Made available in DSpace on 2015-03-26T13:53:33Z (GMT). No. of bitstreams: 1 texto completo.pdf: 402948 bytes, checksum: da3219eefcfbb4dc22f68e1d969b6c0a (MD5) Previous issue date: 2006-03-06 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Salt accumulation in soils is a frequent event in arid or semi-arid regions, where the evapotranspiration is high and the low precipitation is insufficient to promote leaching of the salt excess from the soil profile. Under such conditions the crop yields are reduced in response to osmotic effects, to the toxicity of specific ions in the soil solution or to a joint effect of these factors. Three trials with the common bean cultivars Diamante Negro and OPNS 331 were performed to isolate the effects caused by the high salt concentrations in the solution and to verify responses to osmotic pressure, to sodium, chloride, bicarbonate, and to pH. The treatments consisted of NaNO3, NaCl, NaHCO3, KNO3, KCl, or KHCO3 solutions, and a control treatment in which the seeds were germinated in deionized water and the plants grown in normal nutrient solution. In the first trial, germination and vigor were studied in 6 dS/m solutions. In the second, germination and vigor were studied in 60 mmol/L solutions and growth in a nutrient solution enriched with salts at the indicated concentration; the pH of the control and the nitrate and chloride solutions was maintained at 5.5, and that of the bicarbonate solutions at 8.5. In the third, the seeds were germinated in deionized water and the plantlets transplanted to a nutrient solution enriched with 60 mmol/L salts at the indicated pH values. In this trial, a treatment was added in which the pH of the nutrient solution with NaCl was raised to 8.5 to coincide with the bicarbonate solutions. The effect of sodium chloride was thus tested at the two indicated pH values. Based on the results, the conclusion was drawn that the harmful effects caused by high salt concentrations and pH, in both common bean varieties under study, can be ranked in the order: osmotic pressure > alkalinity > bicarbonate ≈ chloride > sodium. / O acúmulo de sais nos solos é um evento freqüente em regiões áridas ou semi-áridas, onde a evapotranspiração é elevada e a reduzida precipitação é insuficiente para promover a lixiviação do excesso de sais do perfil do solo. Nessas condições, a produtividade das culturas é reduzida, em resposta a eventuais efeitos osmóticos, à toxicidade de íons específicos presentes na solução do solo ou a um efeito conjunto desses fatores. Com o objetivo de isolar os efeitos decorrentes da presença de concentrações elevadas de sais na solução, verificando respostas a pressão osmótica, sódio, cloreto, bicarbonato e pH, foram realizados três ensaios, utilizando duas cultivares de feijoeiro: Diamante Negro e OPNS 331. Os tratamentos foram constituídos de soluções de NaNO3, NaCl, NaHCO3, KNO3, KCl ou KHCO3, além de um tratamento controle, em que as sementes foram germinadas em água deionizada e as plantas crescidas em solução nutritiva normal. No primeiro ensaio, estudou-se a germinação e o vigor em soluções de 6 dS/m. No segundo, germinação e vigor em soluções de 60 mmol/L e, a seguir, o crescimento em solução nutritiva acrescida dos sais na concentração indicada; o pH da testemunha e das soluções que incluíram nitratos e cloretos foi mantido em 5,5, e o das soluções com bicarbonato, em 8,5. No terceiro, as sementes foram germinadas em água deionizada e as plântulas transplantadas para a solução nutritiva com acréscimo de 60 mmol/L dos sais, nos valores de pH indicados. Neste ensaio, houve acréscimo de um tratamento adicional, no qual a solução nutritiva com NaCl teve seu pH elevado a 8,5, para coincidir com o das soluções de bicarbonato. Assim, testou-se o efeito do cloreto de sódio nos dois valores de pH indicados. Analisados os resultados, pôde concluir-se que, nos dois feijoeiros estudados, os efeitos prejudiciais, decorrentes de concentrações salinas e pH elevados, podem ser hierarquizados segundo a ordem: pressão osmótica > alcalinidade > bicarbonato ≈ cloreto > sódio.

