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1
Lewis, G. N. "Flash rusting of steel with water base paints." Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376937.
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2
Gubner, Rolf Juergen. "Biofilms and accelerated low-water corrosion of carbon steel piling in tidal waters." Thesis, University of Portsmouth, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244479.
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3
Chittaladakorn, Kathita. "Cr(VI) Generation and Stability in Drinking Water." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/54018.
Повний текст джерелаАнотація:
The current US Environmental Protection Agency (USEPA) maximum contaminant level (MCL) for total chromium of 100 ppb is under revision to consider a specific level for Cr(VI), which has a proposed MCL of 10 ppb in California. Cr(VI) is a suspected carcinogen, and interconverts with the other most commonly found chromium species, Cr(III). To regulate and further understand the behavior of Cr(VI) in water systems, appropriate sample preservation methods are essential for accurate measurements. The ammonia buffer (recommended by EPA) was proven to be the most effective preservation when a holding time of 14 days is considered.
Apart from proper Cr(VI) preservation, sampling at an appropriate site is important for determining the public's exposure to Cr(VI). The proposed MCL for Cr(VI) in the state of California will be monitored at the entry point of distribution systems. To the extent that Cr(VI) is formed in the distribution system or in water contacting plumbing, measurements at the treatment plant might not reflect consumer exposure at the tap. Cr(VI) can be released to drinking water from Cr present in stainless steel alloys. At the maximum residual disinfectant level (MRDL), Cr(VI) formation decreased in the order chlorine dioxide > chlorine > chloramine. Less Cr(VI) was released from stainless steel at lower pH in the presence of chlorine, but the opposite trend was observed for chlorine dioxide. Stainless steels with a higher chromium content tended to release more Cr(VI).Master of Science
4
Abdulrahman, Ghaith H. "Erosion-corrosion mapping of carbon steel in oil/water slurries." Thesis, University of Strathclyde, 2011. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=16792.
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5
Cen, Hui. "Effect of water on the performance of lubricants and related tribochemistry in boundary lubricated steel/steel contacts." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/5434/.
Повний текст джерелаАнотація:
The objective of the overall project is to assess the effect of water on the performance of lubricants and related tribochemistry in boundary lubricated steel/steel contacts. The effect of water on the bulk properties of the lubricant, the tribological performance of lubricants and the mechanism of tribofilm formulation are the focus of this project. The tribological performance of different lubricants is evaluated by a ball-on-disc test rig as well as a micropitting rig under boundary lubrication and with different levels of humidity. Selected post test samples are analysed to study the reactions occurring during the test and the composition of the tribofilm. The surface analysis techniques used are Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The results of this thesis show that water can change the bulk properties (viscosity and TAN) of some lubricants in specific conditions dependent on the water level in the lubricants. The increase of relative humidity always increases wear of the components no matter whether under pure sliding or rolling-sliding conditions, but addition of water in the oil before the tribological test will not always increase wear. It is also observed from XPS results that there is a direct relationship between the oxygen concentration as oxide on the contact surfaces, the layer thickness on the wear scar of post test ball/roller and relative humidity. Also, it is revealed from the results that not only physical parameters but also chemistry must be considered to evaluate the micropitting behaviour, which is found by XPS analysis to be related to the chain length of the phosphate as well as the oxygen concentration as oxide on the wear scar of the surfaces.
6
Vakili, Soheyl. "Analysis of water cooling process of steel strips on runout table." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/37671.
Повний текст джерелаАнотація:
This study engages in the thermal analysis of water jet cooling of a hot moving steel strip on a run-out table. General 3D FE programs are developed for the direct and inverse heat transfer analysis. Studies show that gradient-based inverse algorithms suffer from high sensitivity to measurement noise and instability in small time steps. These two shortcomings limit their application in modeling of the real problems.
Artificial neural network (ANN), genetic algorithm (GA), and particle swarm optimization (PSO) methods are applied to the inverse heat conduction problem in order to overcome the challenges faced by the gradient-based methods. Among them, GA and PSO are found to be effective. CRPSO, a variation of PSO, shows the best computational performance. However, compared to the gradient-based methods, these algorithms are very slow. Thus, a set of modifications were performed in this research to accelerate their convergence rate. Sequential formulation using the future time steps, multi-objective optimization, and inexact pre-evaluation using surrogate models are some of these modifications.
Inverse analysis of experimental data shows that heat transfer behavior on the plate is mainly a function of the surface temperature, and can be categorized into three zones: High, mid, and low temperature. The effects of jet line configuration, jet line spacing, and plate moving speed were studied. The most uniform distribution happens in the case of fully staggered configuration. In higher jet line distances, the interaction effects become less significant, and a more uniform distribution is observed. The plate speed affects the heat transfer rate under the impingement point for the higher surface temperatures. In the high entry temperatures, the impingement heat transfer rate is lower when the plate is moving at a higher velocity. The plate speed does not significantly change the heat transfer behavior in the parallel flow zone.
Finally, the results of the heat transfer analysis were coupled with the microstructure and structure fields, to study the thermal stresses and deflection occurring in the strips during the cooling process. It was found that fully-staggered jet configuration, larger spacing between jet lines, and lower plate speeds result in a less deformed steel strip.
7
Bierbrauer, Frank. "Mathematical modelling of water-droplet impact on hot galvanised steel surfaces." School of Mathematics and Applied Statistics - Faculty of Informatics, 2004. http://ro.uow.edu.au/theses/400.
