Failure analysis of a stainless steel pipeline

In this study, the failure of a stainless steel (SS) pipeline supplying hydrogen to a hydro cracking reactor of a petrochemical industry is investigated. Leakage was observed in the pipeline during operation. Study revealed that the failure was by chloride stress corrosion cracking. The source of chlorine was found to be the glass wool that was wrapped on the pipeline for thermal insulation purpose. Use of SS foil beneath the thermal insulator facilitated condensation of chloride ions. The protective SS foil was destroyed by pitting corrosion followed by which the pipeline failed by stress corrosion cracking. A detailed analysis of the failure is presented in this paper.