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Shtefan, V. V., Nadiia Kanunnikova, A. Smyrnov, and T. Shepil. "Corrosion resistance of AISI 304 steel from compositional oxide coatings." Thesis, Фізико-механічний інститут ім. Г. В. Карпенка Національної академії наук України, 2020. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48897.
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Shtefan, V. V., Nadiia Kanunnikova, Nataliia Balamut, and Mariia Bofanova. "Influence of chloride on the anode dissolution of aisi 304 steel." Thesis, Sp. z o.o. "Diamond trading tour", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/39039.
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The kinetics of anodic dissolution of stainless steel in acidic sulphate-chloride solutions was studied. The regularities of changes in the electrochemical parameters (stationary potential, passivation potential, passivation current density, transpassivation potential) with varying concentration of NaCl are established.
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Buzit, Sebastien. "Evolution of crystallographic textures and TRIP effects in stainless steel AISI 304." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/19584.
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Sheen, Martin. "Static recrystallization behaviour of AISI 304 stainless steel during hot rolling intervals." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/5472.
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Mozhi, T. Arul. "The effect of nitrogen on sensitization and stress corrosion cracking of AISI 304 stainless steels /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487265143147533.
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Betrabet, Hemant Shridhar. "The influence of nitrogen on the sensitization and microstructural properties of AISI 304 stainless steels /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487264603219054.
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Li, Jing Hui. "Effects of metallurgical variables on the cavitation erosion behaviour of AISI 304 austenitic stainless steel." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691682.
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Costa, Rytney Santos. "Estudo da corrosão do aço inox AISI 304 em álcool etílico hidratado combustível." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265275.
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Orientador: Rodnei BertazzoliTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: O Brasil, em busca de combustíveis alternativos, menos poluentes e com sustentabilidade econômica eficiente, apresentou uma solução para suas necessidades, acrescentando na sua matriz energética o etanol combustível e com isto, submeteu materiais metálicos dos sistemas veiculares e tanques de armazenamento de combustível a processos corrosivos. Aços inoxidáveis têm se mostrado uma alternativa viável, no entanto é necessário estudos para obter dados que permitam averiguar a suscetibilidade desse material a processos corrosivos neste novo meio. O enfoque deste trabalho é analisar os efeitos da corrosão do álcool etílico hidratado combustível (AEHC) sobre o aço inox AISI 304 nas condições de sobtensão e sem tensão, fundamentando-se na possível influência da corrosão nas propriedades mecânicas da liga. Foram realizados ensaios de imersão em longo prazo para avaliação de perda de massa e observação por microscopia eletrônica de varredura (MEV). Paralelamente, amostras na forma de corpos de prova para ensaios de tração e fadiga, foram imersos no meio (AEHC) para avaliação dessas propriedades. Os resultados acusaram, a partir de 3456 horas de imersão, ganho de massa nas condições tensionadas e não tensionadas, sugerindo a ocorrência de passivação do metal. Imagens obtidas por MEV mostraram a formação de pites, cujo tamanho evoluiu em função do tempo de imersão. O ensaio eletroquímico com utilização arranjos de microeletrodos de diâmetros de 10, 20, 30, 100, 200 e 500 ?m acusou baixa corrente de corrosão. As propriedades mecânicas de resistência à tração, limite de escoamento e deformação específica não se mostraram influenciáveis aos efeitos corrosivos do meio sobre a liga. O ensaio de fadiga, usando os parâmetros da distribuição de probabilidade de Weibull e a durabilidade característica (?), mostrou redução da resistência à fadiga da liga quando imersa em AEHC, evidenciando que o meio corrosivo, contendo cloreto, inicializou a nucleação de pites e potencializou a formação de trincas durante os ensaios de fadiga, favorecendo a redução do limite de resistência à fadiga do aço inox AISI 304
Abstract: The Brazil, in search of alternative fuels, cleaner and with economic efficiency, presented a solution to their needs, adding its energy in the fuel ethanol and with that submitted materials of metal vehicle systems and storage tanks of fuel processes corrosive. Stainless steels have proven a viable alternative; however it is necessary studies to obtain data to determine the susceptibility of this material to corrosive processes in this new medium. The focus of this paper is to analyze the effects of corrosion of hydrous ethanol (AEHC) on AISI 304 stainless steel under conditions of tension and without tension, the ground of the possible influence of corrosion on the mechanical properties of the alloy. Immersion tests were conducted to evaluate long-term weight loss and observation by scanning electron microscopy (SEM). In parallel, samples as specimens for tensile and fatigue, were immersed in the medium (AEHC) for evaluation of these properties. The results showed, as of 3456 hours of immersion, the weight gain of not tensioned and stressed conditions, suggesting the occurrence of passivation of the metal. Images obtained by SEM showed the formation of pits whose size has evolved as a function of immersion time. The electrochemical assay using microelectrode arrays of diameters 10, 20, 30, 100, 200 and 500 ?m charged low-current corrosion. The mechanical properties of tensile strength, yield strength and strain specific were not influenced to the corrosive effects of the medium on the league. The fatigue test, using the parameters of the Weibull probability distribution and durability characteristic (?), showed a reduction in fatigue resistance of the alloy when immersed in AEHC, indicating that the corrosive medium, containing chloride, initiated the nucleation of pits and potentiated the formation of cracks during the fatigue tests, favoring the reduction of the fatigue endurance limit of stainless steel AISI 304
Doutorado
Materiais e Processos de Fabricação
Doutor em Engenharia Mecânica
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Ahmed, Omar. "Corrosion behaviour of AISI 304 stainless steel in contact with eutectic salt for concentrated solar power plant applications." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5901.
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In response to the extensive energy demands on national and global levels, concentrated solar power (CSP) plants are designed to harness and convert solar energy to electricity. For such green energy application, robust, reliable and durable materials for CSP constructions are required. The corrosion resistance is among many parameters to consider in these thermal-electrical stations such as for pipes and storage tanks in CSP. In this investigation, the corrosion behavior of AISI 304 stainless steel (18 wt. % Cr, 8 wt. % Ni) with the heat transfer fluid, also known as solar salt, has been examined. The ternary eutectic salt mixture with the composition, 53 wt. % KNO3, 40 wt. % NaNO2, and 7 wt. % NaNO3, that melts at 142°C, has a potential use in CSP as a heat transfer fluid. The solar salt was prepared for this corrosion study from reagent grades of high purity nitrites and nitrates. Samples of AISI 304 stainless steel were sectioned from a sheet stock of the alloy and exposed to solar salt at 530°C in air at 1 atmospheric pressure. After test intervals of 250, 500, and 750 hours in total immersion condition, AISI 304 stainless steel samples have developed a scale of corrosion products made up of multiple oxides. X-ray diffraction and scanning electron microscopy with X-ray energy-dispersive spectroscopy were employed to examine the extent of corrosion and identify the corrosion products. Transmission electron microscopy was used to verify the corrosion products identity via electron diffraction patterns. Oxides of iron were found to be the primary corrosion products in the presence of the molten alkali nitrates-nitrite salt mixture because of the dissolution of the protective chromium oxide (Cr2O3) scale formed on AISI 304 stainless steel coupons. The corrosion scale was uniform in thickness and made up of sodium iron oxide (NaFeO2), iron oxide, hematite (Fe2O3), and chromium-iron oxide (Cr,Fe)2O3 solid solution. The latter was found near the AISI 304 stainless steel. This indicates that the scale formed, particularly on the upper layers with presence of sodium iron oxide and iron oxide, hematite, is protective, and forms an effective barrier against penetration of fused solar salt. At the alloy interface with the bulk corrosion scale, the corrosion process induced a compositional modification in the grains located at the interface. There are iron rich and iron depleted grains at the interface if compared to the nominal iron content of the alloy. The mode of attack is identified as uniform at the test temperature of 530°C, showing a parabolic behavior with a parabolic rate constant (Kp) equals to 1.08&"215;10^(-17)(m2/sec). By extrapolation, annual corrosion rate is estimated to reach 0.784 mils per year. Corrosion behavior of AISI 304 stainless steel is discussed in terms of thermodynamics and reaction paths.M.S.M.S.E.
Masters
Materials Science Engineering
Engineering and Computer Science
Materials Science and Engineering
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Talib, T. N. "The application of electrolytic photoetching and photopolishing to AISI 304 stainless steel and the electrolytic photoetching of amorphous cobalt alloy." Thesis, Cranfield University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374007.
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Kongthep, Juthathip [Verfasser]. "The Fatigue and Corrosion Fatigue Behavior of Austenitic Stainless Steel AISI 304 after Deep Rolling at Various Temperatures / Juthathip Kongthep." Kassel : Universitätsbibliothek Kassel, 2020. http://d-nb.info/1204015015/34.
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Pereira, Silvio André de Lima. "Estudo da influência da deformação plástica na cinética de nitretação em aços inoxidáveis AISI 304 e 316." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-06032013-144147/.
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Foi estudado o comportamento da nitretação de aços inoxidáveis austeniticos AISI 304 e 316 através de comparação entre diferentes graus de deformações anteriores aos processos de nitretações gasosa, plasma e líquida. A microestrutura, espessura, microdureza e microcomposição química foram avaliadas por técnicas de microscopia óptica, microdureza, microscopia eletrônica de varredura e difração de raios x. Por meio destas técnicas observou-se que deformações plásticas prévias não influenciaram diretamente na espessura da camada nitretada. Uma maior profundidade de difusão pode ser observada nos aços AISI 304. Além disso, duas camadas distintas podem ser identificadas como resultado dos tratamentos, uma formada por uma matriz de austenita expandida pelos átomos de nitrogênio e outra abaixo com menor espessura expandida por átomos de carbono.The nitriding behavior of AISI 304 and 316 austenitic stainless steel was studied by different cold work degree before nitriding processes. The microstructure, thickness, microhardness and chemical micro-composition were evaluated through optical microscopy, microhardness, scanner electronic microscopy and x ray diffraction techniques. Through them, it was observed that previous plastic deformations do not have influence on layer thickness. However, a nitrided layer thicker can be noticed in the AISI 304 steel. In addition, two different layers can be identified as resulted of the nitriding, composited for austenitic matrix expanded by nitrogen atoms and another thinner imediatelly below expanded by Carbon atoms.
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Toma, Rafael Eiji. "Comparação de juntas soldadas de aço inoxidável AISI 304 para aplicação em baixa temperatura utilizando-se a soldagem por arco submerso." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-13062013-123100/.
