Дисертації з теми "Steel 40x"
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Яременко, Денис Олегович. "Формування функціональних покриттів на сталі 40Х електроіскровим легуванням хромом та ніобієм". Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2021. https://ela.kpi.ua/handle/123456789/43127.
Повний текст джерелаАнотація:
Об’єкт дослідження – поверхневі шари сталі 40Х, отримані електроіскровим легуванням анодами хромом та ніобієм на повітрі.
Мета роботи – встановити вплив послідовності ЕІЛ хромом і ніобієм на мікроструктуру, фазовий склад і мікротвердість поверхневих шарів сталі 40Х.
Методи дослідження – гравіметричний, мікроструктурний, мікродюрометричний та рентгенофазовий. Показана можливість формування зміцнених покриттів (мікротвердістю 9,5 ГПа – 14,5 ГПа і товщиною 20 мкм – 35 мкм) електроіскровим легуванням Cr та Nb сталі 40Х при різній послідовності нанесення матеріалів анодів.
Встановлено вплив нанесення хрому та ніобію під час електроіскрового легування сталі 40Х на поверхневу мікротвердість, фазовий склад та мікроструктуру модифікованого шару.
Виявлено, що найбільшу мікротвердість (14,5 ГПа) має легований шар після ЕІЛ сталі Nb, а найбільшу товщину (35 мкм) – при пошаровому ЕІЛ у послідовності Cr- Nb.
Практичне значення: одержані в роботі результати та з’ясовані закономірності формування структури та характеристик модифікованих шарів під час електроіскрового легування можуть бути застосовані для подовження строку експлуатації деталей машин та механізмів.The object of the study is the surface layers of 40X steel, obtained by electrospark doping with chromium and niobium anodes in air. The aim of the work is to establish the influence of EIL chromium and niobium sequences on the microstructure, phase composition and microhardness of 40X steel surface layers. Research methods - gravimetric, microstructural, microdyurometric and X-ray phase. The possibility of forming reinforced coatings (microhardness 9.5 GPa – 14.5 GPa and thickness 20 μm – 35 μm) by electrospark alloying of Cr and Nb steel 40X with different sequence of anode materials application is shown. The influence of chromium and niobium deposition during electrospark alloying of 40X steel on the surface microhardness, phase composition and microstructure of the modified layer was established. It was found that the alloyed layer has the highest microhardness (14.5 GPa) after the EIL of Nb steel, and the greatest thickness (35 μm) - with layered EIL in the Cr-Nb sequence. Practical significance: the results obtained in the work and the regularities of the formation of the structure and characteristics of the modified layers during electrospark alloying can be used to extend the service life of machine parts and mechanisms.
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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.
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DeArdo, Ian A. "Mechanical behavior of IF 409 ferritic stainless steel." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21287.
Повний текст джерелаАнотація:
IF 409 stainless steel is a common industrial steel grade used in automotive exhaust systems. It combines a high formability with the corrosion resistance associated with stainless steels. Two particular grades of IF 409 were used in these experiments: a titanium stabilized and a titanium-niobium stabilized. The current work explores the mechanical behavior Of this grade with emphasis on the occurrence of dynamic recrystallization. Hot torsion tests were performed over a range of temperatures and strains to determine the behavior. The tests were analyzed using the flow curves, optical microscopy and texture measurements. The optical micrographs indicated that dynamic recrystallization was occurring. The texture results confirmed that the titanium stabilized steel dynamically recrystallized around 1000°C and the titanium-niobium grade recrystallized around 1200°C. In addition, the effects of strain and temperature were quantified. The results allow the feasibility of dynamic recrystallization in industrial applications to be determined.
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DeArdo, Ian A. "Mechanical behavior of IF 409 ferritic stainless steel." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0025/MQ50600.pdf.
Повний текст джерела
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Chan, Phillip. "Jet impingement boiling heat transfer at low coiling temperatures." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/401.
Повний текст джерелаАнотація:
The production of advanced high strength steels (AHSS) for use in the automotive and construction industries requires complex control of runout table (ROT) cooling. Advanced high strength steels require coiling at temperatures below 500 °C in order to produce a complex multi-phase microstructure. The research described here will investigate the boiling conditions that occur for moving plate experiments when steel is cooled towards low coiling temperatures.
Experiments were performed on a pilot-scale ROT located at the University of British Columbia using industrially supplied steel plates. Tests were performed for four different speeds (0.3, 0.6, 1.0 and 1.3 m/s) and three different initial plate temperatures(350, 500 and 600 °C). Each plate was instrumented with thermocouples in order to record the thermal history of the plate.
