ESTUDO CINÉTICO DA TRANSFORMAÇÃO MARTENSÍTICA NO AÇO MICROLIGADO USISAR 80T
STUDY OF THE KINETICS OF MARTENSITIC TRANSFORMATION IN THE USISAR 80T MICROALLOYED STEEL
Samuel da Silva de Souza, Paulo Sérgio Moreira, Geraldo Lúcio de Faria
Resumo
No presente trabalho, estudou-se a aplicação de modelos cinéticosde transformação martensíticadisponíveis na literatura técnica a fim de modelar curvas de fração da fase austenita transformada em martensita para o aço USISAR 80T, estrutural, microligado, de boa temperabilidade e considerado de boa soldabilidade. Ensaios dilatométricos foram realizados com taxa de aquecimento de 3°C/s até a temperatura de austenitização de 920°C, tempo de encharque de 180 segundos e taxas de resfriamento de 25°C/s, 50°C/s, 75°C/s e 100°C/s. Um dos modelos estudados apresentou boa correlação com os dados experimentais para todas as taxas de resfriamento estudadas, sendo possível então a obtenção de constantes características da transformação estudada e a proposição de um modelo de previsibilidade para o aço USISAR 80T.
Palavras-chave
Abstract
In this work, martensitic kinetic models, available in the technical literature, were studied aiming to model and to predict the austenite to martensite transformation for the USISAR 80T steel, which is a structural, microalloyed, with high hardenability and considered a great weldable steel. Dilatometrictests were performed with a heating rate of 3°C/s until 920°C, with a soaking time of 180 seconds and cooling rates of 25°C/s, 50°C/s, 75°C/s and 100°C/s.One of the studied models showed good agreement with the experimental data for all the employed cooling rates, and it was possible to determinetransformation characteristic constants and suggest a previsibility model for the USISAR 80T steel.
Keywords
Referências
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