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Aços inoxidáveis austeníticos são indicados para aplicações a baixas temperaturas por praticamente não apresentarem temperatura de transição dúctil/frágil. Quando estes aços são soldados há a formação de ferrita na zona fundida que, dependendo da morfologia e da quantidade, pode induzir uma temperatura de transição dúctil/frágil. Este trabalho busca estudar as propriedades mecânicas e microestruturais a baixas temperaturas (-100°C) na zona fundida do cordão de solda. Chapas de aço inoxidável AISI 304 com 25,4 mm de espessura foram soldadas pelo processo de soldagem a arco submerso, empregando-se um arame ER 308L, e dois tipos de fluxos distintos: um neutro e um auto-compensante em cromo. Os procedimentos de soldagem foram realizados utilizando-se corrente contínua em polaridade reversa e corrente alternada de onda quadrada. Esta apresentou melhores resultados de tenacidade que a soldagem em corrente contínua para os dois fluxos estudados. Os corpos de prova soldados com fluxo neutro apresentaram maior tenacidade que os soldados com fluxo autocompensante em cromo, comparando-se o mesmo tipo de corrente na soldagem.Austenitic stainless steels are recommended for low temperature applications due to a very low ductile/brittle transition. When this stainless steel type is welded, there is formation of delta ferrite in the fusion zone which, depending on its morphology and distribution may increase ductile/brittle temperature transition to higher values compared with base metal. This work aims at studying the mechanical properties and microstructure at low temperatures (-100°C) on the weld bead fusion zone using AISI 304 plates 1 inch thick which were welded with submerged arc welding process using ER308L and two different fluxes types: a neutral and a chromium auto-compensating one. The welding procedures were made using reverse polarity continuous current and square wave alternate current. The latter presented better toughness results than the continuous current for both fluxes types. The neutral flux led to greater toughness than the chromium auto-compensating flux, comparing the same current type output.
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Carvalho, Andressa Caroline da Silva. "Análise da furação do aço inoxidável AISI 304 com a aplicação externa de nanofluidos em quantidade reduzida." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/180635.
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A furação é um processo caracterizado por apresentar dificuldades em relação à formação e remoção do cavaco da região de corte, e à geração de altas temperaturas devido ao cisalhamento e encruamento do material no fundo do furo, principalmente, na usinagem do aço inoxidável austenítico. Com isso a presença do fluido de corte com boas propriedades de refrigeração e lubrificação faz-se necessária para preservar a vida da broca e garantir um acabamento satisfatório do furo. Contudo, com a tendência mundial de diminuição da quantidade de fluido de corte dispendido, tem-se buscado técnicas diferentes de aplicação que utilize o lubrirrefrigerante em quantidades reduzidas. Associado a essas novas técnicas, vem sendo empregado cada vez mais o uso de partículas sólidas adicionadas ao fluido com o intuito de aumentar sua eficiência. Um tipo de partícula, que vem sendo aplicada em diversos setores produtivos devido a suas ótimas propriedades mecânicas, químicas e elétricas, é o grafeno. Sendo assim, pretende-se analisar o comportamento da furação do aço inoxidável austenítico AISI 304 utilizando flocos de multicamadas de grafeno dispersos em fluido de corte empregando o projeto de experimentos Box-Behnken A aplicação do fluido é feita externamente utilizando a técnica de quantidade reduzida com três vazões: 1,5 l/h; 2,0 l/h e 2,5 l/h. O comportamento do processo é avaliado pelos esforços de corte (força de avanço e momento torsor), pela rugosidade (média e total), e pelos desvios (dimensional e de circularidade) na entrada e na saída do furo. O desempenho do grafeno é avaliado pela comparação dos resultados da sua utilização com os de outras duas condições de aplicação do fluido de corte sem adições: em quantidade reduzida e em abundância. Teve-se como resultado que todas as variáveis respostas analisadas sofreram alguma influência da velocidade de corte e/ou da vazão do fluido aplicado em quantidades reduzidas. Os benefícios da lubrificação e refrigeração do grafeno são sentidos em alguns resultados, como nos menores valores médios de rugosidade e de desvio dimensional. Mas, na análise do processo como um todo, não se afirma que o fluido de corte com flocos de multicamadas de grafeno aplicado externamente em quantidade reduzida traz mais benefícios que o sem adições.Drilling is a machining process characterized by difficulties in the formation and removal of the chip from the cutting region and the generation of high temperatures due to shearing and hardening of the material at the bottom of the hole, especially in the machining of austenitic stainless steel. Thus the presence of cutting fluid with good cooling and lubrication properties is necessary to preserve the drill life and ensure a satisfactory hole finish. However, with the worldwide trend of decreasing the amount of cutting fluid expended, different application systems have been sought which use the coolant in reduced amounts. Associated with these new techniques, the presence of solid particles added to the fluid has been increasingly used in order to enhance its efficiency. One of these particles, which have been applied in several productive sectors due to its excellent mechanical, chemical and electrical properties, is graphene. Therefore, it is intended to analyze the drilling behavior of AISI 304 austenitic stainless steel using multilayer graphene flakes dispersed in the cutting fluid using the Box- Behnken Design The application of the fluid is done externally by means of reduced quantity lubricant with three flows: 1.5 l/h, 2.0 l/h and 2.5 l/h. The behavior of the process is evaluated via thrust force and torque, average and total roughness, and dimensional and circularity deviations at the input and output holes. The performance of graphene is evaluated by comparing the results of its use with two other cutting fluid conditions: quantity reduced and abundance. It was found that all the analyzed responses variables had some influence of the cutting speed and/or the flow of the applied fluid in reduced quantities. The benefits of graphene lubrication and cooling are felt in some results, such as the lower values of average roughness and dimensional deviation. However, in the analysis of the process as a whole, it is not possible to state that the multilayer graphene flakes cutting fluid externally applied brings more benefits than without additions.
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Morais, Viviane Lima de. "Estudo comparativo da deformação a frio e da resistência à corrosão nos aços inoxidáveis austeníticos AISI 201 e AISI 304." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-23082010-100406/.
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A crescente demanda de aplicações de aços inoxidáveis austeníticos e a constante pressão para redução de custo nas empresas siderúrgicas, devido à alta volatilidade no custo do níquel, resultaram em novos desenvolvimentos de aços da série 200. Esta nova classe de aços inoxidáveis austeníticos contém elevados teores de manganês e nitrogênio em substituição ao elemento níquel. A justificativa para a realização deste trabalho é a escassez de estudos comparativos entre aços inoxidáveis austeníticos da série 200 e série 300 disponíveis na literatura em relação ao comportamento da transformação de fase induzida pela deformação e da resistência à corrosão. Os principais fatores que afetam a microestrutura no endurecimento por deformação são: a energia de defeito de empilhamento, composição química, temperatura, grau, taxa e modo de deformação. Realizou-se uma análise crítica e adequação dos conceitos de níquel e cromo equivalente para os aços AISI 201 e AISI 304. Amostras desses aços foram solubilizadas, laminadas e racionadas em diferentes condições para caracterização microestrutural com o auxílio de técnicas de microscopia óptica, microscopia eletrônica de varredura, difração de raios X, ferritoscópio e microdureza. Curvas de endurecimento em função do grau de deformação, fração volumétrica de martensita em função do grau de deformação, assim como a evolução microestrutural e sua respectiva identificação de fase com o grau de deformação foram resultados obtidos deste trabalho. Em geral, aumentando a deformação plástica a frio, maior é a dureza para ambos os aços e maior é a fração volumétrica de martensita induzida por deformação. O aço AISI 201 é mais susceptível a transformação de fase do que o aço AISI 304 devido a sua menor EDE. Ensaios eletroquímicos de espectroscopia de impedância eletroquímica e polarização potenciodinâmica anódica foram realizados para avaliação da resistência a corrosão e para avaliar o comportamento da repassivação. Ambos os aços apresentaram comportamento similares quanto à resistência à corrosão, além de apresentarem potenciais de corrosão da ordem de 10-8 A/cm², típico de materiais passivos.The continuous increase in the application demand of austenitic stainless steels and the constant pressure for cost reduction in the steelmaking industry, due to the high instability of nickel price, has conduced to new developments of the AISI 200 series steels. This new austenitic stainless steel series employes high manganese and nitrogen contents in substitution to nickel. The reason of this work is the lack of comparative studies in the literature between austenitic stainless steels of 200 and 300 series relative to the martensite strain induced phase transformation and its corrosion resistance. The main factors that affect microstructure on strain-hardening are: stacking fault energy, chemical composition, temperature, strain and strain rate. A critical analysis of the concept related to the nickel and chrome equivalents for the AISI 201 and AISI 304 steels has been carried out. Samples of these steels were heat treated and cold rolled to different strains for subsequent microstructural evaluation using equipments such as optical microscope, scanning electron microscope, X-ray diffraction, microhardness and ferritoscope. Strain hardening versus strain, martensite volume fraction versus strain, as well as microstructure evolution and its respective phase identification with strain are some of the main results obtained in this study. In general, increasing the strain hardening, the higher will be the hardness of both stainless steels and higher is the induced martensite volume fraction. The AISI 201 steel presented higher susceptibility to induced phase transformation in comparison to the AISI 304 steel due to its lower stacking fault energy. Electrochemical impedance spectroscopy and anodic potenciodynamic polarization were the techniques used in this work to evaluate the corrosion resistance and passivation behavior respectively. Both steels presented similar corrosion resistance, apart from presenting a corrosion potential of about 10-8 A/cm² , which is typical for passivated materials.
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Silva, Sandro Luz da. "Análise de juntas soldadas de aços dissimilares AISI 304 e SAE 1020 com metais de adição ER 309L e ER 70S3 pelo processo GTAW /." Guaratinguetá, 2016. http://hdl.handle.net/11449/146732.
