Intergranular pitting and abrasive corrosion of duplex 25Cr-5Ni-6Mo stainless cast steels with nitrogen

The corrosion and corrosion-erosion resistance of duplex steels 22-25% Cr, 6% Ni, 3-5% Mo, 0.1-0.2% N have been investigated in aqueous chloride solutions. The investigated alloys showed very good resistance against pitting and intergranular corrosion in the passive range of temperature up to 50oC. Anodic polarisation measurements performed in aqueous 1M H2SO4 + 1M NaCl solutions show that the morphology and content of ferrite influence the dissolution rate of alloys in the active range - range of potentials were passivation of alloys does not occur. (author)