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Item Efeito do tempo de austenitização na evolução da microestrutura e comportamento mecânico dos aços inoxidáveis UNS S42000 e UNS S41003(Universidade Federal de Goiás, 2023-02-28) Alves, Renata Rodrigues; Cunha, Daniel Fernandes da; http://lattes.cnpq.br/7364532451621106; Cunha, Daniel Fernandes da; Figueireido, Kleber Mendes de; Contin, André; Labiapari, Wilian da SilvaQuenching is one of the most common methods of heat treatment and aims to increase the mechanical strength of the material by transforming austenite into martensite at high temperatures, followed by rapid cooling. The formation of martensite depends on various factors, such as the time the material is held at the austenitization temperature. In the context presented and with the aim of contributing to a better understanding of the microstructure evolution and mechanical behavior of stainless steels with different carbon contents, this study aimed to investigate the effect of austenitization time followed by quenching treatment. The materials studied were low carbon steel, commercially known as UNS S41003 or 410D, and medium carbon steel, commercially known as UNS S42000 or 420A. Two heat treatment conditions were studied, in the first one, the steels were austenitized at 1000 ℃ with varying austenitization time (5 min, 30 min, 60 min, 120 min, and 240 min) and then quenched in water, while in the second condition, the samples were annealed at 800 ℃ and then austenitized at 1000 ℃ with varying austenitization time (5 min, 30 min, 60 min, 120 min, and 240 min), and finally quenched in water. Thermodynamic simulations were performed using Matcalc software to evaluate the relative stability of phases and precipitates under equilibrium conditions. It was observed that both steels would be austenitized at 1000 ℃, and the carbides dissolved, however, it was identified that the carbide dissolution depends on the austenitization time when outside of equilibrium. Despite the low carbon content, austenitization of the 410D steel was possible due to the presence of austenitizing elements such as Ni, Mn, and N, thus, both steels showed a martensitic structure after the water quenching process. It was possible to observe that with an increase in austenitization time, the martensite lath increased due to the gradual increase in grain size. The distribution of the prior austenitic grain size was found to be heterogeneous for longer times, related to the dissolution of carbides. In addition to presenting a similar microstructural evolution, both steels also exhibited similar mechanical behavior, with the material softening as the grain size increased, associated with the freer dislocation movement with increasing austenitization time. Finally, the obtained data on prior austenitic grain size and hardness were treated with a 95% confidence level. It is believed that the results of this study provide a foundation for a better understanding of the austenitization time parameter in the heat treatment of stainless steels.Item Efeito dos parâmetros de usinagem na usinabilidade dos aços inoxidáveis 410D e 420A ferrítico e martensítico no processo de eletroerosão por penetração(Universidade Federal de Goiás, 2023-02-27) Cunha, João Bosco da; Viana, Rhander; http://lattes.cnpq.br/5270141650315822; Cunha, Daniel Fernandes da; http://lattes.cnpq.br/7364532451621106; Cunha, Daniel Fernandes da; Oliveira, Deborah de; Viana, Rhander; Contin, AndréElectrodischarge Machining is an unconventional machining process that has served as an alternative for machining difficult-to-machine materials and complex geometries by removing material through electrical discharges. In the electrical discharge machining (EDM) process, it is necessary to know the parameters that affect material removal, electrode wear and the surface finish of the workpiece. Knowing these parameters provides greater productivity and reduction of costs in machining process. In this context, this work seeks to establish, through a design of experiments (DOE), an analysis about the behavior of the process with different values of electrical current, electrical discharge time and the working GAP during machining AISI stainless steels 410D and 420A, supplied in annealed state. After tempering process, it changes its ferritic to martensitic microstructure. It was statistically verified that electrical current affected material removal rate (MRR), electrode wear rate (EW) and surface roughness. These data confirms literature review about using higher currents for rough machining, sacrificing the electrode tool for increasing material removal process, and smaller electrical currents for finishing machining parameters, guaranteeing the final geometry and better surface quality of the machined cavity. Heat treatment is shown by this research to have no significant influence on material removal rate, electrode wear and surface roughness.Item Avaliação de resistência mecânica e análise de forma geométrica de elementos de fixação por rosca fabricados através de manufatura aditiva(Universidade Federal de Goiás, 2023-08-31) Prado, Thiago Menezes do; Viana, Rhander; http://lattes.cnpq.br/5270141650315822; Cunha, Daniel Fernandes da; http://lattes.cnpq.br/7364532451621106; Cunha, Daniel Fernandes da; Ziberov, Maksyn; Medeiros, Everton Coelho de; Viana, RhanderThe work addresses the mechanical tensile strength of internal fillets in specimens manufactured in PLA and ABS from additive manufacturing by Fused Deposition Modelling (FDM). Test specimens measuring 30 x 30 x 20 mm were manufactured in PLA and ABS with a 3D printer model Ender 3 V2. The through hole of the specimens has measurements M12 x 1.75. Varied parameters used were: infill (p), number of walls (w) and height of the layers (h), to enable the understanding of how the mechanical resistance of the material is affected. Thus, the present study aimed to compare the mechanical resistance of PLA and ABS polymers through tensile tests, defining which material has greater resistance and with low production cost from 3D printing. The tensile tests were carried out using a tensile machine with a maximum capacity of 600 kN, which gradually applied tension to the specimens until the material fractured or ruptured. For the result analysis, relation of resistance from the specimens was verified graphically (force x time) and statistically (ANOVA), judging the influence of variables in individual and collective content in the achieved results. Pieces printed in PLA showed a higher quality of mechanical resistance compared to those made from ABS material when graphic results obtained were verified. As a statistical result, the ANOVA analysis identified the factor with greatest influence on tests were infill (P%), being preponderant both individually and collectively, when analyzing its influence with other two variables.