No description available.

Orientador: Amauri Hassui / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-18T15:21:15Z (GMT). No. of bitstreams: 1 Moraes_Danielde_M.pdf: 2580168 bytes, checksum: 72cdec956f85681dfb95a8361e2e1d24 (MD5) Previous issue date: 2011 / Resumo: Atualmente a competitividade das empresas é um objetivo que vem sendo buscado de forma bastante intensa. Por outro lado, fatores como o meio ambiente e a preocupação com o conforto e a saúde dos seus colaboradores também tem sido motivo de preocupação. Esses dois fatores são as vezes antagônicos e para conseguir atingi-los simultaneamente é necessário a aplicação de conhecimento técnico ao meio produtivo. O ruído do processo de fresamento está relacionado com a vibração do mesmo e pode ser danoso à saúde e ao bem estar dos operadores bem como prejudicar o acabamento superficial e até mesmo causar avarias as ferramentas de corte. O presente trabalho teve como objetivo diminuir o ruído da operação de fresamento de uma das faces do bloco do motor. Uma das características desse fresamento é a presença de diferentes larguras de corte, que faz com que o diâmetro da fresa não seja o ideal em todo o processo. Para atingir o objetivo mencionado, foram feitos ensaios variando-se a velocidade de corte, o avanço por dente, o ângulo de posição e a profundidade de corte, em cada ensaio foram adquiridos os sinais de vibração. Os resultados obtidos mostram que a menor largura de corte, maior avanço por dente, maior profundidade de corte e maior ângulo de posição tendem a gerar maiores vibrações. A velocidade de corte não apresentou uma influência consistente na vibração. Com esses resultados, sugere-se, para menor vibração da operação estudada, trabalhar-se com os níveis mais baixos de avanço por dente e velocidade de corte, com ângulo de posição menor / Abstract: Nowadays the competitiviness of the companies is a target that has been searched in a very intense way. On the other hand, factors like environment and the concerning about workers health and confort has also been important. These two factors are sometimes antogonics and to reach them simultaneously is necessary the application of technical knowledge to the shop floor. The milling process noise is related with the process vibrations and can be harmful to the workers health and welfare as well as to the surface roughness and it can even damage the cutting tools. The present work aimed decrease the milling process noise of engine block surface. One of the features of this milling is the presence of differents cutting width, this makes the diameter of the cutting tool not the ideal one along all the trajectory. To reach the mentioned goal, it was carried out several tests with different cutting speed, feed per tooth, entering angle and cutting depth, in each test they were acquired the vibration signal. The obtained results show that lower cutting width, higher feed per tooth, higher cutting depth and higher entering angle tend to generate higher level of vibration. The cutting speed didn't present a consistent influence on the vibration. With these results, it was suggested, to decrease of vibration of the studied operation, work with the lower level of feed per tooth and cutting speed, with lower entering angle / Mestrado / Manufatura / Mestre em Engenharia Automobilistica