The results show that cooling is more effective at slower speeds within the stagnation zone for surface temperatures over 200 °C. Outside the stagnation zone regardless of speed cooling is primarily governed by air convection and radiation with minor effects from latent heat caused by splashing water. The maximum peak heat flux value increases with decreasing speed and occurs at a surface temperature of approximately 200 °C, regardless of speed. Below a surface temperature of 200 °C, speed has a negligible effect on peak heat flux. The maximum integrated heat flux seems to vary with speed according to a second order polynomial.
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Moses, Robert. "Precipitation behaviour of IF 409 ferritic stainless steels." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22665.
Повний текст джерелаАнотація:
Five slightly different IF 409 ferritic stainless steels were investigated by means of continuous cooling compression (CCC) testing. These compression test were performed at a constant strain rate of $1.8 times10 rm sp{-4}s sp{-1}$ over a 600$ sp circ$C temperature range (i.c. from 1200$ sp circ$C- 600$ sp circ$C) at four different cooling rates (0.25, 0.5. 1.0 and 2.0$ sp circ$C/sec). The reheating temperature and time were varied and the effect of this on precipitation is discussed.The analysis of the CCC test results, and the optical microscopy observations, indicated that neither solute drag nor phase transformation is responsible for the deviations observed in these flow curves. TEM bright field images were used to verify the presence of precipitates, and to calculate the strengthening influence of these particles on the flow curve. It is shown that, in the niobium bearing materials, the precipitation of carbonitrides is responsible for the increase in flow stress. Conversely, in the titanium bearing materials, the titanium carbonitride precipitates were determined to have no effect on the flow stress.
It was discovered that increasing the solution temperature and time resulted in the occurrence of precipitation at higher temperatures, and that these precipitates were coarsened to a greater extent. Also, when the holding temperature and/or the holding time was decreased, the amount of niobium put into solution decreased, which led to precipitation starting at lower temperatures.
A method was developed for determining the precipitation start and finish temperatures from the CCC results. These temperatures were converted to precipitation start and finish times for each of the four cooling rates. This revealed that the precipitation start and finish times increase with decreasing cooling rate in both the 0.2% Nb and 0.1% Nb + 0.1% Ti stainless steels. Finally, a continuous cooling precipitation diagram was constructed for the two niobium bearing materials using these start and finish times.
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Tojal, Thaise Lima. "Contribuição ao estudo da aderência de barras de aço em concreto autoadensável reforçado com fibras metálicas." Universidade Federal de Alagoas, 2011. http://repositorio.ufal.br/handle/riufal/402.
Повний текст джерелаАнотація:
One of the conditions of existence assigned to the concrete as a building material is the adhesion between the concrete and steel. This adhesion has been the subject of several research studies that give rise to models that mathematically describe the behavior of adhesion; present testing techniques and in analysis of the influence of different factors that affect the concrete-steel adhesion. With the technological advancement of the concrete there were some special concrete compositions which contain chemical additives and minerals, and fiber, as is the case of self compacting concrete and concrete reinforced with fibers. These special concretes have shown different behavior compared to conventional concrete, contributing to an improved system of steel-concrete adhesion. Thus, this study used the pullout test of a steel bar of a massive concrete, following the standard model of RILEM-CEB-FIP (1973) known as Pull Out Test (Steel Reinforced Bond Test) were used conventional concrete, self compacting concrete and self compacting concrete with the addition of 1% steel fibers and steel bars used were 10mm and 16mm od diameter. The analyses were based on curves that describe the behavior of the loss of adhesion between the concrete and steel, the tension of pullout of the steel rod and the characteristics presented by the massive concrete during and at the end of the research. The self compacting concrete had a gain of lead capacity in the loss of adhesion compared to conventional concrete, and the addition of steel fibers in this concrete promoted a significant increase in the load required to pull the steel bar of the massive concrete, and this had less damage essay, compared to other specimens of concrete.Fundação de Amparo a Pesquisa do Estado de Alagoas
Uma das condições de existência atribuídas ao concreto armado como material de construção é a aderência existente entre o concreto e o aço. Essa aderência tem sido motivo de estudos em várias pesquisas que dão origem aos modelos que descrevem matematicamente o comportamento da aderência; apresentam técnicas de ensaios e fazem análise da influência de diferentes fatores que interferem na ligação concreto-aço. Com o avanço tecnológico do concreto surgiram alguns concretos especiais cujas composições contêm o uso de aditivos químicos e minerais, além de fibras, como é o caso dos concretos autoadensáveis e dos concretos reforçados com fibras. Esses concretos especiais têm demonstrado comportamento diferenciado em relação aos concretos convencionais, contribuindo para uma melhora do sistema de ligação concreto-aço. Neste sentido, este estudo utilizou o ensaio de arrancamento de uma barra de aço de um maciço de concreto, seguindo o modelo padrão da RILEM-CEB-FIP (1973) conhecido como Pull Out Test (Bond Test Reinforced Steel), foram utilizados o concreto convencional, o concreto autoadensável e o concreto autoadensável com a incorporação de 1% de fibras metálicas e as barras de aço utilizadas foram as de diâmetro de 10mm e 16mm. As análises foram baseadas nas curvas que descrevem o comportamento da perda da aderência entre o concreto e o aço, das tensões de arrancamento da barra de aço do maciço de concreto e das características apresentadas pelos corpos de prova no decorrer e no final do ensaio. O concreto autoadensável apresentou ganho de capacidade de carga na perda da aderência em relação ao concreto convencional, e a adição das fibras metálicas a este concreto autoadensável promoveu um significativo aumento da carga necessária para arrancar a barra de aço do maciço de concreto, e este apresentou menos avarias ao final deste ensaio se comparado aos corpos de prova dos outros concretos.
