DPC materials and corrosion environments.

Energy Technology Data Exchange (ETDEWEB)

Ilgen, Anastasia Gennadyevna; Bryan, Charles R.; Teich-McGoldrick, Stephanie; Hardin, Ernest

2014-10-01

After an exposition of the materials used in DPCs and the factors controlling material corrosion in disposal environments, a survey is given of the corrosion rates, mechanisms, and products for commonly used stainless steels. Research needs are then identified for predicting stability of DPC materials in disposal environments. Stainless steel corrosion rates may be low enough to sustain DPC basket structural integrity for performance periods of as long as 10,000 years, especially in reducing conditions. Uncertainties include basket component design, disposal environment conditions, and the in-package chemical environment including any localized effects from radiolysis. Prospective disposal overpack materials exist for most disposal environments, including both corrosion allowance and corrosion resistant materials. Whereas the behavior of corrosion allowance materials is understood for a wide range of corrosion environments, demonstrating corrosion resistance could be more technically challenging and require environment-specific testing. A preliminary screening of the existing inventory of DPCs and other types of canisters is described, according to the type of closure, whether they can be readily transported, and what types of materials are used in basket construction.

Reactor Structure Materials: Corrosion of Reactor Core Internals

International Nuclear Information System (INIS)

Van Dyck, S.

2000-01-01

The objectives of SCK-CEN's R and D programme on the corrosion of reactor core internals are: (1) to gain mechanistic insight into the Irradition Assisted Stress Corrosion Cracking (IASCC) phenomenon by studying the influence of separate parameters in well controlled experiments; (2) to develop and validate a predictive capability on IASCC by model description and (3) to define and validate countermeasures and monitoring techniques for application in reactors. Progress and achievements in 1999 are described

Corrosion of carbon steel in contact with bentonite

International Nuclear Information System (INIS)

Dobrev, D.; Vokal, A.; Bruha, P.

2010-01-01

Document available in extended abstract form only. Carbon steel canisters were chosen in a number of disposal concepts as reference material for disposal canisters. The corrosion rates of carbon steels in water solution both in aerobic and anaerobic conditions are well known, but only scarce data are available for corrosion behaviour of carbon steels in contact with bentonite. A special apparatus, which enables to measure corrosion rate of carbon steels under conditions simulating conditions in a repository, namely in contact with bentonite under high pressure and elevated temperatures was therefore prepared to study: - Corrosion rate of carbon steels in direct contact with bentonite in comparison with corrosion rate of carbon steels in synthetic bentonite pore water. - Influence of corrosion products on bentonite. The apparatus is composed of corrosion chamber containing a carbon steel disc in direct contact with compacted bentonite. Synthetic granitic water is above compacted bentonite under high pressure (50 - 100 bar) to simulate hydrostatic pressure in a repository. The experiments can be carried out under various temperatures. Bentonites used for experiments were Na-type of bentonite Volclay KWK 80 - 20 and Ca-Mg Czech bentonite from deposit Rokle. Before adding water into corrosion system the corrosion chamber was purged by nitrogen gas. The saturation of bentonite and corrosion rate were monitored by measuring consumption of water, pressure increase caused by swelling pressure of bentonite and by generation of hydrogen. Corrosion rate was also determined after corrosion experiments from weight loss of samples. The results of experiments show that the corrosion behaviour of carbon steels in contact with bentonite is very different from corrosion of carbon steels in water simulating bentonite pore water solution. The corrosion rates of carbon steel in contact with bentonite reached after 30 days of corrosion the values approaching 40 mm/yr contrary to values

Contribution to the study of corrosion in cementitious media for the phenomenological modelling of the long-term behaviour of reinforced concrete structures

International Nuclear Information System (INIS)

L'hostis, V.

2010-12-01

Many of the facilities and structures involved in the nuclear industry call for reinforced concrete (RC) in their construction. The corrosion of rebars is the main ageing pathology that those RC structures will meet during their service life (leading to concrete cracking and structural bearing capacity decrease). Concrete carbonation and chloride ingress in concrete are both at the origin of the active corrosion state. Passive corrosion has also to be considered in a context of very long lifetime (waste management). It is of primary importance to dispose of accurate and validated tools in order to predict where and how damages will appear. In 2002, the Commissariat a l Energie atomique decided to develop an intensive research programme dedicated to predicting the long-term behaviour of RC structures affected by steel corrosion (CIMETAL Project). This document aims at synthesize the main outputs coming from the project and exposes the scientific strategy was drawn and applied in order to predict the long-term behaviour of RCs that were mainly exposed to carbonation conditions. That strategy includes experiments for the characterisation of 'short-term' and 'long-term' corrosion layouts and processes, as well as modelling stages, with a view not only to predicting the behaviour of RC, but also to pointing out phenomena that are further verified experimentally. (author)

Prediction of corrosion rates of water distribution pipelines according to aggressive corrosive water in Korea.

Science.gov (United States)

Chung, W S; Yu, M J; Lee, H D

2004-01-01

The drinking water network serving Korea has been used for almost 100 years. Therefore, pipelines have suffered various degrees of deterioration due to aggressive environments. The pipe breaks were caused by in-external corrosion, water hammer, surface loading, etc. In this paper, we focused on describing corrosion status in water distribution pipes in Korea and reviewing some methods to predict corrosion rates. Results indicate that corrosive water of lakes was more aggressive than river water and the winter was more aggressive compared to other seasons. The roughness growth rates of Dongbok lake showed 0.23 mm/year. The high variation of corrosion rates is controlled by the aging pipes and smaller diameter. Also the phenolphthalein test on a cementitious core of cement mortar lined ductile cast iron pipe indicated the pipes over 15 years old had lost 50-100% of their lime active cross sectional area.

General Corrosion and Localized Corrosion of the Drip Shield

Energy Technology Data Exchange (ETDEWEB)

F. Hua

2004-09-16

The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847]).

General Corrosion and Localized Corrosion of the Drip Shield

International Nuclear Information System (INIS)

F. Hua

2004-01-01

The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847])

Fibre Bragg grating sensors for reinforcement corrosion monitoring in civil engineering structures

International Nuclear Information System (INIS)

Grattan, S K T; Basheer, P; Taylor, S E; Zhao, W; Sun, T; Grattan, K T V

2007-01-01

Fibre optic strain sensors offer a number of advantages over the current electrical resistance type gauges, yet are not widely used in civil engineering applications. The use of fibre optic strain sensors (with a cross comparison with the output of electrical resistance gauges) to monitor the production of corrosion by-products in civil engineering concrete structures containing reinforcement bars has been investigated and results reported

Corrosion fatigue of steels

International Nuclear Information System (INIS)

Spaehn, H.; Wagner, G.H.

1976-01-01

Corrosion fatigue phenomena can be classified into two main groups according to the electrochemical state of the metal surface in the presence of electrolytes: the active and the passive state with an important sub-group of corrosion fatigue in the unstable passive state. The allowable stress for structures exposed to the conjoint action of corrosion and fatigue is influenced by many factors: kind of media, number of cycles, frequency, mean stress, size, notches, loading mode, alloy composition and mechanical strength. A critical literature review shows contradictory results if a classification by the electrochemical surface state is not applied. Case histories and counter measures illustrate the practical importance of corrosion fatigue in many branches of industry as well as the urgent need for a better knowledge about the mutual influence of the phenomena to get rules by which the engineer can appraise the risk of corrosion fatigue. (orig.) [de

New approach to the elucidation of corrosion mechanism of ceramics by the ion implantation

International Nuclear Information System (INIS)

Saito, J.; Hayashi, K.; Tachi, Y.; Kano, S.

1998-08-01

Ceramics possessing high temperature strength are promising materials for the structural application in severe environment. The development of ceramics has been carried out in order to use them in FBR environment such as liquid sodium. In particular, corrosion behavior of ceramics has been investigated to improve the corrosion resistance in liquid sodium. However, the corrosion mechanism of ceramics was not comprehended in detail even now. Because corrosion products which were deposited on the surface of test pieces during corrosion test and played an important role in corrosion behavior, were not detected distinctly after thr corrosion test. In this study, an ion implantation technique was applied to understand the corrosion mechanism of ceramics in stead of the conventional corrosion test. Sodium ions were implanted in ceramics (100 keV, 1.9 x 10 17 ions/cm 2 ) and then heat treatment was performed at either 923 K or 823 K for 36 ks in argon atmosphere. After that, products on the surface were analyzed using SEM and TEM observation and X-ray diffraction. Consequently, the corrosion products were not identified exactly, but their presence was confirmed on the surface. It was caused by the minute amount of corrosion products. In future, it is necessary to carry systematically out the implantation and heat treatment under various conditions. Therefore, it seems that the beneficial information will be obtained to understand the corrosion mechanism of ceramics. (author)

HIGH TEMPERATURE CORROSION RESISTANCE OF METALLIC MATERIALS IN HARSH CONDITIONS

OpenAIRE

Novello, Frederic; Dedry, Olivier; De Noose, Vincent; Lecomte-Beckers, Jacqueline

2014-01-01

Highly efficient energy recovery from renewable sources and from waste incineration causes new problems of corrosion at high temperature. A similar situation exists for new recycling processes and new energy storage units. These corrosions are generally considered to be caused by ashes or molten salts, the composition of which differs considerably from one plant to another. Therefore, for the assessment of corrosion-resistance of advanced materials, it is essential to precisely evaluate the c...

Bridge maintenance to enhance corrosion resistance and performance of steel girder bridges

Science.gov (United States)

Moran Yanez, Luis M.

The integrity and efficiency of any national highway system relies on the condition of the various components. Bridges are fundamental elements of a highway system, representing an important investment and a strategic link that facilitates the transport of persons and goods. The cost to rehabilitate or replace a highway bridge represents an important expenditure to the owner, who needs to evaluate the correct time to assume that cost. Among the several factors that affect the condition of steel highway bridges, corrosion is identified as the main problem. In the USA corrosion is the primary cause of structurally deficient steel bridges. The benefit of regular high-pressure superstructure washing and spot painting were evaluated as effective maintenance activities to reduce the corrosion process. The effectiveness of steel girder washing was assessed by developing models of corrosion deterioration of composite steel girders and analyzing steel coupons at the laboratory under atmospheric corrosion for two alternatives: when high-pressure washing was performed and when washing was not considered. The effectiveness of spot painting was assessed by analyzing the corrosion on steel coupons, with small damages, unprotected and protected by spot painting. A parametric analysis of corroded steel girder bridges was considered. The emphasis was focused on the parametric analyses of corroded steel girder bridges under two alternatives: (a) when steel bridge girder washing is performed according to a particular frequency, and (b) when no bridge washing is performed to the girders. The reduction of structural capacity was observed for both alternatives along the structure service life, estimated at 100 years. An economic analysis, using the Life-Cycle Cost Analysis method, demonstrated that it is more cost-effective to perform steel girder washing as a scheduled maintenance activity in contrast to the no washing alternative.

