Effect of thermal aging conditions on the corrosion properties and hardness of a duplex stainless steel

• Published in: Materials research (São Carlos, São Paulo, Brazil) Vol. 13; no. 4; pp. 431 - 436
• Main Authors: May, José Eduardo, Souza, Carlos Alberto Caldas de, Nascente, Pedro Augusto de Paula, Soares, Paulo, Lepienski, Carlos Mauricio, Kuri, Sebastião Elias
• Format: Journal Article
• Language: English
• Published: ABM, ABC, ABPol 01-12-2010; Associação Brasileira de Metalurgia e Materiais (ABM); Associação Brasileira de Cerâmica (ABC); Associação Brasileira de Polímeros (ABPol)
• Subjects: corrosion; duplex stainless steel; ENGINEERING, CHEMICAL; long-term aging; MATERIALS SCIENCE, MULTIDISCIPLINARY; METALLURGY & METALLURGICAL ENGINEERING; structural characterization; corrosion; long-term aging; duplex stainless steel; structural characterization
• ISSN: 1516-1439; 1980-5373; 1516-1439
• DOI: 10.1590/S1516-14392010000400003

The corrosion properties of a 22.5 wt. (%) Cr duplex stainless steel were investigated after long-term aging of 3000, 5000 and 7000 hours at 300 and 400 ºC. The corrosion resistance was measured based on mass loss in a FeCl3 10 wt. (%) solution and electrochemical measurements in a 0.1 M H2SO4 solution. The results indicate that the corrosion resistance decreased steadily up to 5000 hours of aging. However, the samples subjected to 7000 hours of aging showed better corrosion resistance than those aged for 3000 and 5000 hours. This effect is attributed to the phase transformation that occurs during aging, a finding which was confirmed by hardness, transmission electron microscopy and X-ray photoelectron spectroscopy measurements.