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Orientador: Peterson Luiz FerrandiniCoorientador: José Vitor Candido de Souza
Banca: Luis Rogério de Oliveira Hein
Banca: Cristina de Carvalho Ares Elisei
Resumo: Atualmente os processos de soldagem de juntas dissimilares são muito utilizados na indústria petrolífera e nuclear, caracterizada pela união entre diferentes materiais. No presente trabalho, será estudada a possibilidade da união entre o aço inoxidável AISI 304 e aço carbono SAE 1020. Os quais são largamente utilizados em linhas de vapor em plantas de energia, em reatores nucleares, plantas petroquímicas, devido suas diferentes propriedades mecânicas e resistência à corrosão. Este trabalho tem por objetivo principal, estudar profundamente, as propriedades mecânicas, físicas e químicas, com o auxílio de testes e equipamentos específicos: ensaios de Microdureza Vickers, ensaio de tração, de interpretação das macrografias e micrografias utilizando microscopia ótica e também análise da difração de raios x das juntas soldadas. Foram executadas pesquisas bem fundamentadas, para verificar e discutir os resultados obtidos, justificando a substituição das varetas de aço inoxidável AWS ER 309L, por varetas de aço carbono AWS ER 70S3 como metal de adição, utilizando processo de soldagem manual GTAW (Gas-Shielded Tungsten Arc Welding), objetivando a redução de custo no processo de soldagem e viabilizando um bom investimento para pesquisas futuras
Abstract: Nowadays the welding processes of dissimilar joints are widely used in the oil and nuclear industry, characterized by the union of different materials. In the present work, will be studied the possibility of union between stainless steel AISI 304 and carbon steel SAE 1020. Which are widely used in steam lines in power plants, nuclear reactors, petrochemical plants, due to their different mechanical and corrosion resistance properties. The main objective of this work is to study deeply the mechanical, physical and chemical properties, evaluated by specific tests and equipments: Vickers hardness tests, tensile tests, interpretation of macrographs and micrographs utilizing the optical microscope and also analysis of x-ray diffraction applied to the welded joints. Well-founded research have performed to verify and discuss the results. Justifying the replacement of stainless steel rods AWS ER309L, carbon steel rods AWS ER70S3 as filler metal, using manual welding process GTAW (Gas-Shielded Tungsten Arc Welding), aiming the cost reduction in welding and process, making a possible good investment for future research
Mestre
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Abdelghany, K. "Evaluating the properties of products fabricated from commercial steel powders using the selective laser micro-welding rapid manufacturing technique." Journal for New Generation Sciences, Vol 8, Issue 1: Central University of Technology, Free State, Bloemfontein, 2010. http://hdl.handle.net/11462/546.
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Published ArticleSelective laser micro-welding (SLMW) is a recent rapid manufacturing technique that produces metal parts through the use of a laser beam that selectively scans over the powder layers and fully melts and micro-welds the metallic particles. The advantage of SLMW is that any type of commercial steel alloys or other metal powders can be used to build parts in a single step without the need to add low melting point additives to join the particles as in the former SLS process. In this study, two types of low cost general purpose powders were evaluated as the raw materials for the selective laser micro-welding (SLMW): one powder is AISI304 stainless steel powder from Hoganas, Belgium (cost = $11/kg) and the other isAISI100510w carbon steel locally produced in-house from scrap steel using gas atomizing then de-oxidizing techniques (cost = $1.2/kg). Twelve sample parts were fabricated using two different laser speeds, 70 and 100 mm/s. Dimensions, density, hardness, tensile and microstructure properties were evaluated. Results showed that both powders successfully produced complete parts with accurate dimensions and fine details. Both microstructure phases were austenite due to the rapid heating and cooling cycles. At the higher speed of 100 mm/s mechanical properties deteriorated because of the porosities inside the structure. Using low cost powders gives more potential for the SLMW to spread as an economical manufacturing process in the near future.
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Silva, Sandro Luz da [UNESP]. "Análise de juntas soldadas de aços dissimilares AISI 304 e SAE 1020 com metais de adição ER 309L e ER 70S3 pelo processo GTAW." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/146732.
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Atualmente os processos de soldagem de juntas dissimilares são muito utilizados na indústria petrolífera e nuclear, caracterizada pela união entre diferentes materiais. No presente trabalho, será estudada a possibilidade da união entre o aço inoxidável AISI 304 e aço carbono SAE 1020. Os quais são largamente utilizados em linhas de vapor em plantas de energia, em reatores nucleares, plantas petroquímicas, devido suas diferentes propriedades mecânicas e resistência à corrosão. Este trabalho tem por objetivo principal, estudar profundamente, as propriedades mecânicas, físicas e químicas, com o auxílio de testes e equipamentos específicos: ensaios de Microdureza Vickers, ensaio de tração, de interpretação das macrografias e micrografias utilizando microscopia ótica e também análise da difração de raios x das juntas soldadas. Foram executadas pesquisas bem fundamentadas, para verificar e discutir os resultados obtidos, justificando a substituição das varetas de aço inoxidável AWS ER 309L, por varetas de aço carbono AWS ER 70S3 como metal de adição, utilizando processo de soldagem manual GTAW (Gas-Shielded Tungsten Arc Welding), objetivando a redução de custo no processo de soldagem e viabilizando um bom investimento para pesquisas futuras.
Nowadays the welding processes of dissimilar joints are widely used in the oil and nuclear industry, characterized by the union of different materials. In the present work, will be studied the possibility of union between stainless steel AISI 304 and carbon steel SAE 1020. Which are widely used in steam lines in power plants, nuclear reactors, petrochemical plants, due to their different mechanical and corrosion resistance properties. The main objective of this work is to study deeply the mechanical, physical and chemical properties, evaluated by specific tests and equipments: Vickers hardness tests, tensile tests, interpretation of macrographs and micrographs utilizing the optical microscope and also analysis of x-ray diffraction applied to the welded joints. Well-founded research have performed to verify and discuss the results. Justifying the replacement of stainless steel rods AWS ER309L, carbon steel rods AWS ER70S3 as filler metal, using manual welding process GTAW (Gas-Shielded Tungsten Arc Welding), aiming the cost reduction in welding and process, making a possible good investment for future research.
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Guillamet, René. "Etude spectrométrique des premiers stades de l'oxydation de l'acier AISI 304 à haute température." Rouen, 1993. http://www.theses.fr/1993ROUES013.
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Nous avons oxydé à l'air 900, 1000 et 1100°C, pendant 1, 5, 15 ou 60 minutes, des échantillons, polis mécaniquement (pâte diamentée grade 3 microns) ou décapés dans un mélange HCl/HNO3, d'acier inoxydable austénitique AISI 304 18% de Cr, 10% e Ni, environ 2% de Mn): les oxydes développés ont été analysés par XRD, CEMS, spectroscopie de réflectane (IRFT et UV-visible-PIR), SIMS et MEB. L'oxydation d'échantillons polis commence par l'apparition d'une couche d'oxydes de chrome (Cr2O3 et spinelle MnCr2O4), suivie par le développement d'oxydes de fer. L'oxydation d'échantillons décapés chimiquement consiste uniquement en la montée d'oxydes de fer (alpha-Fe2O3 et petites particules super paramagnétiques de alpha-Fe2O3 et une magnétite partiellement substituée au Cr-Ni). L'oxydation provoque un appauvrissement en Cr (en Mn) du substrat métallique et une transformation de phase gamme (C. F. C. )alpha (C. C. ) dans la matrice (près de l'interface oxydes-métal)
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Soares, Tatiana Pacheco. "Estudo da ação bactericida em regiões próximas à superfície de titânio e AISI 304 pela incorporação de prata." reponame:Repositório Institucional da UCS, 2017. https://repositorio.ucs.br/handle/11338/2820.
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A contaminação por biofilmes bacterianos tem um forte impacto negativo, especialmente quando aderidos na superfície de próteses, implantes, pinos e outros dispositivos médico-cirúrgicos. Neste trabalho foram produzidas amostras metálicas de titânio e AISI 304 com íons Ag+ implantados por IPD a diferentes energias: 2 e 4 keV; e com diferentes tempos de implantação: 30, 45, 60 e 90 min visando a obtenção de superfícies com propriedades bactericidas. A profundidade e o perfil de distribuição dos íons implantados foram estimados por simulação de Monte Carlo utilizando o software SRIM 2008, juntamente com a determinação da concentração de prata incorporada nas amostras por técnicas espectroscópicas. A atividade bactericida das amostras de titânio com diferentes concentrações de prata foi avaliada por meio do tratamento de um efluente industrial líquido, que foi submetido à contagem de Escherichia coli antes e depois do contato do efluente com as amostras. O ângulo de contato foi medido para avaliação da molhabilidade das amostras de titânio que apresentaram as maiores concentrações de prata, fator determinante na adesão de bactérias e células humanas. A citotoxidade foi avaliada através de teste de viabilidade celular e análise morfológica. Obteve-se uma redução de 27% de E.coli no efluente industrial tratado com a amostra implantada a 4 keV por 45 min, com concentração inicial de 3,35 × 1015 átomos cm-2.Não foi detectado efeito tóxico da prata para células humanas MG63, mesmo considerando as maiores concentrações prata, uma vez que não houve redução na adesão e proliferação celular em relação ao titânio não tratado. Para as amostras de AISI 304, os ensaios de adesão microbiana foram realizados para as bactérias Listeria monocytogenes e Salmonella Enteritidis, resultando em uma redução de 65,9 e 69,8%, respectivamente. Por fim, os resultados mostraram que o tratamento estudado para obtenção de materiais metálicos com ação bactericida é promissor para aplicações na área médica, no entanto é necessário uma avaliação em longo prazo para garantir a segurança de sua utilização.Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2017-07-05T14:10:05Z No. of bitstreams: 1 Tese Tatiana Pacheco Soares Zamboni.pdf: 2896094 bytes, checksum: a93cbf9d375f0634bd1237b20bc12d83 (MD5)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES.
Contamination by bacterial biofilms has a strong negative impact, especially when given on the surface of prostheses, implants, pins and other medical-surgical devices. In this study metal samples of Titanium cp and AISI 304 were produced with Ag+ ions implanted by IPD at different energies: 2 and 4 keV and different implantation times: 30, 45, 60 and 90 min to obtain surfaces with bactericidal properties. The depth and the distribution profile of the implanted ions were estimated by Monte Carlo simulation using the SRIM 2008 software. The Ag+ ions concentration incorporated in the samples was determinate by spectroscopic techniques. Bactericidal activity of the titanium samples with different concentration of Ag+ ions was evaluated by the treatment of a liquid industrial waste. It was submitted to Escherichia coli counting before and after the contact of the waste with the samples. The contact angle was measured to evaluate the wettability of the titanium samples that presented the highest silver concentration. Wettability is a determinant factor in the adhesion of bacteria and human cells. Cytotoxicity was evaluated by cell viability test and morphological analysis. A 27% reduction of E. coli in the industrial waste treated with the sample implanted at 4 keV was achieved for 45 min with an initial concentration of 3.35 × 1015 atoms cm2. No toxic effect of silver was detected on human MG63 cells, even considering the higher concentration of silver, since there was no reduction in cell adhesion and proliferation c to untreated titanium. For the AISI 304 samples, the microbial adhesion assays were performed for the bacteria Listeria monocytogenes and Salmonella Enteritidis, resulting in a reduction of 65.9 and 69.8%, respectively. Finally, the results showed that the treatment studied to obtain metallic materials with bactericidal action is promising for applications in the medical field, however a long term evaluation is necessary to guarantee the safety of its use.