Повний текст джерелаАнотація:
Hot-dip galvanising is commonly used in industry to increase the corrosion resistance of cold-rolled steel products for commercial use such as roofing and walling of buildings. Traditionally, the zinc coated steel surface is characterised by a relatively smooth surface with large spangle relief which is detrimental to corrosion resistance. One of the techniques to modify the surface appearance consists of a water-mist spray solution which allows for the creation of a large number of nucleation sites giving rise to micro rather than macro spangles, thereby producing a much smoother surface. In addition, controlling the spray parameters allows the hot, zinc coated, steel surface to be ‘roughened’ facilitating its bonding to concrete or for lamination. The proper control of water droplet impact parameters such as impact velocity, droplet diameter and crater size is essential for a successful implementation of this technique. Certain aspects of the second of these processes, the production of rough, non-skid galvanised steel sheet surfaces, has been addressed by this thesis.Although an experimental investigation of the effect of such water droplet parameters on the formation of zinc surface characteristics such as crater diameter and depth would provide a great deal of valuable data it is fraught with difficulties. The presence of hot metal surfaces exceeding 450oC and the boiling and evaporation of water droplets taking place at very small timescales (microseconds) all combine to make an experimental study difficult to implement not to say unsafe. On the other hand computer simulations with a properly constructed mathematical model are a valuable tool for the investigation of these parameters.A comprehensive modelling of the process would include the process of heat transfer: such as conduction through a vapour layer, internal droplet and vapour convection, radiation from the hot surface, solidification of the zinc liquid layer; as well as the fluid dynamical aspects: such as surface tension at the droplet-air, droplet-zinc and zinc-air interfaces, the droplet impact phenomena such as spreading and splashing and the formation of impact craters and wave propagation in a thin viscous zinc layer. As a first stage in the modelling exercise this thesis will concentrate on an investigation of single water droplet impact on a thin liquid zinc layer with a steel substrate which provides a simplified and computationally tractable model of the spraying process.The objectives of this thesis are twofold: firstly, the development and construction of an accurate, robust mathematical model and, secondly, the solution of the model for the impact of a single water droplet onto a thin liquid layer of zinc on a steel substrate. This model must be able to deal with rapidly deforming moving interfaces and maintain stability in the presence of very large density and viscosity ratios. This moving boundary problem requires the tracking of three fluid interfaces while also maintaining incompressibility. The Godunov-Marker-Particle Projection Scheme developed in this thesis is able to satisfy these requirements. Through a combination of approximate projection methods, Godunov convective differencing, Marker-Particle interface tracking and velocity filters the method is able to treat viscous, multi-fluid free surface flows. The modelling of free surface flows with more than two separate immiscible fluids, to the author’s knowledge not yet published in the literature, is a secondary aim of the thesis. A major part of the thesis deals with the thorough testing of each aspect of the combination of numerical methods used: firstly, the Poisson solver with discontinuous coefficients and homogeneous boundary conditions used in the approximate projection method, analytical solutions for the construction of an initial solenoidal velocity field, testing of the projection and velocity filters and kinematic tests of the Marker-Particle method for tracking of fluid interfaces; secondly, dynamical tests of the viscous incompressible Navier-Stokes equations for: an exact solution, the Lid-Driven Cavity and the Rayleigh-Taylor instability. The combined method is also successfully tested on the limited two-fluid droplet-solid and droplet-liquid impact problems before solving the thesis problem.It is shown that, for the impact of a single water droplet onto a thin liquid zinc layer, impact crater growth, diameter and depth, are linearly dependent on impact velocity. For a given impact velocity, crater diameter is not effected by increasing zinc layer depth although crater depth is linearly dependent. The time at which the droplet commences penetration of the zinc layer is inversely dependent on impact velocity and the maximum crater diameter and depth are nonlinearly dependent on impact velocity. The model shows that, within the convective timescale, droplet impact on thin liquid zinc layers can be approximately described by droplet spreading on a solid zinc surface. The droplet is shown to spread preferentially to the zinc layer splashing after completion of spreading. This shows that adjustment of the droplet impact velocity or zinc layer depth can vary the surface roughness appropriately.
8
Smith, H. E. M. "The protection of poorly prepared steel surfaces using water-borne coatings." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233531.
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9
Rees, R. P. "Removal of oil from process water at an integrated steel works." Thesis, Cardiff University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366458.
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10
Karwa, Nitin. "Experimental Study of Water Jet Impingement Cooling of Hot Steel Plates." Phd thesis, tuprints, 2012. https://tuprints.ulb.tu-darmstadt.de/3041/1/PhD_Thesis_Karwa.pdf.
Повний текст джерелаАнотація:
Liquid jet impingement cooling is critical in many industrial applications. Principle applications include extracting large heat flux from metal parts, such as hot fuel bundle post-loss-of-coolant-accident in nuclear reactors, heat treatment of steel plates post-hot-processing, etc. The ability of liquid jets to extract high heat flux at controlled rates from metal parts, with temperatures as high as 800-1000 ºC, at moderate flow rates has made them indispensable in these applications. Due to the complexity of the process, the mechanism of flow boiling heat transfer during jet impingement cooling is not well understood. Resultantly, the presently used design approaches are based more on experience and rule of thumb than science. The principle challenge in the study of jet impingement cooling for these high temperature applications has been the lack of reliable instrumentation for measuring the cooling rates. To add to this, the conjugate nature of boiling heat transfer, especially on low conductivity metal like steel, makes this problem very complicated to understand. Thus, much of the state of art on this subject has been limited to experiments where either the conjugate problem has not been addressed or the tests have been performed at temperatures that are much lower than in the above mentioned applications.
The basic objective of the present work is to contribute to the understanding of the thermo-hydrodynamic phenomenon occurring during the cooling of a hot steel plate with an impinging water jet. This work also complements a parallel study being conducted at the Institute of Fluid Mechanics and Aerodynamics (Technische Universität Darmstadt), in which the complex transport processes are being treated theoretically and validated against the experimental results of this work.
To achieve the objective, transient cooling experiments have been performed on an instrumented stainless steel AISI-type 314 cylinder. To measure the temperature variation within the stainless steel cylinder during the transient cooling, fast-response thermocouples have been embedded within holes that are precisely drilled though its bottom flat face. The cylinder is induction heated to a homogeneous initial temperature of 900 ºC and is subsequently cooled by means of an axisymmetric subcooled free-surface water jet that impinges on its top flat face (impingement surface). During the cooling, each thermocouple output has been recorded at the rate of 100 samples per second. A two-dimensional axisymmetric inverse heat conduction analysis using these measured temperature data has been performed to estimate the temporospatial variation of temperature and heat flux on the impingement face. Both low and high speed images have been recorded to visualize the two-phase flow. These images and the estimated heat transfer distribution are used to understand the boiling mechanism. The effect of jet parameters, namely subcooling and impingement velocity, on the heat transfer process has been studied. Additionally, the effect of spent liquid accumulation over the impingement surface has been studied in few exploratory plunging jet experiments.
This study presents a systematic methodology for the measurement and estimation of the temporospatial variation of heat transfer on the impingement surface of a hot steel plate. Three distinct regions, with difference in the extent of liquid-wall contact, have been identified on the impingement surface from the recorded images.
i) A wetted region surrounds the jet stagnation region. Nucleate boiling is the principle heat transfer mode in this region. The outer periphery of this region is called the wetting front. No boiling activity has been observed in the high speed images, most likely because the bubbles were small and were unable to reach the liquid free-surface. The maximum heat flux position is determined to be within this region. As the wetted region grows in size with time, the maximum heat flux position also moves radially outwards. The wetting front and maximum heat flux position velocity reduce with increasing radial distance from the impingement point because the liquid velocity and subcooling reduce at the wetting front. Likewise, the wetting front velocity increases with jet velocity and subcooling.
ii) The liquid gets deflected at the wetting front due to the efflux of large vapor bubbles beyond the maximum heat flux position. A term ``wetting front region' has been coined in this thesis to describe this region. The width of this region could not be determined from the high speed images. Transition boiling within a thin superheated liquid film that is continuously replenished by the bulk flow is proposed to be the probable reason for the high heat flux in this region. Further, the radial heat conduction to the wetted region is also significant here.
iii) The impingement surface outside the wetting front region is dry. The dry surface slowly cools down due to film boiling and radial heat conduction to the wetting front region. The film boiling rate is very low in the impingement region. After deflecting away from the impingement surface in the wetting front region, the liquid film breaks into droplets over this region. Looking from the side, droplet deflection angle is observed to be small; still these droplets do not come into direct contact with the impingement surface, as has been confirmed by looking down from the top.
The velocity of the splashed droplets has been determined by analyzing the high speed images. It has been found that the drop velocity is much lower than the liquid film velocity calculated at the wetting front position using single-phase flow relations suggested by Watson. It has been hypothesized that the liquid film in the wetted region is decelerated by the bubbles growing on the impingement surface. Further, measurements reveal that the drop velocity increases with decreasing subcooling, which means that the film and the droplet are accelerated in the radial outward direction by the vapor released in the wetting front region.
It has been shown that the rewetting temperature (analogous to the Leidenfrost temperature for a sessile droplet), which refers here to the temperature below which the direct liquid-wall contact is re-established and the heat flux increases, in both the impingement and radial flow regions is significantly higher than that reported in the literature for pool boiling. Removal of bubbles by the flowing liquid in the early stages of their growth and then their rapid condensation within the subcooled liquid avoids the buildup of vapor near the hot wall, which is the likely reason for the enhancement of the rewetting temperature. This observation confirms that high heat fluxes can be removed at large wall superheats by impinging liquid jets, as practiced in the industry.
