Structural Integrity Assessment of a Pressure Vessel Constructed With ASME SA-212 Gr. B

Abstract ASME SA-212 is a vintage plate steel specification that was first introduced in the early 1940s. The specification covered two high strength carbon silicon steel grades and was widely used for fabricating ASME Section VIII Division 1 pressure vessels until it was withdrawn in the late 1960s. The specification was then replaced with modern pressure vessel materials such as ASME SA-515 and SA-516. During this period of more than 20 years, a large number of pressure vessels were fabricated using the steel specification and many of these vessels are still in service to this date. It has been well acknowledged that the vintage steel has a low toughness and does not meet current ASME Section VIII Division 1 code requirements for low temperature operations. Some restrictions have been imposed in terms of repair, rerating, and relocations of these vessels by industry and jurisdictions. However, the service experience with these vessels have been acceptable and very few incidents have been reported. In this study, a pressure vessel constructed with SA-212 Gr. B was inspected, tested, and evaluated for structural integrity assessment. Destructive testing was conducted to obtain the actual material properties including microstructure, tensile properties, impact toughness, and fracture toughness. The structural integrity assessment was performed in accordance with current fitness for service standards. The inspection suggested the vessel maintained the original construction quality. The assessment results indicated that the vessel had adequate fracture resistance at the stamped minimum metal design temperature and was safe to operate. The results also imply that the risk of brittle failure for these vintage vessels can be managed, and the continuous service can be justified through proper inspection and analysis.