NACE RP 01-69 and Canadian Recommended Practice OCC-1 caution against using polarized potentials less negative than -850 or -770 mV saturated copper sulfate electrode (CSE), respectively, on underground pipelines where other conditions may be conducive to external stress corrosion cracking (SCC). The cautionary statement is based on research, which suggests that application of the 100-mV polarization criterion can promote SCC, but this research has not been developed to the point of being able to provide guidance to pipeline operators. The objective of the research summarized in this paper was to define pipeline conditions where use of the 100-mV polarization criterion may be conducive to possible SCC problems. Paper Number 01592, presented at Corrosion/2001, summarized Part 1 of the research, in which the previous research results were analyzed. In this paper, the results of the laboratory testing are presented.
Keywords: polarized potentials, NACE RP 01-69, Stress corrosion cracking, laboratory testing, copper sulfate electrode