THE INFLUENCE OF AGING ON THE INTERGRANULAR CORROSION OF 22-CHROMIUM 5-NICKEL DUPLEX STAINLESS-STEEL

Duplex stainless steels are widely used in severe corrosive environmen ts because of their good corrosion performance. This paper deals with the influence of aging treatments on the intergranular corrosion (IGC) resistance of a commercial duplex stainless steel, SAF 2205. Duplex s tainless steel was given aging treatments in the range 773-1173 K for time periods ranging from 6 min to 100 h. Optical microscopy and XRD w as carried out on the aged stainless steels for the microstructural st udy. The aged samples were evaluated for the IGC susceptibility with t he ASTM standard practices. Potentiodynamic cyclic polarization studie s were also carried out to investigate the influence of aging treatmen ts on the passivity breakdown. The results indicate that the sigma pha se gets precipitated and is responsible for grain boundary attack.