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Previous issue date: 2014-08-08 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Os fluidos de corte s?o lubrificantes usados no processo de usinagem nas ind?strias metalmec?nica
por apresentarem v?rios benef?cios que variam de acordo com o tipo de opera??o
executada. Estes fluidos s?o largamente utilizados como refrigeradores, como lubrificantes
para melhorar o acabamento de superf?cies met?licas, reduzir o desgaste de ferramentas e
proteg?-las contra a corros?o. Considerando as legisla??es vigentes e a demanda por produtos
e processos considerados ?verdes?. Assim os ?leos vegetais representam uma solu??o para
esses problemas, pois os ?leos vegetais aparecem como uma excelente alternativa para
substitui??o do ?leos minerais. Deste modo, este trabalho teve como objetivo obter um fluido
de corte emulsion?vel a base de ?leo vegetal epoxidado, para uma melhor lubrifica??o e
refrigera??o no processo de usinagem, que n?o seja t?xico ao meio ambiente. O ?leo vegetal
foi modificado quimicamente atrav?s da rea??o de epoxida??o com ?cido f?rmico. Foram
determinadas as principais propriedades f?sico-qu?micas, tais como: densidade, acidez, ?ndice
de iodo, ?ndice de oxirano, viscosidade, estabilidade t?rmica, al?m de caracteriza??es atrav?s
de infravermelho e Resson?ncia Magn?tica Nuclear. O ?leo sintetizado foi utilizado para a
formula??o das emuls?es O/A com diferentes concentra??es de ?leo epoxidado (10%, 20% e
25%) e com diferentes concentra??es de tensoativo (1%, 2,5% e 5%), e realizados estudos
sobre a sua estabilidade. O desempenho tribol?gico das emuls?es O/A foi analisado pelo
trib?metro HFRR (High Frequency Reciprocating Rig), que consiste num ensaio de desgaste
do tipo esfera-plano. Os resultados mostraram que o biolubrificante pode ser sintetizado por
rea??o de epoxida??o, os espectros, demonstraram que n?o houve 100% de convers?o das
insatura??es em an?is ep?xi. Em rela??o ? avalia??o tribol?gica observa-se que o percentual
de ?leo presente na emuls?o influenciou diretamente na forma??o de filme e coeficiente de
atrito para maiores concentra??es o processo de forma??o de filme ? mais lento e inst?vel,
bem como os valores de coeficiente de atrito. Maiores concentra??es de tensoativos n?o
melhoraram o desempenho tribol?gico das emuls?es. O melhor desempenho para o processo
de usinagem ? a emuls?o desenvolvida com 10% e 5% de tensoativo, a sua escara de desgaste
em m?dia foi de WSD = 202?m. / The cutting fluids are lubricants used in machining processes, because they present many
benefits for different processes. They have many functions, such as lubrication, cooling,
improvement in surface finishing, besides they decreases the tool wear and protect it against
corrosion. Therefore due to new environment laws and demand to green products, new cutting
fluids must be development. These shall be biodegradable, non-toxic, safety for environment
and operator healthy. Thus, vegetable oils are a good option to solve this problem, replacing
the mineral oils. In this context, this work aimed to develop an emulsion cutting fluid from
epoxidized vegetable oil, promoting better lubrication and cooling in machining processes,
besides being environment friendly. The methodology was divided in five steps: first one was
the biolubricant synthesis by epoxidation reaction. Following this, the biolubricant was
characterized in terms of density, acidity, iodo index, oxirane index, viscosity, thermal
stability and chemical composition. The third step was to develop an emulsion O/A with
different oil concentration (10, 20 and 25%) and surfactant concentration (1, 2.5 and 5%).
Also, emulsion stability was studied. The emulsion tribological performance were carried out
in HFRR (High Frequency Reciprocating Rig), it consists in ball-disc contact. Results showed
that the vegetable based lubricant may be synthesized by epoxidationreaction, the spectra
showed that there was 100% conversion of the epoxy rings unsaturations. In regard the
tribological assessment is observed that the percentage of oil present in the emulsion directly
influenced the film formation and coefficient of friction for higher concentrations the film
formation process is slow and unstable, and the coefficient of friction. The high
concentrations of surfactants have not improved the emulsions tribological performance. The
best performance in friction reduction was observed to emulsion with 10% of oil and 5% of
surfactant, its average wear scar was 202 ?m.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/19829 |
| Date | 08 August 2014 |
| Creators | Santos, Erin?ia da Silva |
| Contributors | 02046752945, http://lattes.cnpq.br/8550161853747323, Barros Neto, Eduardo Lins de, 59545844434, http://lattes.cnpq.br/2811639726261017, Lucena Neto, Marciano Henrique de, 32288514434, http://lattes.cnpq.br/4809804711785369, Alves, Salete Martins |
| Publisher | Universidade Federal do Rio Grande do Norte, P?S-GRADUA??O EM ENGENHARIA MEC?NICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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