The boiling curve shifts to higher heat flux and superheat with the increase in the jet velocity and subcooling. The maximum heat flux and surface temperature at maximum heat flux increase with both the jet velocity and subcooling. Area-weighted average boiling curves have been determined, which clearly show the enhancement in the heat transfer with jet velocity over the average surface superheat of 100 to 800 K. The enhancement in jet subcooling is, however, noticeable only in the wall superheat range of 300 to 700 K. The maximum heat flux and surface temperature at maximum heat flux decrease with radial distance from the stagnation point before reaching a constant value. The radial distribution of maximum heat flux condition has been classified into three regions based on the relative size of the hydrodynamic/thermal boundary layer and the liquid film.
In the plunging jet impingement studies, it has been found that the wetting front growth slightly slows down due to accumulation of the spent liquid over the impingement surface. Area-weighted average boiling curves show that the heat transfer reduces due to accumulation.
11
Cotterrell, M. H. "The influence of water composition on the pitting behaviour of newly developed corrosion resistant steels." Master's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/21134.
Повний текст джерелаАнотація:
Bibliography: pages 96-103.The mechanisation of the working stapes in South African gold mines has required the introduction of a fundamentally new technology, hydro-power, in which machines are powered hydraulically using mine water fed from above ground. Mine water is aggressive and has a variable acidity and pH, and contains high concentrations of sulphate, chloride and nitrate ions. In order to minimise the pitting corrosion of piping and stoping machinery a compromise between selecting a suitable corrosion resistant material and treating the mine water to an acceptable level of corrosiveness is being sought.
12
Seshadri, Prashant. "Treatment of acid mine drainage with Weirton steel slags." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1730.
Повний текст джерелаАнотація:
Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains vii, 38 p. : ill. Includes abstract. Includes bibliographical references (p. 29-30).
13
Madani, Nogol. "A water-based heat pipe for molten steel applications in a tundish." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97111.
Повний текст джерелаАнотація:
In the continuous casting of steel shapes, a tundish feeds the molten steel alloy into oscillating moulds. Therefore, a better knowledge of some of the parameters of the steel in this phase of the process will lead to better quality with more productivity and in a safer environment. There are many control parameters to be measured in the tundish, especially on a continuous basis, yet in this project we are focused on the following 3 main ones that are the basics of tundish metallurgy: the temperature of the steel, the thickness of the slag, and the composition of the steel.A viewing tube capable of withstanding the intense environment of the steel tundish enables one to obtain information about temperature, slag thickness and composition of the melt on a continuous basis. This probe based on heat pipe technology has been designed and fabricated and tested in two different environments. One was in gaseous environment in a natural gas filled furnace. The other environment in which the heat pipe has been tested was in a molten aluminum bath. The results of the first experiments showed that the heat pipe is capable of extracting 23 kW at a heat flux of 0.5 MW/m while in the next set of tests the heat pipe could not overcome the film boiling limitation. This was a result of the internal design of the pipe, thus, some design modifications are suggested to solve the problem.Dans la coulée en continu pour produire des formes en acier, un panier de coulée alimente des moules basculants en acier en fusion. Par conséquence, une meilleure connaissance de certains des paramètres de l'acier dans cette phase du processus permettra d'améliorer la qualité ainsi que la productivité dans un environnement plus sûr. Il y a beaucoup de paramètres de contrôle qui peuvent être mesurés dans le panier de coulée, surtout sur une base continue, cependant cette étude concerne les trois principaux qui représentent la base fondamentale métallurgique du panier de coulée : la température de l'acier, l'épaisseur des scories, et la composition de l'acier.Un tube capable de résister à l'environnement intense du panier de coulée et permettant l'observation in-situ a été utilisé pour obtenir l'un rend capable d'obtenir des informations sur la température, l'épaisseur de scories et la composition du fond sur une base continue. Cette sonde fondée sur la technologie des caloducs a été conçue, fabriquée et essayée dans deux environnements différents. L'un était dans un environnement gazeux dans une fournaise alimentée en gaz naturel. L'autre environnement dans lequel le caloduc a été essayé était dans un bain d'aluminium en fusion. Les résultats des premières expériences ont montré que le caloduc est capable d'extraire 23 kW à un flux de chaleur de 0,5 MW/m pendant que dans la prochaine série de tests le caloduc ne pouvait pas surmonter la limite imposée par le film qui bout. Ceci était un résultat de la conception interne du caloduc, ainsi, quelques modifications de conception sont suggérées pour résoudre le problème.
14
Zhao, Yongjun. "The cooling of a hot steel plate by an impinging water jet." Access electronically, 2005. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060316.150622/index.html.
Повний текст джерела
15
Prasad, Harsha. "Impact of Municipal Water Characteristics on Corrosion of Steel and Copper Piping." Digital WPI, 2016. https://digitalcommons.wpi.edu/etd-theses/1177.
Повний текст джерелаАнотація:
This research evaluated corrosion and scale deposition in steel and copper pipe sections from apartment complexes located in Rhode Island (RI), Massachusetts (MA), and Maryland (MD). Piping samples from these locations had corroded at an accelerated rate and consisted of HVAC piping, and domestic copper pipes. Pipes were analyzed by scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS) to quantify the elemental composition of the samples. The water chemistry of each system was compared to the elemental data to determine correlations. Particular elements from the EDS analysis in comparison to the water quality parameters, Langelier Saturation Index, and Larson Skold indices exhibited inverse and direct correlations. The deposition of corrosion product and scales occurred in all systems that had implemented corrosion control in the form of pH adjustment and inhibitors to prevent infrastructure degradation. Although measures were taken to prevent corrosion, the current practices were not effective at the current dosing rate showing that the municipalities could consider other options such phosphate blend inhibitors and lime as effective corrosion control mechanisms.
16
Sutton, Daniel Christopher. "Wear modelling of diamond-like carbon coatings against steel in deionised water." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/366526/.
Повний текст джерелаАнотація:
Diamond-Like Carbon (DLC) coatings are thin protective surface coatings used to reduce friction and minimise wear in a wide range of applications. The focus of this work is the use of DLC coatings within Rolls-Royce’s pressurised water reactors. A strong understanding of material behaviour in this environment is compulsory due to the stringent safety requirements of the nuclear industry. Wear testing of a range of commercial DLC coatings against steel in water, and the dependence of the tribology on normal load, sliding distance, and environmental species, was examined. Wear depth was observed to increase with normal load, and increase non-linearly with sliding distance. Uniquely, it was suggested that the tribology of a DLC coating in water was controlled by the velocity accommodation mode (VAM) of the transfer layer. When interfacial sliding was the dominant VAM, the carbonaceous transfer layer was present at all times, and a low specific wear rate was observed. When shear and recirculation of debris was the dominant VAM, the carbonaceous transfer layer initially present was replaced by iron oxide species, and a high specific wear rate was observed as a result of a three-body mechanism involving hematite. Two individual wear models were developed to predict the wear depth of a DLC coating sliding against steel in water. Each model represents a novel extension to the current literature regarding the modelling of wear. Firstly, an analytical differential equation was derived to predict the wear depth of a ball and a flat surface, in relation to any phenomenological law for wear volume. Secondly, a unique formulation of an incremental wear model for an arbitrary geometry was developed for a DLC coating which included the growth of a transfer layer. An efficient methodology was presented to allow fast integration of the equations whilst damping numerical instabilities. A comparison between the analytic and computational wear models showed a strong agreement in the model predictions, with a comparative error of less than 5%.
