Influence of Surface Treatment on the Pitting Corrosion Behaviour of High Alloyed Stainless Steels in a Chloride Solution

The pitting corrosion behaviour of the austenitic stainless steel alloys 31 and A 351 with different surface treatments in a technical MgCl2 solution was investigated. Potentiometric current density-potential measurements were carried out, and critical repassivation temperatures were determined, using a galvanometric method. Pickled, ground, abrasively blast cleaned and shot-peened surfaces, respectively, were analysed concerning roughness, residual stress, work hardening and near-surface structure. The effects of the surface properties on the local corrosion behaviour was investigated. Basically, with increasing roughness, amount of residual stress and work hardening, one can see a tendency to decreasing resistance against pitting corrosion. On the other hand, those effects are superimposed by special properties of the passive layer, e. g., caused by pickling, or from the processing-specific surface texture. © 2001 Carl Hanser Verlag, München.