Orientador: Sergio Tonini Button / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-04T01:40:40Z (GMT). No. of bitstreams: 1 Gentile_FernandoCesar_D.pdf: 18474234 bytes, checksum: b76313390a0c50a06d4c59b7df69e538 (MD5) Previous issue date: 2004 / Resumo: Neste trabalho foram feitas simulações físicas do processo de Laminação Transversal com Cunha (LTC), também conhecido como Cross Wedge Rolling (CWR), para se analisar a influência da temperatura, da velocidade do processo e das características dos materiais empregados na estabilidade do processo. Para o desenvolvimento deste trabalho foram necessários o projeto e construção de uma bancada de simulação que fosse capaz de laminar peças com variados diâmetros e a diferentes taxas de deformação, e também de um par de ferramentas planas que fosse capaz de fabricar peças isentas de defeitos, segundo os diagramas de estabilidade do processo LTC disponíveis na literatura. Foram utilizados como materiais nas simulações: liga de alumínio, aço ABNT 4140 e aço microligado 48MnV3. A escolha do aço microligado foi baseada nas propriedades necessárias para materiais utilizados na fabricação de eixos escalonados. Para este material, foram feitas medidas da área dos defeitos internos, avaliações da macro e da microestrutura e ensaio de dureza Rockwell C. Os resultados mostraram que o diagrama de estabilidade de Hayama, utilizado para o projeto de ferramentas do processo LTC, não leva em consideração da maneira correta as propriedades do material conformado, já que se obteve diferentes defeitos externos para os diferentes materiais utilizados neste trabalho. Os resultados mostraram também que, para o aço microligado, o aumento da temperatura de processo diminui o tamanho dos defeitos internos, favorece o aumento de grão, o aumento da fração volumétrica de perlita e eleva a dureza, porém, não foi possível neste trabalho a correlação da velocidade de processo (taxa de deformação) com o tamanho do defeito interno e com as microestruturas obtidas / Abstract: ln this work tests were held with the Cross Wedge Rolling (CWR) process to analyze the influence of the process temperature, process speed and properties of the workpiece materiaJson the stability of the process. To perform these tests it was necessary to design and assemble a laboratory CWR equipment flexible enough to manufacture shafts with large ranges of diameters and strain rates, with a pak of flat tools able to roll parts free of defects in accord to stability diagrams found in the literature for CWR process. Three different alloys were tested: a commercial aluminum alloy, ABNT 4140 steel and the microalloyed steel 48MnV3. This microalloyed steel was chosen because of its mechanical properties are similar to those necessary to manufacture stepped shafts. The shafts rolled with this steel were analyzed measuring the internal defects, Rockwell C hardness and perform metallographic analysise valuating their macro and microstructures. Results showed that the Hayama stability diagram, that are used to design CWR tools, are not representative of this process because they do not consider the properties of the workpiece material in the correct way. The results also showed that higher temperatures reduce the probability of internal defects formation, rise the grain size, the perlite volume ftaction and hardness, but no conclusions can be made relating these defects an structures with the variation of the process speed. / Doutorado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

This diploma thesis is based on proposal of manufacturing technology forging of connection rod by die forging. The connection rod is made of 12 050 steel and it is part of crank mechanism in combustion engine. Production series was specified to 120 000 pcs. for year. Into technology procedure was implemented method of cross wedge rolling before die forging. The material for transverse cross wedge rolling was chosen 19 554 steel. Process of die forging was selected three operation in vertical forging press LZK 4000 with pressure force 40 MN made by company Šmeral Brno a.s. For die material was chosen 19 552 steel. And finally was carried out technical and economical evaluation of the forging production.

Le laminage transversal est un procédé de mise en forme où un lopin cylindrique est déformé plastiquement en une pièce axisymétrique comportant des réductions de diamètre. Dans le processus de fabrication de bielles, le procédé est utilisé pour l’opération de répartition avant les opérations d’estampage. Par rapport au procédé de laminage à retour, il permet d’atteindre de meilleures mises au mille et de réduire les temps de cycle. L’industrialisation de ce procédé se heurte toutefois à des difficultés liées pour l’essentiel à la conception des outillages.Ces travaux de thèse visent à améliorer le processus d’industrialisation du laminage transversal par une réduction des temps de développement des outillages et par l’allongement de leur durée de vie. Pour cela, deux axes ont été identifiés. D’une part l’amélioration et la formalisation de la méthodologie de conception des outillages et d’autre part, l’identification et la caractérisation des phénomènes défauts se produisant à grand nombre de cycle et provocant l’arrêt de l’outillage.Ces travaux de thèse s’orientent au tour de trois axes majeurs. Premièrement, l’évaluation du potentiel prédictif de la simulation numérique du laminage transversal et sa robustesse vis-à-vis des paramètres numériques et du procédé. Deuxièmement, la mise en place d’un processus de conception d’outillage comportant d’un côté une méthodologie de conception permettant de définir les paramètres de l’outillage en s’appuyant d’un autre côté sur la simulation numérique du procédé. Troisièmement, l’identification et la caractérisation des zones d’usure et ses effets sur la pièce laminée / Cross wedge rolling (CWR) is a metal forming process used in the automotive industry. One of its applications is in the manufacturing process of connecting rods. CWR transforms a cylindrical billet into a complex axisymmetrical shape with an accurate distribution of material. This preform is forged into shape in a forging die. CWR industrialization has still some limitations, mainly the designing of the tools. This thesis work seeks to improve CWR industrialization by reducing the time needed for the design of the tools and by increasing CWR tool lifecycle. In order to achieve these goals, two main axes are identified: improving the tool design procedure and identifying the physical phenomenon affecting the stability of the process, mainly tool wear.This research work is based upon three main topics. First, evaluating of the predictability of the numerical simulation of the CWR process and its robustness towards the numerical parameters of the model and the process parameters. Second, implementing a design methodology that allows the designer to choose the geometrical parameters of the wedge and evaluating the resultant geometry of the tool through the numerical simulations. And third, identifying the wear zones of the tool and the factors leading to its development

