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Comportamento eletroquímico do aço-carbono ABNT 1006 em meio etanólico na presença de cafeína; Electrochemistry behavior of low-carbon steel abnt 1006 in ethanolic medium in the presence of caffeine

Trindade, Letícia Guerreiro da
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
Português
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Neste trabalho foi investigado o efeito inibidor da cafeína nos processos corrosivos do aço-carbono em etanol p.a., utilizando como eletrólito suporte LiCl ou LiClO4. Avaliouse também o efeito inibidor do composto sobre o comportamento do metal em soluções mais agressivas, com adição de água, cloreto e ácido acético, na presença e na ausência de cafeína. As propriedades inibidoras da cafeína foram avaliadas por ensaios de perda de massa, espectroscopia de impedância eletroquímica, voltametria cíclica, curvas de Tafel e cronoamperometria. As curvas de Tafel mostraram tratar-se de um inibido anódico. As diferentes técnicas utilizadas tiveram um resultado similar, mostrando que a cafeína é um bom inibidor para o aço-carbono em etanol, inclusive quando se aumenta a agressividade do meio, com adição de contaminantes. As medidas mostraram que o primeiro passo da interação entre a cafeína e a superfície do metal é através do processo de adsorção. Os valores encontrados para a variação da energia livre de adsorção de Gibbs sugerem um processo de adsorção químico e espontâneo. Em alguns casos constatou-se a diminuição da eficiência de proteção para valores de concentrações maiores de cafeína. Este resultado foi relacionado ao efeito quelante do composto. Alguns dos métodos utilizados mostraram que...

Caracterização da resistência à deformação a quente do aço baixo carbono microligado ao vanádio; Carachterization of the hot deformation resistance of a low carbon steel microalloyed with vanadium

Cunha, Emerson Fernandes da
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
Português
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Este trabalho, realizado em cooperação com a Gerdau Riograndense, tem por finalidade avaliar o comportamento do aço GG1013-M, um aço baixo teor de carbono microligado com vanádio e manganês, na laminação a quente no que tange a sua resistência à deformação, possibilitando assim a tomada de decisão em relação a modificações no processo. Foram realizados testes em simulador termomecânico Gleeble™ para determinação das temperaturas a serem usadas no teste prático no laminador, onde testou-se lotes que cobrissem toda a amplitude da faixa de composição química da qualidade do aço em estudo. No teste prático no laminador, foram retiradas amostras para os ensaios mecânicos, onde identificou-se, por intermédio do tratamento de dados em software estatístico, a influência da variação dentro da faixa da composição química sobre os limites de escoamento e resistência. Como resultado, conseguiu-se determinar a faixa de temperatura mais provável, onde a resistência a deformação a quente é menor, minimizando ou eliminando as conseqüências da redução de ductilidade a quente por conta do endurecimento da matriz por precipitação dos elementos de liga em forma de compostos.; This work was conducted in cooperation with Gerdau Riograndense aiming at the evaluation of the hot rolling behavior of a low carbon steel microalloyed with manganese and vanadium (internally GG1013-M steel).The deformation resistance was evaluated...

FeNbP in ultra-low carbon Nb-added steel containing high P

Ramos, A. S.; Sandim, HRZ; Hashimoto, T. M.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 171-174
Português
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Precipitation of FeTiP is reported to occur in Ti-added IF steels containing high P during thermomechanical processing. An ultra-low carbon (ULC) Nb-added steel ingot containing a higher P content (< 0.8 wt-%) was produced via aluminothermic reduction of Fe2O3 followed by double electron beam melting (EBM). FeNbP coarse precipitates were observed in the as-cast microstructure. After soaking at 1050C for 1 h, the plate was hot rolled from 31 mm down to 7 mm in thickness (total reduction of 77%). During cold rolling of these hot bands we observed embrittlement. We believe that this embrittlement can be attributed to the presence of the FeNbP precipitates. Light optical and scanning electron microscopy (SEM/EDS) were used to characterize the microstructure of this ULC steel. (C) 2000 Elsevier B.V. All rights reserved.

