Stress Corrosion Cracking Process of X60 Steel Immersed in a Brine Solution with Corrosion Inhibitor through the Electrochemical Noise Technique

Abstract

Stress corrosion cracking (SCC) process of an API X60 steel exposed to a brine solution with and without addition of corrosion inhibitor was analyzed through electrochemical noise (EN). A NACE brine solution without and adding 100 ppm of inhibitor was used like electrolyte at atmospheric pressure and 60°C. The SCC assessment was carried out using slow strain rate tests (SSRT) at strain rate of 1x10-6s-1in accordance with NACE TM-198. During SSRT the SCC process was monitored using EN using a set up with three electrodes. A decrease in mechanical properties for samples without corrosion inhibitor was observed. The SCC index obtained from the mechanical properties of SSRT indicate that X60 steel could be susceptible to SCC in brine solution without adding corrosion inhibitor. The time series show fluctuations with high frequency, but of low amplitude (for current and potential) which indicate the presence of a type of localized corrosion, which was corroborated with the index location calculated, where a mix corrosion process type was obtained. A clear effect of corrosion inhibitor was observed, which decrease the corrosion rate considerably.