Efeito da temperatura de recozimento intercrítico e do passe de encruamento na microestrutura e nas propriedades mecânicas de um aço médio manganês (0.09C-8Mn)
Effect of intercritical annealing temperature and skinpass rolling on the microstructure and mechanical behavior of a medium manganese steel (0.09C-8Mn)
Francislaynne Lages Dias, Aline Oliveira Vasconcelos Ferreira, Indiana Rosa Oliveira, Aline Silva Magalhães, Dagoberto Brandão Santos
The third generation of advanced high strength steels have been developed to reach an excellent combination of strength and ductility, ensuring passengers’ safety and good conformability for automotive components. For instance, there are the medium manganese steels, that contain 4 up to 12 wt.% Mn. They exhibit an ultra-fine microstructure with a significant amount of retained austenite. This phase transforms into martensite during mechanical loading due to the TRIP effect (Transformation Induced Plasticity), which provides an attractive combination of the properties previously mentioned. This work, carried out on a pilot scale, evaluated the influence of intercritical annealing temperature on the retained austenite volume fraction of a medium Mn steel. Additionally, it was determined the necessary thickness reduction to eliminate the discontinuous yielding through an additional skin pass step. Thus, the results showed a high austenite volume fraction for all analyzed conditions and the elimination of the discontinuous yielding after skin pass with thickness reductions above 5,5%. These outcomes lead to a significant strength and ductility increase, with a high potential application in the automotive industry
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