Failure Analysis of 304 Stainless Steel Components Used in Petrochemical Industry Applications

Type 304 stainless steel has been used to manufacture metal gaskets used as seals in bolted flange joints of hydrocarbon transfer pipeline in polyethylene plant and piping system used to distribute demineralized water in a polypropylene plant. During reassembling of ten joints after scheduled maintenance, heavy leakage has occurred in one joint. On the other hand, the water pipes have been drained and unused for about 2 months; however, after reuse, leakage has been detected. It is shown that the gasket has been crushed due to improper reassembling practice involving the application of excessive compressive preload generated by tightening the bolts. Most evidence pointed out that the water pipes have been degraded by pitting corrosion due to contamination of the water by chloride ions.