Pitting Susceptibility of Stainless Steels in Bromide Solutions at Elevated Temperatures

Abstract

Abstract The pitting susceptibility of a range of austenitic stainless steels with different molybdenum contents was evaluated in both chloride and bromide solutions at elevated temperatures, using electrochemical polarization techniques. It is found that there is a less beneficial effect of molybdenum in solutions containing bromide ions than in those with chloride. Particular attention has been paid to the pitting behavior of UNS S31254 steel, which is found to be significantly more susceptible in bromide solutions. The effects of inclusions has also been observed on this alloy. The effect of molybdenum on pitting corrosion resistance in different aggressive solutions is discussed, and it is suggested that the interaction of molybdenum with specific aggressive anions should be taken into account in developing possible mechanisms through which this alloying element improves the pitting corrosion resistance of iron-based alloys.