Per: CHARLES HUDSON MARTINS DE VASCONCELOS (INSTITUTO MILITAR DE ENGENHARIA), isaque alan brito moura (instituto militar de engenharia), Mônica Aline Magalhães Gurgel (INSTITUTO MILITAR DE ENGENHARIA), Tatiane Santos Ferreira (PAUMIR DE BARRA MANSA INDÚSTRIA E COMÉRCIO LTDA), Andersan dos Santos Paula (INSTITUTO MILITAR DE ENGENHARIA)
Abstract:
Dual Phase (DP) steels are characterized by a ferritic-martensitic microstructure, which consists of an equiaxial ferrite matrix with 10 to 20% dispersed islands martensite. In this work, samples of low C steel, Nb and Mo micro addition, were used in the cold rolled condition (BFH). The physical simulations, in laboratory scale, were conducted with the objective of obtaining a characteristic microstructural aspect of a DP steel even after thickness reduction through cold rolling and intercritical annealing. The soaking temperature was 800 °C during 180 seconds for intercritical annealing, followed by cooling under two conditions: in water (to criticize the austenite formed fraction on soaking as a function of the ferrite recrystallization potential) and in air (inferred in the ferrite formation and subsequent perlitic, bainitic and / or martensitic transformations in the course of cooling). Using scanning electron microscopy (SEM), it was observed that to obtain the DP steel microstructure characteristic it would be necessary to adjust the annealing parameters as a function of the reduction applied in cold rolling, ie increasing the cold rolling percentage reduction, it is necessary to decrease the soaking temperature or the time so that adequate results are obtained the characteristics of a DP steel.