Orientador: Jefferson de Oliveira Gomes / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-17T00:45:15Z (GMT). No. of bitstreams: 1 Buchli_Marcelo_M.pdf: 3752727 bytes, checksum: 40d7b010cd2e281baaa3faf8554cb691 (MD5) Previous issue date: 2010 / Resumo: Neste trabalho foi estudado o ferro fundido austemperado (ADI) grau 3 para substituir o aço forjado SAE 1045 temperado e revenido na aplicação do eixo comando de válvulas para motores Diesel. Na comparação dos materiais foram verificadas as propriedades mecânicas através de ensaios de laboratório e na literatura. A resistência ao desgaste foi a principal propriedade mecânica avaliada. Com o objetivo de se eliminar a operação de acabamento em retífica, especificada para os eixos comando de válvulas em aço forjado, o acabamento na usinagem de torneamento do ADI grau 3, no estado beneficiado, também foi analisado. O ADI grau3 atendeu à solicitação de desgaste quando comparado ao aço forjado e obteve um acabamento na operação de usinagem em torno, muito próximo ao acabamento do aço forjado na operação de retífica. Os resultados deste trabalho servem como base de estudo para o desenvolvimento e a fabricação de eixo comando de válvulas em ferro fundido austemperado grau 3 para motores Diesel / Abstract: The austempered ductile iron grade 3 was investigated as a substitute to SAE 1045 forged steel quenched & tempered in Diesel engines camshaft application. The mechanical properties for both materials were compared in laboratory tests and in the literature. The main mechanical property studied was the wear resistance. The microstructure, chemical composition was analyzed and correlated to camshaft requirements. The finishing turning machining characteristic of heated treated ADI grade 3 also was tested to verify the possibility of eliminating the grinding operation to SAE 1045 forged steel. As a conclusion of this study the ADI grade 3 complied with wear requirements when compared to forged steel and reached a finishing turning machining very close to grinding operation on forged steel. The results of this study can be used as basis to new development and production of diesel engines camshaft with austempered ductile iron / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Automobilistica

M.Tech (Metallurgy) / Abrasive wear is a major factor in the production costs of the mining industry in South Africa (as is the case in the rest of the world). These costs arise from the need to replace consumables such as digger teeth, mill liners, screens and chutes. Some materials used in these areas have been used for years with little or no change to their properties such as Hadfields manganese steel; others have been significantly modified to improve their performance, as is the case with high chromium white cast iron. Some areas in the mining industry have made a complete chanlfe of material in order to reduce wear rates; the use of 9% Cr stainless steel ( ) is an example of this. In some applications metals have been successfully replaced by ceramics for example the use of alumina in combination with cemented tungsten carbides ash conditioner blades (2) at ESKOM power stations. Significant improvements in profitability (in the form of reduced consumable costs and increased productivity) can be realised by the development of new abrasion resistant materials; hence many organisations are constantly involved in such work. The fundamental property required to resist abrasive wear is hardness, however a degree of toughness is always required depending on the application. Composite materials have the best possibility of combining these properties, for example high chrome white iron can be regarded as a composite material on a microscopic scale with very hard carbides supported by a tough martensitic matrix. This material performs extremely well in many highly erosive environments; it is also relatively cheap as the "composite microstructure" forms directlJ: from casting with a heat treatment process providing a hardened matrix 3). Another example of a composite material is cemented tungsten carbide; this is manufactured as a true composite, i.e. discrete particles of tungsten carbide are sintered with cobalt particles to form a relatively tough extremely hard material. This combines the hard brittle WC with the relatively soft tough cobalt binder acting as a matrix. This material has the best resistance to abrasive wear of all metallic materials. Ceramics have higher hardness but are significantly more brittle hence their application is limited to erosive rather than abrasive environments. Cemented tungsten carbide inserts are brazed or shrunk into steel holders and used as drill tips for rock drilling; this can be regarded as a composite product, using the strong and tough steel to hold the hard tungsten carbide inserts in place.

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Cheng, Lai Fung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaf 79). / Abstracts in English and Chinese. / Cheng, Lai Fung. / Chapter Chapter1 --- Introduction --- p.1 / Chapter 1.1 --- Phase diagram determination --- p.1 / Chapter 1.2 --- Formation of a hump in the free energy curve of L in a eutectic alloy --- p.2 / Chapter 1.3 --- Spinodal decomposition --- p.2 / Chapter 1.4 --- Early experience --- p.3 / Chapter 1.5 --- Bulk metallic glasses (BMG) --- p.5 / Chapter 1.6 --- Metal matrix composites (MMC) --- p.6 / Chapter 1.7 --- Liquid state phase separation and the formation of metal matrix comosites by fluxing --- p.6 / Chapter Chapter2 --- Experimental --- p.15 / Chapter 2.1 --- Introduction --- p.15 / Chapter 2.2 --- Preparation of fused silica tube --- p.15 / Chapter 2.3 --- Sample Preparation --- p.16 / Chapter 2.3.1 --- Alloying --- p.16 / Chapter 2.3.2 --- Fluxing --- p.16 / Chapter 2.4 --- Liquidus of Fe-C-Si specimens --- p.16 / Chapter 2.5 --- Microstructure Analysis --- p.17 / Chapter 2.6 --- Mechanical properties --- p.18 / Chapter 2.6.1 --- Hardness test --- p.18 / Chapter 2.6.2 --- Compressive strength --- p.18 / Chapter Chapter3 --- Formation and mechanical properties of Fe86Si14 network alloys --- p.23 / Chapter 3.1 --- Abstract --- p.23 / Chapter 3.2 --- Introduction --- p.24 / Chapter 3.3 --- Experimental --- p.25 / Chapter 3.4 --- Results --- p.27 / Chapter 3.5 --- Discussion --- p.33 / Chapter Chapter4 --- Dependence of mechanical behavior on C concentration in Fe-C-Si network alloys --- p.63 / Chapter 4.1 --- Abstract --- p.63 / Chapter 4.2 --- Introduction --- p.64 / Chapter 4.3 --- Experimental --- p.66 / Chapter 4.4 --- Results --- p.68 / Chapter 4.5 --- Discussions --- p.76

Chow, Wing Hei = 白鑄鐵特殊的微結構--網絡圖案 / 周穎熙. / Thesis submitted in: November 2007. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Chow, Wing Hei = Bai zhu tie te shu de wei jie gou -- wang luo tu an / Zhou Yingxi. / Abstract --- p.i / Acknowledgements --- p.iii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Background of Thermodynamic --- p.3 / Chapter 1.3 --- Nucleation in pure metals --- p.4 / Chapter 1.4 --- Introduction of Growth --- p.7 / Chapter 1.5 --- Solidification of the Single Phase Binary Alloy --- p.9 / Chapter 1.6 --- Solidification of the Binary Eutectic Alloy --- p.12 / Chapter 1.7 --- Phase Separation by Nucleation and Growth --- p.15 / Chapter 1.8 --- How to obtain large undercooling --- p.19 / References --- p.20 / Figures --- p.22 / Chapter Chapter 2 --- Experiment / Chapter 2.1 --- Experimental Preparation --- p.31 / Chapter 2.2 --- Experimental Procedures --- p.32 / Chapter 2.3 --- Sample Analysis --- p.33 / References --- p.36 / Figures --- p.37 / Chapter Chapter 3 --- Network patterns in a white cast iron / Result --- p.38 / Reference --- p.58 / Figures --- p.64

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Pei C. Chiu, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

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