INFLUÊNCIA DE DIFERENTES TRATAMENTOS TÉRMICOS DE RECOZIMENTO NAS FRAÇÕES DE FASES E NAS PROPRIEDADES MECÂNICAS DO AÇO INOXIDÁVEL DUPLEX UNS S31803
INFLUENCE OF DIFFERENT ANNEALING HEAT TREATMENT ON PHASES FRACTION AND THE MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL UNS S31803
Maria Amélia Martins, Geraldo Lúcio Faria, Tarcísio Reis de Oliveira
Resumo
Neste trabalho a influência de diferentes tratamentos térmicos nas frações de fases (ferrita, austenita e sigma) e seus efeitos nas propriedades mecânicas de um aço inoxidável duplex UNS S31803 foram investigados. A quantificação dessas fases foi feita por técnicas de microscopia óptica e microscopia eletrônica de varredura e as propriedades mecânicas avaliadas através de ensaios de tração uniaxial e impacto Charpy-V. As análises das fases primárias indicaram que a fração de austenita foi superior à de ferrita em todas as condições estudadas. A análise de fase sigma indicou que para uma mesma temperatura de recozimento, quanto maior o tempo de encharque, maiores as frações de sigma encontradas e maiores os valores de limite de resistência. Além disso, as amostras recozidas em menor tempo de encharque foram as que alcançaram os maiores valores de energia de absorvida.
Palavras-chave
Abstract
In this work the influence of different isothermal heat treatments on phase fraction (ferrite, austenite and sigma) and its effects on mechanical properties of duplex stainless steel UNS S31803 were investigated. It has been performed heat treatments varying temperature and aging time. The quantification of phases were analyzed through light optical microscopy and scanning electron microscopy and the mechanical properties were evaluated using uniaxial tensile and Charpy-V impact tests. The results of primary phases have indicated that the austenite fraction was higher than ferrite in all conditions studied. On the other hand, high amounts of sigma phase were observed on the isothermal long time annealing conditions. Furthermore, the results of impact test of samples with low soaking time and, smaller fraction of sigma phase, were the ones that reached the highest values of impact energy absorption.
Keywords
Referências
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