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Berton, Elisiane Maria. "Efeito das temperaturas de têmpera e de revenido na resistência à corrosão da camada martensítica de alto nitrogênio produzida por SHTPN sobre o aço AISI 409." Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/958.
Повний текст джерелаАнотація:
CNPq, CAPES, FINEPDevido à alta resistência a corrosão, os aços inoxidáveis possuem uma larga aplicabilidade em diversos setores industriais, seja indústria química, petroquímica ou alimentícia. Buscando atender solicitações ainda mais severas, métodos que melhorem a relação resistência à corrosão e propriedades mecânicas destes aços tem sido objeto de estudo de diversos pesquisadores. Com o objetivo de aumentar a resistência mecânica, dureza superficial e resistência à corrosão dos aços inoxidáveis propôs-se a introdução de nitrogênio em solução sólida pelo processo de SHTPN (Solution Heat Treatment after Plasma Nitriding), em desenvolvimento no GrMaTS/UTFPR. O nitrogênio apresenta algumas vantagens como a redução da tendência à precipitação, e a estabilização da camada passiva. Além disso, o nitrogênio reage na área anódica, o que neutraliza o efeito da acidez melhorando assim a resistência a corrosão. Neste trabalho avaliou-se a resistência à corrosão do aço inoxidável ferrítico AISI 409, após a obtenção de uma camada martensítica enriquecida com nitrogênio em solução solida por meio do processo SHTPN. Em seguida foram avaliados os efeitos da temperatura de revenimento (200, 400 e 600 °C) e da temperatura de austenitização (950 e 1050 °C) na microestrutura, dureza e resistência à corrosão da camada martensítica obtida. A resistência à corrosão foi avaliada pela técnica de polarização cíclica em solução de NaCl 0,5 mol/L e os perfis de dureza obtidos por medição de dureza Vickers com carga de 0,05 Kgf (0,49 N). A microestrutura foi avaliada por Microscopia Óptica, Eletrônica de Varredura e por Difração de Raios-X. Os resultados indicam que o tratamento de SHTPN promoveu a formação de uma camada martensítica de nitrogênio, com consequente acréscimo de dureza de 160 HV para 580 HV. O tratamento têmpera após SHTPN não afetou significativamente a dureza do aço, contudo, refinou e melhorou a distribuição da martensita de nitrogênio. Os resultados de corrosão para as condições tratadas e revenidas a 200 °C indicam resistência à corrosão superior ou equivalente à da ferrita do material não tratado (AISI 409). Já as amostras revenidas nas temperaturas de 400 e 600 °C apresentaram um decréscimo na resistência à corrosão, bem como foi observada uma diminuição da dureza da amostra revenida a 600 °C.
Due to high corrosion resistance, stainless steels have a wide applicability in many industrial sectors, such as, chemical, petrochemical and food industries. With the demand for corrosion resistance materials becoming more stringent, methods that improve the relation corrosion resistance and mechanical properties of these steels has been studied by many researchers. In order to increase the mechanical strength, surface hardness and corrosion resistance of stainless steels we proposed the introduction of nitrogen in solid solution by the process of SHTPN (Solution Heat Treatment after Plasma Nitriding), under development in GrMaTS/UTFPR . Nitrogen in solid solution has some advantages over materials that have only carbon in the structure such lower tendency for precipitation and stabilization of the passive layer. In addition, the nitrogen reacts in the anodic area, which neutralizes the effect in the acidity thus improving the corrosion resistance. This research evaluate the corrosion resistance of ferritic stainless steel AISI 409, after obtaining a martensitic layer enriched with nitrogen, in solid solution, by SHTPN process. Effects of tempering temperature (200, 400 and 600 °C) and austenitization temperature (950 to 1050 °C) in the microstructure, hardness and corrosion resistance of martensitic layer obtained. Corrosion resistance was evaluated by cyclic polarization technique, with a NaCl solution 0.5 mol/L, and hardness profiles obtained by measuring the Vickers hardness with a load of 0.05 kgf (0.49 N). Samples microstructure was investigated by optical microscopy, scanning electron microscopy and X- ray diffraction. Results indicate that the treatment of SHTPN promoted the formation of a martensitic nitrogen layer, with consequent increase of hardness of 160 HV to 580 HV on sample surface. Tempering treatments, realized after SHTPN did not significantly affect the hardness of steel, however, has refined and improved the distribution of nitrogen martensite. Corrosion results of sample treated and annealed at 200 °C indicate higher or equal resistance to that of the untreated ferrite materials (AISI 409) corrosion. Samples that were annealed at temperatures of 400 and 600 °C showed a decrease in the corrosion resistance as well as a decrease in hardness was observed in the sample tempered at 600 °C.
