Influence of the cold working induced martensite on the electrochemical behavior of AISI 304 stainless steel surfaces

It is clear that the corrosion resistance of carbon steels decreases as cold working amount increases, but for austenitic stainless steels, the relation between cold-working and corrosion performance is not clear. The electrochemical behavior of AISI 304 stainless steel with 3 different cold working amounts is characterized by Mott-Schottky analysis, OCP records, EIS and cyclic polarization curves. An innovative cell with gel electrolyte is used for an easy study of the deformed surfaces without modifying them. After the polarization tests, the influence of the deformation on the amount of pits and on their morphological characteristics is also analyzed. The microstructural changes caused by cold rolling are studied, and the residual stresses are determined by XRD using the sin(2) psi method. It is proved that AISI 304 stainless steel decreases its pitting resistance in a medium with chlorides when it is subjected to moderate cold rolling, but heavy thickness reduction causes a subsequent recovery of corrosion resistance. The results obtained suggest that this trend is related to changes in the magnitude and type of the stresses (tensile or compressive) on the surface of the material. (C) 2018 Published by Elsevier Editora Ltda. on behalf of Brazilian Metallurgical, Materials and Mining Association.

Influence of the cold working induced martensite on the electrochemical behavior of AISI 304 stainless steel surfaces Articles