Abstract
A unique approach would allow to estimate the threshold state of stress corrosion cracking (SCC) was developed by using potential fluctuation measurement. The potential fluctuation (noise) resulting from the initiation of corrosion cracks was measured in a chloride solution at various temperatures. A direct tension specimen to which a constant stress was applied and a U-bend specimen were employed for the working electrode, and senstzed type-304 stainless steels were used for their material. The local anodic currents were estimated from the form of the potential fluctuations by a calculation using a double-layer capacity and the constants of the Tafel's equation obtained from separate experiments. The feature of the electricity quantity's distribution of the estimated local anodic currents was examined.
The peak height of the obtained distributions changed significantly between the temperatures above and below the threshold state of SCC. This suggest this method would be a potential one to monitor the occurance of SCC in chemical plants.