Digital mapping of corrosion risk in coastal urban areas using remote sensing and structural condition assessment: case study in cyprus

Directory of Open Access Journals (Sweden)

Neocleous Kyriacos

2016-01-01

Full Text Available Atmospheric corrosion is one of the main factors leading to performance deterioration of reinforced concrete buildings; and, hence, periodic structural condition monitoring is required to assess and repair the adverse effects of corrosion. However, this can become a cumbersome and expensive task to undertake for large populations of buildings, scattered in large urban areas. To optimize the use of available resources, appropriate tools are required for the assessment of corrosion risk of reinforced concrete construction. This paper proposes a framework for the production of digital corrosion risk maps for urban areas; Cyprus was used as a case study. This framework explored multi-temporal satellite remote sensing data from the Landsat sensors as well as corrosion risk factors derived from the results of a recently completed research project, entitled “STEELCOR”. This framework was used to develop two corrosion risk scenarios within Geographical Information Systems, and to produce corrosion risk maps for three coastal cities of Cyprus. The thematic maps indicated that, for slight corrosion damage, the distance of reinforced concrete buildings from the coast was more influential than the building age. While, for significant corrosion damage, the maps indicated that the age of RC buildings was more influential than the distance from the coast.

Evolution processes of the corrosion behavior and structural characteristics of plasma electrolytic oxidation coatings on AZ31 magnesium alloy

Science.gov (United States)

Chen, Dong; Wang, Ruiqiang; Huang, Zhiquan; Wu, Yekang; Zhang, Yi; Wu, Guorui; Li, Dalong; Guo, Changhong; Jiang, Guirong; Yu, Shengxue; Shen, Dejiu; Nash, Philip

2018-03-01

Evolution processes of the corrosion behavior and structural characteristics of the plasma electrolytic oxidation (PEO) coated AZ31 magnesium alloy were investigated by using scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), potentio-dynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Detached coating samples were fabricated by an electrochemical method and more details of the internal micro-structure of coatings were clearly observed on the fractured cross-section morphologies of the samples compared to general polished cross-section morphologies. Evolution mechanisms of the coating corrosion behavior in relation to the evolution of micro-structural characteristics were discussed in detail.

The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor.

Science.gov (United States)

Minnoş, Bihter; Ilhan-Sungur, Esra; Çotuk, Ayşın; Güngör, Nihal Doğruöz; Cansever, Nurhan

2013-01-01

The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor was investigated over a 10-month period in a hotel. Planktonic and sessile numbers of sulphate reducing bacteria (SRB) and heterotrophic bacteria were monitored. The corrosion rate was determined by the weight loss method. The corrosion products were analyzed by energy dispersive X-ray spectroscopy and X-ray diffraction. A mineralized, heterogeneous biofilm was observed on the coupons. Although a biocide and a corrosion inhibitor were regularly added to the cooling water, the results showed that microorganisms, such as SRB in the mixed species biofilm, caused corrosion of galvanized steel. It was observed that Zn layers on the test coupons were completely depleted after 3 months. The Fe concentrations in the biofilm showed significant correlations with the weight loss and carbohydrate concentration (respectively, p < 0.01 and p < 0.01).

Fabrication of hydrophobic surface with hierarchical structure on Mg alloy and its corrosion resistance

International Nuclear Information System (INIS)

Wang Jun; Li Dandan; Liu Qi; Yin Xi; Zhang Ying; Jing Xiaoyan; Zhang Milin

2010-01-01

A hydrotalcite/hydromagnesite conversion coating with hierarchical structure has been fabricated on a Mg alloy substrate by in situ hydrothermal crystallization method. A MgO layer existing between the hydrotalcite/hydromagnesite film and the substrate was formed prior to the hydrotalcite/hydromagnesite film during the crystallization process. After surface treatment with silane coupling agent, the surface of conversion coating changes from hydrophilic to hydrophobic. Scanning electron microscopy (SEM) revealed that the silylated conversion coating with hierarchical structure maintains the original rough surface of which was composed of numerous micro-scale flakes and beautiful flower-like protrusions. Polarization measurements have shown that the hydrophobic conversion coating exhibited a low corrosion current density value of 0.432 μA/cm 2 , which means that the hydrophobic conversion coating can effectively protect Mg alloy from corrosion. Electrochemical impedance spectroscopy (EIS) showed that the impedance of the hydrophobic conversion coating was 9000 Ω. It means that the coating served as a passive layer with high charge transfer resistance.

Corrosion of metallic materials. Dry corrosion, aqueous corrosion and corrosion by liquid metal, methods of protection

International Nuclear Information System (INIS)

Helie, Max

2015-01-01

This book is based on a course on materials given in an engineering school. The author first gives an overview of metallurgy issues: metallic materials (pure metals, metallic alloys), defects of crystal lattices (point defects, linear defects or dislocations), equilibrium diagrams, steels and cast, thermal processing of steels, stainless steels, aluminium and its alloys, copper and its alloys. The second part addresses the properties and characterization of surfaces and interfaces: singularity of a metal surface, surface energy of a metal, energy of grain boundaries, adsorption at a material surface, metal-electrolyte interface, surface oxide-electrolyte interface, techniques of surface analysis. The third chapter addresses the electrochemical aspects of corrosion: description of the corrosion phenomenon, free enthalpy of a compound and free enthalpy of a reaction, case of dry corrosion (thermodynamic aspect, Ellingham diagram, oxidation mechanisms, experimental study, macroscopic modelling), case of aqueous corrosion (electrochemical thermodynamics and kinetics, experimental determination of corrosion rate). The fourth part addresses the different forms of aqueous corrosion: generalized corrosion (atmospheric corrosion, mechanisms and tests), localized corrosion (galvanic, pitting, cracking, intergranular, erosion and cavitation), particular cases of stress cracking (stress corrosion, fatigue-corrosion, embrittlement by hydrogen), and bi-corrosion (of non alloyed steels, of stainless steels, and of aluminium and copper alloys). The sixth chapter addresses the struggle and the protection against aqueous corrosion: methods of prevention, scope of use of main alloys, geometry-based protection of pieces, use of corrosion inhibitors, use of organic or metallic coatings, electrochemical protection. The last chapter proposes an overview of corrosion types in industrial practices: in the automotive industry, in the oil industry, in the aircraft industry, and in the

Methodology for Assessing the Probability of Corrosion in Concrete Structures on the Basis of Half-Cell Potential and Concrete Resistivity Measurements

OpenAIRE

Sadowski, Lukasz

2013-01-01

In recent years, the corrosion of steel reinforcement has become a major problem in the construction industry. Therefore, much attention has been given to developing methods of predicting the service life of reinforced concrete structures. The progress of corrosion cannot be visually assessed until a crack or a delamination appears. The corrosion process can be tracked using several electrochemical techniques. Most commonly the half-cell potential measurement technique is used for this purpos...

Influence of Pitting Corrosion on Fatigue and Corrosion Fatigue of Ship and Offshore Structures, Part II: Load - Pit - Crack Interaction

Directory of Open Access Journals (Sweden)

Jakubowski Marek

2015-09-01

Full Text Available In the paper has been discussed influence of stresses on general corrosion rate and corrosion pit nucleation rate and growth , whose presence has been questioned by some authors but accepted by most of them. Influence of roughness of pit walls on fatigue life of a plate suffering pit corrosion and presence of the so called „ non-damaging” pits which never lead to initiation of fatigue crack, has been presented. Possibility of prediction of pit-to-crack transition moment by two different ways, i.e. considering a pit a stress concentrator or an equivalent crack, has been analyzed. Also, influence of statistical distribution of depth of corrosion pits as well as anticorrosion protection on fatigue and corrosion fatigue has been described.

XPS and Auger investigation of mechanisms affecting corrosion inhibition of metals

International Nuclear Information System (INIS)

Holmes, R.M.; Surman, D.J.

1989-01-01

Atmospheric corrosion of metal surfaces need not be extremely obvious to cause extensive damage to many products. Very small corrosion pits and spots can cause defects in critical copper sources, often resulting in the catastrophic failure of complete electronic assemblies. Microscopic corrosion in steel can lead to the complete failure of subsequently added coatings or furnishings, the automotive industry has become aware. In addition, corrosion at its earliest stages can initiate other corrosion at a later date, resulting in inferior finishings or coatings. A major interest in atmospheric corrosion is in the mechanism by which the initial corrosion initiated and propagated. The initial phase involves the attack of the very other surface layers, hence it is difficult to observe with conventional techniques such as SEM/EDX. This paper presents some of the results obtained by both Auger electron spectroscopy and x- ray photoelectron spectroscopy, of steel and copper samples exposed to corrosive materials under controlled conditions

Zircaloy-4 corrosion in PWR's

International Nuclear Information System (INIS)

Fyfitch, S.; Smalley, W.R.; Roberts, E.

1985-01-01

Zircaloy-4 waterside corrosion has been studied extensively in the nuclear industry for a number of years. Following the early crud-related corrosion failures in the Saxton test reactor, Westinghouse undertook numerous programs to minimize crud deposition on fuel rods in power reactors through primary coolant chemistry control. Modern plants today are operating with improved coolant chemistry guidelines, and crud deposition levels are very low in proportion to earlier experience. Zircaloy-4 corrosion under a variety of coolant chemistry, heat flux and exposure conditions has been studied extensively. Experience to date, even in relatively high coolant temperature plants, has indicated that -for both fuel cladding and structural components- Zircaloy-4 waterside corrosion performance has been excellent. Recognizing future industry trends, however, which will result in Zircaloy-4 being subjected to ever increasing corrosion duties, Westinghouse will continue accumulating Zircaloy-4 corrosion experience in large power plants. 13 refs.

Durability evaluation method on rebar corrosion of reinforced concrete

International Nuclear Information System (INIS)

Kitsutaka, Yoshinori

2013-01-01

In this paper, method on the durability evaluation in nuclear power plant concrete structures was investigated. In view of the importance of evaluating the degree of deterioration of reinforced concrete structures, relationships should be formulated among the number of years elapsed, t, the amount of action of a deteriorative factor, F, the degree of material deterioration, D, and the performance of the structure, P. Evaluation by PDFt diagrams combining these relationships may be effective. A detailed procedure of durability evaluation for a reinforced concrete structure using PDFt concept is presented for the deterioration of rebar corrosion caused by neutralization and penetration of salinity by referring to the recent papers. (author)

Corrosion mechanism applicable to biodegradable magnesium implants

Energy Technology Data Exchange (ETDEWEB)

Atrens, Andrej, E-mail: Andrejs.Atrens@uq.edu.au [University of Queensland, Division of Materials, Brisbane, Qld 4072 (Australia); Liu Ming; Zainal Abidin, Nor Ishida [University of Queensland, Division of Materials, Brisbane, Qld 4072 (Australia)

2011-12-15

Much of our understanding of the Mg corrosion mechanism is based on research using aggressive chloride based solutions like 3% NaCl, which are appropriate for understand the corrosion for applications such as auto construction. The chloride ions tend to cause break down of the partly protective surface film on the Mg alloy surface. The corrosion rate increases with exposure time until steady state is reached, which may take several weeks. An overview is provided of the aspects which determine the corrosion of Mg alloys: (i) measurement details; (ii) impurity elements Fe, Ni, Cu and Co; (iii) second phases; (iv) surface films and surface condition and (v) stress corrosion cracking (SCC). This understanding is used to help understand Mg corrosion for Mg as a biodegradable implant for medical applications. Solutions that elucidate these applications tend to form surface films and the corrosion rate tends to decrease with immersion time.

