Corrosion Map Research Articles

Digital Radiography Corrosion Mapping on Gas Pipelines

Digital radiography (DR) is a powerful technique that can be used in non-destructive testing for identification of internal or external defects and corrosion mapping. New generation of digital flat panel detectors become more and more competitive to film detectors, however the transition from film to digital radiography is not always the best choice for every NDT organization especially from the point of view of investments. The paper introduces the application of digital corrosive radiography mapping on gas pipelines using a portable flat panel detector. The experimental part is focused on determining the residual thickness of the pipelines in service.

Near-Field Microwave Imaging Using Open-Ended Circular Waveguide Probes

Near-field microwave imaging and subsurface sensing have shown significant potential in a wide range of applications, including corrosion mapping and composite structure inspection. Most of the conventional near-field imaging systems developed so far utilize an antenna (probe) scanned over the structure-under-test (SUT). The near-field interaction between the microwave signal and the SUT reveals the sought-after information about the interior of the irradiated structure. Previous systems commonly used open-ended rectangular waveguides as the near-field imaging probe. In this paper, the utility of circular waveguide probes for near-field imaging will be discussed in detail and compared with the conventional rectangular probe. The motivation behind utilizing the circular probe is the fact that its aperture field distribution yields lower side lobes. Herein, the reflection properties, near-field characteristics, sensitivity, and spatial resolution of both probes are contrasted using simulations and measurements. Furthermore, imaging results of various targets, such as flat-bottom holes, notches, as well as corrosion-under-paint samples acquired using circular and rectangular probes are presented. It will be shown that the circular probes offer key advantages in terms of resolution as well as sensitivity compared with the conventional open-ended rectangular waveguides.

Effect of Temperature on Behavior of Oxygen Transport through Solution Layer Formed on Metals

It is very important for investigate environmental corrosion behavior of steels to maintain and safely use of the steels structures. To understand environmental corrosion behavior of steels, environmental factors such as temperature, relative humidity, amounts of airborne salinity, SOx, and transport behavior of oxygen in thin water layer formed on the steels are also important. Therefore, exposure tests and measurement of some of the environmental factors were carried out in three counties, Japan, Vietnam and Thailand, under "Corrosion Mapping of Structural Materials in Asian Area with Understanding Effects of Environmental Factors, e-Asia Project". The corrosion results showed that the corrosion rate in heavy snow and cold region such as Hokkaido is higher than that expected from temperature. To clarify the unexpected corrosion rate in Hokkaido, transport behavior of oxygen in thin water layer formed on the metals at low temperature was examined. The zinc and iron sheets were used for specimens, and specimens temperature was controlled by Peltier device form 298 K to 273 K. Three different solutions, 0.1 kmol/m3 NaCl, 1 kmol/m3 NaCl, and 1 kmol/m3 NaCl + 0.5 kmol m-3 H3BO3 / 0.05 kmol m-3 Na2B4O7 were used to form thin solution layers. The thickness of the solution layers were controlled by plastic tape from 200 µm to 1 mm. A Pt and AgCl coated Ag wires were used as counter electrode and reference electrode. The cathodic polarization curves were measured to obtain limiting current of oxygen with scanning rate of 20 mV/min. Before the polarization measurements, immersion potential was measured. In order to ensure the reproducibility, more than three times of electrochemical tests were carried out as same conditions. The measured rest potential of both zinc and iron were strongly depends on concentration of used solution, while slightly change of the rest potential was observe by the thickness of the solution layers. A clear limiting current of oxygen was observed in every solution and it increased with increasing invers of the solution thickness. The clear increase was observed with thin solution layer at low specimen temperatures.

