Abstract: This paper analyzes and studies the fracture reasons of 0Cr18Ni9 stainless steel heat exchange tube in methanol synthesis reactor by adopting such methods as chemical component analysis, mechanical performance test, microstructure analysis and SEM observation of fracture and energy spectrum analysis. The results show that the boiler feed water containing Cl-in the shell side of the reactor formed corrosive environment. Under the action of working stress and temperature, cracks initiated in the pitting corrosion region on the outer surface of tube and extended to the inner wall until penetrating. The fracture was characterized by cleavage fracture, which was intergranular and transgranular brittle fracture. The fracture reason of the heat exchange tube was chloride-induced stress corrosion cracking.

Key words: 0Cr18Ni9, methanol synthesis reactor, heat exchange tube, chloride-induced stress corrosion cracking/CISCC