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OLIVEIRA, Matheus José Cunha de. "Soldagem dissimilar de chapas finas de liga com memória de forma NiTi e aço inoxidável AISI 304 usando micro GTAW." Universidade Federal de Campina Grande, 2016. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1120.
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CNPq
As Ligas com Memória de Forma (LMF) foram descobertas nos anos 60 e o desenvolvimento de vários sistemas (NiTi, CuAlNi, CuAlBe, CuZnAl) vem sendo explorado desde então, sendo aquelas do sistema NiTi as mais utilizadas. Devido às suas excelentes propriedades mecânicas, ótima resistência a corrosão e biocompatibilidade, além de apresentarem as melhores propriedades funcionais de efeito de memória de forma e superelasticidade, as LMF NiTi e suas variações ternárias passaram a ser objeto de estudos para várias aplicações nas mais diferentes áreas. Um dos maiores problemas das LMF NiTi ainda está relacionado a dificuldades de conformação mecânica e usinagem. Por esse motivo, o processo de soldagem pode ser uma boa ferramenta alternativa para se conseguir obter peças de geometrias mais complexas, envolvendo a união das LMF NiTi com metais convencionais, como o aço inoxidável. O aço inoxidável é uma opção importante de união com LMF NiTi pois possui igualmente propriedades desejadas de resistência mecânica, biocompatibilidade e resistência a corrosão. A união por soldagem destas duas ligas encontra barreiras diversas, sendo a principal delas a formação de intermetálicos frágeis na junta soldada limitando sua resistência mecânica e consequente aplicação. Nesse contexto, o presente trabalho teve como objetivo geral avaliar a soldabilidade de chapas finas (espessura de 1 mm) de uma LMF NiTi com aço inoxidável (INOX) AISI 304 utilizando o processo micro GTAW e compreender a metalurgia da soldagem na variação das propriedades mecânicas e metalúrgicas das juntas. O processo GTAW foi escolhido por ser mais econômico que os processos usuais de soldagem para estas ligas NiTi, como a soldagem a laser (LBW). As juntas dissimilares NiTi-SS obtidas foram caracterizadas pelas técnicas de MO, MEV, EDS, DSC, ensaios de tração à ruptura e de dureza Vickers. Estas juntas foram soldadas utilizando a própria LMF NiTi e também o Inconel 625 como metais de adição. No geral, constatou-se que as juntas apresentam comportamento frágil, porém ao se utilizar camada intermediária de Inconel 625 na união entre os metais dissimilares e após tratamento térmico para alívio de tensões, é possível aumentar a resistência mecânica da junta para valores da ordem de 150MPa. As juntas apresentaram uma poça de fusão heterogênea devido a formação de elementos fragilizantes ao longo do metal de solda. Observou-se a formação de uma zona parcialmente diluída (ZPD) correlacionada a um aumento excessivo da dureza nesta região e composição química distinta.
Shape Memory Alloys (SMA) were discovered in the 60s and the development of various systems (NiTi, CuAlNi, CuAlBe, CuZnAl) has been explored since then, with those of the NiTi system the most commonly used. Due to its excellent mechanical properties, good corrosion resistance and biocompatibility, in addition to having the best functional properties of shape memory effect and superelasticity, the NiTi SMA and its ternary variations have become the subject of studies for various applications in different areas. One of the main problems of NiTi SMA is also related to difficulties in forming and machining. For this reason, the welding process can be a good alternative tool to achieve more complex geometry parts, involving the union of NiTi SMA with conventional metals, such as stainless steel. Stainless steel is an important option for union with NiTi SMA, since it also has desired properties of mechanical strength, biocompatibility and corrosion resistance. The union by welding between these two alloys find various barriers, the main one being the formation of brittle intermetallic compounds on the welded joint, limiting its mechanical strength and consistent application. In this context, this study aimed to assess the weldability of thin sheet metal (1 mm thick) of a NiTi SMA with AISI 304 stainless steel (SS) using the micro process GTAW, and study the influence of welding metallurgy in mechanical and metallurgical properties of the joints. The GTAW process was chosen because it is more economical than the usual welding processes for these NiTi alloys such as the laser beam welding (LBW). The NiTi-SS dissimilar joints obtained were characterized by optical microscopy techniques, SEM, EDS, DSC, tensile test to rupture and Vickers hardness. These joints were welded using NiTi SMA and also the Inconel 625 as filler metals. Overall, it was found that the joints have brittle behavior, but when using an intermediate layer of Inconel 625 at the junction between dissimilar metals and after heat treatment for stress relief, it is possible to increase the mechanical strength of the joint for values in the order of 150MPa. The joints exhibited a heterogeneous molten weld pool due to formation of elements along the embrittlement of the weld metal. It was observed the formation of a partially diluted zone (PDZ) correlated to an excessive increase of the hardness in that region and different chemical composition.
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Olayinka, Ayotunde. "Analytical and Experimental Evaluation of the Effect of Hydraulic Bulge Process on the Formability and Surface Topography of Annealed AISI 304 Stainless Steel at Micro/Meso-Scale." Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10163314.
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The demand for miniature devices has increased the application of hydroforming process in various micro-scale applications. This research ascertain the material properties of 0.2 mm thick AISI 304 stainless steel using hydraulic bulge test, and it also analyze the surface characteristics of the same material. The work pieces for this work consist of circular and elliptical work pieces. The circular work pieces were formed using dies of cavity diameters 5 mm and 11 mm, while the elliptical work pieces were formed using elliptical cavity dies with aspect ratio of 0.5, 0.8, and 0.67. Analytical methods proposed by Chakrabarty, Ekineev-Kruglov, Jovane, and Marciniak for the determination of the flow curve of sheet metal were compared to the experimental result. The outcome indicates that the Ekineev - Kruglov method has the best correlation with the experiment. An improved approach of the Banabic method was developed for the elliptical workpieces, and the results showed shows considerable improvement on the method. Surface characteristics of the 5 mm and 11 mm die work pieces were tested using the atomic force microscope; the outcome demonstrates that most of the surface parameters exhibit a linear relation with the strain. The roughness increase with increasing strain.
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Bau, Atilano Roberto. "Estudo do processo de estampagem para materiais alternativos na fabricação de um componente para a indústria de máquinas agrícolas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/118876.
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No presente trabalho, a conformabilidade do aço inoxinoxidável AISI 201 foi comparada com o aço inoxidável AISI 304. O aço inoxidável AISI 201 é uma liga baixo níquel ligado com manganês e nitrogênio. Nesse estudo a conformabilidade dos dois materiais foi examinada por meio de ensaios tecnológicos como ensaio de tração, determinação da curva de escoamento, determinação do índice de anisotropia, ensaio Erichsen, dureza, composição química, simulação computacional do processo de estampagem e estampagem dos blanks. O aço inoxidável AISI 201 possui propriedades como limite de escoamento e tensão de ruptura superior as do inoxidável AISI 304. Os dois aços possuem uma similaridade na anisotropia. A máxima altura alcançada no momento da fratura pelo ensaio Erichsen também é semelhante para os dois materiais. O aço inox AISI 201 apresenta uma dureza maior que o inoxidável AISI 304. Na composição química os dois aços apresentam elementos fora do especificado, caracterizando um problema de qualidade na fabricação desses aços. A simulação computacional do processo de estampagem apresentou uma redução de espessura na região mais critica, sem comprometer a estampagem do componente. Uma vez estampadas, obteve-se peças sem indícios de trincas, conforme previsto pela simulação computacional. Os resultados desse trabalho sugerem a possibilidade de utilização do aço inoxidável AISI 201 como opção para substituição ao inoxidável AISI 304, tendo uma observação a ser feita quanto aos cuidados na qualidade durante a fabricação do aço para que atenda os padrões exigidos.In this study, the formability of stainless steel AISI 201 was compared to stainless steel AISI 304 stainless steel AISI 201 is a low alloy nickel alloyed with manganese and nitrogen. In this study, the formability of the two materials was examined by means of technological tests such as tensile test, determination of the flow curve, determining the anisotropy index, Erichsen test, hardness, chemical composition, computer simulation of the stamping process and stamping of the blanks. Stainless steel AISI 201 has properties such as yield strength and higher breakdown voltage of the stainless steel AISI 304. The two steels have a similarity in anisotropy. The maximum height reached at the time of fracture by Erichsen test is also similar for the two materials. Stainless steel AISI 201 has a hardness greater than the stainless steel AISI 304. In chemistry the two steels have elements outside the specified, featuring a quality problem in manufacturing these steels. A computer simulation of the printing process showed a reduction in thickness in the most critical region, without compromising the component stamping. Once stamped, gave no broken pieces of evidence as provided by the computer simulation. The findings suggest the possibility of use of stainless steel AISI 201 as an option to replace the stainless steel AISI 304, with a point to be made about the care as during the manufacture of steel that meets the required standards.
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Ccencho, Maritza, Valeria Quijada, and Leonardo Vinces. "An Automated System for the Stage of Hydrolysis and Filtration in the Extraction of Pectin from the Cocoa Shell." Universidad Peruana de Ciencias Aplicadas (UPC), 2021. http://hdl.handle.net/10757/653786.
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El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.Pectin obtained from cocoa husks has recently been investigated because of its gelling and stabilizing properties that have great potential for the food, cosmetic and pharmaceutical industries. However, its production at the industrial level has not been studied or developed in Peru. A fundamental part of the extraction process is the stage of hydrolysis and filtering of the cocoa shell. Because of this, an automated system for acid-thermal hydrolysis and shell filtration is proposed. The control of both processes is of great importance because the quality and efficiency of the extracted pectin will depend on it. The tests will be carried out in a cylindrical taper with a 100 L capacity which is adapted to contain a 20 L cylindrical filter, both made of AISI 304 stainless steel. The filter has a motor to homogenize the temperature and pH of the mix. The pH of the process is 2 and the temperature is 90 ± 2 °C, since in these ranges the pectin is released more easily from the cocoa shell. The method consists of the structural design of the tank and the filter, and in the design of the pH regulator and the heating system. The yield of the extraction process was achieved by 10%.