Downhole corrosion mechanisms and mitigation strategies

Energy Technology Data Exchange (ETDEWEB)

McDougall, D. [Baker Hughes Canada, Calgary, AB (Canada)

2010-07-01

Pipeline corrosion refers to its deterioration because of a reaction with its environment. Although the physical condition of the metal at the anode initiates the corrosion process, it is the chemistry and composition of the electrolyte that controls the rate of the corrosion reaction and the severity of the corrosion. This presentation described the role of corrosion rate accelerators, with particular reference to dissolved gases such as oxygen, hydrogen sulfides and carbon dioxide, as well as pH levels, salinity, flow rate, temperature and presence of solids such as iron sulfides and sulfur. The effects of these accelerators were shown to be additive. Mitigation strategies include using materials such as resistant metal alloys or fiberglass, and applying coatings and chemical inhibitors. The importance of corrosion monitoring was also emphasized, with particular reference to the value of examining the number of corrosion related failures that have occurred over a fixed period of time. It was concluded that the ability to analyze samples of failed materials results in a better understanding of the cause of the failure, and is an integral part of designing any successful corrosion control program. tabs., figs.

Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure and method of processing

Science.gov (United States)

Brown, Jr., Jesse J.; Hirschfeld, Deidre A.; Li, Tingkai

1993-12-07

Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure are created using sol-gel processes. The processes have particular application in creating calcium magnesium zirconium phosphate, CMZP, coatings and foams.

Optical reflection spectroscopy of thick corrosion layers on 304 stainless steel

International Nuclear Information System (INIS)

Castelli, R.A.; Persans, P.D.; Strohmayer, W.; Parkinson, V.

2007-01-01

Corrosion resistant structural materials of both iron and nickel based alloys are used in the electric power industry for the construction of the coolant loops of both conventional and nuclear power generating stations. These materials, in the presence of high temperature (e.g. 287 o C), high pH (e.g. 10.0 at 20 o C) water with dissolved hydrogen will oxidize and form corrosion films that are double metal oxides (or spinels) of the form AB 2 O 4 . This work describes optical reflectivity techniques that have been developed to study the growth of these films in situ. The optical technique uses a dual-beam specular reflection spectrometer to measure the spectrum of reflected light in small angle (i.e. o ) scatter. The reflection spectra are then calibrated using a set of corrosion coupons with corrosion films that are well known. Results are compared with models based on multilayer reflection and Mie scattering from a particle size distribution. Surface roughness is found to be the dominant cause of reduced reflection as the films grow

A review on stray current-induced steel corrosion in infrastructure

NARCIS (Netherlands)

Chen, Zhipei; Koleva, D.A.; van Breugel, K.

2017-01-01

Metallic corrosion can cause substantial damage at various levels and in almost all types of infrastructure. For metallic corrosion to occur, a certain external environment and the presence of corrodents are the prerequisites. Stray current-induced corrosion, however, is a rather underestimated

Innovative Approach to Establish Root Causes for Cracking in Aggressive Reactor Environments

International Nuclear Information System (INIS)

Bruemmer, Stephen M.; Thomas, Larry E.; Vetrano, John S.; Simonen, Edward P.

2003-01-01

The research focuses on the high-resolution characterization of degradation microstructures and microchemistries in specimens tested under controlled conditions for the environment and for the material where in-service complexities can be minimized. Thermodynamic and kinetic modeling of crack-tip processes is employed to analyze corrosion-induced structures and gain insights into degradation mechanisms. Novel mechanistic ''fingerprinting'' of crack-tip structures is used to isolate causes of environmental cracking in tandem with quantitative measurements of crack growth. Sample preparation methods and advanced analytical techniques are used to characterize corrosion/oxidation reactions and crack-tip structures at near atomic dimensions in order to gain insight into fundamental environmental cracking mechanisms. Reactions at buried interfaces, not accessible by conventional approaches, are being systematically interrogated. Crack-growth experiments in high-temperature water environments are evaluating and isolating the effects of material condition (matrix strength, grain boundary composition and precipitation) on stress corrosion cracking (SCC). The fundamental understanding of crack advance mechanisms will establish the basis to design new corrosion-resistant alloys for current light-water reactors and advanced reactor systems

Erosion-corrosion of structural materials of wet steam turbines

International Nuclear Information System (INIS)

Tomarov, G.V.

1989-01-01

A model of erosion-corrosion wear of elements of a wet steam zone and a condensate-feeding path of turbines is considered. It is shown that diffusion of impurities and corrosion products in pores of an oxide layer is the control mechanism under conditions of laminar flow of a media. Processes of mass transfer are controlling factors in turbulent flow

CORROSION ANALYSIS OF METALLIZED FILMS AFTER PRINTING

OpenAIRE

Mr. Dhirender*1, Mr. Rajeev2 & Mr.Manoj3

2017-01-01

Print quality has always been a point of strong concern among printers and consumers. Metalized films have gain a wide spread popularity among printers because of its low cost and high usages in food packaging applications. But sometimes corrosion spoils the printed products causing huge financial loss to the printers or customers.This paper throws light on major causes of corrosion on metallized films and possible remedies for the same. The metallized films with polyester base were base coat...

Response of reinforced concrete structures to macrocell corrosion of reinforcements. Part I: Before propagation of microcracks via an analytical approach

International Nuclear Information System (INIS)

Kiani, Keivan; Shodja, Hossein M.

2011-01-01

Highlights: ► Response of RC structures to macrocell corrosion of a rebar is studied analytically. ► The problem is solved prior to the onset of microcrack propagation. ► Suitable Love's potential functions are used to study the steel-rust-concrete media. ► The role of crucial factors on the time of onset of concrete cracking is examined. ► The effect of vital factors on the maximum radial stress of concrete is explored. - Abstract: Assessment of the macrocell corrosion which deteriorates reinforced concrete (RC) structures have attracted the attention of many researchers during recent years. In this type of rebar corrosion, the reduction in cross-section of the rebar is significantly accelerated due to the large ratio of the cathode's area to the anode's area. In order to examine the problem, an analytical solution is proposed for prediction of the response of the RC structure from the time of steel depassivation to the stage just prior to the onset of microcrack propagation. To this end, a circular cylindrical RC member under axisymmetric macrocell corrosion of the reinforcement is considered. Both cases of the symmetric and asymmetric rebar corrosion along the length of the anode zone are studied. According to the experimentally observed data, corrosion products are modeled as a thin layer with a nonlinear stress–strain relation. The exact expressions of the elastic fields associated with the steel, and concrete media are obtained using Love's potential function. By imposing the boundary conditions, the resulting set of nonlinear equations are solved in each time step by Newton's method. The effects of the key parameters which have dominating role in the time of the onset of concrete cracking and maximum radial stress field of the concrete have been examined.

Corrosion products in power generating systems

International Nuclear Information System (INIS)

Lister, D.H.

1980-06-01

The important mechanisms of corrosion and corrosion product movement and fouling in the heat transport systems of thermal electric generating stations are reviewed. Oil- and coal-fired boilers are considered, along with nuclear power systems - both direct and indirect cycle. Thus, the fireside and waterside in conventional plants, and the primary coolant and steam-raising circuits in water-cooled reactors, are discussed. Corrosion products in organic- and liquid-metal-cooled reactors also are shown to cause problems if not controlled, while their beneficial effects on the cooling water side of condensers are described. (auth)

Water side corrosion prevention in boilers

International Nuclear Information System (INIS)

Zeid, A.

1993-01-01

Corrosion may be defined as a naturally occurring physical and chemical deterioration of a material due to reaction with the environment or surrounding atmosphere. In boilers the material is subjected on both sides to two different media which may cause severe corrosion. At the water side the content of O 2 considered one of the principal factors which determine the extent of corrosion in the boiler tubes. This paper deals with certain conditions that result in the increase of O 2 in the boiler water and hence increase the corrosion rate, to minimize the effect of these conditions a chemical treatment was carried out the results obtained indicated the success of the treatment procedure in corrosion prevention and boiler material protection. The treatment is traditional. But the study indicates how a simple mean could be applied to solve a serious problem. 4 tab

Causes and mechanisms of thermal embrittlement and corrosion cracking of complex α-titanium alloys

International Nuclear Information System (INIS)

Ushkov, S.S.; Rybin, V.V.; Razuvaeva, I.N.; Nesterova, E.V.; Gunbina, O.A.

1995-01-01

Effect of aging under 500 deg C on mechanical and corrosion-mechanical properties of Ti-6Al base titanium α-alloys with zirconium and carbon additions is studied. Using electron microscopy one determines the reasons of reduction of plasticity and of corrosion-mechanical strength of alloys after aging. It is determined that in the given alloys there are two different processes with occurrence different kinetics: the first one-formation of grain-boundary precipitations of Ti 2 (Fe, Ni) intermetallic compound responsible for plasticity reduction; and the second one-homogeneous decomposition of Ti-Al solid solution responsible for reduction of corrosion-mechanical properties. 14 refs., 6 figs

A New Corrosion Sensor to Determine the Start and Development of Embedded Rebar Corrosion Process at Coastal Concrete

Directory of Open Access Journals (Sweden)

Weiliang Jin

2013-09-01

Full Text Available The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete under drying or saturated conditions due to concrete resistance taking control in macro-cell corrosion. In this paper, a fast weak polarization method to test corrosion state of reinforcements based on electrochemical polarization dynamics was proposed. Furthermore, a new corrosion sensor for monitoring the corrosion state of concrete cover was developed based on the proposed test method. The sensor was tested in cement mortar, with dry-wet cycle tests to accelerate the chloride ingress rate. The results show that the corrosion sensor can effectively monitor chloride penetration into concrete with little influence of the relative humidity in the concrete. With a reasonable corrosion sensor electrode arrangement, it seems the Ohm-drop effect measured by EIS can be ignored, which makes the tested electrochemical parameters more accurate.

A new corrosion sensor to determine the start and development of embedded rebar corrosion process at coastal concrete.

Science.gov (United States)

Xu, Chen; Li, Zhiyuan; Jin, Weiliang

2013-09-30

The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete under drying or saturated conditions due to concrete resistance taking control in macro-cell corrosion. In this paper, a fast weak polarization method to test corrosion state of reinforcements based on electrochemical polarization dynamics was proposed. Furthermore, a new corrosion sensor for monitoring the corrosion state of concrete cover was developed based on the proposed test method. The sensor was tested in cement mortar, with dry-wet cycle tests to accelerate the chloride ingress rate. The results show that the corrosion sensor can effectively monitor chloride penetration into concrete with little influence of the relative humidity in the concrete. With a reasonable corrosion sensor electrode arrangement, it seems the Ohm-drop effect measured by EIS can be ignored, which makes the tested electrochemical parameters more accurate.

Influence of heat treatment conditions on structure and corrosion fracture of welded joints of zirconium alloy with 2.5 % niobium in agressive media

International Nuclear Information System (INIS)

Goncharov, A.B.; Nerodenko, M.M.; Tkachenko, L.M.; Adeeva, L.I.

