Analysis of Leakage Failure of a Type 304 Stainless Steel Tube

Leakage failure occurred at a 304 stainless steel tube after working for three and a half years in a fluorine chemical enterprise. The chemical composition, microstructure, corrosion morphology and corrosion products of the material in failed part of 304 stainless steel tube were studied using direct reading spectrometry, optical microscopy, scanning electron microscopy and X-ray diffraction. The results show that the major failure mode was pitting corrosion and perforation due to local enrichment of Cl^- in the tube, and the existence of H₂S promoted pitting corrosion.