STRESS-CORROSION CRACKING AND LIFE PREDICTION EVALUATION OF AUSTENITIC STAINLESS-STEELS IN CALCIUM-CHLORIDE SOLUTION

The stress corrosion cracking (SCC) susceptibility of austenitic stain less steels (SS) in calcium chloride (CaCl2) solutions was Studied usi ng a constant-load method. Initiation and propagation of stress corros ion cracks were examined using fractography. The distribution of crack s was classified A physical cracking was introduced, and creep deforma tion measurements were performed. The steady-state strain rate (epsilo n(ss)) obtained from the corrosion elongation curve (elongation-vs-tim e curve) showed a linear function of time to failure (t(f)). This impl ied that epsilon(ss) can be applied as a parameter for prediction of t (f). Furthermore, epsilon(ss) below which no failure occurs within a l aboratory time scale was estimated. Based on results obtained, the cri tical values of stress (sigma) below which no SCC occurred were evalua ted. Based upon creep measurements in a noncorrosive environment, the influence of environment on epsilon(ss) was more than fivefold. Cracki ng characteristics were divided into three categories according to the crack initiation distribution Transgranular cracking predominated at relatively low sigma and epsilon(ss).