Unidad de Posgrado Civil y Mecánica

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    Caracterización de elementos estructurales de acero que hayan sido expuestos a diferentes tiempos y temperaturas debido a un incendio
    (Universidad Técnica de Ambato. Facultad de Ingeniería Civil y Mecánica. Maestría en Ingeniería Civil con Mención en Estructuras Metálicas, 2022-03) Guamanquispe Vaca, Fernanda Patricia; Espín Lagos, Segundo Manuel
    In the present investigative work, different structural elements such as columns, beams and steel straps ASTM A 36 exposed to flagella were characterized, considering different times and temperatures of exposure; For the experimental part, the conditions were simulated by using a conventional furnace in which several samples of steel and combustible material were placed, trying to simulate a real scourge, after which samples were taken at temperatures of 600, 800 and 1000 degrees celsius and exposure times of 30, 45 and 60 minutes, to which hardness and macroscopy tests were carried out in the materials laboratory of the Faculty of Civil and Mechanical Engineering and to be able to determine the mechanical properties of the material subjected under these conditions and compare them with those of the unexposed material; By means of the hardness it was possible to determine the ultimate resistance of the material and from the percentages of Ferrite and Perlite it was also verified that the ultimate resistance toxvi traction increased by 9-10 percentage since the samples were cooled by means of a cold water jet, a condition that occurs when a fire is extinguished; Although it is true that the mechanical properties of the specimens did not vary significantly, from the bibliographic review it was possible to determine that in real time of the flagellum, the resistance to creep decreases in inverse proportion with the temperature, so it is possible that the structure collapses. At that time, from the aforementioned, it can also be said that if the structure does not collapse during the fire and is still standing and without deformations in the structure, it can continue to provide service; Finally, after the analysis, it was possible to conclude that the mechanical properties of the structural steel elements at the time of the fire depend on the time and temperature of its exposure.
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    Proceso tecnológico para la fabricación de un aislante térmico mediante la reutilización de residuos de material compuesto de matriz de resina poliéster reforzado con fibra de vidrio
    (Universidad Técnica de Ambato. Facultad de Ingeniería Civil y Mecánica. Maestría en Mecánica Mención Manufactura, 2021-06) Freire Quinga, Erika Pamela; Carrillo Rosero, Carlos Mauricio
    The present investigation develops the technological process for the manufacture of a thermal insulator obtained from the combination of gypsum with crushed waste of a material with glass fiber reinforced polymer (GFRP) for the manufacture of ceiling panels, the mechanical and thermal properties of flexure, hardness and thermal conductivity were evaluated of each volumetric configurations analyzed. From the tests, it was determined that the best mechanical and thermal behavior of the composite material was 50 percent gypsum and 50 percent GFRP with a thickness of 9.5 mm with a flexural strength of 10.93 MPa, surface hardness with a footprint of 13mm and thermal conductivity of 0.11 W / m K,, also the presence of GFRP residues reduces the weight of the ceiling by 60 percent as well as the manufacturing cost. In conclusion, composite material of gypsum with GFRP waste improved the mechanical properties compared to existing gypsum panels.
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    Análisis de la influencia de un dieléctrico ecológico sobre la rugosidad superficial en el maquinado del acero K100 mediante el proceso de electroerosión por hilo (WEDM)
    (Universidad Técnica de Ambato. Facultad de Ingeniería Civil y Mecánica. Maestría en Mecánica Mención Diseño, 2020) Molina Molina, Diego Patricio; Analuiza Maiza, Oscar Iván
    In the Ecuador, non-conventional mechanized process have carried an analysis that is referred to the form of production of mechanic elements of complex geometry, that’s why the necessity of investigate the cuts of wire electroerosion (WEDM); using an alternative dielectric which is ecological in base to the electrochemical effect, for the aim of substitute the common way of coolant without the alteration of the final roughness and hardness on the cutting section, and preserve the equipment integrity, and contributing to the factories dedicated to the sheet metal process, to the ecology and the environment around us. The mentioned process goer together with the adequate cutting parameters study, based on an experimental investigation lead to characterized the representative ones of the surface finishing. The analysis is based on a comparative treatment which permits knowing the variability of the roughness and hardness acquired amounts on the cutting section through a variances analysis ANOVA about the factors that influence on the cutting process, in addition observe the presence of possible alterations on the cutting zone through the application of a scanning electron microscope (SEM). Having as a result the applicability of the alternative dielectric because under the influence of the same is achieved to obtain in average a significant value of roughness equal to 4,658 micrometers which is less to the achieved average amount with the application of the coolant, where the average is 5,253 micrometers. Furthermore, the surface represents less rate of irregularities, and one significant average to hardness it is referred. That is why the ecologic fluent gets to substitute easily, achieving with the asked expectations for the mechanized type.
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    Análisis de la aleación mecánica de aluminio 1060 con porcentajes controlados en peso de zinc y su incidencia en la resistencia última a la tensión, dureza e impacto
    (Universidad Técnica de Ambato. Facultad de Ingeniería Civil y Mecánica. Maestría en Mecánica Mención Diseño, 2019) Pineda Silva, Giovanny Vinicio; López Villacís, Gonzalo Eduardo
    The research project begins due to the need to have technically documented information related to powder metallurgy within the scope of mechanical alloy, manufacturing process that is entering into the National Industry, due to the advantages it presents with respect to traditional processes; being the most representative, a more exact control of the limits of the composition, optimization of raw material and is a process susceptible to automation with good surface finish for serial production of mechanical components. The experimental process of the mechanical alloy begins with the obtaining of mechanical powder of the base elements: Aluminum 1060 with particle size 30 micrometers and alloying: Zinc with particle size between 45−63 micrometers through the use of ball mill and a screening control; mixing process based on the percentages in weight defined for the subsequent compaction and sintering of the test pieces for the correct development of the tests. The study of tensile strength, hardness and impact was developed though the control of variables of percentage by weight of alloying element: 0.5 – 1.0 y 1.5 percentage Zinc, and sintering temperature: 462 celcius degrees y 594 celsius degrees ; the best results were obtained in the case of a study developed with 1 percentage Zinc and a temperature of 594 celsius degrees, where the hardness and tensile strength were increased by 69 percentage and 12.29 percentage respectively in relation to the base element; while the impact resistance as a function of the energy absorbed decreases by 39.40 percentage in the best case 1 percentage Zinc and 462 celsius degrees; in addition, the controlled variables are correlated with each other and directly affect the properties under study according to the statistical analysis developed by Fisher’s test.