High throughput corrosion screening of Mg-Zn combinatorial material libraries

Mg-Zn combinatorial material libraries covering 15–85at.%Mg were deposited on glass substrates using magnetron sputtering at room temperature. To study the phases present in the Mg-Zn combinatorial libraries the as-deposited sample was annealed at 250°C for an hour. The composition, phase content and thickness were characterized using energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and stylus profilometer respectively. The corrosion characteristics of the as-deposited and annealed combinatorial samples immersed in DPBS and PBS were evaluated using a high throughput novel optical screening technique. Corrosion maps of the combinatorial samples were generated from analysis of time lapsed images obtained from the novel optical screening technique. From the time lapsed images the corrosion rate of each composition in the combinatorial material libraries were evaluated. The results showed that compositions with Mg contents ≤40at.% resulted in lower but similar corrosion rate for both as-deposited and annealed samples immersed in DPBS. The corrosion rate increases with increasing Mg content.

Data analysis and visualization for the bridge deck inspection and evaluation robotic system

Abstract Background Bridge deck inspection is essential task to monitor the health of the bridges. Condition monitoring and timely implementation of maintenance and rehabilitation procedures are needed to reduce future costs associated with bridge management. A number of Nondestructive Evaluation (NDE) technologies are currently used in bridge deck inspection and evaluation, including impact-echo (IE), ground penetrating radar (GPR), electrical resistivity (ER), ultrasonic surface waves (USW) testing, and visual inspection. However, current NDE data collection is manually conducted and thus faces with several problems such as prone to human errors, safety risks due to open traffic, and high cost process. Methods This paper reports the automated data collection and analysis for bridge decks based on our novel robotic system which can autonomously and accurately navigate on the bridge. The developed robotic system can lessen the cost and time of the bridge deck data collection and risks of human inspections. The advanced software is developed to allow the robot to collect visual images and conduct NDE measurements. The image stitching algorithm to build a whole bridge deck image from individual images is presented in detail. The ER, IE and USW data collected by the robot are analyzed to generate the corrosion, delamination and concrete elastic modulus maps of the deck, respectively. These condition maps provide detail information of the bridge deck quality. Conclusions The automated bridge deck data collection and analysis is developed. The image stitching algorithm allowed to generate a very high resolution image of the whole bridge deck, and the bridge viewer software allows to calibrate the stitched image to the bridge coordinate. The corrosion, delamination and elastic modulus maps were built based on ER, IE and USW data collected by the robot to provide easy evaluation and condition monitoring of bridge decks.

Kinetics of atmospheric corrosion of mild steel in marine and rural environments

In continuation of the extensive studies carried out to update the corrosion map of India, in this study, the degradation of mild steel by air pollutants was studied at 16 different locations from Nagore to Ammanichatram along the east coast of Tamilnadu, India over a period of two years. The weight loss study showed that the mild steel corrosion was more at Nagapattinam site, when compared to Ammanichatram and Maravakadu sites. A linear regression analysis of the experimental data was attempted to predict the mechanism of the corrosion. The composition of the corrosion products formed on the mild steel surfaces was identified by XRD technique. The corrosion rate values obtained are discussed in the light of the weathering parameters, atmospheric pollutants such as salt content & SO2 levels in the atmosphere, corrosion products formed on the mild steel surfaces.

Air Pollution as an Important Factor in Construction Materials Deterioration in Slovak Republic

Climatic parameters and atmospheric pollution are highly relevant to the degradation of several building materials like construction metallic materials, concrete structures and plasters of buildings, bridges or art sculptures. Degradation of not only metal materials, but also other construction materials (concrete, glass, etc.) by chemical environmental loads is an increasingly serious problem not only in Slovakia, but all over the world. The atmosphere and, ultimately, the hydrosphere could be particularly polluted by industrial activity, thus causing an increased corrosion aggressiveness of atmosphere. In the article, the air pollution impact on stone materials and carbon steel in Slovak Republic is observed. In the evaluation, there are used dose-response functions, which were developed based on long-term research by the other authors. Effectively, multi-annual climatic parameters and parameters of air pollution in Slovak Republic were used for generation of the maps of annual average surface loss of stone materials and carbon steel.One of the priorities of that research is creation of corrosion maps of different materials, which do not help to protect materials, but could be useful for prediction of risks during design, analysis and maintenance. The values obtained from this interpolation of the maps would be used as a basis for a long-term research work in mapping the state of degradation of various materials in Slovak Republic.

