Fracture Failure Analysis of Plate Air Cooler Sheets

Serious cracking of some plate air cooler sheets occurred in short time when operated in a refinery. The chamical composition, metallography, macro-morphology and micro-morphology of the fractured parts and corrosion products on cracked sheets were analyzed by electron probe microscopic analyzer (EPMA), metallurgic microscopy, scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS). The results showed that the cracking in outer layer of plate air coolers was attributed to stress corrosion cracking (SCC), and the cracking in inner layer was attributed to corrosion fatigue.