O processo de roleteamento é um tratamento superficial, comumente utilizado em peças fabricadas em aços e ferros fundidos nodulares, em regiões onde há concentradores de tensões, com o intuito de melhorar as propriedades de resistência à fadiga. Este processo endurece e introduz tensões residuais compressivas na camada superficial do material, através de deformação controlada, provocando uma redução das tensões de tração que atuam na superfície da peça submetida a carregamentos cíclicos. Este trabalho teve como principal objetivo o estudo do efeito do roleteamento superficial sobre o comportamento em fadiga de um ferro fundido nodular de matriz perlítica, utilizado na fabricação de virabrequins pela indústria automobilística. Foram realizados ensaios de fadiga por flexão rotativa em corpos de prova lisos e com entalhe. Os corpos de prova com entalhe foram divididos em dois grupos, com e sem roleteamento superficial. Foi utilizado entalhe com geometria semicircular com raio de 1,20mm e profundidade de 0,70mm. Para o processo de roleteamento foi utilizado um rolete com diâmetro de 15,00mm e com raio de curvatura de 1,30mm e aplicada uma força de compressão de 2390N. A introdução de tensões residuais compressivas pelo trabalho a frio, dificultou a nucleação e a propagação de trincas na camada superficial dos entalhes roleteados. Isto ficou evidenciado pelo aumento do valor do limite de fadiga para 483MPa obtido para o material entalhado e roleteado, enquanto que para o material nas condições de sem entalhe e somente entalhado estes valores foram de 300MPa e 168Mpa, respectivamente. / Surface rolling is a mechanical treatment commonly used in parts fabricated with steel and ductile cast iron, specifically in stress concentration regions, to improve fatigue properties. This process hardens and introduces compressive residual stresses to the surface of the material through the application of controlled strains, thus provoking a reduction of resulting tensile stress at its surface under cyclic loading. This work deals with the effect of surface rolling on high cycle fatigue behavior of a pearlitic ductile cast iron used in crankshaft by automotive industries. Rotating bending fatigue tests were performed in both smooth and notched specimens. The notched specimens were divided into two groups: with and without surface rolling treatment. The specimens notch geometry was semicircular with radius of 1.20mm and depth of 0.70mm. The rolling treatment was carried out using a roller with diameter of 15,00mm, curvature radius of 1.30mm and a compression force of 2390N. The introduction of compressive residual stresses under cold work made difficult the nucleation and propagation of the crack on the rolled surface of the notch. It was confirmed by the increase of the endurance limit of the surface rolled specimens to 483MPa in comparison with the smooth and notched specimens, respectively, 300MPa and 168 MPa.

Les prévisions alarmistes en ressources naturelles encouragent la recherche de solutions alternatives au niveau mondial. Le recyclage devient alors un défi majeur pour la société, en particulier pour les produits dérivés du pétrole comme les huiles de transformateur. Cette étude est basée sur la recherche de nouvelles voies de revalorisation de ces huiles, par l’analyse critique du contexte concurrentiel, des segments de marché potentiels, ainsi que des propriétés physico-chimiques de ces huiles. Nous nous sommes attachés à déterminer l’adéquation des performances et caractéristiques des huiles de transformateur régénérées aux exigences propres au marché de l’usinage et de la mise en forme des métaux. L’usure des matériaux dans le cadre de la lubrification limite et au-delà, est un domaine d’étude complexe combinant la mécanique, la physique du solide, la chimie ainsi que la thermodynamique des phénomènes irréversibles. Dans le cadre de cette étude les performances d’hydrocarbures neufs, usagés (pollué par les Polychlorobiphényls) et régénérés, ayant des propriétés physico-chimiques et rhéologiques proches, sont comparés dans le cadre d’essais sclérométriques et tribométriques sur une fonte à graphite sphéroïdal, matériau de frottement largement employé dans l’industrie du transport. Une séquence de techniques d’analyse de surface est développée afin de caractériser les morphologies des surfaces et quantifier les déformations de matières résultantes du frottement. La complémentarité des essais sclérométriques et tribométriques, qui permettent d’étudier les performances des hydrocarbures dans différents états de contraintes, respectivement de compression et de cisaillement, révèlent les bonnes performances des huiles de transformateurs régénérées. En quantifiant spécifiquement les performances des huiles revalorisée à travers la détermination de paramètres tribologiques classiques, comme les taux de déformations, les coefficients de frottements ou encore les temps d’initiation au grippage. La composition finale de l’huile régénérée, à savoir la longueur des chaines hydrocarbonées, les teneurs en eau et en PCB, conditionne son comportement tribologique. Suite à ce bilan positif portant sur les performances des huiles de transformateur régénérées en usure abrasive et catastrophique, la mise en forme des métaux peut être identifiée comme une nouvelle voie de valorisation matière de ces huiles. / The alarming forecasts of natural resources encourage worldwide the search for alternative solutions. Hence recycling becomes a major challenge for society, especially for petroleum products such as transformer oils. This study is based on finding new ways of valorizing these oils, which is a complex problem that must meet the economic, political, regulatory, environmental and scientific constraints and challenges. A critical analysis of the competitive environment, of the potential market segments, as well as physic-chemical properties of these oils is the basis to determine new ways of revalorization. In this study, we attempted to determine the suitability and performance characteristics of transformer oil regenerated to the specific requirements of the machining and shaping of metals. The wear of materials under boundary lubrication and beyond this regime, is a complex area of study combining mechanics, solid state physics, chemistry and thermodynamics of irreversible processes. In this study the performance of new, used ( polluted by polychlorinated biphenyls ) and regenerated oils with close physic-chemical and rheological properties are compared in scratch test and tribometric with a ductile cast iron, which is friction material widely used in the transportation industry. A sequence of surface analysis techniques is developed to characterize the morphologies of the surfaces and quantify the resulting deformation of the friction material. The complementarity of scratch an tribometric tests for the study of the performance of hydrocarbons in different stress states, respectively compression and shear, reveals the good performances of regenerated transformer oils. This study has allowed discriminating the behavior of various origins oils under conditions of extreme friction, and specifically quantifying the performance of the regenerated oils through the determination of classical tribological parameters such as rate of deformation, friction coefficients or time to seizure. The final composition of the regenerated oils, ie the length and nature of the hydrocarbon chains, the water and PCBs content and the presence of polar molecules, determines its tribological behavior. Thus, the study showed that the performance of regenerated oils increases with the water and PCB content. Following this positive assessment on the regenerated oil performances in case of abrasive and catastrophic wear, machining and shaping of metals can be identified as a new way for regenerated transformers oils.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22067号 / 工博第4648号 / 新制||工||1725(附属図書館) / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 安田 秀幸, 教授 辻 伸泰, 教授 宇田 哲也 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