Atmosphere Aggressivity State Mapping in Slovak Republic for Corrosion of Construction Materials

The paper is focused on the effect of multi-pollution of atmosphere on the construction degradation in the Slovak Republic. Corrosion increases the risk of failure, which has considerable impact on maintenance costs. The objective of the article is a creation of the proposal that should be used for processing of the corrosion maps for the various construction materials. It uses dose-response function that was developed based on long-term research. The corrosion map does not help to protect materials; however it can be useful for prediction of risks by design and analysis. The research done by the other researchers is taken into account also in our work. The results would be used as a basis for the beginning of a long-term research work.

Development of chloride-induced corrosion in pre-cracked RC beams under sustained loading: Effect of load-induced cracks, concrete cover, and exposure conditions

This paper deals with corrosion initiation and propagation in pre-cracked reinforced concrete beams under sustained loading during exposure to a chloride environment. Specimen beams that were cast in 2010 were compared to specimens cast in 1984. The only differences between the two sets of beams were the casting direction in relation to tensile reinforcement and the exposure conditions in the salt-fog chamber. The cracking maps, corrosion maps, chloride profiles, and cross-sectional loss of one group of two beams cast in 2010 were studied and their calculated corrosion rates were compared to that of beams cast in 1984 in order to investigate the factors influencing the natural corrosion process. Experimental results show that, after rapid initiation of corrosion at the crack tip, the corrosion process practically halted and the time elapsing before corrosion resumed depended on the exposure conditions and cover depth.

Periodic mapping of reinforcement corrosion in intrusive chloride contaminated concrete with GPR

This paper presents an experimental effort for developing a novel reinforcement corrosion monitoring technique based on Ground Penetrating Radar (GPR). Experiments were carried out to periodically monitor the accelerated reinforcement corrosion process with GPR. The data were processed in both time and time–frequency domains to investigate the tendencies of GPR signal attribute changes related with corrosion, moisture and chloride contamination. Data processing methods were proposed to visualize the reinforcement corrosion and chloride distribution with target specified signal attribute mapping. Half-Cell Potential (HCP) and Laser-Induced Breakdown Spectroscopy (LIBS) methods were employed to verify the GPR observations.

Prediction of reinforcement corrosion using corrosion induced cracks width in corroded reinforced concrete beams

This paper studies the evolution of reinforcement corrosion in comparison to corrosion crack width in a highly corroded reinforced concrete beam. Cracking and corrosion maps of the beam were drawn and steel reinforcement was recovered from the beam to observe the corrosion pattern and to measure the loss of mass of steel reinforcement. Maximum steel cross-section loss of the main reinforcement and average steel cross-section loss between stirrups were plotted against the crack width. The experimental results were compared with existing models proposed by Rodriguez et al., Vidal et al. and Zhang et al. Time prediction models for a given opening threshold are also compared to experimental results. Steel cross-section loss for stirrups was also measured and was plotted against the crack width. It was observed that steel cross-section loss in the stirrups had no relationship with the crack width of longitudinal corrosion cracks.

Effect of corrosion of reinforcement on the mechanical behaviour of highly corroded RC beams

This paper describes an experimental investigation of the behaviour of corroded reinforced concrete beams. These have been stored in a chloride environment for a period of 26years under service loading so as to be representative of real structural and environmental conditions. The configuration and the widths of the cracks in the two seriously corroded short-span beams were depicted carefully, and then the beams were tested until failure by a three-point loading system. Another two beams of the same age but without corrosion were also tested as control specimens. A short span arrangement was chosen to investigate any effect of a reduction in the area and bond strength of the reinforcement on shear capacity. The relationship of load and deflection was recorded so as to better understand the mechanical behaviour of the corroded beams, together with the slip of the tensile bars. The corrosion maps and the loss of area of the tensile bars were also described after having extracted the corroded bars from the concrete beams. Tensile tests of the main longitudinal bars were also carried out. The residual mechanical behaviour of the beams is discussed in terms of the experimental results and the cracking maps. The results show that the corrosion of the reinforcement in the beams induced by chloride has a very important effect on the mechanical behaviour of the short-span beams, as loss of cross-sectional area and bond strength have a very significant effect on the bending capacity.

