An acoustic emission (AE) monitoring method for chloride stress corrosion cracking (SCC) in SUS304 stainless steel has been proposed to investigate this mechanism. The method combines a droplet SCC monitoring system and an AE system capable of continuous waveform data acquisition and storage. MgCl₂ droplets were placed on a thin plate specimen of SUS304 to induce SCC. Since detected AE waveforms had small amplitudes with large noises, a means of noise filtering was developed to extract these features, based on time-frequency analysis of the continuous waveform. About 200 AE events were taken out after filtering. SEM observation showed that the AE source was attributable to transgranular SCC which cannot be detected by conventional AE monitoring systems. Therefore the new method demonstrated high sensitivity for the SCC monitoring.

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