Alkaline Carbonate SCC Failures at a Refinery

Abstract

A metallurgical evaluation was performed to investigate two failures from carbonate-containing sour water service at a refinery. The failure mechanism for both fractured components (a pipe and a heat exchanger tube) was alkaline carbonate stress corrosion cracking. Alkaline carbonate stress corrosion cracking is a mechanism that has become more widely recognized in refinery service. This paper details the visual, SEM/EDS, metallographic, and microhardness evaluations used to determine the failure mechanism for each refinery component.