EFFECT OF MOLYBDENUM IN THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF THE DUAL-PHASE STEEL DP980
José Francisco da Silva Filho1; Carlos Augusto Silva de Oliveira2; Cássio Aurélio Suski3; Nilceu Novicki3
1 Arcelor Mittal; 2 Universidade Federal de Santa Catarina; 3 Instituto Federal de Santa Catarina
doi:10.20906/CPS/COB-2015-1769
Resumo
High work-hardening rates in combination with excellent elongation give the Dual-Phase steels much higher formability especially with the feature of higher ultimate tensile strengths than conventional steels of similar yield strength. In this paper the investigation will address the results obtained with dual phase steels after being isothermally treated and then quenched in water. These steels differ in chemical composition according to the different Mo contents (0/ 0.15/ 0.30 and 0.45%Mo). Samples of each chemical composition were isothermally heat treated at each temperature (720/ 740/ 760/ 780/ 800/ 820/ 840/ and 860ºC). These samples were tested on tensile machine for mechanical properties and analyzed on optical/scanning electron microscope for investigating the evolution of the microstructures. Discussions were developed, mainly, on the basis in panel where pictures of the microstructures were organized in sequence of according to the temperature and Mo concentration. Supports of others techniques of analyzes such as EBSD, TEM and program Thermocal were used in order to confirm some ideas. The focus of the discussion was pointed on the phenomena of recrystallization, phase transformation and precipitates' behavior.
Palavras-chave: recrystallization; phase transformation; precipitates