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 intergranural corrosion in the passive range at temperature up to 50 degrees centigrade. Anodic polarization measurements performed in aqueous 1mH2SO4+1mNaCl solutions show that the morfology and content of ferrite influence the dissolution rate of alloys in the active range - range of potentials where passivation of alloys does not occure.