Failure Analysis of Corrosion Perforation of Heat Exchanger Plate

In-depth investigation of corrugated plate heat exchanger plate made of 316 stainless steel was carried out with reference to equipment design, service conditions and materials of construction in this paper. The failure mechanism and cause were studied based on metallographic testing, micromorphological analysis and fluid simulation. Macroscopic inspection showed that the channels on the water side were severely blocked by deposits, and holes expanding from the water side were observed after clearing away the deposits. Pitting corrosion was observed on the surface of the heat exchanger plate by scanning electron microscopy (SEM) with a small amount of corrosion products. Oxides and chlorine were detected on both deposits and corrosion pits by energy dispersive spectrum (EDS). In summary, the cause of perforation is attributed to chloride ion pitting corrosion, and the process of chloride ion corrosion on stainless steel and the influencing factors are discussed. The result showed that the root cause of the blockage is a structural design defect in the heat exchanger plate’s diversion area.