Failure Analysis of Fatigue Cracking in Hydrocarbon-Exposed Austenitic Stainless Steel Piping: A Case Study

Fatigue cracking in hydrocarbon-exposed austenitic stainless steel piping is a primary concern in the petrochemical industry, as it can lead to structural failures and premature plant shutdowns. This study investigates the failure of a hydrocarbon vapor stainless steel pipe used in a petrochemical plant through visual inspection, stereoscopy, monitoring vibration, and scanning electron microscopy (SEM). The results reveal that the fatigue crack originated at the toe of the weld, where stress concentration was significant, and propagated circumferentially. Major contributing factors to the failure include welding defects, residual stress accumulation, and excessive vibration from the gas blower. The presence of chevron marks and fatigue striations on the fracture surface indicates that vibration-induced fatigue was the primary failure mechanism. To prevent future failures, improvements in welding quality control and the implementation of vibration suppression techniques, such as dampers, are recommended. This case study provides essential knowledge into failure prevention measures for critical piping components in petrochemical plants and can serve as a guide for similar applications in the industry.