52 resultados para Machinability
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Engenharia Mecânica - FEIS
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Alloy Al-7%Si-0,3Mg (AA356), having an excellent combination of properties such as low solidification shrinkage and good fluidity, good weldability, high wear resistance, high strength to weight particularly in the automotive and aerospace engineering. The refinement of the structure aluminum silicon eutectic alloy is a fairly common practice in the casting, through the treatment knows as modification. You can get the modification for the addition of chemicals and rare earths, these have the ability to modify the structure of the eutectic, but only sodium and strontium produce a strong action modifier when used in low concentrations. The modifying effect of silicon grain turns into a fibrous form branched and enveloped by the metal matrix in the form of a composite structure that has the highest limit of tensile strength, ductility and machinability. This work will be obtained AA356 alloy ingots using two different types of molds: metal mold and sand mold. Macrographs will be made in ingots obtained for observation of the macrostructures obtained in both types of ingots. Will be sampled at strategic locations of the ingots to correlate microstructure and cooling rate. The results showed that the material of the ingot has a strong influence on the resulting micro-andmacrostructure
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The AA356 alloy is an alloy widely used in the automotive industry and aerospace due to its excellent mechanical properties. Refining the structure of eutectic silicon aluminum alloys is a fairly common practice in the foundry through treatment known as modification. This can be achieved by modifying agent adding chemicals such as contained in groups I and IIa of the periodic table and rare earths (europium, céreioi, praseodymium, neodymium, etc.). Has the ability to modify the structure of the eutectic, but only sodium and strontium produce an action modifier strong when used in low concentrations. The modifying effect of the shafts turn silicon into a fibrous form and branched surrounded by metallic matrix in the form of a composite structure that has the highest limit of tensile strength, ductility and machinability. In this work will be obtained ingots with and without the modifier type Al-10% Sr, made in sand molds and are generated and analyzed cooling curves and also the study of the macrostructure and microstructure of the solidified material. It was found that by adding the Al-Sr made shorten the solidification time and lower the grain size
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The nickel superalloys are known as being a material with poor machinability, they have some properties like high hardness, good resistance at high temperature, tendency to weld with the tool material at high temperature, etc. In the aerospace, biomedical and petrochemical industry, are increasing the need to use materials that resist to aggressive process and environment. In these uses, it has increased the use of nickel-based superalloys like Inconel 718 and consequently the need to research new techniques and tools to improve the machinability of this material. For the superalloys and resistant alloys at high temperatures is considered that the difficulty in the machining regards to the combination of the relatively high cutting forces and high temperatures that grow during the machine process, causing deformation or breakage of the cutting tool. This work purpose is to develop the study of the machining of external cylindrical turning of the nickel based alloy Inconel 718, using ceramic tools, seeking the optimization of machining this alloy, looking to provide real productive increases without the need of investments in new production means. The machining test were accomplished using commercials hard metal tools and the results were compared each other to find the best tool and the best parameter. The conclusion is that the tool TNMG160408-23 -class 1005- was the better one, when used with the parameter 60_15_08
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Atualmente, atender as necessidades dos consumidores é uma das metas mais importantes, os consumidores estão em busca de produtos com qualidade e preços mais acessíveis, para isso, é indispensável que as empresas se atualizem para melhorar seus produtos e serviços. Com este cenário, as superligas estão cada vez mais ganhando mercado, pois possuem ótimas propriedades, principalmente em relação a operar em temperaturas elevadas, podendo proporcionar maior eficiência para motores que necessitam trabalhar em altas temperaturas. Em contra partida a essa vantagem, as superligas possuem uma baixa usinabilidade, sendo importante a análise do processo de usinagem para se tornarem mais aplicáveis. Este trabalho visa à otimização do processo de torneamento cilíndrico da superliga Nimonic 80A, com o intuito de melhorar a qualidade do produto, utilizando o Método de Taguchi, com o arranjo ortogonal L16, sendo o comprimento de corte definido como variável resposta e analisados seis fatores que poderiam influenciar na sua variação, tais fatores são: velocidade de corte, avanço, profundidade de corte, tipo de pastilha, lubrificação e dureza do material. Os resultados obtidos demonstraram que os fatores avanço, tipo de pastilha e lubrificação são significativos e exercem influencia no processo, sendo que o avanço deve ser ajustado no nível de 0,12 mm/rev, a pastilha a ser utilizada deve ser CP250 e a lubrificação deve ser feita de maneira abundante, para a otimização do processo. Com a análise dos resultados, também podemos observar a eficiência e confiabilidade do método utilizado, mostrando resultados coerentes
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Pós-graduação em Engenharia Mecânica - FEIS
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Pós-graduação em Engenharia Mecânica - FEG
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Pós-graduação em Engenharia Mecânica - FEG
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Machining is one of the most commonly manufacturing processes used in the modern world, consuming millions of dollars annually. Because of this, it is crucial for the automotive industry to reduce costs on their heat-resistant alloy machining processes, such as compacted graphite iron (CGI), which has shown an increasing trend of its application in diesel engine blocks, brakes disks, among other applications, due to its superior mechanical properties to gray cast iron. Despite this advantage, its use is still limited due to its difficulty of machining, moreover, cutting tools are displayed as the main factor in increasing the machining cost. Seeking an alternative to a better machinability of CGI, this paper aims to study two types of ceramic tools developed in Brazil, and benchmark their performance by dry turning. For this, were used CGI class 450 and two tools: ceramic of silicon nitride (Si3N4) and alumina-based (Al2O3), with a cutting speed (Vc) of 300, 400 and 500 m / min; feed (f) of 0.2 mm / rev and depth of cut (ap) of 0.5 mm, using three replicates and starting with new cutting edges. The results showed that the Al2O3 tool had the best performance in Vc of 500 m / min, while the Si3N4 tool had the best results in Vc of 300 m / min. This can be explained by the tool of Si3N4 based include soft intergranular phase, called amorphous, while alumina has higher abrasion resistance due to its high refractoriness. The results make it clear that the tools have significant potential for machining of compacted graphite iron, being necessary a strict control of the cutting parameters used
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Machining is one of the most commonly manufacturing processes used in the modern world, consuming millions of dollars annually. Because of this, it is crucial for the automotive industry to reduce costs on their heat-resistant alloy machining processes, such as compacted graphite iron (CGI), which has shown an increasing trend of its application in diesel engine blocks, brakes disks, among other applications, due to its superior mechanical properties to gray cast iron. Despite this advantage, its use is still limited due to its difficulty of machining, moreover, cutting tools are displayed as the main factor in increasing the machining cost. Seeking an alternative to a better machinability of CGI, this paper aims to study two types of ceramic tools developed in Brazil, and benchmark their performance by dry turning. For this, were used CGI class 450 and two tools: ceramic of silicon nitride (Si3N4) and alumina-based (Al2O3), with a cutting speed (Vc) of 300, 400 and 500 m / min; feed (f) of 0.2 mm / rev and depth of cut (ap) of 0.5 mm, using three replicates and starting with new cutting edges. The results showed that the Al2O3 tool had the best performance in Vc of 500 m / min, while the Si3N4 tool had the best results in Vc of 300 m / min. This can be explained by the tool of Si3N4 based include soft intergranular phase, called amorphous, while alumina has higher abrasion resistance due to its high refractoriness. The results make it clear that the tools have significant potential for machining of compacted graphite iron, being necessary a strict control of the cutting parameters used