Per: Andre Itman Filho (instituto federal do espírito santo), katia regina cARDOSO (UNIVERSIDADE FEDERAL DE SÃO PAULO), CONRADO RAMOS MOREIRA AFONSO (UNIVERSIDADE FEDERAL DE SÃO CARLOS), ROSANA VILARIM DA SILVA (INSTITUTO FEDERAL DO ESPÍRITO SANTO), KAREN FARIAS CIRILO (INSTITUTO FEDERAL DO ESPÍRITO SANTO), JAQUELINE POLEZI MAZINI (INSTITUTO FEDERAL DO ESPÍRITO SANTO)
Abstract:
Microalloyed steels have a maximum of 2% in alloy elements and are used in various components in the automotive, civil construction and petrochemical industries due to their toughness, corrosion resistance and adequate weldability. In general, these steels have small amounts of molybdenum, niobium, vanadium and titanium, elements that form carbides during cooling or heating in the manufacturing stages. Furthermore, the effectiveness of these precipitates depends on the stoichiometries and volumetric fractions, to improve the mechanical strength with grain refining and secondary hardening. Due to the size of these carbides, identification is difficult by optical and scanning electron microscopy. In this case, an alternative is to use computational thermodynamic simulation with the FactSage software, which allows obtaining the quantities, stoichiometries and solubilization temperatures of precipitated carbides during the manufacturing steps. Within this context, the objective of the research was to identify the carbides of four microalloyed steels, with chemical compositions similar to those used in sheet rolling. The simulation was performed with the FactSage software, varying the temperature from 0 to 1500 oC. The results indicate the presence of carbides M3C2, M7C3 and M23C6.An analysis by scanning electron microscopy with EDS indicated molybdenum as the main alloying element in these carbides.