Revisión por pares
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Milanez, Alexandre. "Microextrusão de peças aplicadas a materiais ferrosos e não ferrosos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/49352.
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Esta tese apresenta o estudo sobre microconformação, no caso microextrusão de quatro materiais diferentes, um aço SAE 1020, um aço inoxidável AISI 304, um alumínio AA6531 e um latão ASTM C34000. Para avaliar o efeito do tamanho da peça sobre o processo de microextrusão, dois tamanhos de corpos de prova foram utilizados, um com ∅ 4 mm e outro com ∅ 1 mm. Para cada tamanho de corpo de prova, três ângulos de extrusão foram utilizados, 30°, 45° e 60°. A primeira parte do trabalho se resume a caracterização dos materiais, com analise química e metalográfica. Após a caracterização dos materiais, as curvas de escoamento através do ensaio de compressão utilizando dois tamanhos de corpos de prova foram feitos em todos os materiais. O atrito foi determinado utilizando o ensaio de anel de atrito com três tamanhos diferentes de corpos de prova. As curvas de calibração foram feitas utilizando o software SIMUFACT. Os ensaios de extrusão foram feitos em uma máquina de ensaio universal com capacidade de captura de dados como força e deslocamento. Um modelo matemático foi utilizado para comparar a força de extrusão calculada com o medido no processo. Os resultados indicam que as curvas de escoamento de tamanho macro podem ser aplicadas a peças de tamanho meso. O atrito medido pelo ensaio de anel de atrito mostrou que os valores de atrito de tamanho micro tem um pequeno valor maior que para tamanho macro. Os valores de força de extrusão calculada e medido no ensaio para peças de tamanho meso tem boa aproximação com diferença de 3,2% para o aço inoxidável. Para peça de tamanho micro, a diferença entre o valor medido e o calculado aumenta chegando a diferença de 995% para o corpos de prova de aço comum.This thesis presents the study about microforming, in this case microextrusion of the four different materials, an SAE 1020 steel, an AISI 304 stainless steel, an AA6531 aluminum and a C34000 brass. To evaluate the size effect about microextrusion process, two sizes of specimens were used, with a ∅ 4 mm and another with ∅ 1 mm. For each size of specimen, three extrusion angles were used, 30 °, 45 ° and 60 °. The first part of the work was to materials characterizations with chemical and metallographic analysis. Following the materials characterization, the flow stress curves was made using the compression test with two sizes of specimens. The friction was determined using the friction ring test with the three different size. Calibration curves were performed using the software SIMUFACT . The extrusion tests were performed in a universal testing machine capable of capturing such as force and displacement data. A mathematical model was used to compare the extrusion force it was calculated and the force measured in microextrusion. The results indicate that the flow stress curves of macro size can be applied to meso sizes. The ring friction test indicate that the friction values of the micro size has a small value greater than macro size. The extrusion force calculated and measured in the test to meso size has good approximation with a difference of 3.2% in the stainless steel. To pieces of the micro size, the difference between the measured and calculated force increases 995% for the samples of SAE 1020 steel.
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AKHTAR, MD JAMIL. "OPTIMISATION OF CUTTING PARAMETERS DURING CNC TURNING OF AISI 304 AUSTENITIC STAINLESS STEEL." Thesis, 2017. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16012.
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In this study, the effect of important parameters of machinability like material removal rate and surface roughness were studied. optimization of machining parameters in turning of AISI 304 austenitic stainless steel using cemented carbide tools. During the experiment, process parameters such as speed, feed and depth of cut are used to explore their effect on the surface roughness (Ra) and Material Removal Rate(MRR) of the work piece. The experiments have been conducted using Orthogonal Array(OA) (Taguchi) design in the Design of Experiments (DOE) on Computer Numerical Controlled (CNC) lathe. Further, the analysis of variance (ANOVA) was used to analyze the influence of process parameters and their interaction during machining. From the analysis, it is observed that the Speed is the most significant factor that influences the surface roughness followed by feed and Depth of cut. The optimum cutting speed the impact of cutting speed, Feed and Depth of cut on Material Removal Rate(MRR) and surface roughness have been studied during turning an AISI 304 austenitic stainless steel using cemented carbide cutting tools.
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Lee, Shin-Min, and 李新民. "Characteristic study on AISI 304 stainless steel using friction drilling." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/h5c9zw.
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博士國立中央大學
機械工程研究所
97
Friction drilling utilizes the heat generated from the friction between the tool and the workpiece for machining. This process produces no chip, shortens the time required for hole-making and incurs less tool wear, thus lengthening the service life of the drill.After the friction drilling operation had been conducted, a thin plate (workpiece) was formed into a bush with a thickness of 3 times larger than that of the workpiece. The bush can provide a longer area of contact which can fit a shaft firmly. The bush can also be taped to create an internal screw without welding a nut.In this study, tungsten carbide drills with and without coating were employed to make holes in AISI 304 stainless steel, which is known to have high ductility, low thermal conductivity and great hardness.After the optimal drilling parameters of friction drilling were obtained, the optimal geometric shape and friction contact area ratio of the friction drill was selected to conduct experiments and compare with the traditional HSS twist drill coated TiN and Tungsten carbide drill. The results showed that HSS coated TiN was damaged seriously after two drilling runs and Tungsten carbide was already to create a serious wear of drill edge after three runs. However, the friction drill showed little wear and still can normally drill the AISI304 material after 60 runs. Therefore, the friction drill has a better performance than both the HSS coated TiN and the Tungsten carbide drill. Furthermore, the friction drill avoids serious tool wears, enhances drilled hole quality, and prolongs the tool life more significantly. TiAIN and AlCrN were coated onto the drill surface by physical vapor deposition (PVD). Performance of coated and uncoated cutting tools were examined for drillings made under different spindle speeds. Changes in relationship between drill surface temperature, tool wear and axial thrust force during machining were also explored. Experimental results reveal that lubricating effect of the coating and low thermal conductivity of AlCrN caused AlCrN-coated drill to produce the highest surface temperature but the lowest axial thrust force with the least tool wear. However, the difference in performance between coated and uncoated drills diminished with increase in number of holes drilled.
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Lai, Ping-Hung, and 賴炳宏. "The Peck Cementation treaced for AISI 304 Stainless Steel Bipolar Plates." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/36946395386146340354.
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碩士元智大學
機械工程學系
98
In this study, AISI 304 stainless steel which is the material used in the research, as the way to use peck cementation process for the chromized. Due to high-temperature thermal diffusion theory, that enabling the surface to form the diffusion layer of Cr-rich. Working on this chromized diffusion layer, it can improve the corrosion resistance and electrical conductivity of the stainless steel material. This study with process temperature 700 ℃ as the standard, and the experiment is divided into two parts. First one for the wafer without rough treatment and simply using mechanical polishing and Electro polishing on the surface of the material to make a leveling action, second one for the wafer already taken rough treatment, mainly working with two ways to rough the surface of the material which are sand blasting and blasting processing / electrolytic polishing to make the irregular surface. Analysis the characteristics of the peck cementation diffusion layer after this four kinds processes (including structure of the plating, ingredient distribution, etc.). Then used the analysis of electrochemical corrosion test and the values of contact resistance, to understand the results of the different temperatures and establish the best data for low-temperature peck cementation process. The results show that, when the process temperature is 700 ℃, its corrosion resistance and contact resistance compared to the process temperature of 900 ℃ didn’t make a big difference. Both are in compliance with regulations set out by the U.S. DOE standard. The best data is 700℃ under processing time of 6he in this study. Wafer without rough treatment of mechanical polishing is the best, the corrosion current density is 1.63μA/cm2. And wafer with rough treatment by blasting processing is the best, the corrosion current density is 2.75μA/cm2. The contact resistance of both is much lower than the ones didn’t take the process and confirmed the potential for applying peck cementation process on the metal bipolar plate. Use both of the data to manufacture bipolar plate for testing the single cell performance. As the results show when applying 0.6V, its current density, power density, it gives a difference of almost 8% between the graphite bipolar plates, and during the 100 hours of long-term test, its current density showed a steady state. If response to the reactive area of 25cm2, their power density is about 0.5 W/cm2, and it confirmed that the low-temperature peck cementation process can be applied on bipolar plate. In the 304-SB-Cr(700-6hr), although the better power can reach 17 W in the beginning, the sand blasting on the surface caused by stess corrosion that affecting cell power generation power. So the rate of single cell power began to tetreat. After 100 hours 0f long tern testing, only 11 W of electricity power left.
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Hsu, Ching-Chiu, and 徐進秋. "Study on Erosion Wear Behaviors of AISI 304/410 Stainless Steel Weldments." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/7j7423.
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碩士國立臺北科技大學
材料科學與工程研究所
96
It is known that AISI 304 austenitic stainless steel is most commonly used due to the advantages of good corrosion resistance, weldability, and formability. In addition, AISI 410 martensitic stainless steel possesses excellent high-temperature strength, wear resistance, and fracture toughness, and it has been widely used in wall and blanket structure, pipes in nuclear power plant reactors,and turbine. In this study, both of 304 and 410 stainless steels were separately divided into the unwelded and welded conditions , and four types of them were adopted as experimental materials to perform erosion tests with an eroding carrier of Al2O3 particles under the different incident angles. The results showed that erosion resistance of the rolled 304 is better than of annealed 410 under thr unwelded condition due to its higher hardness . After the welding, the microstructure of 304 was not changed in spite of the bead and heat affected zone (HAZ), however, microstructure of 410 consisted of austenite and ferrite mixed phases in the bead as well as martensite phase in HAZ. As a result, the welded 410 showed the best erosion resistance during all the specimens. For all specimens, the maximum erosion rate of all of them occurred at an incident angle of 30°, while the deepest penetration occurred at an incident angle of 45° except for the welded 410 (75°). In addition, erosion mechanism of all the specimens showed a mixed ductile and brittle morphology.
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Gochhayat, Soumya Ranjna. "Tungsten Inert Gas (TIG) Assisted TiC-NiCoating on AISI 304 Stainless Steel." Thesis, 2015. http://ethesis.nitrkl.ac.in/7187/1/Tungsten_Gochhayat_2015.pdf.
