Per: Victor Cardoso campideli (universidade federal de ouro preto), Lóren Kelly de Paula Inácio (universidade federal de minas gerais), Raphael França Assumpção (UNIVERSIDADE FEDERAL DE MINAS GERAIS), Dagoberto Brandão Santos (universidade federal de ouro preto), DALILA CHAVES SICUPIRA (UNIVERSIDADE FEDERAL DE OURO PRETO)
Abstract:
Duplex stainless steel has a microstructure composed of approximately equal parts austenite and ferrite. This combination gives this material interesting property such as high mechanical strength and good corrosion resistance. To achieve these properties, the material undergoes rolling, followed by annealing heat treatment. The heat treatment can cause the formation of new phases or decomposition of constituents. This study aims to investigate the phenomenon of spinodal decomposition in samples of duplex steel 2304, in both as-supplied and rolled conditions, subjected to thermal aging at 500°C for 0.5 hours, 24 hours, and 48 hours to evaluate its influence on hardness and corrosion resistance, using microstructural analysis, electrochemistry, and Vickers hardness tests. The results showed that cold rolling led to the formation of a pancaked structure, with alternating bands of ferrite and austenite. Aging resulted in the formation of a structure with a mottled appearance characteristic of spinodal decomposition. The samples exhibited a trend of increased hardness with longer aging times and degree of sensitization, and all samples showed resistance to pitting corrosion in borate solution