Sensitization Resistance of Alloy UNS N08825 after Different Mill-annealing Temperatures and Times

Abstract Designed for applications in the chemical process industry and later also used in the Oil & Gas industry, Alloy UNS(1) N08825 is a fully austenitic nickel-iron-chromium alloy, stabilized by titanium and with additions of copper and molybdenum. It is well known that the susceptibility of the material to intergranular corrosion in the "as delivered” (mill-annealed) condition, so as after the exposure of the material to intermediate temperatures, is strongly dependent on the chemical composition and additionally on the thermal history. This work consists on the variation of the nickel content within the UNS chemical composition of Alloy N08825 and the variation of the annealing temperatures and times in order to better understand the influence of these variables on the intergranular corrosion resistance of material from large-scale production. Samples were tested according to ASTM(2) G28 method A in the "as delivered” condition and after sensitization heat treatment to verify its intergranular corrosion resistance.