Society’s sustainability challenges relatedto materials management have been an area of concern for policymakers, industry and the public for decades. However, if those challenges are managed in a strategic way, they are not only aproblem, but could also bring in new opportunity for companies and other organizations to improve their competitiveness through developingproduct-service systems that promote sustainable development of society. The overall aim of this thesis is to explore how aframework for strategic sustainable development (FSSD) can support the development and design of sustainable materials management strategies in product innovation. This is achieved by four studies investigating howsustainability considerations are, or could be, integrated in decisions regarding materials selection. The studies are informed by the FSSD, Maxwell’s model for qualitative research design and the design research methodology. The first study is a theoretical discussion which provides a base for the following three exploratory studies. The exploratory studies have, through literature reviews and semi-structured interviews, investigated general sustainabilityconsiderations in companies, made a comparison of the strategic potential of two product improvement strategies and finally studied what considerations that are in focus and what types of solutions that are revealed when companies apply a strategic sustainability perspective to materials management. The studies have shown that decisions regarding materials management often arebased on compliance with legislation and on avoiding substances with characteristics commonly considered problematic (such as toxicity, persistency, etc.), and that decision support regarding how materials could be managed in a sustainable way are lacking. However, the results also include some examples from companies that have successfully developed pro-active strategies towards sustainable materials management. They have approached this through managing materials in closedtechnical loops, enabled material substitution through value chain collaboration and reduced material flows through new and innovative design. Most importantly, they have assessedactions not only regarding their potential to reduce a selection of current socio-ecological impacts but also regarding their potential to link toforthcoming actions towards the full scope of socio-ecological sustainability. Through this approach, they have found several ways by which materials with characteristics that are commonly considered problematic can be. The results highlight the possibility of enabling sustainable materials management practices by using a strategic sustainability perspective in combination with material characteristics knowledge and that a static division of “sustainable” vs. “unsustainable” materials (e.g., through lists of forbidden and allowed materials) is not necessarily serving the purpose in the best way. More subtle considerations are needed. By not applying a strategic sustainability perspective to materials management, organizations risk using “sustainable” materials in unsustainable ways or phasing out “unsustainable” materials that, managed differently, could be helpful for sustainable development. Developing decision support for materials management that integrates this new way of thinking will be the focus of future work.

Coil supports are integral load-bearing components employed in generators andmotors. They serve the purpose of preventing excessive deformation and maintaininga stable position of the coils responsible for generating power and magnetic fieldswhen rotating. However, a problem with these coil supports is that they block theairflow aimed to cool the coils. Thus, this master thesis aimed to conduct a topologyoptimization to develop a cooling-air permeable coil support and select a suitablematerial. The new design was required to withstand 30,000 operational cycles andan overspeed test running at 120% speed without plastic deformation or failure. The material selection process was initiated and based on mechanical and physicalproperties requirements. One of these was that the material should be non-magnetic.Utilizing Ansys Granta EduPack, two materials were suggested, the reference materialcurrently used for the coil support, and a titanium alloy, Ti-6Al-4V. The subsequentstep was to create a CAD model of the original design based on technical drawingsprovided by ABB. With the generated design, finite element analysis (FEA) simulationand the topology optimization could be performed. The generated topology optimizedmodel was modified and two new models were created, one with smaller central cutoutsand one with larger central cutouts and a top surface cutout. Furthermore, a thirdmodel was created based on the fundamentals of fluid mechanics, the Rounded originalmodel. Computational Fluid Dynamics (CFD) simulations of the four models wereexecuted. The findings indicate that the design with larger central cutouts exhibited the mostsubstantial increase in airflow through and in between the coil supports, achieving a122 % improvement compared to the original design. The model satisfied the fatiguerequirement and successfully passed the overspeed test. Both the current referencematerial and the Ti-6Al4V alloy are suitable to use for coil support. However, theutilization of a titanium alloy might be deemed excessive in terms of its mechanicalproperties and cost. / Spolstöd