Per: Gabrielle cristine lemos duarte freitas (Universidade federal fluminense), GLÁUCIO SOARES DA FONSECA (UNIVERSIDADE FEDERAL FLUMINENSE), Luciano pessanha moreira (universidade federal fluminense)
Abstract:
Duplex stainless steels are known for their high mechanical strength and high corrosion resistance, properties that justify their development and application in chemical and petrochemical sectors. These properties are associated to the microstructure, which has similar volumetric fractions of ferrite and austenite, through additions of alloying elements such as Cr, Mo and Ni. However, in thermal processes at high temperatures, important microstructural changes can occur, where alloying elements previously arranged in solid solution in the matrix form intermetallic precipitates, which are usually deleterious to the properties of toughness and corrosion resistance. The objective of this work is to study phase transformations resulting in non-isothermal cooling cycles in a stainless duplex SAF 2205. The experiment contemplates a sequence of four simulated thermal cycles in Gleeble 3500®. In order to investigate the phase precipitation process, the dilatometric technique was used, where it was possible to determine the phase transformation temperatures in the samples. This information is validated through the results obtained in the microstructural study using optical microscopy. Through the correlation between the volumetric fraction of the transformed phase and the hardness test performed it was also possible to guarantee the influence of the phases found in the properties of the material.