Solvent-based acrylic carbon paint anodes were installed on the north approach spans of the Yaquina Bay Bridge (Newport OR) in 1985 and performed well after 15 years. Anodes were inexpensive and repairs easy. Depolarization potentials are consistently above 100 with long-term current densities around 2 mA/m 2. Bond strength remains adequate.
A case history is described involving microbiologically influenced corrosion (MIC) of AISI Type 304L stainless steel piping failure after being in contact with untreated stagnant, low chloride potable water for nine months. Specialized microbiological analysis techniques, including scanning electron and optical cmicroscopy, were used in the failure analysis.
Galvele introduced a new framework for localized corrosion with his seminal paper on acidification and chloride accumulation in pits & the need for a critical product of current density & pit depth to sustain this chemistry. This paper is to review the progress in these areas with a particular focus on repassivation potential.
Fe-Cr-Ni alloys such as alloys 600 625 690 and 800 are used in steam generator tubing of nuclear power reactors. Precipitation of impurities on the steam generator tubing can lead to fouling and formation of deposits yielding a partially occluded metal surface. In this work the crevice corrosion susceptibility of these alloys is analyzed.
Resistance of S30400 and S31600 SSs to chloride-induced crevice corrosion was assessed in a wide range of temperatures and chloride concentrations. Repassivation potential of S30400 SS decreased with increasing chloride & temperatures from 0 to 60ºC, and it a constant value in the range from 60 to 90ºC regardless of chloride.
Case study: Cracking occurred in a (UNS S32100) type austenitic stainless steel nozzle fitting at a low point in the reactor effluent piping in a Gasoil Hydrotreater unit following start up. Normal preventive measures had been taken. The failed sample was removed for metallurgical analysis and determination of mechanism(s).
Over 5 years, 70 to 80 FGD scrubber units have exhibited corrosion problems. Many were after only a few months of service. This paper will provide an overview of readily available technical information in the published literature and past experience that could have been used to minimize corrosion problems in these FGD units.
Laboratory exposure testing of carbon steel to water from different regions of the United States, with varying chemistries and chloride content. The results of chemical analyses conducted in the laboratory, including elemental analysis by SEM/EDS and analysis by x-ray diffraction are correlated to water chemistry.