är integrerade lastbärande komponenter som används i generatorer ochmotorer. De har till syfte att förhindra extrem deformation och bibehålla positionenför spolarna som ansvarar för att generera kraft och magnetfält när de roteras. Ettproblem med spolstöden är att de blockerar luftflödet avsett att kyla spolarna. Däravär syftet och målet med detta examensarbetet att genomföra en topologioptimeringför att utveckla luftgenomsläppligt spolstöd för förbättrad kylning samt att välja ettlämpligt material. Den nya konstruktionen är tvungen att klara av 30,000 driftcykleroch ett överspänningsprov vid 120% av hastigheten utan plastisk deformation ellerbrott. Materialvalsprocessen initierades och baserades på mekaniska och fysikaliska krav.En av dessa krav var att materialet skulle vara icke-magnetiskt. Användandet avAnsys Granta EduPack resulterade i två material, referensmaterialet som användsför att producera spolstödet i nuläget och en titanlegering, Ti-6Al-4V. Därefterskapades en CAD-modell av den ursprungliga designen baserat på tekniska ritningartillhandahållna från ABB. Med den genererade modellen kunde finita elementanalys(FEA) och topologioptimeringen utföras. Detta genererade i en topologioptimeradmodel som modifierades och lade grund till två nya modeller, en modell med mindrecentrala hål och en med större centrala hål. En tredje modell skapades dessutom,baserad på grundläggande principer inom fluidmekanik. Fluidmekanik (CFD) beräkningar av de fyra modellerna utfördes och resultatenvisade på att den tolpologioptimerade modellen med stora centrala hål hade denmest betydande ökningen i luftgneomströmning genom och mellan spolstödenmed en förbättring på 122 % jämfört med den ursprungliga designen. Modellenuppfyller även kraven på utmattning och maximal statisk spänning vid rusningsprov.Både referensmaterialet och titanlegeringen var lämpad att användas som spolstöd.Däremot kan användningen av titanlegeringen anses vara överdriven med hänsyn tilldess mekaniska egenskaper och kostnad.

Sustainable materials are prevalent within design, but industrial design lacks mass-manufactured product examples. This research explores this gap in knowledge to understand the influences affecting the selection of sustainable materials and how UK industrial designers could be better supported. A comprehensive literature review explores the selection of sustainable materials within the context of industrial design. Existing tools and resources designed to support industrial designers are analysed to understand the support provision and requirements. The research approach explores individual attitudes, and the influences towards and against selecting sustainable materials. Four UK companies were studied to understand how sustainable materials are considered and utilised for mass-manufactured products. Two frameworks were designed to support and facilitate sustainable material selection. The first depicts the overarching support requirements whilst the second presents the considerations and strategies. Both frameworks were evaluated by experts and previous participants. A workshop with designers evaluated the efficacy of the second framework when used as a tool The majority of industrial designers were aware of general issues of sustainability but rarely considered selecting sustainable materials. All four companies had experienced significant changes recently, including increasing resources and internal initiatives towards the use of sustainable materials. The market for sustainable materials is improving, but risks exist, such as fluctuating availability and market instability. A lack of awareness and understanding has meant that, in order to succeed, some companies have designed methods to educate stakeholders whilst designers have requested support to educate clients. Personal interest of the individual is a key driver, creating champions who raise awareness and boost confidence amongst colleagues. There is a need, not only for greater education and support, but also to improve engagement with sustainable material selection amongst industrial designers and others involved in the process.

As more owners seek to develop sustainable buildings, the construction industry is adapting to new requirements in order to meet owner's concerns. Material selection has been identified as an area where designers and contractors can have a significant impact on the sustainable performance of a building. Objective factors such as design considerations and cost constraints can play a role in the selection of materials. However, there may be subjective factors that could also impact the selection of materials. Building upon the potential impact of sustainability perceptions in an optimization model that can be used to help decision makers to select materials, this study defines and tests an instrument to identify and measure such perceptions. The purpose of this dissertation is to develop a conceptual instrument that measures the user-based assessment of product sustainability and validates decision-maker's perceptions in order to evaluate the contribution of subjective characteristics in materials selection. A survey of design and construction students and practitioners is carried out to capture the subjective factors included in the instrument. A Factor Analysis approach is used to refine and validate the measurement instrument and predict decision-makers' sustainability appraisal due to the factors considered.

