Dissertações
URI permanente para esta coleçãohttps://rigalileo.itegam.org.br/handle/123456789/174
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Item Análise de Tensões Residuais e Flechas em Soldas Planas de AISI 1020 Através de Ensaios de Tração, Microdureza Vickers e Mediçõees por Passe(Universidade Federal do Pará, 2014) SANTOS, Carlos Augusto Cayres; FUJIYAMA, Roberto TetsuoTemperature in the Heat Affected Zone (HAZ) changes according to its position, with time, and cooling conditions during solidification. This variation in temperature can produce phase changes along the crystalline structure and thermal dilatations that originate welding residual stresses. In this work, deflection per passes was analyzed with height measurements, residual stresses in Base Metal (BM) were analyzed with tension tests, in the Heat Affected Zone (HAZ) and Fusion Zone (FZ). The variation through-thickness inside the Heat Affected Zone (HAZ) region was evaluated using Vickers microhardness tests for four different welds: the first one without restraints, the second fully restrained, the third with parallel restrictions on the weld bead, and the fourth with perpendicular restrictions to the weld bead. The results for each weld allowed modeling the deflection through linear adjustments, determining the stress profile according to the type of restraints adopted, the region in which the welded joint shall fail, and identifying regions that present beneficial or harmful stresses according to the type of restrictions and loading. The study concluded that deflection can be mathematically modeled as a welding pass function, and residual stresses observed in the HAZ and Fusion Zone (FZ) increase through thickness.Item Análise de Tensões Residuais e Flechas em Soldas Planas de AISI 1020 Através de Ensaios de Tração, Microdureza Vickers e Medições por Passe(Universidade Federal do Pará, 2014) SANTOS, Carlos Augusto Cayres; Prof. Dr. Roberto Tetsuo FujiyamaTemperature in Heat Affected Zone (HAZ) changes according to its position, with time and cooling conditions during solidification, this variation in temperature can produce phase changing along crystalline structure and thermal dilatations which originates welding residual stresses. In this work were analyzed the deflection per passes with height measurements, the residual stresses in Base Metal (BM) with tension tests, in Heat Affected Zone (HAZ), in Fusion Zone (FZ) and the variation thru-thickness inside Heat Affected Zone (HAZ) region with Vickers microindentation for 4 different welds, the first one without restraints, the second full restricted, the third one with parallel restrictions on the weld bead and the fourth perpendicular to the weld bead restrictions for plane weldings of AISI 1020 carbon steel. Results for each weld allows modeling the deflection thru linear adjustments and determine the stresses profile according to the type of restraints adopted, the region in which the welded joint shall fail and which regions present beneficial or harmful stresses according to the type of restrictions and loading. In this experiment was observed that deflection can be modeled as a welding pass function, that the residual stresses in HAZ and Fusion Zone (FZ) increases thru thickness, that the peak tension in these regions occur next to the welding center region, that to project effect, joints 1x2 and 5x6 are equivalent with tractive residual stresses in Base metal about 10% of the yielding stress, that joint 3x4 presents compressive residual stress in base metal about 66% of yielding stress while joint 7x8 presents a tractive residual stress about 25% of yielding stress for the same region.