1990-01-01

Influence of heat treatment on corrosion resistance of Zr-2.5 % Nb alloy welded joints is studied. It is stated that alloy after annealing in β-region has maximum corrosion resistance in sulfuric acid. Corrosion resistance in acetic acid doesn't depend on heat treatment. The best operating characteristics in steam-water medium of high parameters have welded joints, structure and phase composition of which approach α-phase with fine-dispersed β Nb particles, uniformly distributed in grain matrix. Such structure is attained by annealing in α-region or quenching with the following annealing at 850 K

Accelerated Test Method for Corrosion Protective Coatings

Data.gov (United States)

National Aeronautics and Space Administration — This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as...

A wireless embedded passive sensor for monitoring the corrosion potential of reinforcing steel

International Nuclear Information System (INIS)

Bhadra, Sharmistha; Thomson, Douglas J; Bridges, Greg E

2013-01-01

Corrosion of reinforcing steel, which results in premature deterioration of reinforced concrete structures, is a worldwide problem. Most corrosion sensing techniques require some type of wired connection between the sensor and monitoring electronics. This causes significant problems in their installation and long-term use. In this paper we describe a new type of passive embeddable wireless sensor that is based on an LC coil resonator where the resonant frequency is changed by the corrosion potential of the reinforcing steel. The resonant frequency can be monitored remotely by an interrogator coil inductively coupled to the sensor coil. The sensor unit comprises an inductive coil connected in parallel with a voltage dependent capacitor (varactor) and a pair of corrosion electrodes consisting of a reinforcing steel sensing electrode and a stainless steel reference electrode. Change of potential difference between the electrodes due to variation of the corrosion potential of the reinforcing steel changes the capacitance of the varactor and shifts the resonant frequency of the sensor. A time-domain gating method was used for the interrogation of the inductively coupled corrosion sensor. Results of an accelerated corrosion test using the sensor indicate that the corrosion potential can be monitored with a resolution of less than 10 mV. The sensor is simple in design and requires no power source, making it an inexpensive option for long-term remote monitoring of the corrosion state of reinforcing steel. (paper)

A Survey of Corrosion and Conditions of Corrosion Protection Systems in Civil Works Structures of the U.S. Army Corps of Engineers

Science.gov (United States)

2014-09-01

corrosion: coatings and cathodic protection (CP). Coatings consist of paints, epoxies, enamels , metalizing, and other coatings. CP is a chem- ical means...environmental factors such as water quality and resistivity. One of the major problems associated with lock gates is structural cracking in the...One of the problems described by Mr. Davis is fatigue crack growth resulting from the poor welding usually associated with stress risers and

Bacterial corrosion in low-temperature geothermal. Mechanisms of corrosion by sulphate-reducing bacteria

International Nuclear Information System (INIS)

Daumas, Sylvie

1987-01-01

Within the frame of researches aimed at determining the causes of damages noticed on geothermal equipment, this research thesis aims at assessing the respective importance of physical-chemical processes and bacterial intervention in corrosion phenomena. It proposes an ecological approach of the fluid sampled in the Creil geothermal power station. The aim is to define the adaptation and activity degree of isolated sulphate-reducing bacteria with respect to their environment conditions. The author studied the effect of the development of these bacteria on the corrosion of carbon steel used in geothermal. Thus, he proposes a contribution to the understanding of mechanisms related to iron attack by these bacteria. Electrochemical techniques have been adapted to biological processes and used to measure corrosion [fr

Stress corrosion of low alloy steel forgings

International Nuclear Information System (INIS)

Thornton, D.V.; Mould, P.B.; Patrick, E.C.

1976-01-01

The catastrophic failure of a steam turbine rotor disc at Hinkley Point 'A' Power station was shown to have been caused by the growth of a stress corrosion crack to critical dimensions. This failure has promoted great interest in the stress corrosion susceptibility of medium strength low alloy steel forgings in steam environments. Consequently, initiation and growth of stress corrosion cracks of typical disc steels have been investigated in steam and also in water at 95 0 C. Cracking has been shown to occur, predominantly in an intergranular manner, with growth rates of between 10 -9 and 10 -7 mm sec. -1 . It is observed that corrosion pitting and oxide penetration prior to the establishment of a stress corrosion crack in the plain samples. (author)

Concrete cover cracking due to uniform reinforcement corrosion

DEFF Research Database (Denmark)

Solgaard, Anders Ole Stubbe; Michel, Alexander; Geiker, Mette Rica

2013-01-01

and reinforcement de-passivation is a frequently used limit state. The present paper investigates an alternative limit state: corrosion-induced cover cracking. Results from numerical simulations of concrete cover cracking due to reinforcement corrosion are presented. The potential additional service life...... is calculated using literature data on corrosion rate and Faraday’s law. The parameters varied comprise reinforcement diameter, concrete cover thickness and concrete material properties, viz. concrete tensile strength and ductility (plain concrete and fibre reinforced concrete). Results obtained from......Service life design (SLD) is an important tool for civil engineers to ensure that the structural integrity and functionality of the structure is not compromised within a given time frame, i.e. the service life. In SLD of reinforced concrete structures, reinforcement corrosion is of major concern...

Neural network for prediction of superheater fireside corrosion

Energy Technology Data Exchange (ETDEWEB)

Makkonen, P [Foster Wheeler Energia Oy, Karhula R and D Center, Karhula (Finland)

1999-12-31

Superheater corrosion causes vast annual losses to the power companies. If the corrosion could be reliably predicted, new power plants could be designed accordingly, and knowledge of fuel selection and determination of process conditions could be utilized to minimize superheater corrosion. If relations between inputs and the output are poorly known, conventional models depending on corrosion theories will fail. A prediction model based on a neural network is capable of learning from errors and improving its performance as the amount of data increases. The neural network developed during this study predicts superheater corrosion with 80 % accuracy at early stage of the project. (orig.) 10 refs.

Neural network for prediction of superheater fireside corrosion

Energy Technology Data Exchange (ETDEWEB)

Makkonen, P. [Foster Wheeler Energia Oy, Karhula R and D Center, Karhula (Finland)

1998-12-31

Superheater corrosion causes vast annual losses to the power companies. If the corrosion could be reliably predicted, new power plants could be designed accordingly, and knowledge of fuel selection and determination of process conditions could be utilized to minimize superheater corrosion. If relations between inputs and the output are poorly known, conventional models depending on corrosion theories will fail. A prediction model based on a neural network is capable of learning from errors and improving its performance as the amount of data increases. The neural network developed during this study predicts superheater corrosion with 80 % accuracy at early stage of the project. (orig.) 10 refs.

Corrosion mechanism of copper in palm biodiesel

International Nuclear Information System (INIS)

Fazal, M.A.; Haseeb, A.S.M.A.; Masjuki, H.H.

2013-01-01

Highlights: ► Corrosion of copper in biodiesel increases with the increase of immersion time. ► The corrosion patina is found to be composed of CuO, Cu 2 O, CuCO 3 and Cu(OH) 2 . ► Green CuCO 3 was found as the major corrosion product. ► The mechanisms governing corrosion of copper in palm biodiesel are discussed. - Abstract: Biodiesel is a promising alternative fuel. However, it causes enhanced corrosion of automotive materials, especially of copper based components. In the present study, corrosion mechanism of copper was investigated by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Compositional change of biodiesel due to the exposure of copper was also investigated. Corrosion patina on copper is found to be composed of Cu 2 O, CuO, Cu(OH) 2 and CuCO 3. Dissolved O 2 , H 2 O, CO 2 and RCOO − radical in biodiesel seem to be the leading factors in enhancing the corrosiveness of biodiesel.

The influence of cracks on chloride-induced corrosion of reinforced concrete structures - development of the experimental set-up

NARCIS (Netherlands)

Blagojevic, A.; Koleva, D.A.; Walraven, J.C.

2014-01-01

Chloride-induced corrosion of steel reinforcement is one of the major threats to durability of reinforced concrete structures in aggressive environmental conditions. When the steel reinforcement starts to corrode, structures gradually lose integrity and service life is shortened. Cracks are

Corrosion performance of advanced structural materials in sodium.

Energy Technology Data Exchange (ETDEWEB)

Natesan, K.; Momozaki, Y.; Li, M.; Rink, D.L. (Nuclear Engineering Division)

2012-05-16

This report gives a description of the activities in design, fabrication, construction, and assembling of a pumped sodium loop for the sodium compatibility studies on advanced structural materials. The work is the Argonne National Laboratory (ANL) portion of the effort on the work project entitled, 'Sodium Compatibility of Advanced Fast Reactor Materials,' and is a part of Advanced Materials Development within the Reactor Campaign. The objective of this project is to develop information on sodium corrosion compatibility of advanced materials being considered for sodium reactor applications. This report gives the status of the sodium pumped loop at Argonne National Laboratory, the specimen details, and the technical approach to evaluate the sodium compatibility of advanced structural alloys. This report is a deliverable from ANL in FY2010 (M2GAN10SF050302) under the work package G-AN10SF0503 'Sodium Compatibility of Advanced Fast Reactor Materials.' Two reports were issued in 2009 (Natesan and Meimei Li 2009, Natesan et al. 2009) which examined the thermodynamic and kinetic factors involved in the purity of liquid sodium coolant for sodium reactor applications as well as the design specifications for the ANL pumped loop for testing advanced structural materials. Available information was presented on solubility of several metallic and nonmetallic elements along with a discussion of the possible mechanisms for the accumulation of impurities in sodium. That report concluded that the solubility of many metals in sodium is low (<1 part per million) in the temperature range of interest in sodium reactors and such trace amounts would not impact the mechanical integrity of structural materials and components. The earlier report also analyzed the solubility and transport mechanisms of nonmetallic elements such as oxygen, nitrogen, carbon, and hydrogen in laboratory sodium loops and in reactor systems such as Experimental Breeder Reactor-II, Fast Flux

Corrosion performance of advanced structural materials in sodium

International Nuclear Information System (INIS)

Natesan, K.; Momozaki, Y.; Li, M.; Rink, D.L.

2012-01-01

This report gives a description of the activities in design, fabrication, construction, and assembling of a pumped sodium loop for the sodium compatibility studies on advanced structural materials. The work is the Argonne National Laboratory (ANL) portion of the effort on the work project entitled, 'Sodium Compatibility of Advanced Fast Reactor Materials,' and is a part of Advanced Materials Development within the Reactor Campaign. The objective of this project is to develop information on sodium corrosion compatibility of advanced materials being considered for sodium reactor applications. This report gives the status of the sodium pumped loop at Argonne National Laboratory, the specimen details, and the technical approach to evaluate the sodium compatibility of advanced structural alloys. This report is a deliverable from ANL in FY2010 (M2GAN10SF050302) under the work package G-AN10SF0503 'Sodium Compatibility of Advanced Fast Reactor Materials.' Two reports were issued in 2009 (Natesan and Meimei Li 2009, Natesan et al. 2009) which examined the thermodynamic and kinetic factors involved in the purity of liquid sodium coolant for sodium reactor applications as well as the design specifications for the ANL pumped loop for testing advanced structural materials. Available information was presented on solubility of several metallic and nonmetallic elements along with a discussion of the possible mechanisms for the accumulation of impurities in sodium. That report concluded that the solubility of many metals in sodium is low (<1 part per million) in the temperature range of interest in sodium reactors and such trace amounts would not impact the mechanical integrity of structural materials and components. The earlier report also analyzed the solubility and transport mechanisms of nonmetallic elements such as oxygen, nitrogen, carbon, and hydrogen in laboratory sodium loops and in reactor systems such as Experimental Breeder Reactor-II, Fast Flux Test Facility, and

Assessment of structural integrity of Monju steel liner against sodium leakage and combustion. Modeling of thinning process of liner due to corrosion in structural analysis

International Nuclear Information System (INIS)

Tsukimori, K.; Kato, T.; Furuhashi, I.; Iwata, K.; Akatsu, M.