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Capendale, A. E. "The influence of water composition on the pitting behaviour of stainless steel." Master's thesis, University of Cape Town, 1985. http://hdl.handle.net/11427/21165.
Повний текст джерелаАнотація:
Bibliography: pages 90-97.The new concept of hydropower has been found to be technically feasible in South African gold mines. Chilled mine service water is piped from the surface to deep level stope; where the hydrostatic pressure provides power for stoping machinery. This water varies widely in composition and acidity. High concentrations of sulphate, chloride and nitrate are present. These ions are derived from the leaching of oxidised sulphides from the broken rock, the fissure water and the dissolution of blasting fumes. In order to minimise the deterioration of stoping machinery by corrosion and synergistic corrosive abrasive effects, a compromise between selecting a suitable corrosion resistant material and treating the mine service water to an acceptable level of corrosiveness is being sought.
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Matthews, Ryan Paul. "Oxidation kinetics of 316l stainless steel in the pressurised water reactor environment." Doctoral thesis, Faculty of Engineering and the Built Environment, 2019. http://hdl.handle.net/11427/30416.
Повний текст джерелаАнотація:
With a view to improving the prediction of primary water stress corrosion cracking in austenitic stainless steels, this investigation measured the oxide growth kinetics of 316L stainless steel when exposed to a simulated primary water environment of a pressurised water reactor (PWR). It is generally accepted that intergranular oxidation at the surface of a metal forms a preferential site for stress corrosion crack (SCC) initiation; therefore the kinetics of both surface and intergranular oxidation were measured. The influence of temperature, within the range of PWR primary water (290°C, 320°C and 360°C), as well as the influence of starting condition (annealed, 20% elongated, 30% elongated and 20% cold rolled) was investigated. Samples were prepared with the various starting conditions and exposed to simulated primary water, at the specified temperatures, for various durations from 1 hour through to several thousand hours to plot the oxide growth on a log scale time axis. Subsequent to the exposure tests, the Cr rich inner oxide depth was measured locally at selected locations. The surface and intergranular oxide depth was directly measured from cross-sections either with a transmission electron microscope for short duration exposures or, for longer exposures with deeper oxides, within a scanning electron microscope. No significant difference was noted on the oxide kinetics between the various starting conditions evaluated. Temperature, however, had a significant influence with oxide growth kinetics decreasing, rather counter-intuitively, as temperature increased through the measured range. In addition a strong dependency on grain orientation was observed. A modification to the Point Defect Model was proposed to arrive at a quantitative expression to describe surface and intergranular inner oxide growth as a function of temperature in 316L stainless steel, which accommodated the deviation from Arrhenius behaviour through the measured temperature range. Functions for both the rate constant, ��3 0 , and the transfer coefficient, α3, associated with the metal/oxide interface reactions were developed. The resultant model was able to predict, with reasonable accuracy, the growth of the Cr-rich inner oxide over time. The most consistent explanation for the deviation from Arrhenius behaviour was that the coherency across the metal/oxide interface degraded as the temperature increased through the tested temperature range. This would reduce the potential for ionic transfer across the interface necessary for the interface to migrate and increase the oxide depth. Since a similar temperature dependence on the growth of intergranular stress corrosion cracking (IGSCC) in the primary water environment has been observed within the same temperature range, it is proposed that the above explanation, observed in the absence of applied stress, extends to explain the behaviour of IGSCC kinetics in austenitic stainless steel.
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Hamouda, Karim. "Bronze-Steel Friction Characteristics under the Lubrication of Modified Water/Glycerol Mixtures." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-65217.
Повний текст джерелаАнотація:
Increasing environmental awareness has driven a lot of research to look into various environmentally friendly lubricants which can replace more conventional mineral oil based lubricants. This is true in particular for marine and hydropower applications where the risk of lubricant leakage can be damaging to the local environment. Glycerol is an organic compound produced as a byproduct when producing Biodiesel. It is environmentally friendly and has been used by the pharmaceutical and food industries for a long time. Recent research has shown that glycerol has very good tribological properties and can be used as a lubricant in some applications. However, its high viscosity and high static friction are disadvantageous and needs improvement. The purpose of this study is to investigate possible surface active environmentally adapted additives in glycerol and water solutions. 14 additives have been selected for testing and were tested in a pin-on-disc start-stop friction test to see their effect on the static and dynamic friction coefficients. From these 14 additives two were selected due to their superior performance and were further studied. The effect of concentration of water and additive in glycerol was also investigated using the same test conditions. A phosphor based additive has been found to be the best performing.
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Whant, Louis Mathew. "Stormwater impacts on disharge water quality in licensed drains at the Port Kembla Steelworks." Access electronically, 2005. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060712.144710/index.html.
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Gulbrandsen, Stephani. "Stress corrosion cracking of 316L austenitic stainless steel in high temperature ethanol/water environments." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/47815.
Повний текст джерелаАнотація:
There has been an increase in the production of bio-fuels. Organosolv delignification, high temperature ethanol/water environments, can be used to separate lignin, cellulose, and hemicelluloses in the bio-mass for bio-fuel production. These environments have been shown to induce stress corrosion cracking (SCC) in 316L stainless steel. Previous research has been done in mixed solvent environments at room temperature to understand SCC for stainless steels, but little is known about the behavior in high temperature environments. Simulated organosolv delignification environments were studied, varying water content, temperature, pHe, and Cl- content to understand how these constituents impact SCC. In order for SCC to occur in 316L, there needs to be between 10 and 90 volume % water and the environment needs to be at a temperature around 200°C. Once these two conditions are met, the environment needs to either have pHe < 4 or have more than 10 ppm Cl-. These threshold conditions are based on the organosolv delignification simulated environments tested. SCC severity was seen to increase as water content, temperature, and Cl- content increased and as pHe decreased. To prevent failure of industrial vessels encountering organosolv delignification environments, care needs to be taken to monitor and adjust the constituents to prevent SCC.
22
Martinez, Pablo. "Quenching a steel plate by water - impinging jets and different simultaneous flow rates." Thesis, Högskolan i Gävle, Energisystem och byggnadsteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-30179.
Повний текст джерелаАнотація:
Regarding the great importance of fast cooling in steel industry for the production processes, a deep understanding of heat transfer and fluid dynamics must be held. A steel plate is heated up until a maximum temperature of 700 ⁰ C to be the n cooled down seconds later by a configuration of multi ple impinging water jets. Different flow rates are used simultaneously by different adjacent jets to perform quenching over the sample, so different hardness is obtained in the material over a small area . Temperature drop in time i s measured and monitored by embedded thermocouples and LabVIEW program. To achieve greater understanding of the quenching performance with different flow rates , several parameters are selected to be varied in order to achieve the best working conditions. Jet diameter takes values between 4 and 10 mm, initial temperature of quenching varies from 400 to 700 ⁰ C , subcooling temperature is tested for 65 and 75 K, and jet velocity varies between 1.9 and 3.9 m/s. The result of total number of 9 expe riments shown that v ariation of jet diam eter does not influence substantially on the cooling rate if flow rate is kept constant. High initial quenching temperature (600 - 700 ⁰ C ) led to slightly higher cooling rate in the stagnation region of water jets. The peak value of heat transfer rate in the upwash flow zone was more highlighted for initial quenching temperature 600 ⁰ C and below it. High er values of subcooling and jet velocity produce better cooling rates. The result shown higher jet velocity at one column of water jets changes position of upw ash flow slightly toward the adjacent column of jets with lower jet velocity. In general, the result shown that all the studied parameters did not have negative effect on obtaining various cooling rates over the steel plate.