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Assumpção, Roberto Luís de. "Resistência a corrosão da camada martensitica formada na superfície do aço inoxidável ferrítico 409 tratado por SHTPN." Universidade Tecnológica Federal do Paraná, 2013. http://repositorio.utfpr.edu.br/jspui/handle/1/681.
Повний текст джерелаАнотація:
CNPqOs aços inoxidáveis são amplamente utilizados nas indústrias químicas, petroquímicas, nucleares, de geração de energia, biomédica e de processamento de alimentos. Em geral os aços inoxidáveis apresentam boa resistência à corrosão, entretanto a aplicabilidade destes aços pode ser restringida pela dureza ou pela resistência a corrosão. Usualmente os aços de alta resistência e dureza apresentam elevados teores de carbono, apresentando uma estrutura martensítica, com consequente redução da resistência à corrosão. Por outro lado os aços com maior resistência a corrosão apresentam menor dureza e consequente menor resistência ao desgaste. Diversas soluções têm sido implementadas no sentido de melhorar a resistência a corrosão e ao desgaste simultaneamente desses materiais. Dentre estas a adição de nitrogênio na superfície através da nitretação a plasma, implantação iônica, tratamento térmico de solubilização após nitretação a plasma (SHTPN – Solution Heat Treatment after Plasma Nitriding). Este trabalho tem como objetivo determinar os parâmetros de SHTPN que possibilite obter martensita de nitrogênio na superfície do aço AISI 409, bem como, a avaliação de sua resistência à corrosão. Foi possível verificar uma melhora na resistência à corrosão das condições tratadas por SHTPN, assim como um aumento na resistência mecânica, avaliado pelo perfil de dureza da camada superficial tratada.
Stainless steels are widely used on chemical, petrochemical, nuclear, energy generation, biomedical and food processing industries. In general, stainless steels present good corrosion resistance. However, the application of these materials can be restrained by the hardness and the corrosion resistance. Usually, high strength steels present high carbon content and martensitic structure, what can consequently cause a reduction on corrosion resistance. On the other hand, high corrosion resistance steels present low hardness and weak wear properties. Thereby, many solutions have been made to improve simultaneously wear properties and corrosion resistance of these materials, specially related to the introduction of nitrogen on the surface, through plasma nitriding, ion implantation and SHTPN (Solution Heat Treatment after Plasma Nitriding) processes. The aim of this paper is to determine SHTPN parameters that can form nitrogen martensite on the surface of AISI 409 stailess steel, as well as the evaluation of its corrosion resistance. It was verified an improve on corrosion resistance conditions of SHTPN treated samples. Aditionally, there was an improve on mechanical resistance showed by hardness profiles.
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Souza, Juliana Sarango de. "Estudo da corrosão por pite do aço AISI 409." reponame:Repositório Institucional da UFABC, 2016.
Знайти повний текст джерелаАнотація:
Orientador: Prof. Dr. Renato Altobelli AntunesDissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, 2016.
Os aços inoxidáveis são susceptíveis à corrosão por pite quando expostos à ambiente contendo íons agressivos. Esse fenômeno ocorre devido à quebra do filme passivo. O material estudado neste trabalho foi o aço inoxidável AISI 409. O comportamento de corrosão e a estabilidade do filme passivo foram investigados por ensaios eletroquímicos, utilizando as técnicas de espectroscopia de impedância eletroquímica, polarização potenciodinâmica, análise de Mott-Schotky e cronoamporometria. Os testes foram realizados em solução de 0,1 M de NaCl. Os pites formados foram visualizados por microscopia confocal a laser e tiveram suas dimensões medidas. Análise com MEV da amostra antes e após o ensaio de polarização foi realizado e locais de ocorrência dos pites foi registrado. Foram analisadas amostras na condição como-recebida e na condição solubilizada. O tratamento de solubilização foi realizado na temperatura de 1100 °C por 30 minutos, com o objetivo de homogeneizar a microestrutura dos materiais. Os resultados obtidos foram analisados e discutidos, dando ênfase para a compreensão do processo de corrosão por pite do aço inoxidável AISI 409 nas condições comorecebida e solubilizada. Foi verificada a presença de precipitados ricos em titânio nas amostras. Na amostra como-recebida, os precipitados compostos por Ti (C,N) colaboraram para o início da corrosão localizada. Na amostra solubilizada os precipitados foram identificados como TiN e a ocorrência da corrosão por pite foi dificultada.