Effect of citrate ions on the electrochemical behaviour of low-carbon steel in borate buffer solutions

Modiano, S.; Fugivara, C. S.; Benedetti, A. V.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 529-545
Português
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The electrochemical behaviour of cold-rolled low carbon steel was studied on both active and passive potential regions in borate buffer solutions with and without the addition of sodium citrate (NaCit). In the active region anodic charges increased significantly and RCT values decreased with citrate, due to the formation of soluble complexes. In the passive potential region the film formed at +0.4 V in borate buffer solution with and without 0.010 M NaCit is probably enriched by Fe3O4 oxide, while films formed at +0.8 V are probably enriched by gamma-Fe2O3. The equivalent circuit [R-s(R(CT)Q)] fitted all experimental impedance data. (C) 2003 Elsevier Ltd. All rights reserved.

Optimization of the mechanical properties of low-carbon steels by formation of a multiphase microstructure

Abdalla, Antonio Jorge; De Moura Neto, Carlos; Hashimoto, Tomaz Manabu; Monteiro, Waldemar Alfredo
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência
Português
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In this work five methods of heat treatments are investigated in order to obtained convenient volume fractions of ferrite, bainite, martensite and retained austenite, starting with a low carbon steel and seeking the distinction of the phases, through optical microscopy. Specific chemical etching is improved. The results in tensile and fatigue tests were accomplished and the results were related with the microstructural parameters. The results show that the mechanical properties are closely related with the phases, grains size and the phases morphology. Copyright © 2001 Society of Automotive Engineers, Inc.

Microstructural effects on fatigue crack growth behavior of a microalloyed steel

Laurito, D. F.; Baptista, C. A R P; Torres, M. A S; Abdalla, A. J.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 1915-1925
Português
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Thermal transformations on microalloyed steels can produce multiphase microstructures with different amounts of ferrite, martensite, bainite and retained austenite. These different phases, with distinct morphologies, are determinant of the mechanical behavior of the steel and can, for instance, affect the crack path or promote crack shielding, thus resulting in changes on its propagation rate under cyclic loading. The aim of the present work is to evaluate the effects of microstructure on the tensile strength and fatigue crack growth (FCG) behaviour of a 0.08%C-1,5%Mn (wt. pct.) microalloyed steel, recently developed by a Brazilian steel maker under the designation of RD480. This steel is being considered as a promising alternative to replace low carbon steel in wheel components for the automotive industry. Various microstructural conditions were obtained by means of heat treatments followed by water quench, in which the material samples were kept at the temperatures of 800, 950 and 1200 °C. In order to describe the FCG behavior, two models were tested: the conventional Paris equation and a new exponential equation developed for materials showing non-linear FCG behavior. The results allowed correlating the tensile properties and crack growth resistance to the microstructural features. It is also shown that the Region II FCG curves of the dual and multiphase microstructural conditions present crack growth transitions that are better modeled by dividing them in two parts. The fracture surfaces of the fatigued samples were observed via scanning electron microscopy in order to reveal the fracture mechanisms presented by the various material conditions. © 2010 Published by Elsevier Ltd.

Using the electrochemical impedance spectroscopy to characterize carbon steel in biodiesel medium

Akita, A. H.; Fugivara, C. S.; Aoki, I. V.; Benedetti, A. V.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 71-77
Português
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Electrochemical impedance spectroscopy measurements using two carbon steel electrodes in soybean biodiesel medium, produced by methylic route, were performed in an electrochemical cell that allows positioning the two electrodes face-to-face. To retain the biodiesel between the electrodes and prevent its leakage a porous membrane soaked in biodiesel was used. The amplitude of the AC potential and the area of the electrodes were varied. The linearity between disturbance and response signals was observed for tests when the amplitude of the AC potential was lower than 1500 mV (rms). The electrical resistance of biodiesel dominates the global response and carbon steel presents low corrosion, which is observed only at low frequency, and was confirmed by chemical tests performed in the membrane. In conclusion the electrical resistance of biodiesel can be estimated using electrochemical impedance spectroscopy with two electrodes set up. ©The Electrochemical Society.

