The Features of 304 Nitrogen Controlled Stainless Steel during Slow Strain Rate Test by Electrochemical Noise

摘要

An investigation was carried out on the features of electrochemical noises of 304 nitrogen controlled stainless steel (304NGSS) in solution 4mol/LNaCl +0.01mol/LNa2S2O3 under slow strain rate testing (SSRT) conditions.Electrochemical voltage and current noise were measured simultaneously in the Zero Resistance Ammeter (ZRA) mode.After experiment,there are several cracks on the edge of pit on the specimen.In order to characterize the stress corrosion cracking (SCC) processes of 304NGSS,time analysis of data alongwith the spectral estimation using FFT method,the results show SCC processes consisted of breakdown of the oxide film,the formation of pitting,crack initiation and crack propagation.According to the varieties of spectrums in time and frequency,the different state can be distinguished.The work in this paper will contribute to the research of indicator for real-time detection of SCC in plant.