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Ieamsupapong, Supat. "Mechanisms of Iron Carbonate Formation on Mild Steel in Controlled Water Chemistry Conditions." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1473264400862079.
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Tang, Xuanping. "Effect of Surface State on Water Wetting and Carbon Dioxide Corrosion in Oil-water Two-phase Flow." Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1304638556.
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Ray, Shamik Kumar. "Water modelling studies to predict steel quality in a 4 strand delta-shaped tundish." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99013.
Повний текст джерелаАнотація:
Physical and mathematical modelling of fluid flow phenomena play an important role in studies of steel quality associated with the various steps in steelmaking and steel processing operations.In the continuous casting process, the tundish not only serves as an intermediate buffer, but with increasing demands for high quality steel, it has also evolved into a useful reactor for liquid steel refining. It is now a proven fact that a modern tundish is designed to carry out different metallurgical operations such as inclusion separation and floatation, alloy trimming, superheat control, calcium doped inclusion modification, thermal and particulate homogenization.
To carry out those operations effectively, certain parameters like Residence Time Distribution (RTD), Residual Ratio of Inclusions (RRI), Slag Entrainment and Vortex formation phenomena are generally studied and optimized using various tundish designs, and flow modification devices. These are usually specific to a given plant practice and to a targeted grade of steel.
A full scale physical model of a delta shaped, four strand tundish using water as the simulating fluid for liquid steel was used to study the fluid flow behavior of a 12 t tundish producing aluminium-killed steel billets., The above mentioned parameters were studied to predict the performance of the tundish using two different types of flow modification systems.
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Vepulanont, Klatnatee. "The effect of chlorinated water on the crevice corrosion behaviour of austenitic stainless steel." Thesis, University of Sheffield, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.578693.
Повний текст джерелаАнотація:
In the UK, approval of stainless steel products by the Drinking Water Inspectorate invokes the Operational Guidelines and Code of Practice for Stainless Steel Products in Drinking Water Supply (OGCP) t Munro et al., 2002). Type 304L and 316L stainless steel grades can be used for the majority of applications in water treatment and supply, with the grade selection depending on the chloride and chlorine levels in the water. Currently the guideline suggests that 304L may be used up to 200 ppm chlorides and 2 ppm free chlorine and type 316L up to 1000 ppm chlorides and 5ppm free chlorine at pH levels greater than 6. Although the maximum chloride levels have been well researched and in most applications has supported this for many years, chlorine values are based on limited evaluations and, although they work well in most, more research is required to more closely define them. The purpose of this research is to understand and determine to what extent residual chlorine level, chloride content, and pH will affect the crevice corrosion behaviour of types 304L and 316L stainless steels in particular, and the initiation of crevice corrosion. The study required the creation of a controlled chlorinated system exposing creviced specimen using the multi-crevice assembly technique. The assemblies were immersed for 60 days at 20°C in chloride levels ranging from 200-2000 ppm, residual chlorine levels ranging from 0-10ppm; all at pH 6 and 8 . A fter the immersion period, specimens were investigated by visual examination, Scanning Electron Microscopy (SEM) and Atomic Force vlicroscopy (AFM). Potentiodynamic polarization studies were also 4 carried out for each of the environments. Custom made software programs were developed to analyse the data collected from SEM and AFM results to give a better understanding and clarification of the crevice corrosion phenomena, in each individual condition and to provide more confidence in the selection of chlorination levels for particular chloride water contents. From visual and optical assessment results presented that the earliest noticeable of crevice corrosion had occurred at 0 ppm chlorine, 1000 ppm chloride ppm, pH 6 and 20° C and at 2 chlorine ppm, 1000 chloride ppm, pH 8 and 20° C for 304L specimens while for 316L specimens no significant change was observed. These results supported with OGCP and showed that both type of specimens can be used at slightly higher concentrations of chlorine and chloride than the guideline values depending on how to keep the constant concentration and how much of the surface quality of specimens that will be used throughout the process . . -\FM and SEM results showed that corrosion surface activity had occurred on both 304L and 316L specimens, even the least aggressive chloride and chlorine concentrations. The corrosion surface activity IS proportional to the increase in the chloride and chlorine concentrations. Potentiodynamic polarization curves supported the evidence from AFM and SEM results that chemical activity inside the pit had occurred even at milder concentrations. Cr and Fe were oxidised as 02- and OH- penetrated into the pits. These electron exchanged of these chemical species had been interpreted by polarization curve which showed various 5 stages of these reactions (cathodic reaction, anodic reaction. passive stage and breakdown). The results showed that breakdown potential (Eb) and passive stage are inversely proportional to chloride and chlorine concentrations. The chlorine and chloride concentrations had a more dominant effect than pH especially at high concentrations due to the amount of chemical species inside the pit and electrolyte solution overcome pH effect and the process was under mass transport controlled until pH effect can be neglected. The custom made software offered more clarification of pit characteristics and shapes which will be useful in connected with corroded area and volume calculated and further study or future prediction of characteristic of crevice corrosion that will occur or likely to in different environments.
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Je, Hwanil. "Stress Corrosion Cracking Behavior of Oxide Dispersion Strengthened Ferritic Steel in Supercritical Pressurized Water." Master's thesis, Kyoto University, 2013. http://hdl.handle.net/2433/180448.
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Akbasoglu, Fuat Can. "The effect of microstructure on the performance of bearing steels with particular reference to their operation with water containing lubricants." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670341.
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Gao, Xin. "Localized Corrosion Initiation of Steel in CO2 Environments." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1596657895973621.
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Yang, Dong. "Factors affecting stress assisted corrosion cracking of carbon steel under industrial boiler conditions." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24809.
Повний текст джерелаАнотація:
Thesis (Ph.D.)--Mechanical Engineering, Georgia Institute of Technology, 2008.Committee Co-Chair: Preet M. Singh; Committee Co-Chair: Richard W. Neu; Committee Member: Hamid Garmestani; Committee Member: Timothy Patterson; Committee Member: W. Steven Johnson.
31
Fry, J. C. "A study of the cooling effect of water sprays on steel strip at high temperatures." Thesis, Swansea University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637015.
Повний текст джерелаАнотація:
To meet customers' demands for increased quality and product consistency, together with the production of a wider range of steels there is a need for accurate temperature control throughout the whole cooling path on the hot Strip Mill. This requires a cooling system that couples the required cooling rate with the heat transfer capabilities of the water spray system and the production speed and line length, however, information on the heat transfer characteristics of water sprays is sparse. Therefore, the project described in this thesis has investigated the heat transfer characteristics of water sprays. The project has been two fold. Initially a steady state test apparatus has been designed, built and commissioned which allows the heat transfer coefficient of a single pressure atomised water spray to be evaluated under various operating conditions. Secondly, the apparatus has been used to conduct experiments on two commercially available spray nozzles with the aim of determining the relationship between the spray operating conditions and the heat transfer coefficient. The work has demonstrated that a steady state technique can be used to determine the heat transfer coefficient of a spray at surface temperatures between 650°C and 950°C. The experimental work has shown that the heat transfer coefficient increases with increasing surface temperature, increasing flow rate and decreasing stand off distance. For the two nozzles tested correlation equations have been derived which allow the heat transfer coefficient to be evaluated in terms of the surface temperature, flow rate and stand off distance. Finally, the application of the correlation equations to the design and improvement of water cooling lines has been considered.