Experimental and analytical study of corroded shear-critical reinforced concrete beams

This paper presents the experimental results of two highly corroded shear-critical deep beams subjected to a chloride environment to assess the shear behavior of long-term-corrosion damaged beams. A 26-year-old reinforced concrete beam corroded by exposure to a chloride environment was cut into two small short-shear-span beams, or deep beams, which were tested under three point bending until failure, along with a control beam of the same age, same length and same cross-section (115 × 28 × 15 cm). Cracking and corrosion maps were drawn for the corroded beams in order to assess the corrosion. Force displacement curves were drawn for the corroded and control beams. After testing the beams until failure, the main steel bars and the stirrups were extracted from the beams and loss of mass was measured and plotted for both longitudinal and transverse reinforcement. It was noted that the loss of mass of transverse and longitudinal reinforcements had not had an important influence on the failure mode and it had not affected the load-bearing capacity of the beam. It was found that the stirrups came into action after the failure of the compression strut and thus decreased the ductility of the corroded beams. Analytical investigations were made to compare the experimental shear capacity with the theoretical value. Strut and tie model predictions were more accurate than the conventional sectional methods provided for in ACI 318-08 and Eurocode 2.

Atmospheric corrosion map of an oil refinery

PurposeThe purpose of this paper is to draw up an atmospheric corrosion map for an industrial zone to determine the best coating system for each location.Design/methodology/approachThe outdoor atmospheric corrosion rate was measured at eight locations distributed in an oil refinery during a year. Corrosion rates were measured by weight loss of carbon steel coupons, according to ISO Standard 9223. Weathering conditions, including temperature, time of wetness, and atmospheric pollution such as chloride precipitation and sulfur content also were measured. The results were analyzed using “Surfer 8” software and the corrosion map of the refinery was derived.FindingsAn atmospheric corrosion map was derived for the oil refinery. By this approach, coating system for equipment can be selected based exactly on where the plant item is located.Originality/valueExterior coating systems for equipment now can be selected based on their application, regardless of their position in any refinery. In this article, an atmospheric corrosion map was developed for a refinery for the first time. The position of equipment on the corrosion map is a new parameter that should be considered for coating system selection.

Steel Corrosion Map of Vietnam

In the framework of an International cooperation program in Australia-Asia, the atmospheric corrosion of metals in five nations located in this tropical zone: Australia, Vietnam, Thailand, Philippines and Indonesia was investigated. In this program, mild steel, zinc and copper were tested on a set of sites, representative for different climatic conditions: severe marine, marine, industrial, urban and rural, simultaneously with the collection of climatic parameters and pollutants. Based on the data obtained in the Program and referring to the bank of data collected in the Vietnam National Projects, modeling was used to construct a corrosion map of steel for Vietnam. The correlation of the data derived from the map compared with those from National Projects is very high, in most cases, differing by less than 2-3%.

Corrosion Maps for Aluminium Alloys: Defining the Property Space and the Role of Microstructure and Chemistry in Corrosion

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Structural performance of a 26-year-old corroded reinforced concrete beam

