IGOR PASSOS DOS SANTOS

IGOR PASSOS DOS SANTOS

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Produção de energia elétrica a partir de fontes nucleares
2015 - SANTOS, I.P.; LEVY, D.S.
This study reports a pedagogical experiment in high school classes, in a private school in São Paulo. The purpose of this experiment was to put students in touch with topics related to electric power generation from radioactive sources This project was developed with emphasis on the content available in an educational online portal, the site www.radioatividades.com.br. The site has been created in order to disseminate knowledge to children, adolescents, parents and teachers about the peaceful use of nuclear energy. The portal content is free to access and use for educational purposes. The project had three stages: initial dynamics on the subject with students, working with research groups, conducting short courses in the portal "radioatividades" and a final evaluation, which consisted in seminars prepared by students themselves. The first stage aimed to verify the previous knowledge that students had on nuclear energy, raising common prejudices that usually appear. The second phase of the project aimed to demystify some concepts, such as the insecurity linked to the use of atomic energy. For this research there were used reliable sources, as the site of the National Nuclear Energy Commission (CNEN), Institute of Radiation Protection and Dosimetry (IRD) and International Atomic Energy Agency (IAEA), as well as short courses offered by the portal "Radioatividades". To finish the project, the students formed groups and presented seminars for their classmates, with split topics, illustrative slides and post presentation time to answer questions. There were highly satisfactory results at the end of the project, performances with good theoretical foundation and valuable clarifications on nuclear energy.
Microstructural characterization of air quenched valve seat inserts obtained with AISI D2 tool steel
2017 - 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.
Influence of air quenching on apparent hardness of valve seat inserts obtained with AISI M2 high-speed steel powder
2017 - 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.
Characterization of sintered valve seat inserts obtained with AISI M2 high-speed steel after air quenching
2017 - 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.
Valve seat insert: air quenching and characterization of components obtained with AISI M3:2 high-speed steel
2018 - GOMES, M.P.; SANTOS, I.P.; REIS, L.A.M.; COUTO, C.P.; BETINI, E.G.; MUCSI, C.S.; COLOSIO, M.A.; ROSSI, J.L.
The development of components ecologically correct is something more and more necessary. The first developement of valve seat inserts (VSI) take in account the use of cobalt and lead in its chemical composition. Such elements are avoided in the current applications due to its high cost and toxicological effects, respectively. In the present work was used VSI developed with a new chemical composition. The aim of this work were to air quench and characterize such components. The studied VSI were obtained with AISI M3:2 high-speed steel admixed with iron powder and another additives such as manganese sulphide, graphite, zinc stearate and carbides. All the air quenched VSI were double tempered, for one hour each, at seven equidistant temperature from 100 °C until 700 °C. The air quenched components had its mechanical and physical properties determined by means of its apparent density, apparent hardness and crush radial strength. The chemical composition was measured through the gases analyses and energy dispersive X-ray fluorescence spectrometry techniques. Microstructural and phase characterizations were performed with the support of optical microscopy, scanning electron microscopy and energy dispersive spectroscopy. Regarding the VSI required properties, the best results were obtained with the components air quenched and double tempered at 600 °C.
Heat treatment of sintered valve seat inserts
2018 - 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.
Têmpera ao ar de insertos de assentos de válvulas obtidos com aço ferramenta AISI D2
2017 - 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.
P/M valve seat inserts: air quenching and characterization
2017 - GOMES, MAURILIO P.; SANTOS, IGOR; COUTO, CAMILA; MUCSI, CRISTIANO; ROSSI, JESUALDO L.; COLOSIO, MARCO
This work consists of evaluating the influence of heat treatment on sintered valve seat insert (VSI) obtained with two different highspeed steels powders and one tool steel: AISI M3:2, AISI M2 and AISI D2, respectively. The high-speed / tool steel powders were mixed with iron powders and additives such as manganese sulphide, zinc stearate, graphite and niobium carbide. All the high-speed / tool steel powders had its particle size distribution and morphology analyzed. The heat treatment of the VSI consisted of air quenching followed by double tempering it in seven different and equidistant temperatures, ranging from 100 °C until 700 °C. A data acquisition system with a thermocouple type k attached to the samples was used to determine the air-quenching cooling rate. The mechanical and physical properties measurements were carried out, i.e., apparent density, apparent hardness and crush radial strength. The microstructural evaluation consisted of etching the VSI and then analyzing it using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that the VSI obtained with the AISI M3:2 and M2 high-speed steel powders mixtures showed the best results regarding its apparent hardness and crush radial strength after air quenching and double tempering it at 600 °C.
Têmpera ao ar de insertos de assentos de válvulas obtidos com o aço ferramenta AISI D2
2017 - GOMES, MAURILIO P.; SANTOS, IGOR P. dos; COUTO, CAMILA P.; MUCSI, CRISTIANO S.; ROSSI, JESUALDO L.; COLOSIO, MARCO A.
Study of the mechanical and metallurgical properties of sintered steels for valve seat inserts application
2016 - GOMES, M.P.; SANTOS, I.P.; MUCSI, C.S.; COLOSIO, M.A.; ROSSI, J.L.
The aim of this work was to study the valve seat insert (VSI) produced with three different alloys (mainly modified from the original AISI M3/2, M2 and D2 high-speed steels) from the mechanical and metallurgical point of view. These alloys modifications were intended as an alternative to replace cobalt and lead used in the original alloy due to their high cost and toxicological effect respectively. Such alloys have been developed for internal combustion engines VSI manufacture. The VSI studied in this work was previously produced by the powder metallurgy (P/M) route. The VSI production was performed using a uniaxial hydraulic press and a belt conveyor furnace. The VSI was submitted to metallic infiltration during the sintering process using copper as filler. The studies were performed according to standardized apparent density (ASTM C 373-88), apparent hardness (ASTM E 92-82) and radial crush strength (MPIF Standard 35) tests. The VSI produced with M3/2 alloy proved to be more advantageous considering the highest values obtained in the apparent hardness and radial crush strength tests.