Investigation of the Leak Failure of a Stainless Steel Condenser Tube Stimulated by Microbiological-Influenced Corrosion

This paper investigates the leak failure of an austenitic stainless steel condenser tube observed during the hydrostatic test operation using visual inspection, scale analysis, and the micrographic analysis by scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (SEM/EDS). The results showed that the inner surface of the failed condenser tube experienced the localized pitting corrosion, initiated from the inner, and continued through the thickness of the tube. Rod-like and leaf stalk-like microorganisms and the biofilm were found in the scale layer covering the affected area. Tunneling corrosion attack was also clearly found. EDS spectra results indicated the significant sulfur content in corrosion pits. All of the findings indicate that microbiological-influenced corrosion assisted by sulfate reduction bacteria was response for the leakage failure of the condenser tube.