As the green movement begins to sweep through the construction industry, decision-makers are beginning to include a sustainable aspect to their purchase decisions. Selecting a product solely based on its sustainability, however, is not enough to drive product selection in the construction industry. Cost still dominates the selection of building products. The level of sustainability of a product and its cost are not interconnected as market prices do not reflect the cost of environmental impacts, such as the cost of global warming or fossil fuel depletion. Having two distinct aspects to consider adds complexity in the product selection process. Typically, it constrains decision-makers to perform a trade-off analysis that does not necessarily guarantee the most environmentally preferable purchase decision. This study proposes a life-cycle management (LCM) system that reinforces the choices made by decision-makers by providing a scientific justification for those decisions. The proposed system analyses the environmental and economic performance of building product through life-cycle analysis and purchase price analysis. It operates on tools publicly available in the market and state-of-the-art analysis, assessment, and interpretation methods. The LCM system combines two distinct product attributes into a single performance score that can be easily interpreted. It allows decision-makers to compare product scores and ultimately make the most environmentally responsible and financially viable selection. A comprehensive approach is used to refine and test the LCM system using case studies comprised of an environmental and economic performance evaluation of flooring products. The contribution of this research includes the consideration of a holistic approach to product selection based on environmental and cost performance. Pre-construction estimators and construction managers could improve their estimating and product selection practices using the proposed system. Material suppliers can also benefit from this approach, as they can use it to enhance their pricing strategies, marketing plans, and overall product competitiveness.

The early stages of a product’s design are a critical time for decisions that impact the entire life-cycle cost. Product designers have mastered the first generation; however, they currently do not have the ability to know the impact of their decisions on the multi-generational view. This thesis aims at closing the gap between total life-cycle information and the traditional design process in order to harbor sustainable value creation among all stakeholders involved. A framework is presented that uses a combination of a life-cycle costing methodology and an evolutionary algorithm in order to achieve a sustainability assessment for a true multi-generational component. An illustration of the implementation of the framework shows the value to current engineering scenarios. A foundation is also laid for the overall future vision of this work to utilize proper databases and existing design tools to evaluate the overall sustainability and life-cycle cost of multi-generational components.

A pesquisa ressalta a importância da reflexão na prática aplicada sustentada no processo científico para construção do conhecimento da área têxtil de malharia retilínea. A abordagem de intervenção utilizada permite heurísticas projetuais que proporcionam análises reflexivas sobre a percepção imaginativa e física dos objetos orientados deste estudo, com base em variáveis como: a seleção de materiais e a simulação virtual. Os objetos orientados são avaliados como ferramentas de mediação dos processos de concepção de produtos têxteis centrados ao usuário, ao processo e ao produto. Verifica-se a importância de construir um instrumento de análise, amparado no conceito de design de interação, através de uma relação contínua de pesquisa-ação onde as construções cognitivas, culturais e sociais são apontadas como fator determinante para o fluxo comunicacional no processo. Sendo utilizados processos integrados de simulação virtual através do sistema CAD SDS ONE FULL RD Shima Seiki. Para tanto, a pesquisa compreende estudos de caso envolvendo empresas do setor com configurações organizacionais e projetuais diferentes, os quais apresentaram resultados significativos da aplicação do design interativo no contexto projetual têxtil. A Diana Têxtil SA. consiste em uma empresa de grande porte, sediada em Timbó, Santa Catarina. Neste estudo de caso é descrito um projeto piloto que proporcionou a concepção da primeira coleção virtual de malharia retilínea realizada no Brasil. E, apresenta através da análise do seu contexto o fluxo complexo de interações culturais e conexões dos agentes e tecnologias, que configuraram a realização desse evento. A Arco Baleno Ltda. é uma empresa de pequeno porte sediada em Flores da Cunha, Rio Grande do Sul. Este estudo apresenta um processo de design interativo guiado pelo estilista como agente de inovação. O projeto é realizado através de parcerias entre a empresa fornecedora de tecnologia e a micro empresa analisada que também conta com subsídios financeiros do Sebrae para realização de seus projetos de design. Através desse estudo foi realizada uma pesquisa afetiva com usuário final crianças de 5 a 12 anos, para avaliar a aceitação de texturas específicas e da personagem da marca. A Marisol SA. é uma empresa de grande porte sediada em Jaraguá, Santa Catarina. Este estudo apresenta uma análise sobre a implementação de processos inovadores apresentados em um workshop realizado na empresa. Compreende a avaliação de seus profissionais especialistas quanto à importância da seleção de materiais e a simulação virtual para concepção de novos produtos. A Best Malhas