Soldagem a ponto por resistencia eletrica de juntas de chapa/chapa e chapa/tubo de aço de baixo carbono com diferentes composições quimicas, espessuras e revestimentos; Resistance spot welding of low-carbon steel for sheet/sheet and sheet/tube joints, with different composition, thickness, and coating

Astrid Damasco
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 21/02/1995 Português
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A motivação deste trabalho surgiu do fato da indústria automobilística usar em larga escala o processo de soldagem a ponto por resistência elétrica para a produção de juntas de chapa/chapa e de chapa/tubo com diferentes espessuras, revestimentos e composição química, sendo que ainda há uma série de dificuldades práticas associadas a algumas combinações chapa-tubo- revestimentos e, inclusive, com poucos dados disponíveis na bibliografia especializada. Foi feito, neste trabalho, a caracterização e análise do processo de soldagem a ponto por resistência elétrica para juntas de chapa sobre chapa e de chapa sobre tubo constituídas de aço baixo carbono, com diferentes composição química, espessura e revestimento. Para tanto, foram utilizadas chapas de aço ASTM 1005, de 0,95 mm de espessura, zincadas e tubos de aço ASTM 1023, de seção quadrada 30X30 mm2, com espessuras de 1,5 mm, 2,0 mm e 3,0 mm, todos fosfatizados. Com esses materiais foram obtidas juntas de chapa/chapa e chapa/tubo com diferentes combinações de espessuras ( 0,95/1,5 mm; 0,95/2,0 mm e 0,95/3,0 mm) e revestimentos (zinco/fosfato; zinco/zinco e decapados). As juntas de interesse foram submetidas ao processo de soldagem a ponto por resistência...

Electrochemical evidences of linalyl acetate (LA) adsorption on low-carbon steel in aqueous and ethanol medium

Grosser,Fabiana N.; Barros,Tainá I. T.; Gonçalves,Reinaldo S.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2014 Português
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The electrochemical behavior of low-carbon steel in 0.10 mol L-1 KNO3 aqueous solutions and 0.10 mol L-1 tetraethyl ammonium chloride ethanolic solutions was studied in absence and with different concentrations of linalyl acetate (LA). Electrochemical techniques such as potentiometry, cyclic voltammetry, chronoamperometry, Tafel polarization and electrochemical impedance spectroscopy were used in order to comprehend the interaction between the organic compound and electrode surface. Experiments involving weight loss measurements were performed. LA adsorbs on the low-carbon steel surface even in the presence of a large amount of water or ethanol. The adsorption energy for this process was -25.98 kJ mol-1 for aqueous solutions and -26.71 kJ mol-1 for ethanolic solutions. It was also detected that the adsorbed species on metal surface decreases the anodic current density values as well as the weight loss of the metal species. This effect allows us to classify the linalyl acetate as a green corrosion inhibitor of low-carbon steel in aqueous and ethanol medium.

Effects of hot and warm rolling on microstructure, texture and properties of low carbon steel

Bruna,Roberto Gerardo
Fonte: Escola de Minas Publicador: Escola de Minas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2011 Português
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It is well-known that variations in the thermomechanical processing can have a profound effect on the microstructure and mechanical properties of Low Carbon steels. Numerous studies have been published on the effect of composition, slab reheating temperature (SRT), hot rolling finishing temperature (FRT), coiling temperature after rolling (CT), amount of deformation during hot and cold rolling, and annealing temperature on the mechanical properties of LC steels. There are, however, some disagreements in the results presented in the literature. In this work the FRT and CT effects on the microstructure, recrystallization behavior and texture of LC steels rolled under hot and warm-rolling industrial conditions were investigated. The results in terms of the microstructure, crystallographic texture and properties are shown and discussed. In addition, this study will present the possible mechanisms responsible for the microstructure and mechanical properties observed.

