Stress corrosion cracking and hydrogen embrittlement of cold worked AISI type 304 austenitic stainless steel in mode I and mode III

Comparative testing of cold worked AISI type 304 austenitic stainless steel in mode I and mode III under conditions of cathodic charging and chloride stress corrosion cracking (SCC) has been used to assess the role of hydrogen in SCC. The experimental results of these tests and those previously published have been used to deduce the mechanism and rate controlling step for SCC. The mechanism for chloride SCC in mode I is anodic dissolution of active slip planes containing hydrogen with the rate controlling step being the transport of hydrogen to these slip planes. The mechanism of SCC in mode III is tunnelling corrosion followed by overload again occurring on a plane of maximum hydrogen concentration.MST/348