Ltda. é uma empresa de médio porte sediada em Caxias do Sul. Este estudo apresenta descrições de novas concepções estratégicas do posicionamento do designer dentro do contexto de serviço e apresenta tarefas distintas atribuídas a esse profissional. Uma visão holística do processo de design é analisada para subsidiar a compreensão do design do processo de design. O quinto estudo de caso é amparado em uma plataforma global de relacionamentos profissionais o LinkedIn. Esse estudo de caso de profissionais especialistas descreve a criação de uma rede social com expertises específicas, os designers de malharia retilínea, através da plataforma do LinkedIn. Foi realizada uma survey, através de questionários para coleta de dados específicos que permitiram a análises sobre as características do perfil desses profissionais da área, bem como a sua pré-disposição as variáveis desta pesquisa. Através dessa rede social potencializada pelas tecnologias, foram coletadas informações dos especialistas ―estilistas de malharia retilínea‖. Tal processo valoriza a integração de expertises, da sintonia dos pares e proporciona através da dinâmica democrática e virtuosa o ―feedback ―para este objeto de estudo. Esta dissertação possui relevância econômica, social, científica e tecnológica, pois, aponta lacunas na área têxtil de malharia retilínea. Apresenta coerência em uma abordagem de adequação – sócio técnica, no qual é atribuído ao estilista o papel de um agente estratégico de inovação, através da possibilidade descrita que esse profissional possui ao integrar processos avançados para comunicação de seus projetos. / The research point the importance of reflection in applied practice sustained in the scientific process to build the knowledge of the textile flat knitting´s textile area. The used intervention approach allows projectual heuristics that provide reflexive analysis about imaginative and physical perception of the oriented objects of this study, based on variables such as material selection and virtual simulation. The oriented objects are evaluated like mediation tools of conception processes of textile products centered on the user, on the process, and on the product. It is verified the importance of building an analysis tool, supported on the concept of interaction design, through an ongoing relationship of research-action where the cognitive, cultural and social constructions are cited as a determinant factor to communication flow in the process. Integrated processes of virtual simulation are used through the CAD system SDS ONE FULL RD Shima Seiki. Therefore, the research includes case studies involving companies of the sector with different organizational and projectual configurations, which presented significant results from the application of interactive design within the textile projectual context. Diana Textil SA. consists in a large-sized company, localized in Timbo, Santa Catarina. This case study describes a pilot project that provided the conception of the flat knitting's first virtual collection developed in Brazil. And it presents, through the analysis of its context, the complex flow of cultural interactions and connections of agents and technologies that shaped the realization of this event. Arco Baleno Ltda. is a small-sized company localized in Flores da Cunha, Rio Grande do Sul. This study presents an interactive design process conducted by the designer as the agent of innovation. The project is realized through partnerships between the company that is provider of technology and the analyzed small company, which also has the Sebrae's financial subsidies to perform their design projects. Through this study it was realized an affective research with the end user, children between 5 and 12 years old, to evaluate the acceptance of specific textures and character of the mark. Marisol SA. is a large-sized company localized in Jaraguá do Sul, Santa Catarina. This study presents an analysis about implementation of innovative processes presented in a workshop realized at the company. It includes the evaluation of their professionals about the importance of material selection and virtual simulation for conception of new products. Best Malhas Ltda. is a medium-sized company localized in Caxias do Sul, Rio Grande do Sul. This study presents descriptions of new strategic conceptions of designer positioning within the service context and presents different tasks assigned to this professional. A holistic view of the design process is analyzed to subsidize the comprehension of the design process' design. The fifth case study is supported on a global platform of professional relationships, LinkedIn. This professional's case study describes the expertise to creation of a social network with specific expertise, the flat knitting designers, through LinkedIn platform. A survey was conducted using questionnaires to collect specific data that allowed the analysis about the profile characteristics of these area professionals, as well as their pre-disposing to the variables of this research. Through this social network augmented by technology, informations was gathered from the experts "flat knitting designers". This process enhances the expertises integration, the tune of pairs and offers the ―feedback‖ for this study object through the virtuous and democratic dynamics. This dissertation has economic, social, scientific and technological importance because it indicates gaps on flat knitting textile area. It shows the consistency in an approach of social- technical adequacy, which is attributed to the designer the potential of a strategic innovation agent, through the described possibility that this professional has to integrate advanced processes for communication of their projects.