A study of isochronal austenitization kinetics in a low carbon steel

Lopes,Maximiano Maicon Batista; Cota,André Barros
Fonte: Escola de Minas Publicador: Escola de Minas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 Português
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The austenite formation under isochronal conditions in Nb microalloyed low carbon steel was studied by means of dilatometric analysis and the data was adjusted to the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation, for different heating rates and for three initial microstructures. It was shown that the kinetics of austenitization of a pearlite+ferrite structure is faster than that of martensite (tempered martensite) at a heating rate of 0.1ºC/s. For heating rates higher than 0.1ºC/s, the kinetics of austenitization of a martensite structure is faster than of pearlite+ferrite one. The K parameter of the JMAK equation increases with the heating rate for the three previous microstructures and it is greater for the initial microstructure composed of ferrite+pearlite. At lower heating rates, the formation of austenite in this steel is controlled by carbon diffusion, independently of the initial microstructure. At higher heating rates, the formation of austenite from an initial microstructure composed of pearlite and ferrite is controlled by interface-controlled transformation.

Study of the nature of non-metallic inclusions in samples of aluminum and silicon killed low carbon steels, collected in the refining treatment and continuous casting stages

Pires,José Carlos Santos; Garcia,Amauri
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2004 Português
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The amount, distribution, size and chemical composition of non-metallic inclusions have a direct influence on steel properties. By controlling size and chemical composition of these inclusions, it is possible to get a product with good quality. The identification of the nature and the control of inclusion formation are very important for steel cleanness. The behavior of these inclusions is predictable, in some extent, by the determination of the chemical composition of non-metallic phases that form such inclusions. With the objective of studying the chemical composition, the size and the distribution of such inclusions, samples of aluminum and silicon killed low carbon steels were collected in a national steel industry in the secondary refining and continuous casting stages. These samples were analyzed in the scanning electron microscope (SEM) coupled to an energy dispersive analysis system (EDS). From the results, it was possible to evaluate the nature of inclusions and to analyze the effectiveness of the refining process in the reduction of the number and area fraction of the inclusions. It was also possible to verify that the inclusions that remained after treatment, are less damage both to the steel properties as to the continuous casting process (clogging of the submerged valve).

Kinetics of austenite formation during continuous heating in a low carbon steel

Oliveira, Fernando Lucas Gon?alves e; Andrade, Margareth Spangler; Cota, Andr? Barros
Fonte: Universidade Federal de Ouro Preto Publicador: Universidade Federal de Ouro Preto
Tipo: Artigo publicado em periodico
Português
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The kinetics and microstructural evolution of austenite formation in a low carbon steel, with initial microstructure composed of ferrite and pearlite, were studied during continuous heating, by using dilatometric analysis and measurements of microstructural parameters. The formation of austenite was observed to occur in two stages: (a) pearlite dissolution and (b) ferrite to austenite transformation. The critical temperatures of austenite formation in continuous heating increase with increasing heating rate, with greater influence on the finishing temperature of austenite formation. For both the 1 ?C/s and 0.1 ?C/s heating rates, the formation rate of austenite reaches a maximum at approximately the finishing temperature of pearlite dissolution, and the formation rate of austenite as a function of the temperature is greater at the higher heating rate.

Factors affecting the strength and toughness of ultra-low carbon steel weld metal

Van Slyke, Jonathon J.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado
Português
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The factors that affect strength and toughness often ultra-low carbon steel weld samples (HSLA-80 and HSLA-100), welded using the gas metal arc welding (GMAW) process and new ultra-low carbon consumable electrodes, were studied. The analysis was confined only to the weld metal, and the base metal was not considered. Analysis methods included optical microscopy, scanning electron microscopy, and transmission electron microscopy. Energy dispersive x- ray analysis was performed in the transmission electron microscope to analyze the chemical composition of non-metallic inclusions. The microstructure was found to be primarily granular ferrite with some primary ferrite, bainite, and martensite. Very little acicular ferrite was found (< 18 %). Because of this, to get the best mechanical properties in the weld, the size and volume fraction of non-metallic inclusions needs to be minimized. This can be accomplished by minimizing the amount of oxygen while increasing the amount of titanium and aluminum in the weld metal. EDX analysis revealed that the non-metallic inclusions were multi-phase particles with two predominant phases: a TiO-MnO phase and a MnO-SiO2-Al2O3, phase. Copper-sulfide caps were also found on the surface of some inclusions. This inclusion chemistry is typical of what is found in welding HSLA steel

