304不锈钢点蚀声发射监测研究
Research on acoustic emission monitoring of pitting corrosion on 304 stainless steel
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摘要: 为研究304不锈钢在高于常温条件下的点蚀声发射特性,对70℃下6%氯化铁溶液中304不锈钢点蚀过程进行了声发射监测。采用参数和波形分析相结合的方法处理信号,并通过点蚀形貌观察进行验证。结果表明声发射撞击和能量随时间逐渐增加,在某一时段达到峰值,随后下降并维持平稳状态。信号波形主要由幅度、能量较大的低频段(<100kHz)弯曲波和幅度、能量较小的高频段(>100 kHz)扩展波构成。研究结果对304不锈钢高于常温条件下声发射点蚀监测具有一定意义。Abstract: 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.