2001-01-01

The lining structure of LMFBR (Liquid Metal cooled Fast Breeder Reactor) has an important role to prohibit leaking sodium from touching a concrete floor in a sodium leakage incident. JNC (Japan Nuclear Cycle Development Institute) experienced a sodium leakage incident in 1995 in the secondary heat transport system room of the prototype LMFBR MONJU. In this incident, a part of the liner was covered with a certain amount of high temperature leaked sodium and its compounds. Visible but small distortion and thinning of the liner were detected, which were due to heating by sodium fire and chemical corrosion, respectively. To simulate the MONJU incident, JNC conducted a series of sodium leakage tests, in one of which severer corrosion (molten salt type corrosion) than that in the MONJU incident was observed. In order to secure the conservativeness in the integrity assessment of the liner, consideration of a severest corrosion process was demanded. This means that the loss of parts of the structure with time should be considered in the structural analyses. In this study a modeling of thinning process of the liner was developed in order to realize reasonable analysis from the point of view of actual phenomena. The concept of the method is to release the stress of the lost region by using artificial creep and reducing Young's modulus. The necessity of this kind of model and the validity was verified through an application analysis of the liner in the secondary heat transport system room of MONJU. (authors)

Understanding and managing corrosion in nuclear power plants

International Nuclear Information System (INIS)

Johnson, A.B. Jr.; Jarrell, D.B.; Sinha, U.P.; Shah, V.N.

1991-03-01

The main theme of this paper is a concept: understanding and managing corrosion in nuclear power plants. The concept is not new--in various forms the concept has been applied throughout the development and maturing of nuclear technology. However, the concept has frequently not been well conceived and applied. Too often, understanding corrosion has been based on reaction rather than on anticipation. Regulatory and utility industry initiatives are creating a climate and framework for more effective application of the concept. This paper characterizes the framework and provides some illustrations of how the concept is being applied, drawing from work conducted under the Nuclear Plant Aging Research (NPAR) Program, sponsored by the Nuclear Regulatory Commission's (NRCs) Office of Research. Nuclear plants are becoming an increasingly important factor in the national electrical grid. Initiatives are currently underway to extend the operating licenses beyond the current 40-year period and to evaluate advanced reactor designs the feature higher safety factors. Corrosion has not caused a major nuclear accident, but numerous corrosion mechanisms, have degraded nuclear systems and components. New corrosion phenomena continue to appear, and occasionally corrosion phenomena cause reactor shutdowns. Effective application of understanding and managing corrosion is important to safe and economic operation of the nuclear plants and also to public perception of a soundly operated technology. 53 refs., 11 figs., 5 tabs

Corrosion Measurements in Reinforced Fly Ash Concrete Containing Steel Fibres Using Strain Gauge Technique

Directory of Open Access Journals (Sweden)

V. M. Sounthararajan

2013-01-01

Full Text Available Corrosion of steel bars in concrete is a serious problem leading to phenomenal volume expansion and thereby leading to cover concrete spalling. It is well known that the reinforced concrete structures subjected to chloride attack during its service life cause these detrimental effects. The early detection of this damage potential can extend the service life of concrete. This study reports the comprehensive experimental studies conducted on the identification of corrosion mechanism in different types of reinforced concrete containing class-F fly ash and hooked steel fibres. Fly ash replaced concrete mixes were prepared with 25% and 50% fly ash containing steel fibres at 0.5%, 1.0%, and 1.5% by volume fraction. Corrosion process was investigated in an embedded steel bar (8 mm diameter reinforced in concrete by passing an impressed current in sodium chloride solution. Strain gauge attached to the rebars was monitored for electrical measurements using strain conditioner. Strain gauge readings observed during the corrosion process exhibited the volume changes of the reinforcement embedded inside the concrete. The corrosion potential of different steel fibre reinforced concrete mixes with fly ash addition showed higher resistance towards the corrosion initiation.

Molten salt: Corrosion problems and electrometallurgy in nuclear applications

International Nuclear Information System (INIS)

Santarini, G.

1981-01-01

A bibliographic survey is given of corrosion problems and electrometallurgical problems of molten salt in nuclear reactor applications. Due to the high potential to be achieved, their high ionic conductivity and the rapidity of reactions in a molten salt atmosphere, molten salts are interesting solvents for various electrometallurgical processes. Another important field of application is in the separation or electrolytical refining of various metals (Be, U, Pu, Th, Hf, Zr). However, these very characteristics of molten salts may also cause serious corrosion problems. Results obtained for the molten-salt reactor and the different causes of corrosion are reviewed an possible countermeasures analyzed. (orig.)

Materials characterization center workshop on corrosion of engineered barriers

Energy Technology Data Exchange (ETDEWEB)

Merz, M.D.; Zima, G.E.; Jones, R.H.; Westerman, R.E.

1981-03-01

A workshop on corrosion test procedures for materials to be used as barriers in nuclear waste repositories was conducted August 19 and 20, 1980, at the Battelle Seattle Research Center. The purpose of the meeting was to obtain guidance for the Materials Characterization Center in preparing test procedures to be approved by the Materials Review Board. The workshop identified test procedures that address failure modes of uniform corrosion, pitting and crevice corrosion, stress corrosion, and hydrogen effects that can cause delayed failures. The principal areas that will require further consideration beyond current engineering practices involve the analyses of pitting, crevice corrosion, and stress corrosion, especially with respect to quantitative predictions of the lifetime of barriers. Special techniques involving accelerated corrosion testing for uniform attack will require development.

Materials characterization center workshop on corrosion of engineered barriers

International Nuclear Information System (INIS)

Merz, M.D.; Zima, G.E.; Jones, R.H.; Westerman, R.E.

1981-03-01

A workshop on corrosion test procedures for materials to be used as barriers in nuclear waste repositories was conducted August 19 and 20, 1980, at the Battelle Seattle Research Center. The purpose of the meeting was to obtain guidance for the Materials Characterization Center in preparing test procedures to be approved by the Materials Review Board. The workshop identified test procedures that address failure modes of uniform corrosion, pitting and crevice corrosion, stress corrosion, and hydrogen effects that can cause delayed failures. The principal areas that will require further consideration beyond current engineering practices involve the analyses of pitting, crevice corrosion, and stress corrosion, especially with respect to quantitative predictions of the lifetime of barriers. Special techniques involving accelerated corrosion testing for uniform attack will require development

Structural and corrosion characterization of hydroxyapatite/zirconium nitride-coated AZ91 magnesium alloy by ion beam sputtering

Energy Technology Data Exchange (ETDEWEB)

Kiahosseini, Seyed Rahim, E-mail: rkiahoseyni@yahoo.com [Young Researchers and Elite Club, Damghan Branch, Islamic Azad University, Damghan (Iran, Islamic Republic of); Afshar, Abdollah [Department of Material Science and Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Mojtahedzadeh Larijani, Majid [Radiation Applications Research School, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Yousefpour, Mardali [Faculty of Materials and Metallurgical Engineering, Semnan University, Semnan, 35131-19111 (Iran, Islamic Republic of)

2017-04-15

Highlights: • The thickness of HA coatings increase by ion beam sputtering time. • The residual strain in HA structure decrease by deposition time increment. • Crystallite size of HA coatings increase by deposition time increment. • The best corrosion resistance occurs at intermediate deposition time. - Abstract: The adhesion of hydroxyapatite (HA) as a coating for the AZ91 magnesium alloy substrate can be improved by using the sputtering method and an intermediate layer, such as ZrN. In this study, HA coatings were applied on ZrN intermediate layers at a temperature of 300 °C for 180, 240, 300, 360, and 420 min by ion beam sputtering. A profilometer device was used to study the HA coating thickness, which changed from 2 μm for the 180-min deposition to 4.7 μm for 420-min deposition. The grazing incidence X-ray diffraction analysis method and the Williamson–Hall analysis were used for structural investigation. As the deposition time increased, the crystalline size increased from 50 nm to 690 nm. However, given sufficient time for stress relief on the coating structure, the lattice strain values were close to zero. Energy-dispersive X-ray spectroscopy results showed that the Ca/P ratio ranged from 1.73 to 1.81. The external indentation method was used to evaluate the coating adhesion to the substrate. The slope of curve for applied force changes versus the radius of cracks in the coating (dP/dr) varied in the range of 0.2–0.07 by the deposition time, indicating that the adhesion increased with the increase in coating thickness. The potentiodynamic polarization technique was used to study the corrosion behavior. With increasing deposition time, the corrosion potential of samples did not show a significant change, and the corrosion potential of all samples (coated and uncoated substrates) was more positive than approximately 55 mV. When the deposition time increased to 360 min, the corrosion current density decreased from 5.5 μA/cm{sup 2} to 0.33 �

Application of Nano-Structured Coatings for Mitigation of Flow-Accelerated Corrosion in Secondary Pipe Systems of Nuclear Power Plants

Energy Technology Data Exchange (ETDEWEB)

Kim, Seung Hyun; Kim, Jong Jin; Yoo, Seung Chang; Huh, Jae Hoon; Kim, Ji Hyun [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2014-05-15

Flow-accelerated corrosion (FAC) is a complex corrosion process combined with mechanical reaction with fluid. There were lots of research to mitigate FAC such as controlling temperature or water chemistry but in this research, we adopt active coating techniques especially nano-particle reinforced coatings. One of the general characteristics of FAC and its mitigation is that surface friction due to surface morphology makes a significant effect on FAC. Therefore to form a uniform coating layers, nano-particles including TiO2, SiC, Fe-Cr-W and Graphene were utilized. Those materials are known as greatly improve the corrosion resistance of substrates such as carbon steels but their effects on mitigation of FAC are not revealed clearly. Therefore in this research, the FAC resistive performance of nano-structured coatings were tested by electrochemical impedance spectroscopy (EIS) in room temperature 15 wt% sulfuric acid. As the flow-accelerated corrosion inhibitors in secondary piping system of nuclear power plants, various kinds of nano-structured coatings were prepared and tested in room-temperature electrochemical cells. SHS7740 with two types of Densifiers, electroless nickel plating with TiO2 are prepared. Electropolarization curves shows the outstanding corrosion mitigation performance of SHS7740 but EIS results shows the promising potential of Ni-P and Ni-P-TiO2 electroless nickel plating. For future work, high-temperature electrochemical analysis system will be constructed and in secondary water chemistry will be simulated.

Techniques for the identification of corrosion products

International Nuclear Information System (INIS)

Ramanathan, L.V.

