Failure analysis of AISI 304 stainless steel pipeline transmission a petrochemical plant

Abstract

Abstract This paper presents the failure analysis of AISI304 stainless steel pipeline that was fabricated by welding and used for CO2 transmission in a petrochemical plant. After a years of satisfactory operation, significant cracking was observed adjacent to the weld joints of valve and pipeline. The failure investigation was carried out on welded pipe samples using optical and fractography, micro hardness measurements, XRF and XRD testing. The hardness test results show faults occur in the HAZ region. Fractured surface macrostructure and morphology analysis shows inter-granular brittle fracture mode. The inter-granular fault begins with the presence of very intensive inter-granular corrosion, especially on the outer metal surface and progressively propagates to the inside of the metal. The results of XRD found peak of carbide from the secondary phase of SS 304 austenite steel. The material experienced sensitization that is indicated by the presence of carbides at the grain boundary.