Research on acoustic emission monitoring of pitting corrosion on 304 stainless steel

In order to study acoustic emission (AE) characteristics of pitting corrosion on 304 stainless steel under higher than normal temperature, Pitting corrosion process of 304 stainless steel in 6% ferric chloride solution at 70℃ was monitored by AE technology. Conventional parameter-based approach and signal-based analysis were combined to deal with recorded AE signals, and micromorphologic observation was performed for further verification. The results showed that AE hit and energy increased gradually with time and reached the peak at certain time, and then declined and maintained a stable condition. Signal waveform was mainly composed of low-frequency (〈 100 kHz) flexural wave with larger amplitude & energy and high-frequency (〉 100 kHz) expansion wave with lesser amplitude & energy. The research results have some certain significance for AE monitoring of pitting corrosion on 304 stainless steel under higher than normal temperature.