Failure Analysis of 316L Air Cooler Stainless Steel Tube in a Natural Gas Production Field

In spite of the excellent resistance of stainless steel (SS) towards uniform corrosion, overcoming various localized corrosion could be a real challenge. This work presents an analysis of the failure behavior of 316L SS air chiller tube with a peripheral crack used in a Qatari gas company in Qatar. Macroscopic failure characteristics were analyzed by means of visual inspection, digital imaging while light microscopy, electron microscopy (SEM / EDX), and X-ray fluorescence (XRF) were employed for microstructural and fractographic characterization. The results indicate that the failure phenomenon that was primarily initiated by Cl led to an eventual autocatalytic pitting corrosion. The failure reasons of the tube are related to the combined effect of constant and cyclic external stresses, as well as internal residual stress originated from various operating conditions.