Stainless steels are susceptible to pitting corrosion when exposed to environment containing aggressive ions. This phenomenon occurs due to the breakdown of the passive film. Stainless steel AISI 409 was studied in this work. The corrosion behavior and the stability of the passive film were investigated by electrochemical tests, using electrochemical impedance spectroscopy, potentiodynamic polarization, Mott-Shottky analysis and choronoamperometry measurements. The tests were carried out in NaCl 0.1 M solution. The pits formed were observed and measured by confocal laser scanning microscopy. SEM images were carried out before and after the potentiodynamic polarization and the regions associated with pitting formation were recorded. Samples were analyzed in the as-received and solutionized conditions. The solution annealing treatment was performed at 1100 °C for 30 minutes in order to homogenize the microstructure of the materials. The results obtained were analyzed and discussed, giving emphasis to the understanding of the pitting corrosion behavior of the AISI 409 stainless steel in the as-received and solutionized states. The presence of titanium-rich precipitates in the samples was checked. In the as-received state, Ti (C,N) precipitates have contributed to the onset of pitting corrosion. For the solution annealed samples the precipitates were identified as TiN and the occurrence of pitting corrosion was difficult.
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Loetzsch, Martin Verfasser], Hans-Dieter [Akademischer Betreuer] Burkhard, Luc [Akademischer Betreuer] [Steels, and Raúl [Akademischer Betreuer] Rojas. "Lexicon formation in autonomous robots / Martin Loetzsch. Gutachter: Hans-Dieter Burkhard ; Luc Steels ; Raul Rojas." Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2015. http://d-nb.info/1066727120/34.
Повний текст джерела
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Loetzsch, Martin [Verfasser], Hans-Dieter Akademischer Betreuer] Burkhard, Luc [Akademischer Betreuer] [Steels, and Raúl [Akademischer Betreuer] Rojas. "Lexicon formation in autonomous robots / Martin Loetzsch. Gutachter: Hans-Dieter Burkhard ; Luc Steels ; Raul Rojas." Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2015. http://d-nb.info/1066727120/34.
Повний текст джерела
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Adiguzel, Sinem. "Determining Surface Residual Stress In Steel Sheets After Deep Drawing And Bulging Processes." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613054/index.pdf.
Повний текст джерелаАнотація:
The aim of this thesis is to investigate the effects of bulging and deep drawing processes on St4 cold rolled steel by simulation and experimental characterization. In the simulations, commercial software programs MSC Marc and Simufact.forming were used. The experimental studies cover metallographic investigations, hardness measurements, and residual stress measurements. Residual stress measurements were carried out by different non- destructive characterization methodsX-ray diffraction and Magnetic Barkhausen Noise. The experimental and simulation results were correlated with each other.
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Sonmez, Caglar. "Investigation Of The Deep Drawability Of Steel And Aluminum Sheets By Finite Element Simulation." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606007/index.pdf.
Повний текст джерелаАнотація:
Sheet metal forming processes, especially deep drawing processes give diverse results by various materials. Extreme differences occur between steel sheets and aluminum sheets. The main causes of this variance are anisotropy, elastic modulus and microscopic material properties.
The aim of this thesis is to evaluate the deep drawing properties and also to develop suitable process parameters for aluminum and steel sheets by finite element simulation. In the simulation, the commercial dynamic-explicit code PAM-STAMP has been used. The reliability of the finite element package was verified by a comparison with the NUMISHEET 2002 benchmarks. Additionally, a commercial part is numerically simulated for experimental verification. The results of the simulations have been compared with several experiments that were performed in Metallurgical and Materials Engineering and Mechanical Engineering Departments. Finally, the simulation results are compared with analytical expressions for verification of results.
The materials investigated for the deep drawability comparison is a deep drawing quality mild steel and an aluminum alloy designated as 6111-T4. For experimental verification St4 steel is used.
Results are in agreement with the fact that aluminum and steel materials behave differently upon deep drawing in terms of the onset of failure, wrinkling and final shape. Aluminum is found to be less formable than steel for cup drawing operations.
15
Simsir, Caner. "3d Finite Element Simulation Of Steel Quenching In Order To Determine The Microstructure And Residual Stresses." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609412/index.pdf.
