Contribution to the study of effects of surface state of welded joints in stainless steel upon resistance towards pitting corrosion

Successful corrosion resistance of stainless steels is based on their natural ability of passivation, i.e. formation of film of chromium oxides that prevents corrosion in many environments. Any nonuniformity of surface layers may be initial spot for corrosion processes and damages. In this contribution, beside real corrosion damages occurred in practice, results of testing of pitting corrosion resistance of weld beads made applying TIG process on AISI 316L steel grade are presented. SEM and EDX testing, as well as electrochemical corrosion testing confirmed adverse effects of heat tints zones upon corrosion resistance of stainless steels.