Orientador: Sergio Tonini Button / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-11T13:27:48Z (GMT). No. of bitstreams: 1 Silva_MarioLuizNunesda_D.pdf: 5214131 bytes, checksum: d3b65bf8a08ad05e43b1a4cb009f56b7 (MD5) Previous issue date: 2008 / Resumo: O processo Laminação Transversal com Cunha (conhecido em inglês como cross wedge rolling ou CWR) consiste na conformação plástica de produtos por meio de ferramentas em forma de cunhas fixadas em placas planas, côncavas ou convexas ou ainda em rolos de equipamentos de laminação. Apesar das vantagens desse processo associadas à elevada produtividade e minimização das perdas de matéria-prima, o surgimento do defeito interno denominado Mannesmann exige uma inspeção cuidadosa das peças produzidas. Esse defeito tem sua origem no centro das peças laminadas e suas causas ainda não estão totalmente identificadas. Baseando-se no método de elementos finitos, simulações numéricas em três dimensões do processo CWR foram estudadas utilizando-se o programa de simulação MSC Superform para analisar-se a influência das variáveis geométricas (ângulos de conformação e de estiramento e redução relativa) e de processo (temperatura de pré-aquecimento e velocidade de laminação) no aparecimento desse que é considerado o principal defeito do processo. Ensaios experimentais em equipamento existente no Laboratório de Conformação Mecânica da Faculdade de Engenharia Mecânica também foram realizados abrangendo as mesmas variáveis citadas para a simulação. Os dados obtidos nestes ensaios foram confrontados com os das simulações para se estudar as possíveis causas do defeito e também para se avaliar o grau de representatividade do processo pelo programa de simulação. Concluiu-se que sob o critério de análise da deformação máxima equivalente, à medida que se aumenta a redução relativa e diminuem-se o ângulo de conformação e a velocidade de processo aumenta-se a probabilidade de ocorrência dos defeitos internos. Tanto nas simulações como nos ensaios práticos, não se notou uma tendência definida para a variável temperatura com relação à sua influência na formação dos defeitos internos / Abstract: Cross-wedge rolling (CWR) is a metal forming process in which wedge shaped tools are assembled to rollers, and concave or convex plates. Despite the advantages of this process associated with high productivity and reduction of raw materials, the formation of an internal defect, called Mannesmann, requires a careful inspection of the rolled parts. This defect has its origin in the center of the rolled pieces and its causes are not yet fully identified. Based on the finite element method, numerical simulations of the CWR process in three dimensions were studied using the simulation software MSC Superform, in order to analyze the influence of some geometric (forming and stretching angles and relative reduction) and process (initial temperature and speed process) variables on the formation of this that is considered the main defect of the process. Tests were also performed in an experimental equipment available in the Mechanical Forming Laboratory of the School of Mechanical Engineering covering the same variables cited for the simulation. The data from these tests were confronted with simulation results to determine the possible causes of the defect and also to evaluate the agreement of these results. From the analysis of the maximum equivalent strain, the higher relative reduction and smaller forming angle and process speed values the higher probability that the internal defects occur. It was not noticed a good trend about the influence of the initial temperature on the formation of the internal defects / Doutorado / Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica

The thesis deals with the design of technology for production of weapon conclusion by die forging. The weapon conclusion will be made of C45 steel in series of 500 000 pieces per year. Before forging, the base semi-finished product will be treated using cross-wedge rolling technology. Thanks to the chosen production process, the forging will be made as four pieces. A simulation of the forging process was made for the created design. Results of a simulation showed that metal did not fill entire hollow. Based on these results was made changes in design and the simulation was performed again. According to the results of the second simulation, the hollow has already been filled with metal. For the forging was chosen the machine LZK 2500P from Šmeral a.s with a nominal force 25MN. In the conclusion there was a technical-economic evaluation of costs for the material required for production of entire series.