Influence of Chloride Concentration on Stress Corrosion Cracking of Austenitic Stainless Steel in LiCl Solutions

At constant temperature, the corrosion potential of Type 304 stainless steel in LiCl solutions is independent of Cl− concentration over the range of 2.5 to 11.8 N, whereas, the cracking potential becomes more noble with decreasing concentration. This reduction in the polarization of Ecor relative to Ecc is a primary factor responsible for the influence of Cl− concentration on time to failure at the open circuit potential. The corrosion and cracking potentials are independent of temperature at constant Cl− concentration. Failure time decreases with increasing temperature; however, the thermally activated process responsible for this behavior has not been identified. Stress induced film rupture leads to trench corrosion, and stress corrosion cracks subsequently evolve from these trenches.