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Metal components very often lose their functionality through wear by various modes such as abrasion, impact or corrosion. To counteract such problems, and there by to extend the service life, modification of surfaces are frequently done. This surface engineering approach finds application across many sectors namely defense, mining, steel, power, cement, petrochemical sugarcane and food. Generally the base material of the component is selected on the ground of strength and cost involved, while the details of the surface properties are adopted for local tribological conditions to which the vulnerable section will be subjected during its service period. There have been wide range advancement in surface engineering technology to square up surface failure in steels. But each technology that evolved has its own limitations. Deposition of thin hard coatings of 0.5 mm can improve tribological properties in terms of low friction and wear resistance. But in case of light metal alloys, when the load is high, the coating may fail by deformation. In such cases reinforcement of metals with ceramics can increase the physical and surface properties like strength, stiffness, wear resistance, high temperature strength and a reduction in weight. Over the years, modification of the matrix close to the surface, as well as reinforcement, has been introduced. The addition of ceramic particles into the molten metal surfaces to form a metal matrix composite (MMC) is a very popular one and is widely used worldwide. The formation of MMC meets the specifications required for specific applications. Tungsten Inert Gas (TIG) welding method produces a small modified hemispherical surface which has a width of few millimeters. It also incorporates less cost compared to laser treatment, so widely in practice. TiC is used as a reinforcement material as it has received some attention being a wear resistance substrate. Ni is used as it is a very good binder that produces a well-mixed Tic-Ni mixture. TIG process was used to melt the TiCNi MMC on an AISI 304 stainless steel. This achieved an approximate micro hardness value of 800HV.
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Nitesh. "Effect of Pulsed Current for Autogenous TIG Welding of AISI 304 Stainless Steel." Thesis, 2016. http://ethesis.nitrkl.ac.in/9185/1/2016_MT_Nitesh.pdf.
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Tungsten Inert gas (TIG) welding is an arc welding process which produces reliable and high quality weld joint. However conventional TIG welding has certain limitation like low power density and large weld bead along with high residual stress. In the present work, prior to actual welding, welding simulation was performed by ANSYS 15 to obtain the heat energy range required for melting of 3 mm SS 304 plate. Conventional Autogenous TIG welding has been performed on 3 mm thick SS304 stainless steel without using any filler material with different values of welding current. Pulsed Autogenous TIG welding has also been performed with different value of pulse frequencies. Pulse frequency increases the power density or concentration of energy due to arc shrinkage which ultimately leads to the higher melt pool depth and narrower weld width. Effect of pulse current also cause refinement of the grain as compared to constant current welding, which leads to the lower residual stress and improved mechanical properties.
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郭家維. "Fire investigation and spatter identification in arc welding fire of AISI 304 stainless steel." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/k4zcut.
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Wang, Peng-Shuen, and 王鵬舜. "The Effect of Eccentric and Magnetic Vibrator on AISI 304 Stainless Steel Vibration Welding." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/23656402795226839655.
Full textAbstract:
碩士國立中興大學
材料科學與工程學系所
98
The study of AISI 304 stainless steel vibration welding used by magnetic vibrator under sub-resonant（362Hz）and resonant（376Hz）, and by eccentric vbrator under sub-resonant（59.3Hz）and resonant（60.9Hz）, respectively. Microstructure, residual δ-ferrite content, crystal structure, residual stress and mechanical properties of the weld bead have been investigated by using optical microscope (OM), X-ray diffraction (XRD), and Vickers hardness tester, respectively. By the observation of microstructure, vibration welding can reduce the temperature gradient under resonant frequency, results the refinement of grain size and increase the number of grains. With regard to residual δ-ferrite, it can be observed as primary δ-ferrite grain refinement, the morphology of residual δ-ferrite is discontinuous. It was noted that residual δ-ferrite content was the least 5.5 % in eccentric vibration with resonance frequency. X-ray diffraction analysis showed that there is no change in crystal structure of AISI 304 stainless steel with or without vibration. But the diffraction intensity decreases and FWHM（Full Width at Half Maximum）of X-ray diffraction profile broadened due to increased the internal defects, as a mechanism of stress relief by stacking faults generation. In addition, residual stress can be effectively reduced by vibration welding. There is the least residual stress can be obtained in resonance frequency. To compared with two vibration mode, the eccentric vibration had better stress relief due to eccentric vibration with more directional stress overlay. The hardness was enhanced in vibration welding, the hardness has obvious raised about 7.3% while resonance frequency was applied.
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Lo, Shih-Chung, and 羅仕忠. "The Study of Forge Joining of AISI 304 Stainless Steel and Copper Heterojunction Metal." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/61352305788849754642.
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碩士國立屏東科技大學
機械工程系
93
The purposes of these studies are to investigate the mechanical properties and damping properties of the AISI304 and C1100 pure copper or CB7 Sn-Cu alloy, which have been welded under vacuum and then been hot-forged in the range of 800℃~1000℃ for various forge rate. Based on to the present study, some main results are described as followings: 1. The optimum hot-forged process for the stainless steel and copper alloy that the forge temperature is 50~130℃ under the copper melt point. The alloy liquidization would be occurred in the higher hot-forged temperature. And, when forged in the lower temperature, the composite metals could be not joined. 2. Being hot-forged in the range of 20~80% forge rate, the changes of the hardness of the AISI304, C1100 and CB7 alloys are from Hv200~205 to Hv283~286, Hv50~55 to Hv75~80 and Hv135~140 to Hv170~178, respectively. 3. Being welded and hot-forged in the range of 800~1000℃ for the 20~80% forge rate, the changes of tensile strength, elongation and hardness of the AISI304 and C1100 alloys are from 400MPa to 460MPa, 64% to 56%, and Hv172 to Hv195, respectively. 4. Being welded and hot-forged in the range of 800~1000℃ for the 20~80% forge rate, the changes of tensile strength, elongation and hardness of the AISI304 and BC7 alloys are from 310MPa to 410MPa, 42% to 31%, and Hv145 to Hv180, respectively.
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Wu, Kuan-Ting, and 吳冠霆. "Study on Low-temperature Gas Nitriding and Plasma Polishing of Stainless Steel AISI 304." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/34585437170771135899.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
104
AISI 304 stainless steel is one of the commonly-used steel among austenitic stainless steel. This stainless steel has excellent corrosion resistance thanks to its high concentration of chromium and nickel. The surface is coated with a passive film that helps protect the steel from oxidation. However, it shows low hardness because of its austenite phase, and it can not be strengthened with heat treatment such as quenching, giving rise to drawbacks such as being prone to wear, scratches, and abrasion. Thus, the method of solid solution strengthening is often used to improve the hardness of AISI 304. This study aims to strengthen the surface of austenitic stainless steel, and reduce the surface roughness. The experiments are divided into three parts: activation treatment, low temperature gas nitriding, and plasma polishing. In order to remove the oxidation film on the surface, the specimens will go through activation treatment using HCl gas in high temperature for a short period of time. After the treatment, the surface hardness is strengthened by low temperature gas nitriding. Having been through the processes above, the surface will become rougher due to side effects like etching and lattice expansion. In order to reduce the surface roughness, the method of plasma polishing is studied in the third part. Plasma polishing is a polishing method by treating the specimen as the positive electrode. The specimen will be immersed in low concentration electrolyte, and applied with hundreds of voltages. Then, the surface would become polished when the plasma film is formed in appropriate conditions. The main results of the experiments are: (1) With longer time span and higher temperature of gas nitriding, the nitrided layer grows thicker. The nitrided layer contains rich nitrogen and high hardness. However, overheating would cause a decrease of corrosion resistance. (2) With lower temperature and higher current density of plasma polishing, the polishing efficiency becomes higher. The surface will become uniform when the polishing efficiency is higher than corrosion rate. (3) The surface roughness is reduced when the polishing time is increased, but the roughness would maintain at a certain level after polished for a long time. (4) With adequate polishing efficiency, the surface roughness could be reduced in a short period of time while maintaining enough thickness of nitrided layer.
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Sahu, Sushanta Kumar. "An Investigation of Dissimilar Pipe Welding of AISI 304 Stainless Steel with CP Copper." Thesis, 2020. http://ethesis.nitrkl.ac.in/10111/1/2020_PhD_SKSahu_511ME616_AnInvestigation.pdf.
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A study on dissimilar metal welding of commercially pure copper and AISI 304 SS pipes with different thicknesses has been carried out. Three different welding processes, namely, pulsed Nd:YAG laser beam, pulsed TIG Arc and continuous CO2 laser beam welding have been compared. For studying the effects of process parameters, viz. peak power, pulse duration, frequency, beam diameter (for laser beam) / stand-off distance (for TIG), processing speed, energy density etc. Controlled set of experiments are conducted as per standard DOE (Design of Experiment) methods. Temperature buildup during welding has been measured by K-type thermocouples with a data acquisition system. Mechanical and metallurgical characterization of the welds, i.e., tensile strength, bead geometry, microhardness, etc., have been performed. Microstructure of the weld pool has been characterized by SEM, EDX and XRD. Effect of ramp down parameters on the closure bead shape has been studied in pulsed TIG arc welding. The results have been analyzed statistically with RSM (Response Surface Method). Finite element modeling of the process has been done and simulations have been run at the parameter combination levels selected during experimentation. Customized jigs and attachments have been designed and fabricated for automation of the welding process of pipes.
Results from mechanical testings have been encouraging, with weld strengths realized in between those of the base metals. In most cases, joint failure has taken place away from the fusion zone and in the weaker component (Copper). A few welds fabricated with pulsed Nd:YAG laser failed at HAZ or in the base metal. Some parametric combinations resulted in solidification cracking at the crown. Microstructural characterization shows presence of unmixed zones, partially mixed zones and carbide precipitation similar to results reported by previous researchers. Use of frequency as a tool for controlling weld pool agitation and the weld bead shape has been tried and found to be effective. Pulsed TIG arc welding and CO2 laser welding have been found to be more suitable for welding load bearing structures. Pulsed Nd:YAG laser has been found to be more suitable for welding smaller pipe thicknesses. The results and the models proposed by the present study can serve as an useful tool for further improvisations in autogenous welding of CP Copper and AISI 304 SS.