32
Xue, Dingchuan. "Electro-deposition of resin-modified water-based hydrophobic silane on HDG steel for corrosion protection." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1229010186.
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Christman, Timothy Keane. "The effects of organic acids on the stress-corrosion cracking of type 304 stainless steel in high temperature water /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487262825077113.
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Sousa, Josà Arimateia Cavalcante de. "Cathodic protection semisubmersÃveis floating metal chambers for water catchment. Case Study: Weir GaviÃo." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11364.
Повний текст джерелаАнотація:
As part of the water resources policy of the state of CearÃ, in Northeast Brazil,
COGERH, as an operational instrument, has among its tasks the distribution of bulk water for
various uses. Among the water systems that COGERH operates are the pumping stations,
which are responsible for supplying water for cities, industries, irrigation, etc. It is vital that
these structures operate satisfactorily and efficiently. Among the many devices that make up
the pumping stations are the semisubmersible floating metal chambers that are located on the
water surface of the reservoirs, providing support to the pumps and motors such that they can
be set and operated reliably and efficiently. However, these structures are made from steel and
therefore are subject to severe corrosion processes, making it necessary for the painting of the submerged areas to ensure the necessary protection to avoid oxidation of them. As painting alone is not a process that ensures 100% efficiency in terms of coating and has a relatively short lifespan, complementary processes are necessary to ensure safe protection against corrosion. Among these processes is the Cathodic Protection, which ensures that, while a difference in electrochemical potential is being generated between the structure to be protected and a sacrificial anode, the structure will not undergo corrosion processes. For this study, it has been designed and installed an Impressed Current Cathodic Protection System with a potential ON of protection of -2.67 Volts (DC) for the Pumping Station known as "EB GaviÃoâ chosen due to its strategic importance within the state infrastructure of water resources, responsible for supplying water for major cities and industries.
Keywords :Dentro da polÃtica dos recursos hÃdricos do estado do CearÃ, no Nordeste do Brasil, a COGERH, como instrumento operacional, tem entre suas atribuiÃÃes a distribuiÃÃo de Ãgua bruta para usos diversos. Dentre os sistemas que a COGERH operacionaliza estÃo as estaÃÃes de bombeamento, as quais sÃo responsÃveis por abastecer cidades, indÃstrias, irrigantes, etc. à fundamental que tais estruturas operem de forma satisfatÃria e eficiente. Dentre os muitos equipamentos que compÃem as estaÃÃes de bombeamento estÃo Ãs cÃmaras metÃlicas flutuantes emisubmersÃveis que se localizam na superfÃcie de Ãgua dos reservatÃrios, dando sustentaÃÃo para que as bombas e motores possam ser fixados e operados de forma confiÃvel e eficiente. No entanto estas estruturas, por serem de aÃo, estÃo sujeitas a processos de corrosÃo severos, fazendo-se necessÃrio que a pintura das Ãreas submersas assegurem a proteÃÃo necessÃria para que nÃo haja oxidaÃÃo das mesmas. Como a pintura nÃo à um processo que garante uma eficiÃncia de 100% e termos de revestimento e tem uma vida Ãtil relativamente curta, fazem-se necessÃrios processos complementares para uma segura proteÃÃo anti-corrosÃo. Dentre esses processos està a ProteÃÃo CatÃdica que assegura que enquanto estiver sendo gerada uma âdiferenÃa de potencial eletroquÃmicoâ entre a estrutura a ser protegida e um anodo de sacrifÃcio a estrutura nÃo sofrerà severos processos de corrosÃo. Neste estudo foi dimensionado e instalado um Sistema de ProteÃÃo CatÃdica por Corrente Impressa assegurando um potencial ON de proteÃÃo de -2,67 Vcc para a estaÃÃo de bombeamento denominada âEB GaviÃoâ pela importÃncia estratÃgica que ocupa dentro da infraestrutura estadual de recursos hÃdricos, fazendo parte de sistema responsÃvel pelo abastecimento de importantes cidades e indÃstrias.
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Hariramabadran, Anantha Krishnan. "Study of Total Oxygen Content and Oxide composition Formed During Water Atomization of Steel Powders due to Manganese Variation." Thesis, KTH, Materialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101665.
Повний текст джерелаАнотація:
Powder metallurgy (PM) is a technology used to manufacture near net shape components for an increasing number of applications like automobile components, aircraft components, cutting tools, refractory, household appliances, etc. The general PM process comprises of Powder manufacturing/powder tailoring, Compacting, and Sintering. Based on product’s final requirements, optional secondary operations are performed. PM components for automotive application are experiencing a growth coupled with new challenges. PM´s capability for producing complex net shaped components with desired properties has enabled it to be an alternative to other traditional manufacturing processes. Average U.S. made vehicle in 2010 contained an estimated 41.6 pounds of PM parts and in Europe, the average per vehicle PM parts in 2010 is estimated 18.5 pounds [3]. New design goals set by OEMs (original equipment manufacturers) demands for complex shaped components with high mechanical properties. Stupendous developments are done in the field of PM component manufacturing and PM raw material manufacturing, endeavoring to cater the technical and economic needs set by OEMs. Based on the application, unique powder characteristics are demanded which are in turn associated with the quality of powders produced. Powder production for conventional PM application encompasses reduction or atomization followed by annealing. Reduced powders are called sponge iron powders, used for low density (density of PM component) application and atomized powders are used for relatively high density application. Atomization can be further classified into water atomization and gas atomization. Coarse, irregular shapes are the common features of water atomized powders and fine, spherical shapes are the common features of gas atomized powders. Water atomization is one of the prominent methods used in production of powders for conventional PM application. Oxygen content of the powders produced by water atomization plays an important role in determining it’s as sintered properties. In this work, oxide formation during various stages of water atomization and annealing were studied for iron, carbon and manganese alloy system and iron, carbon, chromium, molybdenum and manganese alloy system. Manganese content was varied (0.0%, 0.5%, 1.0%) in the above said two alloy system maintaining the same amount of other alloying constituents for comparison. Total oxygen content and oxide composition formed during processing were studied. Both alloy system showed that total oxygen content increases with increasing manganese content. The composition of oxides includes manganese, chromium and iron for Fe+C+Cr+Mo+Mn alloy system and manganese and iron for Fe+C+Mn alloy system. Key words: Powder metallurgy, Water atomization, Gas atomization, Reduced powders, Oxygen content, Oxide composition, Annealing, Sintered properties, Iron, Chromium, Molybdenum, Manganese.
36
Feng, Tao. "Measurements on stress corrosion crack initiation for A533B steel in BWR water using tapered tensile specimens." Thesis, University of Newcastle Upon Tyne, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388128.
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Hussain, Essam A. M. "An electrochemical investigation of erosion corrosion of duplex stainless steel in sea water containing sand particles." Thesis, Cranfield University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393705.
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Lucas, Timothy R. "The effect of thermal aging and boiling water reactor environment on Type 316L stainless steel welds." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/76921.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 185-191).
