COMPARAÇÃO MICROESTRUTURAL DO AÇO ASTM A213 NAS CONDIÇÕES T22 E T91 COM E SEM TRATAMENTO DE ALÍVIO DE TENSÃO PÓS SOLDA

Ano: 2019

Instituições de ensino: Faculdade de Tecnologia de Sertãozinho, Faculdade de Tecnologia de Sertaozinho, Centro Estadual de Educação Tecnológica Paula Souza, Faculdade de Tecnologia de Sertãozinho, Nenhuma

Idioma: Portugues

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Resumo

The present work aims to evaluate the influence of the heat treatment after welding on the ASTM A213 T22 and T91 steel in the formed microstructure and the hardness of the material. According to ASME code, parts made from T22 gr grades do not require post-weld stress relief, provided they have a wall thickness of less than 16 mm. The gr. T91 require post-weld tension relief for any wall thickness. In this way, thin-thickness samples of these two steels were evaluated and the conditions with and without post-weld stress relief were studied. The microstructures were obtained by optical microscopy and the hardness was evaluated by Vickers microhardness measurements. It was found that for gr. T22 post-weld stress relief causes coalescing of the grains and dissolution of the dispersed carbides in the matrix, resulting in a very low hardness value. For gr. T91 the heat treatment of post-weld stress relief is shown to be necessary for a change in the martensite formed during welding and in the increase of the bainite fraction in the melt zone of the weld pool.

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