Stimulation of various forms of stress corrosion in an austenitic stainless steel
Abstract
A heat-treated AISI304 austenitic stainless steel has been studied in a 1N H2SO4 + 0.2N NaCl solution at constant load and at room temperature and80°C.
The SEM examination has been used to ascertain the morphology and evolution of attack, initiated at preformed pits having critical dimensions, owing to the effect of polarization in the imperfect passivity zone and subsequently, alternatively in the regions of perfect passivity, active-passive transition, activity and in freely-corroding conditions. Reverse and direct polarization sequences have been investigated.
It has been observed that in some cases the integranular mode of attack changes to transgranular. In other cases it is intensified. While in yet others it is depressed. Attack that is initially transgranular cannot be modified to intergranular.
With the methodologies applied it has been possible at will to induce the appearance of various stress-corrosion cracking forms or to ensure the degeneration thereof into other forms of attack.