1988-12-01

This paper presents the different techniques that can be used to identify corrosion/oxidation products through determination of either their composition or their structure, chemical analysis and spectrochemical analysis are commonly used to determine the composition of gross corrosion products. Surface anaLysis techniques such as electron microprobe, AES, ESCA, SIMS, ISS, neutron activation analysis, etc., can be used not only to detect the concentration of the various elements present, but also to obtain the concentration profiles of these elements through the corrosion products. The structure of corrosion products is normally determined with the aid of either X-ray or electron diffraction techniques. This paper describes the basic principles, typical characteristics, limitations and the types of information that can be obtained from each of the techniques along with some typical examples. (author) [pt

Effects of Variations in Salt-Spray Conditions on the Corrosion Mechanisms of an AE44 Magnesium Alloy

Directory of Open Access Journals (Sweden)

Holly J. Martin

2010-01-01

Full Text Available The understanding of how corrosion affects magnesium alloys is of utmost importance as the automotive and aerospace industries have become interested in the use of these lightweight alloys. However, the standardized salt-spray test does not produce adequate corrosion results when compared with field data, due to the lack of multiple exposure environments. This research explored four test combinations through three sets of cycles to determine how the corrosion mechanisms of pitting, intergranular corrosion, and general corrosion were affected by the environment. Of the four test combinations, Humidity-Drying was the least corrosive, while the most corrosive test condition was Salt Spray-Humidity-Drying. The differences in corrosivity of the test conditions are due to the various reactions needed to cause corrosion, including the presence of chloride ions to cause pit nucleation, the presence of humidity to cause galvanic corrosion, and the drying phase which trapped chloride ions beneath the corrosion by-products.

Corrosion Prevention And Control In High Pressure Oil And Gas Transmission Pipelines

International Nuclear Information System (INIS)

Hafez, M.T.; Radwan, M.H.; Jones, D.G.

2004-01-01

At the start of the 1990s there were concerns over the increasing threat of corrosion to the integrity of high-pressure oil and gas transmission pipelines. For example: corrosion was the major cause of reportable incidents in North America (1]. Corrosion was the major cause of pipeline failure in the Gulf of Mexico [2]. Corrosion in a North American onshore oil pipeline had required over $1 billion in repairs(3]. Internal corrosion along the complete length of pipelines had resulted in replacement[4] . However, the worldwide published failure statistics indicate that the incidents of corrosion are not increasing year on year(5-9]. Indeed, CONCA WE[8,9] statistics (for pipelines In Western Europe) show that the failure rate from corrosion (the most likely failure mode with increasing age) has not increased with pipeline age (Figure 1). In fact the statistics for gas pipelines in Europe

Virtual Instrumentation Corrosion Controller for Natural Gas Pipelines

Science.gov (United States)

Gopalakrishnan, J.; Agnihotri, G.; Deshpande, D. M.

2012-12-01

Corrosion is an electrochemical process. Corrosion in natural gas (methane) pipelines leads to leakages. Corrosion occurs when anode and cathode are connected through electrolyte. Rate of corrosion in metallic pipeline can be controlled by impressing current to it and thereby making it to act as cathode of corrosion cell. Technologically advanced and energy efficient corrosion controller is required to protect natural gas pipelines. Proposed virtual instrumentation (VI) based corrosion controller precisely controls the external corrosion in underground metallic pipelines, enhances its life and ensures safety. Designing and development of proportional-integral-differential (PID) corrosion controller using VI (LabVIEW) is carried out. When the designed controller is deployed at field, it maintains the pipe to soil potential (PSP) within safe operating limit and not entering into over/under protection zone. Horizontal deployment of this technique can be done to protect all metallic structure, oil pipelines, which need corrosion protection.

Stress-corrosion cracking of indium tin oxide coated polyethylene terephthalate for flexible optoelectronic devices

International Nuclear Information System (INIS)

Sierros, Konstantinos A.; Morris, Nicholas J.; Ramji, Karpagavalli; Cairns, Darran R.

2009-01-01

Stress corrosion cracking of transparent conductive layers of indium tin oxide (ITO), sputtered on polyethylene terephthalate (PET) substrates, is an issue of paramount importance in flexible optoelectronic devices. These components, when used in flexible device stacks, can be in contact with acid containing pressure-sensitive adhesives or with conductive polymers doped in acids. Acids can corrode the brittle ITO layer, stress can cause cracking and delamination, and stress-corrosion cracking can cause more rapid failure than corrosion alone. The combined effect of an externally-applied mechanical stress to bend the device and the corrosive environment provided by the acid is investigated in this work. We show that acrylic acid which is contained in many pressure-sensitive adhesives can cause corrosion of ITO coatings on PET. We also investigate and report on the combined effect of external mechanical stress and corrosion on ITO-coated PET composite films. Also, it is shown that the combination of stress and corrosion by acrylic acid can cause ITO cracking to occur at stresses less than a quarter of those needed for failure with no corrosion. In addition, the time to failure, under ∼ 1% tensile strain can reduce the total time to failure by as much as a third

Benefits from corrosion management of ORBEL-I pipeline; Resultados obtidos com o gerenciamento da corrosao do oleoduto ORBEL-I

Energy Technology Data Exchange (ETDEWEB)

Lima, Aline de Souza [PETROBRAS Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil); Fernandes Junior, Anibal Augusto; Viana, Flavio Godinho [PETROBRAS, Rio de Janeiro, RJ (Brazil)

2005-07-01

This work has for objective to present the results gotten with the management of the implanted internal corrosion in the pipeline Rio de Janeiro - Belo Horizonte I (ORBEL I), with 363 kilometers of extension and 18 inch of diameter. This management has for purpose to prevent and to control the corrosive process in the internal structure of the pipe through the identification of the basic causes of the corrosive process and the implantation of actions adjusted for the control of the process. The applied techniques and actions had been based on the described recommendations in the Communication Technique 116/99 No. - Management of the Corrosion of ORBEL I emitted for the Center of Research of PETROBRAS (CENPES). The applied actions had been: determination of the corrosion rate with the coupon use of loss of mass and probe, races of pig of cleanness, chemical analyses of the pumped product and the residue of corrosion, inhibitor injection and water reduction in the product. The results obtained show the decrease of corrosion rates and of corrosiveness of the products transported. (author)

An expert system for microbiologically influenced corrosion

International Nuclear Information System (INIS)

Carney, C.E.; Licina, G.J.

1991-01-01

Microbiologically Influenced Corrosion (MIC) is a damage mechanism that can cause serious degradation of service water system components. MIC can be particularly insidious since damage can occur very quickly, even in environments otherwise resistant to corrosion. Plant operations or maintenance personnel or system engineers typically do not have sufficient expertise to predict when and where MIC may occur or what methods of treatment are effective. An expert system (MICPro) has been devised which provides a tool for utilities to predict where MIC will occur, which systems or components are most susceptible, how operating parameters may affect vulnerability, and how to implement corrective and preventative measures. The system is designed to be simple to use: required inputs are common system parameters and results are presented as numbers from 1 to 10 indicating the likelihood of damage due to the given input. In this paper the structure and operation of the system is described, and future refinements are discussed

Study of API 5L X70 steel corrosion processes when in contact with some Brazilian soils

International Nuclear Information System (INIS)

Jesus, Sergio Luis de

2007-01-01

Pipelines, fuel storage tanks and other metallic structures are in permanent contact and exposed to different types of soils, of horizons or layers, or of soil aggressiveness. This interaction may cause expressive damages to the environment and to the planned work. Contamination may occur due to leakage of stored products, splitting during transportation, accidents caused by pipelines without extensive maintenance. The result of these accidents could be, among others, some financial losses. In order to recognize the dynamic interactions between metallic surfaces and the environment it is crucial to have preventive actions and to develop better-applied materials. API steel 5L X70 has been used in structures of low and high pressure with high mechanical strength and corrosion and, even so, it is susceptible to etching corrosion since it is in contact with different environments from mangrove regions to industrial environments. The present case evaluated the role of 5L X70 API steel in contact with different soil horizons representative of the Brazilian soil. This investigation correlated chemical species with solute ions in soil solution, secondary and primary phase minerals besides physical and chemical characteristics as pH, electric conductivity, total dissolved solids, among others, to the results of corrosion resistance and ways of corrosion. The evaluation was carried out using x-ray diffractometry, scanning electron microscopy, total reflection x-ray fluorescence, fuel injection flow besides texture and gravimetric analyses to soil characterization and mineralogy, identification of corrosion products, soil solution analyses, evaluation of tested materials and classification of ways and types of corrosion. This was an attempt to integrate the data to a better understanding of the process involving reagents and products. The results showed that different soil horizons such as different types of analyzed soils produce specific etching in metallic structures

Application of hydrogen water chemistry to moderate corrosive circumstances around the reactor pressure vessel bottom of boiling water reactors

International Nuclear Information System (INIS)

Uchida, Shunsuke; Ibe, Eishi; Nakata, Kiyatomo; Fuse, Motomasa; Ohsumi, Katsumi; Takashima, Yoshie

1995-01-01

Many efforts to preserve the structural integrity of major piping, components, and structures in a boiling water reactor (BWR) primary cooling system have been directed toward avoiding intergranular stress corrosion cracking (IGSCC). Application of hydrogen water chemistry (HWC) to moderate corrosive circumstances is a promising approach to preserve the structural integrity during extended lifetimes of BWRs. The benefits of HWC application are (a) avoiding the occurrence of IGSCC on structural materials around the bottom of the crack growth rate, even if microcracks are present on the structural materials. Several disadvantage caused by HWC are evaluated to develop suitable countermeasures prior to HWC application. The advantages and disadvantages of HWC are quantitatively evaluated base on both BWR plant data and laboratory data shown in unclassified publications. Their trade-offs are discussed, and suitable applications of HWC are described. It is concluded that an optimal amount of Hydrogen injected into the feedwater can moderate corrosive circumstances, in the region to be preserved, without serious disadvantages. The conclusions have been drawn by combining experimental and theoretical results. Experiments in BWR plants -- e.g., direct measurements of electrochemical corrosion potential and crack growth rate at the RPV bottom -- are planned that would collect data to support the theoretical considerations

Structure and corrosion properties of Cr coating deposited on aerospace bearing steel

Science.gov (United States)

Wang, Fangfang; Zhang, Fengxiang; Zheng, Lijing; Zhang, Hu

2017-11-01

The corrosion protection of chromium coating deposited on aerospace bearing steels by using the Filtered Cathodic Vacuum Arc deposition- Metal Evaporation Vacuum Arc duplex technique (MEVVA-FCVA) had been investigated. The protection efficiency of chromium coating on different substrate materials had also been evaluated. The chromium coating was mainly composed of nanocrystallineα-Cr in a range of 50-200 nm. The orientation distributions of α-Cr film on substrates with different composition had a certain difference to each other. Electrochemical experimental results indicated that the chromium coating significantly improved the corrosion resistance of experimental bearing steels in 3.5% NaCl solution. The protective efficiency of chromium films were all over 98%. The corrosion resistance of chromium coating was influenced by the chemical composition of substrate material. The chromium coatings on higher Cr-containing substrate displayed lower corrosion current density and more positive corrosion potential. The increase of passive film thickness and the formation of a mass of chromium oxide and hydroxide on the surface are responsible for the improved corrosion properties.

