Estudo da viabilidade de ferramentas cerâmicas experimentais de Al2O3+Cr2O3, Al2O3+MgO e Al2O3+Ni2O3 no torneamento do ferro fundido vermicular
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Data
2022-02-24
Autores
Duarte, Anna Karina Buainain Sarquis
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Universidade Estadual Paulista (Unesp)
Resumo
Na usinagem existe uma contínua necessidade de melhoria das ferramentas de corte devido ao surgimento de novos materiais e/ou melhoria de suas propriedades influenciando de forma significativa no processo, tornando o desenvolvimento contínuo das mesmas fundamental. Entre as ferramentas de corte, as de materiais cerâmicos possuem propriedades como alta dureza a quente e baixa afinidade química, de extrema importância para atender as especificações dos processos de usinagem. No entanto no Brasil, a produção de ferramentas de corte carece de maior investigação e desenvolvimento, sendo objeto de grande interesse por parte das indústrias metal-mecânicas. Somando-se a isso, o ferro fundido vermicular, com propriedades mecânicas superiores às do ferro fundido cinzento, tem sido explorado, por exemplo, como alternativa na fabricação de motores à combustão, cujo aperfeiçoamento da usinagem, ainda é necessário. Assim, nesta pesquisa foi analisada a viabilidade do uso de ferramentas experimentais à base de Alumina (Al2O3) com duas camadas (duplex), uma com óxido de magnésio (MgO) e outra com óxido de cromo (Cr2O3) e uma segunda ferramenta à base de Alumina com óxido de Níquel (Ni2O3) aplicadas no torneamento do ferro fundido vermicular. Analisou-se ainda a utilização de uma ferramenta de metal duro recoberta por Ti(C,N)+ Al2O3 nas mesmas condições. Para a realização da pesquisa usou-se um planejamento de experimentos do tipo Taguchi L16, para as diferentes ferramentas, variando: velocidades de corte (Vc) de 100-150-200-250 m/min, avanços (f) de 0,05-0,1-0,15-0,2 mm/rev e profundidades (ap) de 0,5-1,0 mm, usinando sem fluido de corte. A viabilidade das ferramentas foi verificada analisando sua vida, os tipos e mecanismos de desgaste, qualidade superficial da peça usinada, potência consumida média e máxima, formas dos cavacos gerados, emissão acústica média e máxima, além das vibrações geradas médias e máximas. Observou-se que a dopagem com diferentes materiais altera o comportamento das ferramentas e que o avanço é o parâmetro mais significativo na usinagem do ferro fundido vermicular por ferramentas cerâmicas. A ferramenta duplex mostrou resultados promissores como ferramenta de corte apresentando bons resultados para rugosidade dentro da norma, juntamente com a ferramenta de Al2O3+Ni2O3, apresentando melhor desgaste entre as ferramentas cerâmicas.
In machining there is a continuous and recurrent need to cutting tools improvement driven due to the evolution of new materials and improvement of properties directly impacting the machining processes and making the tool development fundamental. Among the available cutting tool materials, the ceramic cutting tools present several relevant properties that allow to attend the machining requirements and specifications, such as higher hot hardness and chemical stability. However, in Brazil the production and application of cutting tools lacks information, being an object of great interest to the metal-mechanical industries. In addition, the compact graphite iron (CGI) with superior mechanical properties than the gray cast iron, have been explored as an alternative to the manufacture of combustion engines and demands the improvement of several steps during its machining process. Therefore, this research analyzed the viability of experimental Alumina-based cutting tools (Al2O3) with two different layers (duplex tool), one layer of Alumina doped with Magnesium oxide (MgO) and also one layer with Chromium oxide (Cr2O3) and a second cutting tool of Alumina doped with Nickel oxide (Ni2O3) on the vermicular cast iron’s turning compared to a Ti(C,N)+ Al2O3 coated carbide tool, under the same conditions. To execute the research, a Taguchi planning was applied to the machining experiments of each different cutting tool, varying: cutting speeds (Vc) of 100-150-200-250 m.min-1, feed rate (f) of 0.05-0.1-0.15-0.2 mm/rev and depth of cut (ap) of 0.5-1.0, and machining without cutting fluids. The viability of the tools application was verified by analyzing the tools life, types of wear mechanisms, superficial quality of the machined piece, average and maximum power consumed, types and shapes of the chips created, average and maximum acoustic emission and vibrations generated during the process. It was observed that doping process with smaller percentages of additives significantly changes the tool’s behavior and that the feed rate is the most significant parameter in the machining of the vermicular cast iron using ceramic cutting tools. The duplex tool presents promising results as a cutting tool, with good results for roughness within de norm, as well the Al2O3 + Ni2O3 tool, presenting better wear among the ceramics tools.
In machining there is a continuous and recurrent need to cutting tools improvement driven due to the evolution of new materials and improvement of properties directly impacting the machining processes and making the tool development fundamental. Among the available cutting tool materials, the ceramic cutting tools present several relevant properties that allow to attend the machining requirements and specifications, such as higher hot hardness and chemical stability. However, in Brazil the production and application of cutting tools lacks information, being an object of great interest to the metal-mechanical industries. In addition, the compact graphite iron (CGI) with superior mechanical properties than the gray cast iron, have been explored as an alternative to the manufacture of combustion engines and demands the improvement of several steps during its machining process. Therefore, this research analyzed the viability of experimental Alumina-based cutting tools (Al2O3) with two different layers (duplex tool), one layer of Alumina doped with Magnesium oxide (MgO) and also one layer with Chromium oxide (Cr2O3) and a second cutting tool of Alumina doped with Nickel oxide (Ni2O3) on the vermicular cast iron’s turning compared to a Ti(C,N)+ Al2O3 coated carbide tool, under the same conditions. To execute the research, a Taguchi planning was applied to the machining experiments of each different cutting tool, varying: cutting speeds (Vc) of 100-150-200-250 m.min-1, feed rate (f) of 0.05-0.1-0.15-0.2 mm/rev and depth of cut (ap) of 0.5-1.0, and machining without cutting fluids. The viability of the tools application was verified by analyzing the tools life, types of wear mechanisms, superficial quality of the machined piece, average and maximum power consumed, types and shapes of the chips created, average and maximum acoustic emission and vibrations generated during the process. It was observed that doping process with smaller percentages of additives significantly changes the tool’s behavior and that the feed rate is the most significant parameter in the machining of the vermicular cast iron using ceramic cutting tools. The duplex tool presents promising results as a cutting tool, with good results for roughness within de norm, as well the Al2O3 + Ni2O3 tool, presenting better wear among the ceramics tools.
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Palavras-chave
Ferramenta duplex, Rugosidade, Potência consumida, Desgaste, Vibração, Usinagem, Duplex tool, Roughness, Power consumed, Wear, Vibration, Machining, Ferramentas de corte, Material cerâmico, Planejamento experimental