Повний текст джерелаАнотація:
In the course of thermal treatments, materials are usually subjected to continuous heating and cooling cycles during which microstructural evolution and mechanical interactions occur simultaneously at different length and time scales. Modeling of these processes necessitates dealing with inherent complexities such as large material property variations, complex couplings and boundary conditions, coupled heat and mass transfer mechanisms and phase transformations. In this study, a mathematical framework based on finite element method (FEM) capable of predicting temperature history, evolution of phases and internal stresses during heat treatment of metals and alloys was developed. The model was integrated into the commercial FEA software MSC.Marc®by user subroutines. The accuracy of the model was verified by simulating the quenching of eccentrically drilled steel cylinders. Simulation results were justified via SEM observations and XRD residual stress measurements. According to the results, the model can effectively predict the trends in the distribution of microstructure and residual stresses with a remarkable accuracy.
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Sklenář, Zdeněk. "Svařování otěruvzdorných ocelí laserovým svazkem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230125.
Повний текст джерелаАнотація:
The project, prepared by the engineering study compares the welding abrasive steel HARDOX 400, fiber laser welding method, which will be compared with a MAG welding method and using different protective gases (argon and helium). In the theoretical part, i worked both welding technology's and the issue of high-strength steel. In the experimental part were performed and evaluated by destructive mechanical testing and bending test, the transverse tension test, test macrostructure and microstructure of welds. In conclusion the thesis deduced the final results of the experiment.
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PADIAL, ARMANDO G. F. "Caracterizacao microestrutural do aco maraging de grau 400 de resistencia mecanica ultra-elevada." reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10998.
Повний текст джерелаАнотація:
Made available in DSpace on 2014-10-09T12:46:42Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T13:56:09Z (GMT). No. of bitstreams: 1 07613.pdf: 5555459 bytes, checksum: 0047c9f052248797761d648268e841ba (MD5)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Ayan, Elif. "Parameter Optimization Of Steel Fiber Reinforced High Strength Concrete By Statistical Design And Analysis Of Experiments." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/1051960/index.pdf.
Повний текст джерелаАнотація:
This thesis illustrates parameter optimization of compressive strength, flexural
strength and impact resistance of steel fiber reinforced high strength concrete
(SFRHSC) by statistical design and analysis of experiments. Among several
factors affecting the compressive strength, flexural strength and impact
resistance of SFRHSC, five parameters that maximize all of the responses have
been chosen as the most important ones as age of testing, binder type, binder
amount, curing type and steel fiber volume fraction. Taguchi and regression
analysis techniques have been used to evaluate L27(313) Taguchi�
s orthogonal array and 3421 full factorial experimental design results. Signal to noise ratio transformation and ANOVA have been applied to the results of experiments in Taguchi analysis. Response surface methodology has been employed to optimize the best regression model selected for all the three responses. In this study Charpy Impact Test, which is a different kind of impact test, have been applied to SFRHSC for the first time. The mean of compressive strength, flexural strength and impact resistance have been observed as around 125 MPa, 14.5 MPa and 9.5 kgf.m respectively which are very close to the desired values. Moreover, this study is unique in the sense that the derived models enable the identification of underlying primary factors and their interactions that influence the modeled responses of steel fiber reinforced high strength concrete.
19
Andrade, Milton. "Heavy metal removal from bilge water by electrocoagulation treatment." ScholarWorks@UNO, 2009. http://scholarworks.uno.edu/td/1092.
Повний текст джерелаАнотація:
The purpose of this research was to observe the removal efficiency for copper (Cu), nickel (Ni), and zinc (Zn) using Electrocoagulation (EC) technique in a continuous flow reactor with a synthetic bilge water emulsion; and additionally, to discuss the operation cost of the treatment. The optimal configuration for EC treatment used combined electrodes, aluminum and carbon steel; flow rate of 1 L/min; effluent recycling and 7.5 amps; this optimal configuration achieved 99% of zinc removal efficiency, 70% of both, copper and nickel removal efficiency, and low operation costs. The current intensity did not have significance incidence on the removal efficiency. The analysis of cost per gram of removed contaminant indicated that nickel had an average cost of $1.95 per gram removed, zinc and copper had $0.60 and $0.88 per gram removed, respectively. To develop additional experiments with the EC reactor are required in order to optimize metal removal efficiency.
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Morel, Bayram Murat. "Investigation Of The Effects Of Temperature On Physical And Mechanical Properties Of Monolithic Refractory Made With Pozzolanic Materials." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606700/index.pdf.
Повний текст джерелаАнотація:
In recent years, scientific studies are carried out to find new refractory
material. Having good mechanical properties under very high temperatures,
refractories are widely used in industries like iron, steel, glass, cement and pottery.
Researches are focused on monolithic refractory making because of their superior
properties comparing to conventional firebrick refractories. Providing a mono-block
body, having no joints makes the monolithic refractories more durable at elevated
temperatures. Easier production and installation are two main points that people are
choosing monolithic refractories, thus an economy is made.
