Superduplex stainless steels have been used in seawater systems since 1986 as castings and since 1990 as wrought product. The present paper describes some of the service environments commonly in use and the conditions that give rise to specific operating potentials. The limits of use under these conditions are described utilizing both laboratory and service experience.
Multiple leaks occurred with a carbon steel pipe carrying hot condensate water (300F and 140 psi). A root cause analysis was performed, including visual and metallographic examination of two failed samples chemical, analysis of weld metal and base metal and chemical analysis of water samples. Results show that flow accelerated corrosion (FAC) was the responsible mechanism leading to the failures.
Field experience was studied to identify the best solutions to Localized corrosion of 316 stainless steel instrument and chemical injection tubing in marine environment. Laboratory tests and exposure in marine environment of samples have been used to evaluate possible alternative materials and protective chemicals.