Este trabalho tem por objetivo apresentar os resultados obtidos com o uso da técnica de campo magnético induzido durante o tratamento térmico do Ferro Fundido Nodular em desenvolvimento de núcleos de alto-falantes. Para este estudo foi escolhido como material o Ferro Fundido Nodular devido ao baixo custo de obtenção das peças e também por ser um material de fácil aquisição no mercado. Foram confeccionadas 90 amostras deste Ferro Fundido Nodular com percentuais diferenciados de Ferro, Silício e Carbono, sendo que as amostras quando foram submetidas ao tratamento térmico de recozimento também sofreram a indução magnética. Os parâmetros utilizados no tratamento térmico situaram-se na faixa de temperatura de aquecimento de 900ºC até 920ºC e uma indução magnética "B" entre 16000 e 20000 Gauss. O grande desafio deste trabalho estava no fato de que variações de composição das ligas de ferro fundido nodular, aliadas as inclusões de outros materiais não magnetizáveis, modificavam, para pior, o desempenho dos núcleos dos alto-falantes. Para obter-se, então, uma estrutura em que o fluxo magnético pudesse permear, buscou-se primeiramente selecionar a liga de ferro fundido eliminando ao máximo os materiais não magnetizáveis, e só então, estudar um processo de tratamento térmico com indução magnética que tornasse o material adequado ao uso nos núcleos de alto-falantes Para melhorar as propriedades magnéticas de forma contundente, buscou-se através do recozimento com campo induzido um alinhamento dos domínios, ou seja, uma ordenação dos "spins" dentro dos grãos do material que juntamente com a elevação de temperatura tenderam a ter um mesmo sentido, facilitando de maneira significativa a passagem do fluxo magnético, propriedade importante para o desempenho dos núcleos de alto-falantes. Foram realizados recozimentos com campo induzido observando-se o desempenho da permeabilidade magnética inicial das peças e posteriormente medidas com equipamento de saturação de campo. Esses resultados foram correlacionados com os dados obtidos pelo uso do aço SAE 1020, nas mesmas condições de uso e teste de laboratório. Foram realizados estudos metalográficos, além de análises de composição química das amostras e a relação destes fatores com as propriedades magnéticas. Também foram estudados os dados de usinabilidade das amostras do ferro fundido nodular tratadas termicamente com indução magnética e subseqüentemente comparados com o Aço SAE 1020. Do ponto de vista científico, uma das contribuições deste trabalho, está na influência da indução de campo magnético durante o tratamento térmico das amostras, pois é possível verificar um ganho significativo nas propriedades magnéticas apresentadas pelos núcleos dos alto-falantes durante os testes de desempenho. A outra está no fato de que ganhos correlacionados ao design do produto possibilitam utilizar o ferro fundido como uma alternativa economicamente viável e perfeitamente ajustável à alta performance dos alto-falantes. Como resultado deste estudo foi demonstrado à possibilidade do uso do recozimento com indução magnética, como forma de aumentar a permeabilidade de um material com alto teor de carbono, no caso específico, o ferro fundido nodular. Este trabalho permite afirmar que é possível desenvolver núcleos magnéticos de alto-falantes em ferro fundido nodular com alto desempenho e também sugerir que outras aplicações onde seja necessário aumento do desempenho magnético esta técnica possa ser aplicada. / This work aims to present the results obtained with the use of induced magnetic field during the heat treatment of Nodular Cast Iron for speaker cores. For this study development, the chosen material is the nodular cast iron due to the low trading costs and ease of purchase on the market. Ninety samples of nodular cast iron were constructed, with different iron, silicon and carbon contents. Samples, when subjected to annealing, were also subjected to magnetic induction. The final temperature on the heat treatment was in the range of 900ºC to 920ºC, and the magnetic induction was in the range of 16000 to 20000 Gauss. The challenge of this work was in the fact that compositional changes in the nodular cast iron, allied to inclusions of non-magnetizable