In this study, for monolithic refractory production, high alumina cement was
used as binding material. It is known that the increase in alumina (Al2O3) content
increases the high temperature resistance, so that crushed firebrick, having 85%
Al2O3 was used as aggregate. Pozzolanic materials, which are silica fume, fly ash,
ground granulated firebrick and ground granulated blast furnace slag, were added to
improve physical and mechanical properties of mortar. With the addition of steel
fibres, change in compressive strength and flexural strength was observed.Superplasticizer was used to understand its behaviour under high temperatures.
Portland cement containing mortars were also prepared to make comparison with
high alumina cement containing specimens.
Specimens were prepared in 5x5x5 cm and 4x4x16 cm prisms. They were
cured for one day at curing room, then heated to 105°C and then heated to 1100°
C. Weight, size and ultrasound velocity change, compressive strength and flexural strength tests were done to determine physical and mechanical properties of the monolithic refractories, before and after heating. Heated and non-heated specimens were pulverized for microstructural investigation with X-Ray diffraction (XRD) method. Using high alumina cement with 50 &ndash
60 % granulated blast furnace slag or granulated firebrick, by the weight of cement, and crushed firebrick as aggregate, a satisfactory monolithic refractory material was made. It was observed that, mechanical properties were decreased at the Portland cement used mortars after several times of heating and cooling cycles. Also, it was determined that the microstructure of the high alumina cement containing mortars did not deteriorate much at 1100°
C, as long as there was no change observed from the results.
21
Hung, Chia-Po, and 洪佳博. "Hydrogen Embrittlement of AISI 403 Stainless Steel." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/50957527070156974501.
Повний текст джерелаАнотація:
碩士國立臺灣海洋大學
材料工程研究所
93
The aim of this work is to study the effect of cold work on hydrogen embrittlement and mechanical in AISI 403 stainless steel. Hydrogen embrittlement of as received, 10% and 20% cold worked AISI 403 stainless steel has been evaluated by using electrochemical permeation measurement and tensile test in this study. For electrochemical permeation measurement, it is known that hydrogen effective diffusivity and permeation rate increase with increase cold work. Cold may cause some micro-crack in microstructure, thus resulting in the high rate of hydrogen permeation. For slow train rate tests, the ultimate tensile strength increase with the amount of cold work, while elongation decrease with cold work. After hydrogen charging, hydrogen diffused into the the microstructure, resulting the elongation decayed significantly. The fractography of precharged specimens shows that the ductile fracture has changed to the brittle fracture, and some hydrogen-assisted secondary cracks were also observed in the specimens.
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Shaigan, Nima. "Protective/Conductive Coatings for Ferritic Stainless Steel Interconnects Used in Solid Oxide Fuel Cells." Phd thesis, 2009. http://hdl.handle.net/10048/402.
Повний текст джерелаАнотація:
Ferritic stainless steels are the most commonly used materials for solid oxide fuel cell interconnect application. Although these alloys may meet the criteria for interconnect application for short periods of service, their application is limited for long-term use (i.e., 40,000 h) due to poor oxidation behaviour that results in a rapid increase in contact resistance. In addition, volatile Cr species migrating from the chromia scale can poison the cathode resulting in a considerable drop in performance of the cell. Coatings and surface modifications have been developed in order to mitigate the abovementioned problems.
In this study, composite electrodeposition of reactive element containing particles in a metal matrix was considered as a solution to the interconnect problems. Nickel and Co were used as the metal matrix and LaCrO3 particles as the reactive element containing particles. The role of the particles was to improve the oxidation resistance and oxide scale adhesion, while the role of Ni or Co was to provide a matrix for embedding of the particles. Also, oxidation of the Ni or Co matrix led to the formation of conductive oxides. Moreover, as another part of this study, the effect of substrate composition on performance of steel interconnects was investigated.
Numerous experimental techniques were used to study and characterise the oxidation behaviour of the composite coatings, as well as the metal-oxide scale interface properties. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX), as well as surface analysis techniques including Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS), were used for the purpose of characterization. The substrate used for coating was AISI-SAE 430 stainless steel that is considered as a typical, formerly used interconnect material. Also, for the purpose of the metal-oxide scale interfacial study, ZMG232 stainless steel that is a specially designed interconnect alloy was used.
It is shown that the composite coatings greatly reduce the contact resistance and effectively inhibit Cr outward migration. In addition, it was determined that the presence of impurities in the steel, especially Si, and the absence of reactive elements drastically contribute to interconnect degradation.Materials Science and Engineering
23
Chang, Y. M., and 張育民. "Fatigue Crack Growth of 403 Stainless Steel Hardened by Laser." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/07857659794546967055.