This diploma thesis deals with the creation of penetration of cast iron with graphite casting cast into bentonite molds. In the first part of the thesis is theoretically described the formation of penetration, its main causes, consequences and the elimination of this defect. The second part analyzes the causes of the defect with the Minitab statistical software and shows the possible connections of the input materials to the occurrence of the defect. Next, the experimental finding of the cause of the defect, which is focused on the measurement of the pressures in the form of the casting, is devoted to it.

The diploma thesis deals with the modification and inoculation of cast iron with spheroidal graphite, the influence of the chemical composition on the shape and size of the graphite nodules and ferrite/perlite ratio in the structure. The aim of the practical part was to determine the effect of inoculant containing bismuth (SMW 605) on microstructure and mechanical properties of ferritic ductile cast iron GJS 400-15. The dissolving time of mold inoculant was further investigated. The samples were subjected to a tensile test, Charpy impact test, hardness test and graphite morphology and ferrite/perlite examination using standard ČSN EN ISO 945-1.

The aim of this work is to find a suitable cutting tool and suitable cutting conditions for the production of hydrostatic surfaces of a crossmember with the quality of the surface structure of Ra 0.8 mm. The technology described in the thesis deals with finishing hydrostatic surfaces by milling, with the quality of the surface structure of Ra 0.8mm. As the production method cutting operations using CNC machines is used. To assure the quality of the surface insert tools are used, which are selected and evaluated based on experimental testing from six different suppliers. The technological process of production solves the problem of the hydrostatic surface production from the first gripping all the way to the final manufacture of the surfaces.

