Corrosion of the 1.4362 Duplex Stainless Steel in a Nitric Acid Environment at 333 K

T. Lipiński University of Warmia and Mazury in Olsztyn, The Faculty of Technical Sciences, S. Oczapowskiego 11, 10-957 Olsztyn, Poland

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Duplex stainless steels offer economic properties of strength and corrosion resistance. They are very popular ferritic-austenitic stainless steel construction material used in industrial applications. The fraction of each phase constitutes approximately 50%. These steels present excellent corrosion resistance, which is characteristic of austenite steel and the high mechanical properties of ferrite steel. The corrosion resistance of stainless steels depends on the chromium content and the microstructure morphology. The percentage contribution of each phase (and, thus, the steel properties) depends on the composition, technological processes and heat treatments. However, the performance presented by duplex stainless steels can be drastically compromised by the precipitation of undesirable phases, such as sigma phase, chi phase, secondary austenite, and large volumes of chromium-rich carbides. The aim of this paper was to ascertain the effect of corrosion time on the relative mass loss (in %), corrosion rate and roughness parameters of the 1.4362 duplex stainless steel profile after 30 min isothermal heat treatment at the temperature of 1423 K and cooling in air. The effect of nitric acid at 333 K on the steel corrosion resistance was determined based on weight loss and profile roughness parameters.

DOI:10.12693/APhysPolA.135.203 topics: steel, duplex steel, stainless steel, corrosion