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Chou, Tang-Fu, and 周登富. "The corrosion resistance characteristics of electroless plated AISI 304 stainless steel for bipolar plate applications." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/6aa4a4.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
96
In this study, the corrosion behavior of electroless Ni, Au and Ag plating on AISI 304 stainless steel is investigated in simulated polymer electrolyte membrane fuel cell (PEMFC) environment. The main purposes are to offer fundamental information for the development of metal bipolar plates in PEMFC, and to obtain a deeper understanding of the electrochemical corrosion characteristics for electroless plating systems. This study addresses the corrosion resistance characteristics of electroless plating on AISI 304 stainless steel for PEMFC bipolar plate applications. Corrosion properties of this material were studied by using potentiodynamic and potentiostatic tests. Electroless Ag plating on AISI 304 stainless steel showed excellent corrosion resistance (corrosion current density, 1.876nA/cm2) in anodic and cathodic atmospheres under potentiostatic conditions. Moreover, electroless Ag plating on AISI 304 stainless steel showed lower the interfacial contact resistance of as compared to Ni and Au electroless plated on AISI 304 stainless steel, and respectively. Keyword: PEMFC, bipolar plate, corrosion, conductivity
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Poddar, Ayush. "Experimental investigation of MRR, surface roughness and overcut of AISI 304 stainless steel in EDM." Thesis, 2012. http://ethesis.nitrkl.ac.in/3407/1/final_thesis.pdf.
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EDM has become an important and cost-effective method of machining extremely tough and brittle electrically conductive materials. It is widely used in the process of making moulds and dies and sections of complex geometry and intricate shapes. The workpiece material selected in this experiment is AISI 304 Stainless steel taking into account its wide usage in industrial applications. In today’s world 304 stainless steel contributes to almost half of the world’s production and consumption for industrial purposes. The input variable parameters are current, pulse on time and duty cycle. Taguchi method is applied to create an L27 orthogonal array of input variables using the Design of Experiments (DOE). The effect of the variable parameters mentioned above upon machining characteristics such as Material Removal Rate (MRR), Surface Roughness (SR) and Overcut (OC) is studied and investigated. The tool material is copper.
The results obtained showed that current was the most significant parameter followed by pulse on time and the least significant was the duty cycle for the entire three responses namely Material removal rate, Surface roughness and overcut. With the increase in current and duty cycle MRR increased but for pulse on time it increased only up to 100 µs and then started to decrease. SR increased significantly with the increase in current; for pulse on time it increased up to 100 µs and after that there was no significant increase; and in case of duty cycle SR increased up to 70% and then started to decrease. OC increased with the increase in current and pulse on time but in different fashion and in case of duty cycle, OC increased up to 70% and then started decreasing.
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Gattu, Naga Pavan Kumar. "Surface Modification of AISI 304 Stainless Steel by Electrical Discharge Coating Using Powder Suspension Method." Thesis, 2016. http://ethesis.nitrkl.ac.in/9258/1/2016_MT__NPKGattu.pdf.
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Electro Discharge Machining (EDM) is an extensively used non-traditional material removal process to machine complicated geometrical parts and extremely hard materials that are otherwise very challenging to machine by conventional machining processes. A very special aspect of this process apart from machining is surface modification by depositing material from tool electrode to workpiece. The present study examines the method of depositing TiC and (TiC+TiB2) on AISI 304 stainless steel substrate by suspending titanium and boron carbide powders in dielectric fluid. Reverse polarity mode (tool positive and workpiece negative) was employed by using copper as tool electrode. The effect of parameters, peak current (Ip), pulse on time (Ton), voltage (V) and duty factor (Tau) during the process on surface roughness, micro hardness and wear rate has been studied. Micro structure of the surface was examined using scanning electron microscopy (SEM) and compounds present on the surface were evaluated by X-Ray diffraction (XRD) technique.
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Shaibu, V. B. "Thermo-mechanical Investigation of Dissimilar Welding of AISI 304 Stainless Steel with Commercially Pure Copper." Thesis, 2021. http://ethesis.nitrkl.ac.in/10353/1/2021_PhD_VBShaibu_512ME1033_Thermo.pdf.
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Laser welding represents a delicate balance between heating and cooling within a spatially localized volume overlapping two or more solids such that a liquid pool is formed and remains stable until solidification. The main objective of this research work is to analyses thermal, metallurgical and physical stages of AISI 304 Stainless Steel – Copper dissimilar couple during laser welding in keyhole mode by numerically and then validate it experimentally. 10.6 μm wavelength CO2 laser and 1.064 μm wavelength Nd: YAG welder machine is used for conducting this experimental analysis and ANSYS FLUENT® software is used for simulation. The difference in metallurgical, chemical, thermal and physical properties of AISI 304 Stainless Steel and Copper makes their laser welding a challenging task. When compared to steel, the thermal conductivity and diffusivity of copper is very high. This result in 90-98% reflection of total laser power impinged on the copper surface, i.e., the property of absorptivity decreases with increase in diffusivity of metal. The transport phenomena (heat transfer, fluid flow and species distribution) are numerically modelled for the case of laser welding of dissimilar metals. The model involves convection in the weld pool along with melting and mixing. The associated metallurgical phenomenon is an extremely complex one, and the present work is a preliminary attempt to model the process after making suitable assumptions. The numerical study is performed using a pressure based finite volume technique after making appropriate modifications to the algorithm to include the associated phase change processes and dissimilarity in the metal properties. The phase change process is modelled using an enthalpy-porosity technique, while the dissimilar metal properties are handled using appropriate mixture theories. As a case study, we have used dissimilar couples of copper- 304 SS. It is observed that the weld pool shape becomes asymmetric when the heat source is symmetrically applied on the two metals forming the couple. As the weld pool develops, the side melting earlier is found to experience more convection and better mixing. Corresponding experiments are performed using the same parameters as in the computations, showing a good qualitative agreement between the two results. After a calibration phase between simulation and experimental results for the same working environment, the FLUENT® model has been very good agreement with the experimental tests.
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Мурашкінцев, Андрій Володимирович. "Вплив хімічних елементів на корозійну тривкість сталі AISI 304." Магістерська робота, 2021. https://dspace.znu.edu.ua/jspui/handle/12345/5351.
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Мурашкінцев А. В. Вплив хімічних елементів на корозійну тривкість сталі AISI 304 : кваліфікаційна робота магістра спеціальності 105 "Прикладна фізика та наноматеріали" / наук. керівник В. Л. Сніжной. Запоріжжя : ЗНУ, 2021. 65 с.UA : Робота викладена на 65 сторінках друкованого тексту, містить 5 таблиць, 18 рисунків, було використано 53 літературних джерела. Об'єктом дослідження є процеси корозії, що відбуваються в сталі AISI 304 в хлоридовмісних середовищах та їх кореляційна залежність від магнітних параметрів і легуючих компонентів. Мета роботи – використовуючи експериментальну кореляційну залежність швидкості корозії від магнітних параметрів та сумарної кількості всіх елементів Q проаналізувати вплив легувальних елементів на пітінгову корозію у хлоридовмісних середовищах сталі AISI 304. Методи дослідження – експериментальний (магнітометричний), аналітичний, розрахунковий. У кваліфікаційній роботі використано новий магнітометричний метод дослідження пітингової корозії сталі за допомогою експериментально визначених параметрів питомої магнітної сприйнятливості аустеніту і кількості δ – фериту. Виявлено параболічні залежності швидкості корозії від вмісту хімічних елементів. Показано, що елементи С, N, Cr і Ni впливають на корозійну швидкість неоднозначно, тобто одному значенню швидкості корозії відповідає два значення вмісту елементу. Результати роботи рекомендовано використовувати для прогнозування корозійних властивостей аустенітних сталей за допомогою вимірювання магнітних параметрів.
EN : Qualification work of the master «Influence of chemical elements on corrosion duration of steel AISI 304»: 65 pag., 18 figures, 5 tables, 53 references. The object of research are the corrosion processes occurring in AISI 304 steel in chloride-containing environments and their correlation dependence on magnetic parameters and alloying components. The aim of the work is to analyze the influence of alloying elements on pitting corrosion in chloride-containing environments of AISI 304 steel using the experimental correlation dependence of the corrosion rate on the magnetic parameters and the total number of all elements Q. The methods of research – experimental (magnetometric), analytical, computational. A new magnetometric method of studying pitting corrosion of steel with the help of experimentally determined parameters of specific magnetic susceptibility of austenite and amount of δ - ferrite was used in the qualification work. Parabolic dependences of corrosion rate on the content of chemical elements are revealed. It is shown that the elements C, N, Cr and Ni affect the corrosion rate ambiguously, that is one value of the corrosion rate corresponds to two values of the content of the element. It is recommended to use the results to predict the corrosion properties of austenitic steels by measuring magnetic parameters.
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Lin, Zhao-Hong, and 林昭宏. "Bias Effects on Characteristics of Arc Deposited TiAlCrN Coatings for Application on AISI 304 Stainless Steel." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/47754996911691489098.
Full textAbstract:
碩士大同大學
材料工程學系(所)
96
There are various kinds of hard thin films,as TiN,CrN, and TiAlN… etc, which is the common used materials in nowadays. The purpose of this study was by Cathodic Arc Deposition (CAD) system to deposit multilayered TiAlCrN coatings by various bias voltages on AISI 304 stainless steel. and then study the structure of the coatings by XRD, the morphology by SEM and AFM, on the characteristics, we measure the adhesions, the hardness, the corrosion, the Wear and the erosion behaviors.
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Li, Chi-yang, and 李琪揚. "The effect of electrochemical polishing pretreatment on AISI 304 stainless steel of electroplating Tin-Nickel alloy." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/97451411354454833622.
Full textAbstract:
碩士大同大學
材料工程學系(所)
101
This experiment is to study the effect of electrochemical polishing on AISI 304 stainless steel of electroplating Tin-Nickel alloy. The electrochemical polishing of the type of current density and the polishing time improves the glossiness and roughness of stainless steel surface, and effect of appearance and properties with different sulfur content of additive to Tin-Nickel alloy film. The experiment results showed that after the electrochemical polishing of AISI 304 stainless steel, the surface roughness decreased from 0.20μm to 0.04μm, surface glossiness from 143GU increased to 768.5GU. It is observed from the OM that the surface of AISI 304 stainless steel is flat and smooth after the electrochemical polishing process. The surface roughness decrease of electrochemical polishing and electroplating tin-nickel alloy, due to the increase of sulfur content of additive on film, the gloss and chromaticity decrease. The sulfur-containing of additive content will change with surface morphology of film. Co-deposition of Tin-nickel alloy, Crystallization meticulous smooth of film, improved corrosion resistance, surface showed as black film.
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Soni, Lalit. "TiC Coating on AISI 304 Stainless Steel by Tungsten Inert Gas (TIG) Cladding Using Preplaced Powder." Thesis, 2015. http://ethesis.nitrkl.ac.in/7205/1/TiC_Soni_2015.pdf.
