SCC damage evolution on martensitic stainless steel by using acoustic emission technique

In the present work, acoustic emission testing (AE) technique was successfully applied to identify damage phenomena occurred during stress corrosion cracking (SCC) in chloride-containing environment of a precipitation hardening martensitic stainless steel. Through the use of multi-variable statistical analysis [by coupling principal component analysis (PCA) and self-organising map (SOM)], the different stages of SCC mechanisms (i.e. activation, growth and propagation of cracks) have been identified and analysed. In particular each mechanism was related to specific and significant AE patterns allowing its univocal recognition.