This article presents experimental results and the modelling of a highly corroded beam subjected to a chloride environment to assess the performance of long-term-corrosion-damaged beams. A reinforced concrete beam corroded by 26 years of exposure to a chloride environment was tested until failure, as was a control beam of the same age. Cracking maps and corrosion maps were drawn for the corroded beam. Force displacement curves for both beams and stress strain curves for the steel bars were also plotted. From the results it appears that corrosion has a significant impact on the load carrying capacity, stiffness and deflection of beams. The modelling approach using Macro Finite Element (MFE) shows good agreement with experimental results in terms of load capacity, stiffness of the beam and ultimate deflection. Cet article présente les résultats expérimentaux et la modélisation du comportement mécanique d’une poutre sévèrement corrodée par 26 années de conservation en atmosphère saline. Après avoir été testée en flexion jusqu’à la rupture, la poutre a été désossée afin de déterminer la carte de corrosion des armatures et de faire des tests de traction sur les armatures corrodées. Les résultats montrent que la corrosion des armatures a une influence importante sur la capacité portante, la raideur en service et la ductilité (flèche à rupture) L’approche de modélisation par macro-élement montre une bonne corrélation en terme de charge ultime, raideur et déplacement maximal.

Mapping Atmospheric Corrosion on Materials of Archaeological Importance in Athens

Atmospheric pollution is known to induce corrosion effects on various materials. For Greece, stone deterioration could emerge severe costs in the case of damaging cultural monuments. This work aims to investigate the corrosion process on materials of archaeological importance (marble, limestone, and sandstone) in the Greater Athens Area (GAA) by using sophisticated geoanalytical methods together with dose–response functions for selected materials, in order to derive corrosion maps for GAA in the period 2000–2009. Also, a corrosion trend analysis is performed, which can be a very helpful tool for the prediction of potential risks to monuments of cultural heritage due to atmospheric pollution. The corrosion effects on the selected materials are generally weak. Nevertheless, increasing corrosion trends are found in the eastern regions of GAA for all sheltered materials and in the northern parts of GAA for unsheltered marble. The technique is finally applied to 12 locations in GAA, which include some of the most important archaeological monuments of Athens, and provides comprehensive results for the estimation of the impact of atmospheric corrosion on the structural materials of these archaeological sites.

A corrosion map of Abu Dhabi

AbstractThis paper outlines how a corrosion map of zinc was developed for Abu‐Dhabi. It presents inputs into the model being databases of RH, rainfall, salt deposition and time of wetness and explains how these inputs are combined to product the corrosion map of Abu Dhabi. It is found that although the corrosion rate generally falls with distance from the Arabian Gulf, corrosion rates in the hinterland of the central coast and in the Hajar Mountains are higher than would be expected from a simple dependence on distance from the coast. The higher corrosion rates around the central coast are associated with the extremely low rainfall while those in the Hajar Mountains may be associated with the transport of airborne salinity from the Gulf of Oman. In general, the corrosion rates in Abu Dhabi are much higher than observed at sites in Australia and South East Asia with similar levels of airborne salinity which is attributed to the much higher quantities of salt that are retained on metal surfaces in Abu Dhabi (relative to Australia) due to the fact that rain washing events, which are frequent and effective in Australia, are very infrequent in Abu Dhabi.

Micro-abrasion–corrosion interactions of Ni–Cr/WC based coatings: Approaches to construction of tribo-corrosion maps for the abrasion–corrosion synergism

The process of micro-abrasion–corrosion has been the subject of much research in recent years due to the fact that the action of micron sized particles, typically less than 10 μm in diameter, can cause significant degradation of materials in many diverse environments involving aqueous corrosion. Cermet based coatings are often used to combat micro-abrasion–corrosion, but there has been little work carried out to characterize the performance of such coatings exposed to micro-abrasion–corrosion or to provide a basis for coating optimisation. In addition, a basis for defining the various micro-abrasion–corrosion interactions has not been suggested to date. In this study, the micro-abrasion–corrosion performance of a Ni–Cr/WC coating was assessed and compared to the performance of the steel substrate. The results were used to identify regimes of micro-abrasive wear as a function of applied load and pH of the solution. In addition, micro-abrasion–corrosion maps were constructed based on the results, showing the variation between micro-abrasion–corrosion regimes, as a function of applied load and pH of the solution.