Luciano Lazzari

Relationship Between the Electrochemical and Corrosion Behavior and the Structure of Stainless Steels Subjected to Cold Plastic Deformation

The present inves t iga t ion forms pa r t of a sys temat ic s tudy about the influence of cold p las t ic deformat ion on the electrochemical and corrosion b e hav ior of meta l l ic mater ials , wi th the aim of de te rmining and e luc ida t ing such aspects of the i r behavior and corre la t ing them wi th the micros t ruc tura l effects of the deformat ion, these being analyzed by meta l lographic and x r a y techniques and by t ransmiss ion e lec t ron microscopy. In this respect, the influence of cold plast ic deformat ion on the e lectrochemical and corrosion behavior of two stainless steels (AISI 304 L and 316 L) in different aggressive media (wi th and wi thout chlor ide ions) has been s tudied wi th reference to the fol lowing points: (i) de format ion type, i.e., tensi le stress, cold drawing, or cold roll ing, and conditions, i.e., at room t empera tu r e and at --196~ (ii) re la t ive or ien ta t ion of the exposed surface wi th the deformat ion direction, i.e., para l l e l and perpendicu la r ; (iii) texture , defects, and mar tens i t e t ransformat ion. t ion of these mate r ia l s which are of ten used in the w o r k h a r d e n e d state. The corre la t ion be tween the elect rochemical behavior and the s t ruc tura l effects p ro duced by cold plast ic deformat ion, i.e., texture , surface Fig. 1. Test cell (cross section) The s tudy of the influence of cold plast ic de fo rmat ion on the e lect rochemical and corrosion behavior of austenit ic s tainless steels was carr ied out in our In s t i tu te main ly because of the need for a sys temat ic collection of da ta as a basis for a more re l iab le u t i l iza* Electrochemical Society Act ive Member. 1 Present address: Cent ro Informazioni Studi Esperienze ( CISE ), Milano, I taly.