Abstract: Corrosion cracking occurred on the tube bundles in 0Cr18Ni10Ti stainless steel stripping tower exchangers of pyrolysis fuel oil hydrogenation unit in a petrochemical company. The macro corrosion investigation, spectral analysis, metallographic analysis, SEM observation, EDS analysis, XRD analysis and corrosion medium analysis methods are adopted to examine and analyze the corrosion condition, chemical composition, metallographic structure and corrosion products. The results showed that the solution treatment effect of heat exchange tube was not good; there was certain amount of residual stress; the fracture was cleavage fracture morphology; the crack presented transcrystalline expanding. These were the characteristics of typical stress corrosion cracking. The analysis results indicated that the corrosion cracking of the heat exchange tube was chloride stress corrosion cracking and the residual stress of heat exchange tube itself and chloride of cold high oil for 0Cr18Ni10Ti stainless steel pipe provided necessary conditions for stress corrosion cracking.

Key words: stainless steel, heat exchanger tube, corrosion products, crack, stress corrosion cracking/SCC