Engenharia Mecânica

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http://repositorio.ufes.br/handle/10/17620
Programa de Pós-Graduação em Engenharia Mecânica

Centro: CT
Telefone: (27) 4009 2116
URL do programa: http://www.engenhariamecanica.ufes.br/pos-graduacao/PPGEM

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Navegando Engenharia Mecânica por Assunto "Aço"

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    Análise dos estágios iniciais da corrosão de aço-carbono e aço patinável expostos em ambiente marinho-industrial e rural
    (Universidade Federal do Espírito Santo, 2002-09-02) Oliveira, Luciano Sacramento de; Queiroz, Rogério Silveira de; Macêdo, Marcelo Camargo Severo de; Larica, Carlos; Bastos, Ivan Napoleão
    ASTM A36 and ASTM A242 steel samples were exposed for 4 months in marineindustrial and rural sites. The meteorological conditions and the SO2, SO4 -2, Cl- and TSP concentrations were evaluated during all the research period. The corrosion products were characterized by x-ray difractometry and Mössbauer spectroscopy. The samples exposed in rural environment showed g-FeOOH and g-Fe2O3, while samples exposed in marine-industrial environment showed a-FeOOH and g-FeOOH. Corrosion rates and thickness losses were determined through mass loss essay. ASTM A36 mass loss was larger than ASTM A242 mass loss. Simple linear regressions were performed for mass loss in function of time and multiple linear regressions were performed in order to produce equations for corrosion rates in function of environmental parameters for ASTM A36 and ASTM A242 steels. It was verified that Cl- and SO4 -2 ions were the more influent factors in corrosion of samples exposed in marine- industrial environment. There must be a competitive adsortion process between Cl- and SO4 -2 ions for marineindustrial environment. For samples exposed in rural environment, it was verified that pollutants probably don t influence linearly their corrosion rates. Therefore, meteorological factors as humidity must be more important to corrosion of steel exposed in this environment.
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    Estudo do desgaste por erosão de ligas metálicas utilizadas em sistemas mecânicos de plantas siderúrgicas
    (Universidade Federal do Espírito Santo, 2011-12-16) Ewald, Heiter; Scandian, Cherlio; Franco Júnior, Adonias Ribeiro; Macêdo, Marcelo Camargo Severo de
    The solid particle erosion is a serious and continuing problem in many industrial operations. Several mechanical systems are continuously exposed to environments where there are hard particles travelling at substancial speed. These particles impact and degrade the materials used there. This work aims to study three candidate materials for use in coif converters. The study was based initially on conditions presented by ASTM G 76-02 which governs the use of air jet impingement erosion rig - equipment used. These conditions are: speeds of 30 and 70 m/s and impact angle of 90°. To approach this study of actual conditions of coif converters, also conducted tests on the impact angle of 30°. The materials used were A36 steel, steel 15Mo3 and Inconel 625. The test results confirmed several concepts and behaviors already described in the literature on erosion and also presented an interesting variation in performance wear steel 15Mo3 with the variation of impact velocity. This behavior was attributed to the different mechanical energy density of the materials.
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    Influência do tipo de abrasivo de jateamento no desempenho de esquemas de pintura sobre aço carbono
    (Universidade Federal do Espírito Santo, 2008-08-22) Caser, Giovani do Carmo; Macêdo, Marcelo Camargo Severo de; Lima Neto, Pedro de; Scandian, Cherlio
    The object of this study is to analyze the use of steel converter slag, a steel plant byproduct, as an abrasive for blasting and its influence in paint systems performance. Steel coupons were blasted with such abrasive particles and coated with epoxy and alkyd products. For comparison, other samples were blasted using copper slag, a well-known abrasive used by the industry. Besides the abrasive particles own characteristics like morphology, hardness, specific mass, etc., it was analyzed the abrasive effect on the blasted surfaces like topography, surface chemical composition, general appearance and adherence of coatings. Coated coupons were also exposed to accelerated tests in salt spray cabinet, immersion in distilled water and in cathodic disbondment cell, to understand the surface preparation behaviour with such different abrasives. Converter slag blasted against steel samples were able removing a layer of hard and smooth oxide layer, formed in the plate hot mill (mill scale), creating a topography with surface parameters (Ra, Rz, Rt e Rq), similar to the ones normally obtained by use of others abrasives. Characteristics like particle hardness, specific mass, morphology and grain size distribution certainly influenced the results. Converter slag analyzed showed high contents of soluble ions, mainly calcium, which were transferred to the blasted surfaces. The performance of alkyd and epoxy coatings applied over such substrates and tested for adherence, corrosion and blistering formation in salt spray and immersion in distilled water, was clearly inferior to the ones blasted with black copper slag. This trend was not seen in the epoxy coated samples, which showed similar performance between abrasives, indicating a real possibility for use with such coatings.
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    Síntese e caracterização do compósito nanoestruturado aço (ARBL) / cerâmica (TiB2)
    (Universidade Federal do Espírito Santo, 2019-03-11) Miranda, Mariane Gonçalves de; Orlando, Marcos Tadeu D'Azeredo; Martins, Charles de Abreu; Martinelli, Antonio Eduardo; Alves, Haimon Diniz Lopes
    abstract