Structure and corrosion properties of PVD Cr-N coatings

CERN Document Server

Liu, C; Ziegele, H; Leyland, A; Matthews, A

2002-01-01

PVD Cr-N coatings produced by physical vapor deposition (PVD) are increasingly used for mechanical and tribological applications in various industrial sectors. These coatings are particularly attractive for their excellent corrosion resistance, which further enhances the lifetime and service quality of coated components. PVD Cr-N coated steels in an aqueous solution are usually corroded by galvanic attack via through-coating 'permeable' defects (e.g., pores). Therefore, the corrosion performance of Cr-N coated steel is determined by a number of variables of the coating properties and corrosive environment. These variables include: (i) surface continuity and uniformity; (ii) through-coating porosity; (iii) film density and chemical stability; (iv) growth stresses; (v) interfacial and intermediate layers; (vi) coating thickness; (vii) coating composition; and (viii) substrate properties. In this article, PVD Cr-N coatings were prepared, by electron-beam PVD and sputter deposition, with different compositions, t...

Aluminium alloy containing iron and nickel. Influence of structure and composition on the corrosion behaviour in high temperature water; Alliages d'aluminium contenant du fer et du nickel. Influence de la structure et de la teneur sur la resistance a la corrosion par l'eau a haute temperature

Energy Technology Data Exchange (ETDEWEB)

Coriou, H; Grall, L; Hure, J; Roux, A [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

The corrosion structures are determined on a series of aluminium (A{sub 9}) base alloys which contain a total Fe + Ni not superior to 3%. The tests are carried out to 5,000 hours in 350 deg. C deionized water in autoclave. The principal results were as follows: - For iron and nickel contents superior to 0,5%, the first factor is the distribution structure of insoluble intermetallic compounds: the particles must be as fine and randomly dispersed as possible. - The corrosion products developed on the surface may be subdivided in three distinct layers which total thickness tends rapidly towards a limit and stabilises itself. (author) [French] On a determine les structures de corrosion d'une gamme d'alliages a base d'aluminium A{sub 9} ayant une teneur Fe + Ni ne depassant pas 3%. Les essais ont ete effectues jusqu'a 5000 heures en autoclave a 350 deg. C dans l'eau demineralisee. Les resultats principaux sont les suivants: - Pour les teneurs superieures a 0,5 % en fer et en nickel, le facteur preponderant est la structure de repartition des composes intermetalliques en phase separee, qui doivent etre en particules aussi fines et uniformement reparties que possible. - Les produits de corrosion developpes en surface se subdivisent en trois couches distinctes dont l'epaisseur totale tend rapidement vers une limite et se stabilise. (auteur)

Rebar corrosion due to carbonation in structural reinforced concretes for near-surface LLW repositories: A critical failure mechanism

Energy Technology Data Exchange (ETDEWEB)

Torok, J

1995-03-01

The concrete roof of a near-surface radioactive waste repository is the principle protection against water infiltration and intrusion. The following potential roof failure mechanism is examined: carbon dioxide generated by the biodegradation of organic materials in the repository initiates corrosion of reinforcing steel embedded in the concrete roof. Because the bottom surface of the roof is mostly under tension, it is susceptible to cracking. The migration path for carbon dioxide is through cracks in the concrete between the bottom of the roof and the reinforcing bars. Carbonate corrosion of the reinforcing bars may result in concrete spalling, more extensive rebar corrosion and ultimately structural failure. Attention is brought to this failure mechanism because it has generally been overlooked in repository performance assessments. Literature relevant to the above failure is reviewed. Prerequisites for rebar corrosion are the presence of carbon dioxide and oxygen in the repository gas, high relative humidity and through-cracks in the concrete. High carbon dioxide concentrations and relative humidity are expected in the repository. The oxygen concentration in the repository is expected to be very low, and that is expected to minimize rebar corrosion rates. Cracks are likely to form in locations with high tensile stresses. Healing of the cracks could be a mitigating factor, but based on our analysis, it can not be relied on. To minimize the potential of this failure mechanism occurring with the Intrusion Resistant Underground Structure (IRUS), Canada`s proposed near-surface repository, carbon dioxide from the repository gas will be absorbed by the reactive, porous concrete placed between the waste and the roof. (author). 4 refs.

Rebar corrosion due to carbonation in structural reinforced concretes for near-surface LLW repositories: A critical failure mechanism

International Nuclear Information System (INIS)

Torok, J.

1995-03-01

The concrete roof of a near-surface radioactive waste repository is the principle protection against water infiltration and intrusion. The following potential roof failure mechanism is examined: carbon dioxide generated by the biodegradation of organic materials in the repository initiates corrosion of reinforcing steel embedded in the concrete roof. Because the bottom surface of the roof is mostly under tension, it is susceptible to cracking. The migration path for carbon dioxide is through cracks in the concrete between the bottom of the roof and the reinforcing bars. Carbonate corrosion of the reinforcing bars may result in concrete spalling, more extensive rebar corrosion and ultimately structural failure. Attention is brought to this failure mechanism because it has generally been overlooked in repository performance assessments. Literature relevant to the above failure is reviewed. Prerequisites for rebar corrosion are the presence of carbon dioxide and oxygen in the repository gas, high relative humidity and through-cracks in the concrete. High carbon dioxide concentrations and relative humidity are expected in the repository. The oxygen concentration in the repository is expected to be very low, and that is expected to minimize rebar corrosion rates. Cracks are likely to form in locations with high tensile stresses. Healing of the cracks could be a mitigating factor, but based on our analysis, it can not be relied on. To minimize the potential of this failure mechanism occurring with the Intrusion Resistant Underground Structure (IRUS), Canada's proposed near-surface repository, carbon dioxide from the repository gas will be absorbed by the reactive, porous concrete placed between the waste and the roof. (author). 4 refs

Nanofilm-coated long-period fiber grating humidity sensors for corrosion detection in structural health monitoring

Science.gov (United States)

Zheng, Shijie; Zhu, Yinian; Krishnaswamy, Sridhar

2011-04-01

Long-period gratings (LPGs) have shown their significant promising applications in sensors owing to the attractive features that they posses such as small size, immunity for electromagnetic interference, geometric versatility, multiplexing capability, and resistance to corrosive and hazardous environments. Recent researches have revealed that LPGs written on the standard optical fibers could be used as a powerful sensing platform for structural health monitoring. In this work, we inscribe LPGs into SMF-28 optical fiber by focused-beam CO2 laser, demonstrating as a refractive index sensor for nondestructive chemical detections in the civil infrastructures. Although evanescent-field based LPG sensors have been applied in quantitatively monitoring chemical analytes including moisture, chloride, and corrosion by-product, etc., the sensitivity, selectivity, and response time as well as thermo-stability of such sensors are still the issues for some special purposes. In order to improve those characteristics of the sensors, we propose two types of nano-film to be coated in grating region by electrostatic self-assembly (ESA) deposition processing. The primary coating does not affect on LPG transmission parameters such as resonance wavelength and its intensity that can be used for sensing, but it increases the sensitivity to refractive index change of surrounding material. The secondary coating is for selectively absorption of analyte molecule of interest. Response time of the nanofilm-coated LPG sensor is dependent on the analyte absorption and de-absorption rates as well as the thicknesses of the coating materials, which is also investigated. Multi-channel sensor system is being designed to monitor different analytes simultaneously, which is continuing to further explore the monitoring of structural health conditions through in situ measurements of corrosion in the concrete structures.

Solidified Structure and Corrosion Behavior of Laser-melt Magnesium Alloy

Directory of Open Access Journals (Sweden)

FANG Zhi-hao

2017-12-01

Full Text Available The AZ91D magnesium alloy samples were scanned by millisecond pulse Nd:YAG laser under high pure argon protection. The surface morphology, microstructure and composition of the treated magnesium alloy were studied by X-ray diffraction, optical microscopy, scanning electron microscopy, atomic force microscopy. In addition, the corrosion surface which was corroded using simulated body fluid and the mass fraction of 3.5%NaCl solution was observed and material corrosion rate was calculated. The results show that, at the same corrosion time, compared with the untreated samples, the surface corrosion resistance is improved by the enrichment of Al at the irradiated surface by the joint effect of the combination of refined homogeneous microstructure of α-Mg phase and β-Mg17Al12 phase and the selective vaporization and the chemical composition of base metal in the laser-treated AZ91D alloy; the solidification equation is obtained by calculating the relation between the size of the dendrite cell and the cooling rate in laser melting zone.

New corrosion issues in gas sweetening plants

Energy Technology Data Exchange (ETDEWEB)

Asperger, R.G. (CLI International and Asperger Technologies, Houston, TX (United States))

Gas treating plants are experiencing corrosion problems which impact on efficiency and safety. While general corrosion is not particularly hazardous in the gas processing industry, local corrosion is very dangerous since it has several different mechanisms, all of which have dangerously high rates, and it occurs at locations which are hard to find and hard to predict. A newly discovered, velocity-dependent type of corrosion is reported. It is related to yet-undefined species which cause excessively high corrosion in areas of turbulence. This accelerated corrosion is not due to erosion or cavitation, but to a diffusion-limited reaction accelerated by turbulence. A full-flow test loop was built to evaluate the corrosiveness of gas plant solutions at their normal temperature and flow rates. Test runs were conducted with Co[sub 2]-loaded amine solutions for periods of 12 days. Carbon steel specimens mounted in the test loop were examined and corrosion rates calculated. Chromium alloys were shown to be attacked by corrodents in the low-velocity part of the loop and very aggressively attacked in the high-velocity part. The tests demonstrate the need for rigorous monitoring of corrosion in areas of higher velocity such as piping elbows and other points of turbulence. 5 refs., 2 figs., 3 tabs.

Method for inhibiting corrosion of nickel-containing alloys

Science.gov (United States)

DeVan, J.H.; Selle, J.E.

Nickel-containing alloys are protected against corrosion by contacting the alloy with a molten alkali metal having dissolved therein aluminum, silicon or manganese to cause the formation of a corrosion-resistant intermetallic layer. Components can be protected by applying the coating after an apparatus is assembled.

Structurally Integrated Coatings for Wear and Corrosion

Energy Technology Data Exchange (ETDEWEB)

Beardsley, M. Brad; Sebright, Jason L.

2008-11-18

Wear and corrosion of structures cuts across industries and continues to challenge materials scientists and engineers to develop cost effective solutions. Industries typically seek mature technologies that can be implemented for production with rapid or minimal development and have little appetite for the longer-term materials research and development required to solve complex problems. The collaborative work performed in this project addressed the complexity of this problem in a multi-year program that industries would be reluctant to undertake without government partnership. This effort built upon the prior development of Advanced Abrasion Resistant Materials conduct by Caterpillar Inc. under DOE Cooperative Agreement No. DE-FC26-01NT41054. In this referenced work, coatings were developed that exhibited significant wear life improvements over standard carburized heat treated steel in abrasive wear applications. The technology used in this referenced work, arc lamp fusing of thermal spray coatings, was one of the primary technical paths in this work effort. In addition to extending the capability of the coating technology to address corrosion issues, additional competitive coating technologies were evaluated to insure that the best technology was developed to meet the goals of the program. From this, plasma transferred arc (PTA) welding was selected as the second primary technology that was investigated. Specifically, this project developed improved, cost effective surfacing materials and processes for wear and corrosion resistance in both sliding and abrasive wear applications. Materials with wear and corrosion performance improvements that are 4 to 5 times greater than heat treated steels were developed. The materials developed were based on low cost material systems utilizing ferrous substrates and stainless steel type matrix with hard particulates formed from borides and carbides. Affordability was assessed against other competing hard surfacing or coating

Galvanic corrosion of laser weldments of AA6061 aluminium alloy

International Nuclear Information System (INIS)

Rahman, A.B.M. Mujibur; Kumar, S.; Gerson, A.R.