materials, modify for worse the performance of speaker cores. To obtain a structure that the magnetic field could permeate, the cast iron alloys were selected to eliminate, at most, the presence of non-magnetizable materials, and only then consider a heat treatment process with magnetic induction to make the material suitable for use in speaker cores. To improve the magnetic properties, an alignment of dipoles of the material, through induced magnetic field during annealing was intended. Annealing with induced magnetic field was carried out, observing the performance of the initial magnetic permeability of the samples, and subsequently measured with field saturation equipment The results were correlated with the obtained data from the use of the SAE 1020 steel, with the same conditions of use and laboratory tests. Metallographic and chemical composition analyses were carried out on the samples, and the correlation of these data with the magnetic properties was estmated. Also machinability of the thermal treated with magnetic induction nodular cast iron samples were analyzed and compared with the SAE 1020 steel. From the scientific point of view, one of the contributions of this work is the influence of induced magnetic field during the heat treatment of the samples, since it was possible to verify a significant gain in the magnetic properties of the speaker cores during the performance tests. Another contribution is the fact that gains correlated with the design of the product enable the use of cast iron as an economically viable and fully adjustable material to the high performance of subwoofers. As a result of this work, the possibility of using annealing with magnetic induction was presented as a way to increase the permeability of a material with high carbon content, in this particular case, the nodular cast iron. This research allows asserting that it is possible to develop speaker magnetic cores of nodular cast iron with high performance and also suggest that this technique can be applied to other applications where it is necessary to increase their magnetic performance.

Este trabalho tem por objetivo apresentar os resultados obtidos com o uso da técnica de campo magnético induzido durante o tratamento térmico do Ferro Fundido Nodular em desenvolvimento de núcleos de alto-falantes. Para este estudo foi escolhido como material o Ferro Fundido Nodular devido ao baixo custo de obtenção das peças e também por ser um material de fácil aquisição no mercado. Foram confeccionadas 90 amostras deste Ferro Fundido Nodular com percentuais diferenciados de Ferro, Silício e Carbono, sendo que as amostras quando foram submetidas ao tratamento térmico de recozimento também sofreram a indução magnética. Os parâmetros utilizados no tratamento térmico situaram-se na faixa de temperatura de aquecimento de 900ºC até 920ºC e uma indução magnética "B" entre 16000 e 20000 Gauss. O grande desafio deste trabalho estava no fato de que variações de composição das ligas de ferro fundido nodular, aliadas as inclusões de outros materiais não magnetizáveis, modificavam, para pior, o desempenho dos núcleos dos alto-falantes. Para obter-se, então, uma estrutura em que o fluxo magnético pudesse permear, buscou-se primeiramente selecionar a liga de ferro fundido eliminando ao máximo os materiais não magnetizáveis, e só então, estudar um processo de tratamento térmico com indução magnética que tornasse o material adequado ao uso nos núcleos de alto-falantes Para melhorar as propriedades magnéticas de forma contundente, buscou-se através do recozimento com campo induzido um alinhamento dos domínios, ou seja, uma ordenação dos "spins" dentro dos grãos do material que juntamente com a elevação de temperatura tenderam a ter um mesmo sentido, facilitando de maneira significativa a passagem do fluxo magnético, propriedade importante para o desempenho dos núcleos de alto-falantes. Foram realizados recozimentos com campo induzido observando-se o desempenho da permeabilidade magnética inicial das peças e posteriormente medidas com equipamento de saturação de campo. Esses resultados foram correlacionados com os dados obtidos pelo uso do aço SAE 1020, nas mesmas condições de uso e teste de