This standard practice presents guidelines for preplanning for, recovering from, and repassivation after a low pH excursion in open recirculating water systems, no matter what the cause. The procedures presented in this standard inno way preclude the use of other procedures but are presented as best practices developed over years of experienceinavarietyofplants.Theprovisionsofthisstandardshouldbeappliedunderthedirectionofqualifiedwater-treatmentpersonnelfromwater-treatmentsuppliersand/orconsultants andplantpersonnel.
The stress corrosion cracking (SCC) behavior of Fe13Cr5Ni- and Fe17Cr5.5Ni-based alloys in HTHP CO2 environments was investigated through slow strain rate tests (SSRT) and electrochemical methods. The results show that a remarkable decrease in tensile strength and elongation to failure was observed when testing in CO2 environment as compared with air. Fe17Cr5.5Ni-based alloys possessed better SCC resistance than Fe13Cr5Ni-based alloys. The increase of Cr and Ni content tended to enhance the resistance to SCC and pitting corrosion. The SCC behaviors of Fe13Cr5Ni- and Fe17Cr5.5Ni-based alloys were closely associated with the repassivation capacity and the resistance to pitting corrosion.