2007-01-01

Galvanic corrosion of laser welded AA6061 aluminium alloy, arising from the varying rest potentials of the various weldment regions, was examined. The weld fusion zone is found to be the most cathodic region of the weldment while the base material is the most anodic region. The rate of galvanic corrosion, controlled by the cathodic process at the weld fusion zone, increases with time until a steady state maximum is reached. On galvanic corrosion the corrosion potential of the weld fusion zone shifts in the positive direction and the free corrosion current increases. It is proposed that the cathodic process at the weld fusion zone causes a local increase in pH that in turn causes dissolution of the surface film resulting in the loss of Al to solution and the increase of intermetallic phases. The increase in galvanic corrosion may result from either the build up of the intermetallic phases in the surface layer and/or significant increase in surface area of the weld fusion zone due to the porous nature of the surface layer

USMC Environmental and Corrosion Control Issues

Science.gov (United States)

2010-12-01

b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Minimizing Hexavalent Chromium...Corrosion causes damage to seals and failure of hydraulic system Two similar aged M9 ACE vehicles, one with intact chrome plating, one with heavily...cadmium – Use of hexavalent chromium – Potential incompatibilities with alternatives – Use of non-corrosion resistant hardware in harsh

EVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

Energy Technology Data Exchange (ETDEWEB)

Bill W. Bogan; Wendy R. Sullivan; Kristine M. H. Cruz; Kristine L. Lowe; John J. Kilbane II

2004-04-30

The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Previous testing of pepper extracts resulted in preliminary data indicating that some pepper extracts inhibit the growth of some corrosion-associated microorganisms. This quarter additional tests were performed to more specifically investigate the ability of three pepper extracts to inhibit the growth, and to influence the metal corrosion caused by two microbial species: Desulfovibrio vulgaris, and Comomonas denitrificans. All three pepper extracts rapidly killed Desulfovibrio vulgaris, but did not appear to inhibit Comomonas denitrificans. While corrosion rates were at control levels in experiments with Desulfovibrio vulgaris that received pepper extract, corrosion rates were increased in the presence of Comomonas denitrificans plus pepper extract. Further testing with a wider range of pure bacterial cultures, and more importantly, with mixed bacterial cultures should be performed to determine the potential effectiveness of pepper extracts to inhibit MIC.

SCC and Corrosion Fatigue characterization of a Ti-6Al-4V alloy in a corrosive environment – experiments and numerical models

Directory of Open Access Journals (Sweden)

S. Baragetti

2014-10-01

Full Text Available In the present article, a review of the complete characterization in different aggressive media of a Ti-6Al-4V titanium alloy, performed by the Structural Mechanics Laboratory of the University of Bergamo, is presented. The light alloy has been investigated in terms of corrosion fatigue, by axial fatigue testing (R = 0.1 of smooth and notched flat dogbone specimens in laboratory air, 3.5% wt. NaCl–water mixture and methanol–water mixture at different concentrations. The first corrosive medium reproduced a marine environment, while the latter was used as a reference aggressive environment. Results showed that a certain corrosion fatigue resistance is found in a salt water medium, while the methanol environment caused a significant drop – from 23% to 55% in terms of limiting stress reduction – of the fatigue resistance of the Ti-6Al-4V alloy, even for a solution containing 5% of methanol. A Stress Corrosion Cracking (SCC experimental campaign at different methanol concentrations has been conducted over slightly notched dog-bone specimens (Kt = 1.18, to characterize the corrosion resistance of the alloy under quasi-static load conditions. Finally, crack propagation models have been implemented to predict the crack propagation rates for smooth specimens, by using Paris, Walker and Kato-Deng-Inoue-Takatsu propagation formulae. The different outcomes from the forecasting numerical models were compared with experimental results, proposing modeling procedures for the numerical simulation of fatigue behavior of a Ti-6Al-4V alloy.

Non-destructive elecrochemical monitoring of reinforcement corrosion

DEFF Research Database (Denmark)

Nygaard, Peter Vagn

been widely accepted as a non-destructive ”state of the art” technique for detection of corrosion in concrete structures. And, over the last decade, the trend in corrosion monitoring has moved towards quantitative non-destructive monitoring of the corrosion rate of the steel reinforcement. A few...... corrosion rate measurement instruments have been developed and are commercially available. The main features of these instruments are the combined use of an electrochemical technique for determining the corrosion rate and a so-called ”confinement technique”, which in principle controls the polarised surface...... area of the reinforcement, i.e. the measurement area. Both on-site investigations and laboratory studies have shown that varying corrosion rates are obtained when the various commercially available instruments are used. And in the published studies, conflicting explanations are given illustrating...

The Effects of Corrosive Chemicals on Corrosion Rate of Steel Reinforcement Bars: I. Swamp Water

Directory of Open Access Journals (Sweden)

Sulistyoweni Widanarko

2010-10-01

Full Text Available Most of infrastructures using steel concrete to reinforce the strength of concrete. Steel concrete is so vulnerable to chemical compounds that can cause corrosion. It can happen due to the presence of chemical compounds in acid environment in low pH level. These chemical compounds are SO42-, Cl-, NO3-. There are many swamp area in Indonesia. The acid contents and the concentration of ion sulphate, chlorides, and nitrate are higher in the swamp water than in the ground water .The objective of this research was to find out the influence of corrosive chemicals in the swamp water to the steel concrete corrosion rate. There were two treatment used: (1 emerging ST 37 and ST 60 within 60 days in the 'polluted' swamp water, (2 moving the ST 37 up and down periodically in the ' polluted' swamp water. Three variation of 'polluted' swamp water were made by increasing the concentration of corrosive chemical up to 1X, 5X and 10X respectively. The corrosion rate was measured by using an Immersion Method. The result of Immersion test showed that chloride had the greatest influence to corrosion rate of ST 37 and ST 60 and followed by sulphate and Nitrate. Corrosion rate value for ST 37 is 24.29 mpy and for ST 60 is 22.76 mpy. By moving the sample up and down, the corrosion rate of ST 37 increase up to 37.59 mpy, and chloride still having the greatest influence, followed by sulphate and nitrate.

Erosion and corrosion of nuclear power plant materials

International Nuclear Information System (INIS)

1994-01-01

This conference is composed of 23 papers, grouped in 3 sessions which main themes are: analysis of corrosion and erosion damages of nuclear power plant equipment and influence of water chemistry, temperature, irradiations, metallurgical and electrochemical factors, flow assisted cracking, stress cracking; monitoring and control of erosion and corrosion in nuclear power plants; susceptibility of structural materials to erosion and corrosion and ways to improve the resistance of materials, steels, coatings, etc. to erosion, corrosion and cracking

Effects of climate and corrosion on concrete behaviour

Science.gov (United States)

Ismail, Mohammad; Egba, Ernest Ituma

2017-11-01

Corrosion of steel is a damaging agent that reduces the functional and structural responsibilities of reinforced concrete structures. Accordingly, reinforced concrete members in the environments that are prone to concrete carbonation or chloride attack coupled with high temperature and relative humidity suffer from accelerated corrosion of reinforcing material. Also, literature proves that climate influences corrosion of concrete, and suggests investigation of impact of corrosion on concrete based on climate zone. Therefore, this paper presents the effects of climate and corrosion on concrete behavior, using bond strength of concrete as a case study. Concrete specimens were prepared form concrete mix that was infested with 3.5 kgm-3 of sodium chloride to accelerate corrosion. The specimens were cured sodium chloride solution 3.5% by weight of water for 28 days before placing them in the exposure conditions. Pull-out tests were conducted at time intervals for one year to measure the impact of exposure condition and corrosion on bond strength of concrete. The results show reduction of bond strength of concrete by 32%, 28% and 8% after one year of subjection of the specimens to the unsheltered natural climate, sheltered natural climate, and laboratory ambient environment respectively. The findings indicate that the climate influences corrosion, which reduces the interlocking bond between the reinforcing bar and the adjacent concrete.

Structure, mechanical properties, corrosion behavior and cytotoxicity of biodegradable Mg-X (X=Sn, Ga, In) alloys.

Science.gov (United States)

Kubásek, J; Vojtěch, D; Lipov, J; Ruml, T

2013-05-01

As-cast Mg-Sn, Mg-Ga and Mg-In alloys containing 1-7 wt.% of alloying elements were studied in this work. Structural and chemical analysis of the alloys was performed by using light and scanning electron microscopy, energy dispersive spectrometry, x-ray diffraction, x-ray photoelectron spectroscopy and glow discharge spectrometry. Mechanical properties were determined by Vickers hardness measurements and tensile testing. Corrosion behavior in a simulated physiological solution (9 g/l NaCl) was studied by immersion tests and potentiodynamic measurements. The cytotoxicity effect of the alloys on human osteosarcoma cells (U-2 OS) was determined by an indirect contact assay. Structural investigation revealed the dendritic morphology of the as-cast alloys with the presence of secondary eutectic phases in the Mg-Sn and Mg-Ga alloys. All the alloying elements showed hardening and strengthening effects on magnesium. This effect was the most pronounced in the case of Ga. All the alloying elements at low concentrations of approximately 1 wt.% were also shown to positively affect the corrosion resistance of Mg. But at higher concentrations of Ga and Sn the corrosion resistance worsened due to galvanic effects of secondary phases. Cytotoxicity tests indicated that Ga had the lowest toxicity, followed by Sn. The most severe toxicity was observed in the case of In. Copyright © 2013 Elsevier B.V. All rights reserved.

A Visualization Method for Corrosion Damage on Aluminum Plates Using an Nd:YAG Pulsed Laser Scanning System.

Science.gov (United States)

Lee, Inbok; Zhang, Aoqi; Lee, Changgil; Park, Seunghee

2016-12-16

This paper proposes a non-contact nondestructive evaluation (NDE) technique that uses laser-induced ultrasonic waves to visualize corrosion damage in aluminum alloy plate structures. The non-contact, pulsed-laser ultrasonic measurement system generates ultrasonic waves using a galvanometer-based Q-switched Nd:YAG laser and measures the ultrasonic waves using a piezoelectric (PZT) sensor. During scanning, a wavefield can be acquired by changing the excitation location of the laser point and measuring waves using the PZT sensor. The corrosion damage can be detected in the wavefield snapshots using the scattering characteristics of the waves that encounter corrosion. The structural damage is visualized by calculating the logarithmic values of the root mean square (RMS), with a weighting parameter to compensate for the attenuation caused by geometrical spreading and dispersion of the waves. An intact specimen is used to conduct a comparison with corrosion at different depths and sizes in other specimens. Both sides of the plate are scanned with the same scanning area to observe the effect of the location where corrosion has formed. The results show that the damage can be successfully visualized for almost all cases using the RMS-based functions, whether it formed on the front or back side. Also, the system is confirmed to have distinguished corroded areas at different depths.