Factors affecting the impact toughness of ultra low carbon steel weld metal

Gwin, Mary Elizabeth
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: 91 p.
Português
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Approved for public release; distribution is unlimited; The fundamental factors affecting the impact toughness of four gas metal arc welds (GMAW) made on HSLA-100 base plate using a newly developed steel weld wire were studied. The weld metal analysis included chemistry, mechanical testing (hardness, CVN/FATT), as well as optical, scanning and transmission electron microscopy. Studies of inclusion composition using energy dispersive x-ray (EDX), and electron energy loss spectroscopy (EELS) in the transmission electron microscope were also performed. It was found that increasing oxygen content of the weld metal (due to increased oxygen in the shielding gas) led to increased non-metallic inclusion size and volume fraction; which in turn, led to both decreasing strength and toughness. The strength was lowered because increasing oxygen in the shielding gas led to increased 'consumption' of strengthening alloys such as carbon, manganese and silicon. The toughness was compromised by the increasing size and number of oxide inclusions as these provide sites for void formation and subsequent fracture; http://archive.org/details/factorsaffecting00gwin; Lieutenant Commander, United States Navy

Effects Of Thermal Exchange On Material Flow During Steel Thixoextrusion Process

BECKER, Eric; GU, Guochao; LANGLOIS, Laurent; PESCI, Raphaël; BIGOT, Régis
Fonte: AIP Publicador: AIP
Português
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Semi-solid processing is an innovative technology for near net-shape production of components, where the metallic alloys are processed in the semi-solid state. Taking advantage of the thixotropic behavior of alloys in the semi-solid state, significant progress has been made in semi-solid processing. However, the consequences of such behavior on the flow during thixoforming are still not completely understood. To explore and better understand the influence of the different parameters on material flow during thixoextrusion process, thixoextrusion experiments were performed using the low carbon steel C38. The billet was partially melted at high solid fraction. Effects of various process parameters including the initial billet temperature, the temperature of die, the punch speed during process and the presence of a Ceraspray layer at the interface of tool and billet were investigated through experiments and simulation. After analyzing the results thus obtained, it was identified that the aforementioned parameters mainly affect thermal exchanges between die and part. The Ceraspray layer not only plays a lubricant role, but also acts as a thermal barrier at the interface of tool and billet. Furthermore, the thermal effects can affect the material flow which is composed of various distinct zones.

Aspectos da melhoria da estampabilidade de chapas de aço baixo teor de carbono.; Aspects of formability improvement of low carbom steel sheets.

Lopes, André Sereno
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 09/08/2006 Português
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O processo de conformação de chapas planas, estampagem, consiste na obtenção de peças conforme o projeto do processo e do produto. Faz-se necessária uma margem de segurança para que as variações de processo e do material possam ser absorvidas e o sucesso seja alcançado no processo de produção do componente. O presente trabalho mostra aspectos de estampabilidade de uma chapa de aço de baixo teor de carbono, o material mais utilizado no processo de estampagem. Estes aspectos são descritos e demonstrados como influenciam no processo de estampagem. No caso prático apresentado, evidencia-se que com a aplicação dos conhecimentos científicos de comportamento mecânico do material obtém-se uma melhoria no desempenho do processo e, conseqüentemente, na redução de custos e no aumento de competitividade. Como objetivo principal, tem o presente trabalho estudar a influência da redução a frio de acabamento do processo de relaminação no coeficiente de encruamento e mostrar como este estudo teve participação na solução e aplicação de uma peça-exemplo. Conseqüentemente há como objetivos secundários o estudo da influencia do tamanho de grão no coeficiente de encruamento, o desenvolvimento da textura cristalográfica antes e após a conformação da peça-exemplo e demonstrar a importância da utilização do método de elementos finitos no processo de conformação por estampagem para determinação dos tipos de conformação predominante no processo. Para realização do trabalho foram utilizados dois aços de baixo teor de carbono com composição química semelhantes porem com processos de fabricação diferenciados. Atenção especial foi dada a redução aplicada na laminação de acabamento de ambos os aços...