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In order to improve the hardness and microstructural behaviour of AISI 304 austenitic stainless steel, TiC and TiC- steel composite layer was deposited by tungsten inert gas (TIG) cladding/alloying process. Depending upon the heat input into the molten pool and mixing ratio with steel substrate, TiC clad layer or TiC-steel alloyed layer deposited on or within the steel substrate. Clad/alloyed layer height/depth and corresponding microstructure was analyzed by FESEM and EDS. The composition of the clad/alloyed layer was assessed by Xray diffraction (XRD), and hardness was measured by Vickers micro indentation hardness tester. Also effect of TIG welding current and scan velocity on the clad/alloyed layer geometry (depth, width and crater depth) and corresponding microstructure was investigated
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Liao, Shen-Peng, and 廖森鵬. "Effects of Repeated Weld-Repairs on the Mechanical Propertiesof the HAZ in AISI 304 Stainless Steel Weld." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/36657796316689274835.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
96
The effect of multiple thermal cycles related with repeated weld-repairs on the variation of hardness, microstructure and mechanical properties in the HAZ of AISI 304 stainless steel welds was investigated in this study. The welding procedures and parameters used in this work were designed to approach to the practical applications in the field. The first pass of welding was conducted by gas tungsten arc welding (GTAW) process and the remained passes were completed by shield metal arc welding (SMAW) process. After the final pass was finished, the weld metal was removed by grinding. Repeated procedures were conducted and lasted for five times. The results indicate that the low energy input of SMAW process had less influence on varying the grain size and hardness in the HAZ of 304 stainless steel weld. For the repaired welds, the tensile strength was less than that of the un-welded base metal, but still met the requirement of ASME code. In regarding to impact tests at low temperature down to -40℃, the impact values and lateral expansion of repeated weld-repairs specimens were not deteriorated by the multiple thermal cycles in comparison with un-welded base metal. Besides, the lateral expansions of repeated weld-repairs specimens were higher than ASME B31.3 code requirement. It shows the impact toughness and ductility of AISI 304 were not affected by repeated weld-repairs.
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Lee, Han-Ni, and 李函霓. "Effect of Rotation Rate on Characterisitics of AISI 304 Stainless Steel Arc-deposited TiN/CrN Multilayer Films." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/00162719977373502260.
Full textAbstract:
碩士大同大學
材料工程學系(所)
100
In this study, the TiCrN multilayered coating were deposoted on AISI 304 stainless steel substrate by cathodic arc deposotion (CAD) system using the different rotation rates (1,2,4,8 rpm). Then the coating morphologies and properties such as roughness, chemical composition, structure, and adhesion were all analyzed. Moreover, wear tests, erosion test,polarization tests, and immersion tests were also performed for exploring the effect of rotation rate on the wear and corrosion behavior of the coated AISI 304 stainless steel. The experiment results showed that the TiN/CrN multilayer mainly was a F.C.C structure. When the rotation rate was set at 4rpm, the TiN/CrN multilayer obtained had a dense structure, smallest surface roughness (Rq value = 0.328 μm ), and the best adhesion (HF1). In wear resistance, the TiN/CrN multilayer(4rpm) had a lowest friction coefficient (0.5) due to the highest H/E value. Moreover, the optimum coating(4rpm) had better corrosion resistance in 3.5 wt% NaCl and 10 vol% HCl solutions, respectively.
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Moharana, Bikash Ranjan. "Mechanical and Metallurgical Investigation of AISI 304 Stainless Steel and Commercially Pure Copper Dissimilar Metal Couple Weldments." Thesis, 2017. http://ethesis.nitrkl.ac.in/9416/1/2017_PhD_BRMoharana_511ME615_Mechanical.pdf.
Full textAbstract:
In recent years, the complex equipment/systems require a variety of materials with contradictory properties to improve performance and to reduce cost. This has resulted in increased demands for techniques to weld dissimilar materials and for use in large scale industrial production. Particularly the joining of AISI 304 stainless steel and commercially pure copper dissimilar metal couple is extensively employed for various industrial applications, i.e., in the field of electrical and electronics, cryogenics, power generation and transmission, food processing plants, neutron absorbent coolant system, automotive turbo compressor fan and shaft joints, etc. The main purpose of this combination is to utilize the high strength of the steel and high electrical conductivity of copper simultaneously with significant corrosion resistance.
The objectives of the present research work are to characterize and determine the weldability of AISI 304 SS and CP copper dissimilar metal couples without use of any kind of filler materials based on experimental, numerical simulation and statistical modeling approaches. The investigations are carried out by three different types of fusion welding processes such as continuous wave CO2 laser, pulsed wave TIG arc and pulsed wave Nd:YAG laser. The experimental work aimed to investigate the welding induces microstructure, microhardness, residual stress, compositional analysis and tensile properties of butt joint of SS-Cu weldments under different welding conditions separately. The numerical simulation (using ANSYS 15.0 FLUENT® environment) including weld pool shape and temperature obtained during welding have been investigated for laser welding and validate with the experimental results. The aim of statistical modeling is to predict and optimize the SS-Cu weldments in industrial application through desired weld structure with proper microstructure and minimum defects. The design of experiments (DOE) approaches are implemented to design the experiments, develop mathematical models and optimize the welding operations with proper parametric settings.
Although joining of dissimilar metals is a tough task due to their mismatch in properties like physical, chemical thermal, etc., the experimental results showed that a successful weldment of SS-Cu butt joint has been achieved by all three welding processes. The HAZ in CO2 laser welded specimens are found minimum i.e. 10 μm compared to other welding processes, and it is narrower for SS side in comparison to Cu side. The microhardness in the weld zone found to be more than the base materials. The numerical simulation results shows a good agreement with the experimental results in terms of shape of the weld pool and temperature profile for CO2 laser and Nd:YAG laser respectively. A greater fitness of the Taguchi orthogonal array design model for all welding processes, confirms from the corresponding ANOVA table, probability and residual plots. In pulsed TIG arc welding, the formation of weld craters at the end of the weld is resolved by varying ramp down time experimentally. Welding approaches like proper selection of input process parameters and preheating of welding specimens are successfully applied for improvement of weld strength as well as penetration depth during pulsed wave Nd:YAG laser welding processes.
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Lin, Tzu-Chun, and 林子鈞. "Phase Transition, Mechanical Properties and Wettability of Zr(N,O) thin films on AISI 304 stainless steel substrate." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/34001280227275441090.
Full textAbstract:
碩士國立清華大學
工程與系統科學系
96
本實驗使用非平衡磁控濺鍍系統，於304不鏽鋼基材製備奈米晶氮氧化鋯薄膜。在本研究中，將探討氧氣流量（自0到2 sccm）對氮氧化鋯薄膜的成分、結構以及性質之影響。藉由Ｘ光光電子能譜儀量測到氮氧化鋯薄膜的氧含量，隨著氧氣流量增加而明顯增加。從ｘ光繞射圖的觀察中則發現，伴隨著氧含量的增加，薄膜的主要相出現之順序為：面心立方晶之氮化鋯（ZrN），立方晶之氮氧化鋯（Zr2ON2），最後是單斜晶之二氧化鋯(ZrO2)，由這些薄膜的特徵可以將試片分為三區，各區分別以氮化鋯(Zone I)、氮氧化鋯(Zone II)、及二氧化鋯 (Zone III)為主相。使用改良式X光繞射之sin2ψ的方法來量測氮化鋯、氮氧化鋯及二氧化鋯個別相的殘餘應力，氮化鋯的殘餘應力隨著氧含量上升而得到釋放，而氮氧化鋯及二氧化鋯則為低應力相。氮氧化鋯薄膜之硬度因為隨著氧含量增加形成較軟的氧化相而下降。在歐傑電子能譜儀(ＡＥＳ)的分析中，發現所有通氧的試片存在著一層氧化鋯介層。本研究中，使用兩種材料間的接觸角來作為材料間可濕性的指標，接觸角是由材料的表面能計算所得，使用接觸角的方法發現，二氧化鋯在304不鏽鋼的附著性不佳，此結果說明鹽霧試驗之後，氮氧化鋯薄膜從基板上碎裂可能是由於二氧化鋯介層的影響。
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Chang, Chi-Yu, and 張紀宇. "CO2 Flow Rate and Bias Effects on Characteristics of AISI 304 Stainless Steel Arc-deposited Cr-C-O Composite Coatings." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/26146359162363525051.
Full textAbstract:
碩士大同大學
材料工程學系(所)
98
In this study, the Cr-C-O composite coatings were synthesized on AISI 304 stainless steel substrate by cathodic vacuum arc (CVA) deposition system using CO2 reactive gas and Chromium (99%) target. In the process, we try to vary the CO2 flow rate and the bias as the coating parameters, and the coating morphologies and properties such as roughness, chemical composition, structure, and adhesion were all analyzed. Moreover, polarization tests, immersion tests, wear tests, and erosion tests were also performed for exploring the effects of bias and CO2 flow rate on the coated AISI 304 stainless steel. The experiment results showed that the Cr-C-O composite coatings can improve the properties of AISI 304 stainless steel, such as wear resistance and corrosion resistance. In the aspect of corrosion behaviors, the polarization test and immersion test showed that the coatings have the best quality at 40sccm with -150V. At the same parameter, due to a higher value of H/E and the best adhesion, it also has a well performance in wear test and wet erosion test. In conclusions, the Cr-C-O coated specimens can improve the properties of AISI 304 stainless steel.
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Huang, Guo Zhang, and 黃國彰. "Growth Retardation of Fatigue Crack by Cold Expanded with Ring Indented and Spot heating Methods for AISI 304 Stainless Steel." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/48094703554497498060.
Full textAbstract:
碩士國立高雄應用科技大學
土木工程與防災科技研究所
96
Drilled, cold expanded with ring indented and spot heating methods were employed for crack-tip on the both sides and front side of the specimens, thus buildup the residual compressive stresses, strain hardening and plasticity induced closure, and lead toward crack growth retardation. The compact tension specimens of AISI 304 stainless steel were used drilled, cold expanded with ring indented in the fatigue test. The experimental methods were drilled(diameter=2mm ), cold expanded(diameter=2.074mm) and ring indented(diameter=6mm) both sides at 2mm and 1mm position of the crack-tip in the specimen, then apply 0, 6, and 9kN test loads, respectively. In addition, spot heating is at 1mm position of front crack-tip for the specimens. The experimental results showed that, for the same test position, the number of delay cycles result from cold expanded than that of drilled and the number of delay cycles are 220798. For the same position, the stronger test load is, the greater crack growth retardation effect is. For the same position of spot heating, the higher temperature buildup the greater residual compressive stresses, and results in a good crack growth retardation.