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    Análisis de aceros y recubrimientos utilizados en tambores de mezclado de los mixers de la empresa Holcim Ambato y su influencia en el desgaste abrasivo bajo la norma ASTM G105
    (Universidad Técnica de Ambato. Facultad de Ingeniería Civil y Mecánica. Maestría en Diseño Mecánico, 2017) Villacrés Padilla, David Andrés; Núñez Núñez, Diego Fernando
    This research project was developed under the objective of analyzing the types of steels and coatings used in the mixing drums of the mixers of the HOLCIM company Ambato and its influence on the abrasive wear under the ASTM G105 standard, which tests were carried out from abrasive wear and an analysis of the rate of such coatings. For the development of the research, a bibliographic, field and experimental methodology was used, also exploratory and descriptive to address the study phenomenon that included 8 trials with the application of different configurations for the evaluation of the variable, besides a 40 sample scheme was developed with ASTM AISI 1020 steels and ASTM A514 grade F high strength steel corresponding to the Holcim Mixer drum, which were applied to three types of coatings such as nitrided, metallized and cemented. Due to this it was possible to conclude that the application of coatings and thermal treatments on the steels improve the characteristics and properties with respect to the abrasive wear, these processes contribute to a greater hardness and abrasive resistance. In addition, it is determined that, in the case of the amorphous tungsten alloy coating, it presents the greatest increase of hardness of the surfaces, which defines as the best treatment applicable in the steels, reason why a procedure for the recovery of the mixers according to the location of the parts of the mixer drum of the HOLCIM company.
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    Análisis del blindaje del acero AISI 1045 por proyección térmica de aleación micropulverizada Eutalloy 11496 y su influencia en la resistencia al desgaste superficial
    (Universidad Técnica de Ambato, Facultad de Ingeniería Civil y Mecánica. Maestría en Diseño Mecánico, 2017) Paredes Zumbana, Jorge Alexandro; Espín Lagos, Segundo Manuel
    In the present research, shielding tests were carried out on three surfaces of different roughness, which have as substrate the AISI 1045 steel, extracted from a cane miller. The three types of roughness were obtained by means of the processes of mechanical polishing with abrasive disc, sandblasting with mineral abrasive of volcanic nature and metallic blasting. The shielding material was the Eutalloy micropulverized alloy 11496, applied by means of the flame thermal projection technique. Shielded samples were subjected to abrasion wear tests and accelerated corrosion wear in a salt spray chamber; The results indicate that the best resistance to abrasive wear occurs in samples prepared superficially by sandblasting, which have a surface preheating between 320 and 420 ° C, to achieve a suitable anchorage of the metal alloy. The results of accelerated corrosion showed the highest corrosion rates in the unshielded substrate and it was also evidenced that the corrosion resistance in the shielding is good as long as there are no surface defects. Finally, a procedure proposal is proposed for the shielding of a cane mill tipping machine, in order to ensure that its useful life is favorable to milling with a duration of 8 months.
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    Estudio del tratamiento térmico post soldadura del acero inoxidable martensítico ASTM A743 grado CA6-NM y su incidencia en las propiedades mecánicas del material aplicado a la recuperación de rodetes hidráulicos
    (Universidad Técnica de Ambato, Facultad de Ingeniería Civil y Mecánica. Maestría en Diseño Mecánico, 2017) Auz Mogrovejo, Juan José; Vaca Ortega, Wilson Henry
    ASTM A743 grade CA6-NM Martensitic Stainless Steel is used in the manufacture of runners and other components of hydraulic turbines to provide a good combination between mechanical properties and resistance to cavitation and corrosion. Due to its low carbon content it has good weldability; however, it is necessary to perform post-weld heat treatment to alleviate stress and to fine tune the microstructure and mechanical properties in order to recover characteristics similar to those of the original material. Through the present work the effect of the heat treatment of ASTM A743 grade CA6-NM steel was studied after applying deposits of multi-step welding of accumulation type or restoration the thickness of the base metal using a GMAW robotized process with ER410NiMo electrodes on slotted coupons which reproduce part of the worn surface of a hydraulic runner. The welded coupons were subjected to different heat treatments in order to compare the mechanical properties of the weld material without heat treatment and with post-weld tempering at a temperature of 600 °C during two different holding times, one and two hours; in addition, this process was performed for one, two and three cycles of recovery by welding plus heat treatment. Eight cases of study were considered, including the original base material, the weld without heat treatment and six cases of post-welding tempering, which were subjected to tests of tension, impact, hardness and metallography to characterize and establish the variation of the mechanical properties. From this analysis it was determined that the post-weld heat treatment applied allows to improve the properties that are affected by the welding process. The best combination of mechanical properties was obtained for tempering at 600 °C during two hours in the first recovery. It was verified that even in the third recovery the properties of the material are within the parameters required by the standard ASTM A743. Finally, a procedure is proposed for the recovery of Francis hydraulic runners as an alternative for the maintenance of turbines at a lower cost.