Abstract:

Cracking and leakage of heat exchange tubes occurred during the operation of a spiral wound heat exchanger of a company. By means of macroscopic observation, chemical composition analysis, hardness test, metallographic and fracture analysis, the reasons for the cracking of TP304 heat exchange tubes were analyzed. The results showed that chloride stress corrosion cracking occurred in the heat exchange tubes. The shell side medium contained a certain amount of Cl-, which led to the rupture of passivation film on the surface of heat exchange tubes and the formation of corrosion pits. With the enrichment and concentration of Cl- in the corrosion pits, stress corrosion cracks began to initiate under the action of machining residual stress. With the passage of time, the cracks continued to expand, resulting in leakage through the heat exchange tubes.

Key words: TP304, heat exchange tube, Cl^-, stress corrosion cracking