Analysis of failed stainless steel pipe

A failed stainless steel pipe from a hydro cracking reactor was analyzed. Examination revealed that the pipe had failed by chloride induced stress corrosion cracking (SCC). Evidences suggest that the insulation material (glass wool) was the source of chlorine. The chlorine present in the glass wool had resulted in pitting corrosion in the protective layer of stainless steel foil. Once the protective layer was perforated, chlorine ion could easily migrate to the underlying hot surface of the stainless steel pipe. A detailed analysis of the failure is presented in this report. A few recommendations are also suggested to prevent recurrence of similar failure