Many alloys, notably the austenitic stainless steels, exhibit intergranular as well as transgranular stress corrosion cracking (SCC) in CT environments. The mechanism of cracking in both these modes and the conditions under which the transition from trans to intergranular cracking or vice versa occur are topics of much debate and research. Some recent work have suggested that the mechanism of trans and intergranular stress corrosion cracking are identical. In this study, by using the load pulsing technique, it has been determined that the velocity in intergranular SCC is about 2 to 3 times higher than tmnsgranular SCC. Also, by studying the effect of temperature on the crack propagation rate the activation energy in both modes of cracking was found to be similar thereby suggesting that the rate limiting step in both types of cracking may be the same.
Keywords: intergranular stress corrosion cracking, transgranular stress corrosion cracking, activation energy, austenitic stainless steel, load pulsing technique.