Intergranular attack during crevice corrosion of stainless steels

The crevice corrosion resistance of AISI type 316 stainless steel was investigated as a function of carbide precipitation and grain size in 0.5 M NaCl solution using a potentiodynamic technique and a specially designed crevice assembly. It has been found that if there is chromium depletion along the grain boundaries (for sensitized material) or if there is a large grain boundary area per unit volume (for fine grained material), the intergranular attack takes place in the crevice due to the presence of more active areas along the grain boundaries.