Publicación: Unión de riel ferroviario mediante soldadura SMAW utilizando AWS E7018 y AW NIQ MANG como aporte (I)
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2024-10-22
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info:eu-repo/semantics/openAccess
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Universidad Nacional de Educación a Distancia (España), Universidad de Concepción - Chile. Departamento de Ingeniería Mecánica
Resumen
En este trabajo de investigación se realizó y caracterizo la soldadura de riel de ferrocarril (acero R350HT), mediante la técnica de electrodo revestido (SMAW), se seleccionaron dos electrodos revestidos, AWS E7018 AW NIQ MANG de 3 mm respectivamente. Comúnmente este riel ferroviario se suelda mediante la técnica de aluminotermia, en la literatura abierta se encuentran muy pocos trabajos sobre otras técnicas de soldadura del mismo. Se diseñó y fabrico un tipo de junta en V a 60°, para facilitar la unión y la penetración de la soldadura, se caracterizó la junta utilizando ultrasonido, se examinó la zona de soldadura y zona afectada por el calor (ZAC) mediante microscopia óptica, se midió la dureza HRc y microdureza HV en el material base, soldadura y zona afectada por el calor, se obtuvo una junta homogénea en ambos casos y las pruebas de ultrasonido demuestran que la cantidad de discontinuidades son menores y aceptables de acuerdo con la norma AWSD1.1/D1.1M:2020, se observó que la dureza es constante y muy cercana a la dureza del acero soldado (45 HRc), las fases observadas son consistentes de la soldadura con el acero, se observó cementita y perlita (E7018), en el caso de AW NIQ MANG, se aprecia cementita en matriz perlítica y la formación de carburos en la zona afectada por el calor, en ambos casos se observó que la dureza aumenta, esto como consecuencia de la formación de carburos aportados por ambas aleaciones. La unión soldada requirió el aporte de 1 kilogramo de soldadura en ambos casos y la aplicación requirió de 2 horas en tiempo para ser realizada, con estos datos se demuestra que es posible sustituir la soldadura aluminotérmica con soldadura de electrodo revestido, aunque aún se requieren más pruebas mecánicas que puedan confirmarlo
In this research work, the welding of railway rail (R350HT steel) was carried out and characterized, using the coated electrode technique (SMAW), two coated electrodes were selected, AWS E7018 AW NIQ MANG of 3 mm respectively. This railway rail is commonly welded using the aluminothermal technique; very few works on other welding techniques are found in the open literature. A type of 60° V joint was designed and manufactured to facilitate the union and penetration of the weld, the joint was characterized using ultrasound, the weld zone and heat affected zone (HAZ) were examined using optical microscopy. The HRc hardness and HV microhardness were measured in the base material, weld and heat-affected zone, a homogeneous joint was obtained in both cases and the ultrasound tests show that the number of discontinuities are minor and acceptable according to the AWSD1.1/D1.1M:2020 standard, it was observed that the hardness is constant and very close to the hardness of the welded steel (45 HRc). The observed phases are consistent with the weld with the steel, cementite and perlite were observed (E7018), in the case of AW NIQ MANG, cementite is seen in a perlitic matrix and the formation of carbides in the heat-affected zone. In both cases, it was observed that the hardness increases, this as a consequence of the formation of added carbides for both alloys. The welded joint required the contribution of 1 kilogram of solder in both cases and the application required 2 hours in time to be carried out. These data show that it is possible to replace aluminothermic welding with covered electrode welding, although more is still required mechanical tests that can confirm it.
In this research work, the welding of railway rail (R350HT steel) was carried out and characterized, using the coated electrode technique (SMAW), two coated electrodes were selected, AWS E7018 AW NIQ MANG of 3 mm respectively. This railway rail is commonly welded using the aluminothermal technique; very few works on other welding techniques are found in the open literature. A type of 60° V joint was designed and manufactured to facilitate the union and penetration of the weld, the joint was characterized using ultrasound, the weld zone and heat affected zone (HAZ) were examined using optical microscopy. The HRc hardness and HV microhardness were measured in the base material, weld and heat-affected zone, a homogeneous joint was obtained in both cases and the ultrasound tests show that the number of discontinuities are minor and acceptable according to the AWSD1.1/D1.1M:2020 standard, it was observed that the hardness is constant and very close to the hardness of the welded steel (45 HRc). The observed phases are consistent with the weld with the steel, cementite and perlite were observed (E7018), in the case of AW NIQ MANG, cementite is seen in a perlitic matrix and the formation of carbides in the heat-affected zone. In both cases, it was observed that the hardness increases, this as a consequence of the formation of added carbides for both alloys. The welded joint required the contribution of 1 kilogram of solder in both cases and the application required 2 hours in time to be carried out. These data show that it is possible to replace aluminothermic welding with covered electrode welding, although more is still required mechanical tests that can confirm it.
Descripción
Organizado y patrocinado por: Federación iberoamericana de Ingeniería Mecánica y 'Universidad de Concepción - Chile. Departamento de Mecánica', FeIbIm – FeIbEM
Categorías UNESCO
Palabras clave
riel ferroviario, soldadura, zona afectada por el calor, discontinuidad, railway rail, welding, heat affected zone, discontinuity
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E.T.S. de Ingenieros Industriales
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Mecánica