Papers by Author: José Carlos Santos

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Authors: Marcelo Luiz Eugênio, Marco Antonio Colosio, José Carlos Santos
Abstract: Currently, new and uncommon materials are being more used in automotive components, such as the manufactured by Powder Metallurgy due to new cost reduction strategies adopted by carmakers. The companies are searching more and with stronger aggressiveness the ways of finding cost reduction opportunities of a product and/or process. With this intention and for being it tracked by technical and commercial interests, new departments are being created with different names and structures. The ways to find out a reduction of viable cost are discussed in different ways of approaching of this question, which may be originated from the standardization of an item utilized in similar products, in the removal of components with questionable importance, in the change of manufacture processes, in the localization of items and finally, in the change of material and/or project. Starting from known approaches, the present work relates the most different ways of proposals and characterizes and quantifies them in graphical forms, adopted procedures, and by descriptions of ways pursued to reach a financial goal of reduction, mentioning typical examples of proposals with potential of implementation after a technical and critical analysis. Finally, the focus of this study is the approach of materials and specifications, said currently as the most complex and difficult field; however, with inexhaustible ways in the last instance in the field of Cost Reductions, and then the acquired knowledge should be used in sintered material.
Authors: Thiago Sekeres, Cleber Fernandes, José Carlos Santos, Eduardo Nunes, Ronald Lesley Plaut
Abstract: A typical car stamping is analyzed in terms of FEM and its press signature is evaluated in detail. Microstructural, crystallographic texture and surface roughness evolution are studied in conjuntion with press performance. Careful press signature calibration is discussed in order to point out relevant aspects. Deep drawing steels are analyzed in terms of their evolution in microstructure and texture and path-related to the FLD (Forming Limit Diagram). 3D-Surface roughness is tentatively evaluated and related to the steel stampability.
Authors: E.S. Jesus Filho, Lucio Salgado, S.L. de Jesus, Jesualdo Luiz Rossi, Marco Antonio Colosio, José Carlos Santos
Abstract: This article shows some fabrication aspects related to the obtention of sintered valve seat insert. This insert was made of a mixture of high-speed steel powders and iron powders plus NbC. This is a new development aiming the substitution of Co alloys currently used for valve seat inserts. The physical properties, mechanical properties and machining behaviour are discussed. The machining characteristics in terms of tool wear, cutting forces and chips morphology of the insert was compared to available commercial insert. The machining results indicate that the material under development has potential for commercial application and shows good machining evidences, in terms of equivalent cutting forces for ceramic tool. In addition, the machining using hard metal tool was susceptible to hardness variation observed for the material under development. Therefore, the machining tests point out the necessity for a microstructure homogenisation of the obtained material.
Authors: E.S. Jesus Filho, Edilson Rosa Barbarosa Jesus, Lucio Salgado, S.L. Jesus, Marco Antonio Colosio, José Carlos Santos, S. Yoshida, C.H. Sartori, Jesualdo Luiz Rossi
Abstract: This work presents aspects related to new sintered materials for valve seat inserts application. Two types of materials were evaluated. The materials were made using powder metallurgy technique from a basic mixture of high-speed steel (AISI M3/2), iron and carbide powders. The microstructures of these materials before and after heat treatment are presented. Under the heat treatment condition, the activation of the diffusion mechanism among phases was promoted and a better distribution of the Cu phases along the matrix was achieved. The results indicate that the materials under development have a potential for commercial application as valve seat inserts.
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