The thermal aging and consequent embrittlement of materials are ongoing issues in cast stainless steels and duplex stainless steels. Spinodal decomposition is largely responsible for the well known "475°C" embrittlement that results in drastic reductions in ductility and toughness in these materials, and this process is operative also in welds of either cast or wrought stainless steels where 6-ferrite is present. While the embrittlement can occur after several hundred hours of aging at 475°C, the process is also operative at lower temperatures, at the 288°C operating temperature of a boiling water reactor (BWR) for example, where ductility reductions have been observed after several tens of thousands of hours. An experimental study has been completed in order to understand how the spinodal decomposition may affect material properties changes in BWR pipe weld metals as well as the effects of the BWR environment on Type 316L stainless steel welds. This thesis also represents the first systematic and rigorous investigation of environmental fracture. In addition, weld metal centerline SCC crack growth rate has been quantified. Material characterization includes SCC crack growth, in-situ fracture toughness, fracture toughness in air, as well as Charpy-V and tensile property evaluation as a function of aging time and temperature. SCC crack growth rate results in BWR normal water chemistry indicate an approximately 2X increase in crack growth rate over that of the unaged material. In-situ fracture toughness measurements indicate that environmental exposure can result in a reduction of toughness by up to 40% over the corresponding at-temperature air values. This has been termed "environmental fracture" Detailed analyses of the results strongly suggest that spinodal decomposition is responsible for the degradation in properties measured ex-environment. SCC crack growth rate and fracture toughness have been linked to the microstructural features of the Type 316L weld metal. Analysis of the results also strongly suggests that the in-situ properties degradation is the result of hydrogen absorbed by the material during exposure to the high temperature aqueous environment.
by Timothy R. Lucas.
Ph.D.
39
Mohamed, Mohd Farid. "Water Chemistry and Corrosion Inhibition in High Pressure CO2 Corrosion of Mild Steel." Ohio University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1429223819.
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Gatzanis, Gustav Ernest. "Abrasion-corrosion and stress corrosion resistance of a 9Cr-2Ni-0.7Mo steel in simulated mine water." Master's thesis, University of Cape Town, 1991. http://hdl.handle.net/11427/21957.
Повний текст джерелаАнотація:
Bibliography: pages 101-109.The locally (RSA) developed 9Cr-2Ni-0.7Mo steel designated 927 formed the subject of this study. Its abrasion-corrosion and stress corrosion performances were assessed in laboratory tests simulating the underground environment in South African gold mines. The results indicate that the alloy performs favourably in abrasive-corrosive applications, outperforming several other higher chromium containing steels which have been designed for the purpose. The alloy is also highly resistant to sec at free corrosion potential in simulated mine water. The good abrasion-corrosion resistance is attributed to the adequate corrosion resistance of the alloy acting in conjunction with the favourable combination of strength and toughness afforded the alloy by its fine grain size and microduplex microstructure of martensite and interlath retained austenite. The production variables of plate thickness and prior cold working were found to exert negligible influence on corrosion-abrasion resistance. This is ascribed to the small influence of these processes on the hardness and associated mechanical properties due the inherent low work hardening ability of the alloy. Slow strain rate (SSR) stress corrosion cracking tests were performed on the alloy in four microstructural conditions viz. as-rolled, tempered, welded and post weld heat treated. The material showed an immunity to sec in all the microstructural conditions for tests conducted at open circuit potential. This apparent immunity is attributed to the difficulty in initiating sec by pitting on the plain specimens over the relatively short test durations. Polarisation to extreme cathodic potentials (-1200m V) resulted in hydrogen embrittlement of this high strength alloy with failure predominantly along prior austenite grain boundaries. Anodic potentials in the excess of OmV induced tunnel-like corrosion pitting attack. Fractographical evidence of sec at the base of these pits indicates the development of the conditions necessary for sec within the pit confines. This is cited as evidence in support of the hypothesis of sec initiation difficulty.
41
Wang, Mi. "Electrochemical Behaviour of Stainless Steel under Radiation and Exposed to Representative Chemistry in Pressurised Water Reactor Conditions." Palaiseau, Ecole polytechnique, 2013. http://pastel.archives-ouvertes.fr/docs/00/91/55/75/PDF/Mi_WANG_thesis.pdf.
Повний текст джерелаАнотація:
Cette thèse est dédiée à l'étude du comportement des aciers inoxydables sous irradiation exposés en condition primaire des réacteurs à eau pressurisée (REP). Le potentiel électrochimique de l'acier inoxydable austénitique 316L et les paramètres environnementaux comme la teneur en hydrogène, ont été mesurés de façon continue à haute température (HT) et haute pression (HT) grâce à un dispositif expérimental unique, la cellule HTHP. Deux sources d'irradiation ont été utilisées: les protons et les électrons. Le comportement électrochimique du 316L s'est avéré similaire dans les deux cas: (i) une augmentation du potentiel sous irradiation de l'ordre de la dizaine de millivolts ("réponse oxydative"); (ii) l'augmentation de la teneur en hydrogène diminue cette augmentation du potentiel sous irradiation; (iii) une synergie est observée entre le vieillissement à 300 C et la fluence qui conduit également à limiter la réponse oxydative sous irradiation. Les observations du film passif d'oxydes mettent en évidence la présence de nickel métallique dans l'ensemble des oxydes (interne et externe) en présence d'hydrogène, sans irradiation. Après les irradiations les plus fortes, des cavités (piqûres) sont observées en surface du 316L. Ces défauts sont attribués à l'effet de la radiolyse de l'eau et de l'irradiation de la couche passive. La radiolyse influence également l'évolution de la chimie du milieu primaire qui devient plus acide et plus oxydante. Il en résulte une augmentation du relâchement des cations métalliques et la présence d'hématite ( a-Fe2O3) sur le film d'oxyde externe de l'acier inoxydable lorsque les cavités (piqûres) sont forméesThe dissertation focuses on the behaviour of stainless steel under irradiation and exposed to primary PWR conditions. The electrochemical potential of austenitic 316L stainless steel and the environmental parameters (hydrogen pressure, temperature, etc. ,) have been measured continuously at high temperature (HT) and high pressure (HP) under irradiation, using a unique experimental HTHP working cell. Two sources of irradiation, proton and electron beams, have been employed in the study. A high similarity of electrochemical behaviour under both types of irradiations has been observed: (i) an oxidative potential response under irradiation (few tens of millivolts); (ii) an increase in the hydrogen pressure reduces the oxidative potential response; (iii) a synergetic effect of thermal ageing and fluence leading to a decrease of the oxidative response under irradiation. The observations of the oxide film showed that without irradiation, metallic nickel in the inner and outer oxide films has been observed under a high hydrogen pressure. Under irradiation, um scale cavities (pits) have been observed in the strongly electron irradiated oxide film formed on 316L stainless steel. These defects are induced by the effect of irradiation of the passive film and water radiolysis. It is also shown that water radiolysis influences the PWR water chemistry by making it become a stronger oxidant at the oxide/solution interface. As a result, the release of metallic cations is increased and a-Fe2O3 hematite has been observed on the irradiated outer oxide film where cavities were formed
42
Schaffer, Matthew Jason. "Influence of Nozzle Pressure, Standoff Distance, and Reinforcing Steel Cage on Water Jetting of CIDH Pile Anomalies." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/475.
