Soldagem dissimilar autógena com laser pulsado Nd:YAG dos aços austenítico AISI 316L e ferrítico AISI 430
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Data
2022-12-16
Autores
Bastos, Raquel Rodrigues de Oliveira
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Universidade Estadual Paulista (Unesp)
Resumo
Há muito tempo vem se aperfeiçoando materiais e métodos, principalmente dentro da indústria mecânica. O estudo de materiais vem se aprimorando pois muitas vezes é o fator limitante para a realização de projetos. Desde 1912 vem se estudando o uso de aços inoxidáveis, pois apresentam resistência à corrosão em ambientes mais severos.
Além do foco em materiais, os processos de fabricação também vêm sendo desenvolvidos, e a soldagem a laser apresenta muitas vantagens em relação à solda convencional, por apresentar menor espessura de cordão de solda, pequena zona afetada termicamente, agride menos o material apresentando poucas distorções, é um processo muito rápido comparado aos processos de solda tradicionais, a região soldada tem sua dureza mecânica aumentada e com maior resistência a tensão.
O presente trabalho teve como objetivo analisar uma chapa com 1,5 mm de espessura com laser Nd:YAG pulsado, na condição autógena, entre os aços austenítico AISI 316L e Ferrítico AISI 430. As soldagens foram realizadas em juntas de topo e sem abertura de raiz. A energia do pulso foi fixada em 10J, com potência de pico de 2kw e largura temporal de 5ms. A frequência variou de 1,8 Hz a 9 Hz. Soldou-se amostras somente composta, por aço inox austenítico AISI 316L, depois somente aço ferrítico AISI 430 e por último três amostras contendo ambos aços se variando a taxa de sobreposição do cordão de solda entre 50%, 70% e 90%. Foram realizadas analises macrográficas e micrográficas da junta soldada através de microscopia ótica e microscopia eletrônica de varredura. Foram realizados ensaios mecânico de dureza Vickers para comparar a dureza ao longo dos metais base e da junta soldada. Os resultados mostraram que a soldagem dissimilar entre os aços austenítico AISI 316L e Ferrítico AISI 430 gera microestrutura duplex no cordão de solda. A junta soldada apresenta balanço microestrutural apresentou em média 48% de austenita e 52% ferrita, indicando uma correção do balanço entre 50% de ferrita e austenita. Houve um aumento da dureza da zoa soldada em relação a dureza isolada dos metais base.
Materials and methods have been improved for a long time, especially within the mechanical industry. The study of materials has been improving because it is often the limiting factor for the realization of projects. Since 1912 the use of stainless steels has been studied, because they present resistance to corrosion in more severe environments. Besides the focus in materials, the manufacturing processes have also been developed, and the laser welding presents many advantages in relation to the conventional welding, because it presents smaller thickness of the weld seam, small heat affected zone, it harms less the material presenting few distortions, it is a very fast process compared to the traditional welding processes, the welded region has its mechanical hardness increased and with higher resistance to tension. The present work had as objective to analyze a plate with 1,5 mm of thickness with laser Nd:YAG pulsed, in the autogenous condition, between austenitic AISI 316L and ferritic AISI 430. The welds were performed in butt joints and without root gap. The pulse energy was set at 10J, with a peak power of 2kw and a temporal width of 5ms. The frequency ranged from 1.8 Hz to 9 Hz. Samples were welded consisting only of austenitic stainless steel AISI 316L, then only ferritic steel AISI 430, and finally three samples containing both steels, varying the overlap rate of the weld bead between 50%, 70% and 90%. Macrographic and micrographic analyses of the welded joint were performed using light microscopy and scanning electron microscopy. Mechanical Vickers hardness tests were performed to compare the hardness along the base metals and the welded joint. The results showed that dissimilar welding between austenitic AISI 316L and ferritic AISI 430 steels generates duplex microstructure in the weld bead. The welded joint microstructural balance showed an average of 48% austenite and 52% ferrite, indicating a balance correction between 50% ferrite and austenite. There was an increase in the hardness of the welded zone relative to the hardness of the base metals alone.
Materials and methods have been improved for a long time, especially within the mechanical industry. The study of materials has been improving because it is often the limiting factor for the realization of projects. Since 1912 the use of stainless steels has been studied, because they present resistance to corrosion in more severe environments. Besides the focus in materials, the manufacturing processes have also been developed, and the laser welding presents many advantages in relation to the conventional welding, because it presents smaller thickness of the weld seam, small heat affected zone, it harms less the material presenting few distortions, it is a very fast process compared to the traditional welding processes, the welded region has its mechanical hardness increased and with higher resistance to tension. The present work had as objective to analyze a plate with 1,5 mm of thickness with laser Nd:YAG pulsed, in the autogenous condition, between austenitic AISI 316L and ferritic AISI 430. The welds were performed in butt joints and without root gap. The pulse energy was set at 10J, with a peak power of 2kw and a temporal width of 5ms. The frequency ranged from 1.8 Hz to 9 Hz. Samples were welded consisting only of austenitic stainless steel AISI 316L, then only ferritic steel AISI 430, and finally three samples containing both steels, varying the overlap rate of the weld bead between 50%, 70% and 90%. Macrographic and micrographic analyses of the welded joint were performed using light microscopy and scanning electron microscopy. Mechanical Vickers hardness tests were performed to compare the hardness along the base metals and the welded joint. The results showed that dissimilar welding between austenitic AISI 316L and ferritic AISI 430 steels generates duplex microstructure in the weld bead. The welded joint microstructural balance showed an average of 48% austenite and 52% ferrite, indicating a balance correction between 50% ferrite and austenite. There was an increase in the hardness of the welded zone relative to the hardness of the base metals alone.
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Palavras-chave
Soldagem laser, Nd:YAG, Aço austenítico, Aço ferrítico, AISI 430, AISI 316L, Laser welding, Austenitic steel, Ferritic steel