laboratório. Foram realizados estudos metalográficos, além de análises de composição química das amostras e a relação destes fatores com as propriedades magnéticas. Também foram estudados os dados de usinabilidade das amostras do ferro fundido nodular tratadas termicamente com indução magnética e subseqüentemente comparados com o Aço SAE 1020. Do ponto de vista científico, uma das contribuições deste trabalho, está na influência da indução de campo magnético durante o tratamento térmico das amostras, pois é possível verificar um ganho significativo nas propriedades magnéticas apresentadas pelos núcleos dos alto-falantes durante os testes de desempenho. A outra está no fato de que ganhos correlacionados ao design do produto possibilitam utilizar o ferro fundido como uma alternativa economicamente viável e perfeitamente ajustável à alta performance dos alto-falantes. Como resultado deste estudo foi demonstrado à possibilidade do uso do recozimento com indução magnética, como forma de aumentar a permeabilidade de um material com alto teor de carbono, no caso específico, o ferro fundido nodular. Este trabalho permite afirmar que é possível desenvolver núcleos magnéticos de alto-falantes em ferro fundido nodular com alto desempenho e também sugerir que outras aplicações onde seja necessário aumento do desempenho magnético esta técnica possa ser aplicada. / This work aims to present the results obtained with the use of induced magnetic field during the heat treatment of Nodular Cast Iron for speaker cores. For this study development, the chosen material is the nodular cast iron due to the low trading costs and ease of purchase on the market. Ninety samples of nodular cast iron were constructed, with different iron, silicon and carbon contents. Samples, when subjected to annealing, were also subjected to magnetic induction. The final temperature on the heat treatment was in the range of 900ºC to 920ºC, and the magnetic induction was in the range of 16000 to 20000 Gauss. The challenge of this work was in the fact that compositional changes in the nodular cast iron, allied to inclusions of non-magnetizable materials, modify for worse the performance of speaker cores. To obtain a structure that the magnetic field could permeate, the cast iron alloys were selected to eliminate, at most, the presence of non-magnetizable materials, and only then consider a heat treatment process with magnetic induction to make the material suitable for use in speaker cores. To improve the magnetic properties, an alignment of dipoles of the material, through induced magnetic field during annealing was intended. Annealing with induced magnetic field was carried out, observing the performance of the initial magnetic permeability of the samples, and subsequently measured with field saturation equipment The results were correlated with the obtained data from the use of the SAE 1020 steel, with the same conditions of use and laboratory tests. Metallographic and chemical composition analyses were carried out on the samples, and the correlation of these data with the magnetic properties was estmated. Also machinability of the thermal treated with magnetic induction nodular cast iron samples were analyzed and compared with the SAE 1020 steel. From the scientific point of view, one of the contributions of this work is the influence of induced magnetic field during the heat treatment of the samples, since it was possible to verify a significant gain in the magnetic properties of the speaker cores during the performance tests. Another contribution is the fact that gains correlated with the design of the product enable the use of cast iron as an economically viable and fully adjustable material to the high performance of subwoofers. As a result of this work, the possibility of using annealing with magnetic induction was presented as a way to increase the permeability of a material with high carbon content, in this particular case, the nodular cast iron. This research allows asserting that it is possible to develop speaker magnetic cores of nodular cast iron with high performance and also suggest that this technique can be applied to other applications where it is necessary to increase their magnetic performance.