Повний текст джерелаАнотація:
The effectiveness of removing anomalous material from cast-in-drilled-hole (CIDH) piles by water jetting was examined. The primary objectives of this research were to examine how reinforcing steel influences water jetting and to evaluate how jetting pressures and standoff distance from the material surface affect water jetting of concrete type materials and PVC tubing. The experimental work consisted of water blasting submerged test specimens using rotary jets, nozzles, pumping equipment, and testing procedures currently used in construction practice. The concrete test specimens were comprised of ring- and cylinder-shaped samples, containing materials with compressive strengths of approximately 160 and 3,600 psi. Typical PVC tubing used as inspection access holes for non-destructive testing in CIDH piles was utilized for tubing specimens. During testing, erosion depths were measured as a function of standoff distance and jetting pressure. Water jetted specimens containing reinforcing steel were cut apart after testing to permit inspection of the erosion cavity and eroded material surfaces behind the steel reinforcement. Reinforcing steel bars in CIDH piles do interfere with the jet path and will locally influence material erosion and water-jetting effectiveness. For a relatively weak material, water-jetting pressures between 10,000 and 11,000 psi produced erosion up to a radial distance of approximately 12 inches from the water jet. This erosion distance is less than half the typical maximum design spacing of PVC inspection access tubing installed in CIDH piles.
43
Pyc, Wioleta A. "Performance Evaluation of Epoxy-Coated Reinforcing Steel and Corrosion Inhibitors in a Simulated Concrete Pore Water Solution." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36569.
Повний текст джерелаАнотація:
Three epoxy-coated reinforcing steel (ECR) types removed from job sites, one shipped directly from the coater's plant, three commercial corrosion inhibitors, and one ECR plus a corrosion inhibitor were evaluated as reinforcing steel corrosion protection systems against chloride induced corrosion. The three corrosion inhibitors were calcium nitrite, an aqueous mixture of esters and amines, and a mixture of alcohol and amine. The ECR was tested in two groups, 0% and 1% coating damage. Corrosion protection performance was evaluated by the amount of visually observed blister surface area, for the ECR, and corroded surface area, for the tested corrosion inhibitors.
Results of the ECR testing demonstrated that coating debondment and corrosion of ECR is directly related to the amount of damage present in the coating, as well as coating thickness. For the bare steel tested with and without corrosion inhibitors, the results showed that corrosion increases with increasing chloride concentrations. Corrosion inhibition characteristics were demonstrated only by the calcium nitrite corrosion inhibitor.
A corrosion protection evaluation test was developed for concrete corrosion inhibitor admixtures. The test solution is a simulated concrete pore water. Corrosion is accelerated by evaluating the temperature to field conditions of 40 C. The test consists of a 7 day pretreatment period followed by a 90 day test period. The corrosive sodium chloride is added to the solution containing the bare or epoxy-coated reinforcing steel specimens after the 7 day pretreatment period. In addition, the solution is periodically saturated with oxygen.Master of Science
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Rebak, Raúl Basilio. "Environmentally induced cracking in alloy 600 and SA 302 steel in pressurized water reactor steam generator conditions /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487846885777343.
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Permeh, Samanbar. "On the Role of the Pore Water Chemistry of Deficient Post-Tension Grout to Promote Steel Corrosion." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2445.
Повний текст джерелаАнотація:
Corrosion failure of post-tension tendons with pre-packaged thixotropic grout was documented in Florida Bridges in less than 10 years of service. Analysis of deficient grout in Florida post-tensioned (PT) bridges where severe corrosion developed indicated enhanced sulfate ion concentration, high pore water pH, enhanced moisture and low chloride content. The corrosion wasn’t consistent with the conventional causes of steel corrosion such as bleed water accumulation in grout void spaces, chloride contamination and pore water carbonation. Corrosion development was associated with deficient grout with enhanced sulfate levels. However, limited information is available on the corrosion behavior of PT strand in grout materials with enhanced sulfate content. Review of the technical literature has not shown consistent evidence of the role of sulfate ions in the corrosion of steel in solution and in hydrated cementitious material. In this research, the role of sulfates in cementitous materials was examined including identifying practical limits for sulfates in grout materials.
Laboratory samples were created with 15% and 20% excess water to enhance deficient grout materials and included enhanced sodium and chloride content. Enhanced sulfate and chloride ion presence was thought to provide aggressive corrosion condition of steel in segregated grout. Testing was intended to differentiate the corrosion of steel in pore water condition of deficient grout.
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Chockalingam, Mano. "Micropitting Testing and Failure Analysis of High-Performance Gear Thermoplastics and Bearing Steel." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1607087595599047.
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Yousaf, Naeem. "Calucaltion of waste heat from hot rolled steel coils at SSAB and its recovery." Thesis, Högskolan Dalarna, Maskinteknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:du-4516.
Повний текст джерелаАнотація:
Hot rolling process is heat input process. The heat energy in hot rolled steel coils can be utilized. At SSAB Strip Product Borlänge when the hot rolled steel coils came out of the hot rolling mill they are at the temperature range of 500°C to 800°C. Heat energy contained by the one hot rolled steel coil is about 1981Kwh whereas the total heat energy for the year 2008 is 230 GWh/year.The potential of heat is too much but the heat dissipation rate is too slow. Different factors on which heat dissipation rate depends are discussed.Three suggestions are proposed to collect the waste heat from hot rolled steel coils.The 2nd proposal in which water basin is suggested would help not only to collect the waste heat but to decrease in the cooling time.
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Li, Chong. "Effect of Corrosion Inhibitor on Water Wetting and Carbon Dioxide Corrosion in Oil-Water Two-Phase Flow." View abstract, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3371584.
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Segerdahl, Karin. "The breakdown of the protective oxide on 11% chromium steel : the influence of water vapour and gaseous KCl /." Göteborg : Chalmers university of technology, 2003. http://catalogue.bnf.fr/ark:/12148/cb40125707m.
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Millar, Peter G. "Corrosion fatigue crack propagation behaviour of a high strength low alloy steel in a synthetic sea water environment." Thesis, Cranfield University, 1986. http://dspace.lib.cranfield.ac.uk/handle/1826/4443.
Повний текст джерелаАнотація:
The corrosion fatigue crack propagation behaviour of a high strength low alloy steel, N-A-XTRA 70, in a synthetic sea water solution was tested using S. E. N. specimens subjected to a loading frequency of 0.1 Hz and a load ratio of 0.6. In order to simulate the conditions encountered by a thumbnail type crack several specimens from each of the microstructural types tested, namely parent plate, heat affected zone and heat treated material, had their crack sides covered by transparent plastic covers. Severe overprotection and slight underprotection conditions were produced using cathodic protection potentials of -1400, -1300, -1200 and -700 mV (S. C. E. ). The Paris relationship da/dN = CLKm was found to be a useful tool in describing the crack propagation rate data. Results obtained, presented in the form of plots of log da/dN against log AK, show that for parent plate, H. A. Z. and heat treated material, covering the crack sides of specimens produces enhanced corrosion fatigue crack propagation rates, at cathodic protection potentials of -1400 and -1300 mV (S. C. E. ), when compared to non covered specimens. This trend was also true for H. A. Z. specimens at a potential of -700 mV (S. C. E. ). For parent plate specimens, however, covering the crack sides at a potential of -700 mV (S. C. E. ) produced reduced crack propagation rates over non covered specimens. It is believed restriced oxygen access may account for these results. Plots of the Paris exponent m and constant C for the three microstructures tested produced three lines of the form m= alnC +b where a and b were found to be dependent upon material parameters. Comparison of results with BS 4360: 50D revealed that N-A-XTRA 70 exhibited superior fatigue performance when tested in air but behaved worse under conditions of free corrosion.