MAURILIO PEREIRA GOMES
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Artigo IPEN-doc 27002 Microstructural characterization of air quenched valve seat inserts obtained with AISI D2 tool steel2017 - GOMES, M.P.; SANTOS, I.P.; COUTO, C.P.; BETINI, E.G.; COLOSIO, M.A.; ROSSI, J.L.The obtention of valve seat insert (VSI) by powder metallurgy using a mixture of iron powder and tool steel is fulfilling the requirements for substitution of cobalt and lead in commercial parts, aiming cost reduction and avoid the lead toxicity. The aim of this work consisted of evaluate the influence of heat treatment on VSI obtained with AISI D2 tool steel powder. The AISI D2 tool steel powder was mixed with iron powder and additives such as manganese sulphide, zinc stearate, graphite and carbides. The heat treatment of the VSI consisted of air quenching followed by double tempering it at 500 °C. The microstructural characterization was performed using scanning electron microscopy and energy dispersive spectroscopy.Artigo IPEN-doc 27001 Influence of air quenching on apparent hardness of valve seat inserts obtained with AISI M2 high-speed steel powder2017 - GOMES, M.P.; SANTOS, I.P.; REIS, L.A.M.; CIONE, F.C.; COLOSIO, M.A.; ROSSI, J.L.The aim of this work consisted of evaluate the influence of heat treatment on sintered valve seat inserts (VSI) obtained with the AISI M2 high-speed steel powder. The AISI M2 high-speed steel powder was mixed with iron powder and additives such as manganese sulphide, zinc stearate, graphite and carbides. The heat treatment of the VSI consisted of air quenching followed by double tempering it in seven different equidistant temperatures, from 100 °C until 700 °C. The mechanical property was measured regarding the VSI apparent hardness. The results indicated that the VSI obtained with the AISI M2 high-speed steel powders mixtures showed the best results regarding its apparent hardness after air quenching and double tempering it at 600 °C.Artigo IPEN-doc 26953 Characterization of sintered valve seat inserts obtained with AISI M2 high-speed steel after air quenching2017 - GOMES, MAURILIO P.; SANTOS, IGOR P. dos; REIS, LUIS A.M. dos; COUTO, CAMILA P.; MUCSI, CRISTIANO S.; COLOSIO, MARCO A.; ROSSI, JESUALDO L.The aim of this work was to heat treat and characterize sintered valve seat inserts (VSI). The powder metallurgy route was the only way found to substitute cobalt and lead, used in the VSI original alloy, due to their high cost and toxicological effect, respectively. The studied VSI was obtained with AISI M2 high-speed steel powder mixed with iron powder and other additives such as manganese sulphide, graphite, zinc stearate, carbides and copper, which was added by metallic infiltration. All the VSI were air quenched and double tempered, for one hour each, at seven different equidistantly temperatures, ranging from 100 °C up to 700 °C. The physical and mechanical properties were evaluated by means of the VSI apparent density, apparent hardness and crush radial strength. The chemical composition was determined through gas analysis, for the light elements such as carbon and sulfur, and energy dispersive X-ray fluorescence spectrometry for other elements. Microstructural characterization was performed with the support of scanning electron microscopy and energy dispersive spectroscopy. Regarding the VSI final application, the best results were achieved with the inserts air quenched and double tempered at 600 °C.Artigo IPEN-doc 25096 Heat treatment of sintered valve seat inserts2018 - GOMES, MAURILIO P.; SANTOS, IGOR P. dos; COUTO, CAMILA P.; BETINI, EVANDRO G.; REIS, LUIS A.M. dos; MUCSI, CRISTIANO S.; COLOSIO, MARCO A.; ROSSI, JESUALDO L.The characterization of sintered valve seat inserts (VSIs) after being subjected to different heat treatment operations has been carried out. The VSIs were obtained from three different alloys by mixing iron powder with AISI M3:2, AISI M2 high-speed steels, and AISI D2 tool steel. After sintering, the VSI were quenched in air followed by double tempering at seven different temperatures. The cooling rate during air quenching was measured by means of a thermocouple type k attached to a data acquisition system. The characterization of the mechanical and physical properties of the VSIs was achieved by measuring relative density, apparent hardness and crush radial strength. The resulting microstructures for the sintered parts were interpreted using the isothermal and continuous cooling transformation diagrams for similar alloys. The VSI obtained with AISI M3:2 and AISI M2 high-speed steels after air quenching and double tempering at 600 ºC showed the best results in terms of apparent hardness and crush radial strength.Artigo IPEN-doc 25026 Têmpera ao ar de insertos de assentos de válvulas obtidos com aço ferramenta AISI D22017 - GOMES, MAURILIO P.; SANTOS, IGOR P. dos; COUTO, CAMILA P.; MUCSI, CRISTIANO S.; COLOSIO, MARCO A.; ROSSI, JESUALDO L.A obtenção de insertos de assentos de válvulas por metalurgia de pó usando uma mistura de pó de ferro e aços rápidos ou aços ferramenta está atendendo os requisitos para a substituição do cobalto e chumbo em peças comerciais, visando a redução de custo e evitando a toxicidade do chumbo. O objetivo do presente trabalho foi o de tratar termicamente e caracterizar os insertos de assentos de válvulas sinterizados obtidos utilizando-se uma mistura de pós. Essa mistura de pós foi constituída pelo aço ferramenta AISI D2, ferro, sulfato de manganês, carboneto de nióbio, grafite, estearato de zinco e cobre. O ciclo de temperatura da têmpera ao ar foi determinado por meio do termopar tipo k acoplado a um sistema de aquisição de dados. As propriedades físicas e mecânicas foram medidas em relação à dureza aparente dos insertos, densidade aparente e a sua resistência à ruptura radial. A caracterização microestrutural foi realizada utilizando-se a microscopia óptica, microscopia eletrônica de varredura e espectroscopia por dispersão de energia. Os insertos temperados ao ar e duplamente revenido a 500 °C mostraram os melhores resultados no que tange a dureza e resistência à ruptura radial.Artigo IPEN-doc 24417 Têmpera ao ar de insertos de assentos de válvulas obtidos com o aço ferramenta AISI D22017 - GOMES, MAURILIO P.; SANTOS, IGOR P. dos; COUTO, CAMILA P.; MUCSI, CRISTIANO S.; ROSSI, JESUALDO L.; COLOSIO, MARCO A.