Abstract：The causes for circumferential cracking of stainless-steel heat exchange tube in the vertical heat exchanger were analyzed by the means of macroscopic observation of crack morphology and corrosion morphology of adjacent carbon steel tube, physical and chemical analysis of material, metallographic examination, fracture observation by SEM and X-ray energy dispersive spectrometer, corrosive anion analysis of cooling water, etc. The results showed that the crack originated from the outer wall of the heat exchange tube. The crack morphology and fracture morphology showed the characteristics of stress corrosion, while the cooling water outside the pipe had high concentration of chloride ion and sulfate. Moreover, the local oxygen content in cracking area was relatively high. The analysis indicated that the stress corrosion was the cause for cracking of the heat exchange tube.
2023, Vol. 41 