Повний текст джерела
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Sue, Yu-Cheng, and 蘇育誠. "Slurry Erosion Characteristics of Hot Rolled SUS 403 Stainless Steel." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/15773656006220617059.
Повний текст джерелаАнотація:
碩士中華技術學院
機電光工程研究所碩士班
97
The slurry erosion characteristics of hot-rolled SUS 403 stainless steel was studied in a function of reduction ratios and temperatures. The experimental material was hot rolled with reduction ratios of 15, 30 and 50%. Then, the sample of 50% reduction ratio was tempered at 200-500℃ to investigate the influence of tempering temperatures on the erosion. Both 15% and 30% reduction ratio samples were tempered at 500℃ to compare the effect of rolling reduction ratio on the erosion with those of 50% reduction ratio sample. In this study, the erosion mode, rolling reduction, tempering temperature, grain size and mechanical properties repeat to erosion rate at different impact angle were discussed partially. The results show that a fine grained structure was obtained after hot rolling and the grain size decreased with increasing in reduction. The dominated mechanism for material removal at oblique impact angle (15° and 30°) is cutting. At higher impact angle (90°), the mechanism is based on extrusion crater. However, at medium impact angle (45° and 60°), the wear is dominated by transition of mechanism mixed with cutting and crater. For all reduction ration samples, when the samples were tempered at 500℃, the maximum erosion rate occurred at impact angle of 30°, while the minimum erosion rate occurred at normal impact angle. When the 50% reduction samples were tempered at 200-500℃, apart the 200℃ tempering sample, the maximum erosion rate occurred at impact angle of 45°, the others were at impact angle of 30°. Generally, the maximum erosion rate decreased with increasing in reduction ratios. Because the tensile strength, hardness, ductility and toughness were increased with decreasing in grain size, and then the erosion resistance was improved. The XRD analysis also show that the strain-induced transformed ε-martensite increased with increasing in impact angle.
25
Pettus, Jeremy Glen. "Evaluation of experimental bridge Massman Drive bridge over Interstate 40 in Davidson County /." 2005. http://etd.utk.edu/2005/PettusJeremy.pdf.
Повний текст джерелаАнотація:
Thesis (M.S.) -- University of Tennessee, Knoxville, 2005.Title from title page screen (viewed on Sept. 6, 2005). Thesis advisor: Edwin G. Burdette. Document formatted into pages (xii, 85 p. : ill. (some col.)). Vita. Includes bibliographical references (p. 35-37).
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Huang, Chao-Jan, and 黃昭然. "Study on Mechanical and Ultrasonic Properties of SUS 403 Martensitic Stainless Steel after TMT Treatments." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/6aqmhj.
Повний текст джерелаАнотація:
碩士大同大學
材料工程學系(所)
95
SUS 403 martensitic stainless steels is commonly used in high stress parts such as nuclear power plant. This research has used thermal mechanical treatment (TMT) to improve the disadvantages of coarse grain size of SUS 403 stainless steels. In general, finer grain sizes have several advantages on mechanical properties, such as increasing ultimate tensile strength, ductility, hardness and impact toughness. Also, the degree of grain fineness can result in the difference in ultrasonic responses because the sound waves traveling in the material interact with grain boundaries which show up the variation of ultrasonic velocity and ultrasonic attenuation. Thus, the purpose of this study is to explore the possibility that grain size refinement of SUS 403 by TMT processing and the relationship between its mechanical properties and ultrasonic characteristics. It was found that the as-received SUS 403 was composed of ferrite and martensite phases with high chromium alloy carbides at grain boundary. After austenitization at 1010℃ for 2hrs, the carbides was dissolved into matrix. In addition, the grain sizes were refined with the increase of the rolled amount. The average grain size is 60~100µm for 20% rolled material and 10~20µm for 40% rolled material as compared to the as-received (>100µm). Moreover, the mechanical properties consisting of tensile strength, ductility, hardness and impact toughness were all improved when the grain sizes were refined. From the experimental results, it was also found that the carbides reappeared after tempering at 300℃~600℃. In particular, tempering at 500℃, fine alloy carbides were precipitated from martensite resulting in secondary hardening of this material. However, elongation decreased. Higher temperature tempering (>600℃) could increase impact toughness and ultimate tensile strength but hardness decrease. It is because martensite was decomposited to form ferrite. In the case of ultrasonic properties, it was found that ultrasonic velocity decreased and ultrasonic attenuation increased with the refinement of grain size. Moreover, it was found that the second hardening occurred at the ultrasonic velocity of 5888~5894m/s for 20% rolled material and of 5886m/s for 40% rolled material; and its ultrasonic attenuation is 0.130054dB/mm for 20% rolled material and 0.134408dB/mm for 40% rolled material, respectively.