Orientador: Marcos Valerio Ribeiro / Resumo: The development of new materials is extremely important, due to the need to obtain materials with good properties and low cost. There is a continuing need to improve tools for machining materials that have high strength at elevated temperatures that meet the vermicular cast iron. Small advances in the development of new tools could mean important aspects in the field of machining, in addition to making the market more competitive. The set of production and application of ceramic cutting tools in the machining processes of vermicular cast iron (GJV450) needs further advances, being an object of great industrial interest. In this context, the present work determined the best application condition of the ceramic tools based on Alumina (Al2O3), doped with magnesium oxide (MgO) on a laboratory scale, in the machining without cutting fluid of the vermicular iron class GJV450 in comparison with a commercial carbide tool coated with alumina, based on the need for machining vermicular cast iron in industries and foundries. For turning vermicular cast iron with a ceramic tool, the parameters used were cutting speeds of 300-350-400-450-500-550-600-650 m / min; feed of 0.1-0.3 mm / rev and machining depth of 0.5 -1.0 mm and for the carbide tool, cutting speeds of 150-250-350-450 m / min; feed rate of 0.1-0.3 mm / rev and machining depth of 0.5 -1.0 mm. The previously defined input variables (Vc, f, ap), were correlated with the output variables such as roughness (Ra and Rt), power, acous... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

La diffusion des techniques et du savoir-faire est un thème fort en matière d’hydraulique somptuaire. Les recherches menées sur la communauté des fontainiers français au service du roi d’Espagne Philippe V permettent d’approfondir cette problématique. Installés sur le domaine royal de La Granja de San Ildefonso dans la Sierra de Guadarrama près de Ségovie, les fontainiers mettent en œuvre les innovations techniques déjà appliquées sur le chantier de Versailles. Cette étude de cas ouvre la réflexion, d'une part, sur les transferts techniques et la circulation des savoirs entre France et Espagne à l'époque moderne, à une période où des liens étroits se sont tissés entre la cour madrilène et la cour versaillaise, et d'autre part, sur la place de l'Espagne comme centre d'innovation technologique.Les jardins et leurs fontaines deviennent objet de démonstration du pouvoir, expression de la domination politique et de la puissance royale. La symbolique de faste associée aux effets d'eau des fontaines de La Granja de San Ildefonso nécessite l'installation d'un nouveau réseau de techniciens spécialisés. Le roi d'Espagne fait alors appel à des fontainiers issus de Sceaux, Versailles, Trianon, Marly et Chantilly. Ces experts hydrauliciens participent pleinement au succès de l'opération, aux côtés des jardiniers, sculpteurs et architectes, prenant part à la conception des systèmes d’alimentation en eau des jardins et à l'entretien de ces infrastructures au quotidien.Tout au long du XVIIIe siècle, les innovations techniques mises en œuvre sur les jardins royaux français, transmises par l'intermédiaire de cette communauté de fontainiers expatriés, vont s'agréger à la tradition locale hydraulique espagnole, déjà le fruit de plusieurs transferts technologiques. Les jardins de San Ildefonso doivent être replacés dans une perspective à dimension européenne de diffusion des savoir-faire du personnel technique royal français. / The study about the community of French hydraulic engineers in Spain in the service of King Philip V is to question the history of technology focusing on royal palaces hydraulics and the circulation of knowledge. The arrival of the French hydraulic engineers in La Granja de San Ildefonso changed the hydraulic technologies in Spain. From this perspective, hydraulics is an expression of political domination. This case study allows to investigate technological innovations and their transfers between France and Spain during modern times, a period when the links between both the Madrid and the Versailles courts were very close.A new network of specialized technicians was necessary to give full dimension to the political domination which was perfectly conveyed by the fountains of La Granja de San Ildefonso with their highly symbolic and breath-taking water effects. That is why the King of Spain hired hydraulic engineers from Sceaux, Versailles, Trianon, Marly and Chantilly. It was thanks to these experts who designed water supply systems and daily routines to take care of the installations, by the side of gardeners, sculptors and architects, that the project ended up being a great success.During the whole 18th century, technical innovations were implemented in the French royal gardens, taught through this community of expatriated hydraulic engineers and enriched the local hydraulic Spanish tradition which was already the result of various technological transfers. The San Ildefonso gardens must be placed on a European perspective regarding the expertise of the French royal technical workforce.