Effect of hot rolling and cooling conditions on intergranular corrosion behavior in Alloy625 clad steel

The effects of hot rolling and subsequent cooling conditions on intergranular corrosion behavior in Alloy625 clad steel were investigated. Intergranular corrosion resistance of Alloy625 at finishing rolling temperatures (FT) ranging from 800 °C to 900 °C was almost the same as that of solution treatment. Corrosion rate of 750 °C FT increased due to sensitization by precipitations. Corrosion rate also increased at 1000 °C FT, but this is not due to sensitization. Preferential corrosion at recrystallized grain boundaries due to an anodic reaction concentration is a possible mechanism. Corrosion rate of Alloy625 which was air-cooled after rolling increased owing to grain boundary segregation.