Propriedades de fadiga em alto ciclo de um aço baixo carbono microligado com titanio e niobio em duas condiçoes microestruturais distintas; Fatigue properties of high cycle titanium and niobium microalloyed low carbon steel in two different microstructural conditions

Jairo Aparecido Martins
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/08/1997 Português
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Atualmente, grandes esforços tem sido direcionados no sentido de se obter aços de baixo custo, com rnicroestruturas que proporcionem as melhores combinações de propriedades mecânicas, sobretudo aquelas relacionadas com fadiga em alto ciclo. Este trabalho tem como objetivos analisar as propriedades mecânicas monotônicas e cíclicas do aço API 5L X65 aço de baixo teor de carbono e microligado com titânio e nióbio-, em duas condições microestruturais distintas; a primeira na condição como fornecida (CF) e a segunda na condição tratada termicamente (T77) (normalizada a 1193K + tratada na região intercrítica a 1043 K e resfriado em óleo a uma taxa de 30 'Ks POT. -1'). A primeira condição analisada, como fornecida (CF) apresentou microestrutura ferrítico-perlítica (84,9% de ferrita para 15,1% de perlita) enquanto a segunda condição (T77) apresentou microestrutura ferrítico-martensítica (82,7% de ferrita para 17,3% de martensita). Foram analisadas as propriedades de tração ('sigma' IND. t ), limite de escoamento ('sigma' IND. e) redução de área (RA) e o limite de resistência à fadiga ('S IND. f') para as duas condições. Verificou-se um aumento do limite de resistência à tração em 14% (de 615 MPa para 800 MPa)...

Electrochemical, Activations and Adsorption Studies for the Corrosion Inhibition of Low Carbon Steel in Acidic Media

Khadom,A. A.; Yaro,A. S.; AlTaie,A. S.; Kadum,A. A. H.
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 Português
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The effect of phenylthiourea as a corrosion inhibitor for low carbon steel at different hydrochloric acid concentrations, different temperatures and fixed speed of electrode rotation, were addressed in this work. Polarization technique was used to evaluate the corrosion rates parameters. The corrosion rate of low carbon steel increases with temperature and follows Arrhenius equation in all acid concentrations in presence and absence of the inhibitor. Detailed thermodynamic parameters of activation (ΔHact and ΔSact) for the corrosion reaction were obtained using nonlinear estimation method, while adsorption parameters (ΔGads, ΔHads and ΔSads) were obtained using graphical method. Maximum inhibitor efficiency was (96.44%) obtained at 1 M HCl at 333 K and 1 g/L inhibitor concentration.

Corrosion Inhibition of Some Organic Compounds on Low Carbon Steel in Hydrochloric Acid Solution

Khalifa,Omyma R.; Abdallah,Shadia M.
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 Português
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The effect of N-[N`-(4-methoxyphenyl)benzenesulphonamido]-3-carboxy-4-methyl-4-(4-methylphenyl)-3-butenamide 1, N-(N`-phenylbenzenesulphonamido)-3-carboxy-4-methyl-4-(4-methylphenyl)-3-butenamide 2, and N-[N`-(4-chlorophenyl)benzenesul-phonamido]-3-carboxy-4-methyl-4-(4-methylphenyl)-3-butenamide 3, on the corrosion of low carbon steel in 1 M hydrochloric acid solution has been studied by weight loss measurements and potentiodynamic technique over the temperature range 30-60 °C. Results obtained showed that protection efficiency increased with the increase in concentration of the different organic compounds used and decreased with the increase in temperature. Langmuir adsorption isotherm at all temperatures was studied. The phenomenon of physical adsorption is proposed from the values of Ea and ∆G˚ads. Results obtained showed that compound 1 is the best inhibitor, and the protection efficiency follows the order: 1 > 2 > 3.