Prediction of remaining life of a FCCU reactor plate A.K. Ray*, Y.N. Tiwari, R. Singh, S. Tarafder MTE Division, National Metallurgical Laboratory, Jamshedpur 831007, India Received 10 January 1999; accepted 5 March 1999 Abstract Evaluation of mechanical properties is a powerful tool for investigating and assessing the performance of service exposed materials. The trends recently observed in service exposed (32 years) plain carbon steels used as a reactor vessel material in a petrochemical plant have been highlighted in this paper. Health assessment of both base and welded joint was made using impact tests at room temperature, destructive accelerated stress rupture and tensile tests at dierent temperatures, and some nondestructive tests. From the stress rupture tests it could be concluded that a life of more than 10 years at the hoop stress level of the material can be obtained, provided no localised damage in the form of cracks or dents have been developed. It is recommended that a health check should be carried out after 5 years of service exposure at 4858C. # 2000 Elsevier Science Ltd. All rights reserved. Keywords: Service exposed; Petrochemical; Stress rupture test; Tensile properties; Remaining life 1. Introduction Dierent grades of carbon and Cr±Mo steels are extensively used as high temperature components in petrochemical industries and power plants respectively [1±10]. Cr±Mo steels are mostly used in power plant components since the operating stresses and temperatures are high, whereas carbon steels are used for components in petrochemical plant as the operating stresses are not so high but they also operate at high temperature. Even though most of these components have a speci®c design life of 20 years, many of these are known to have survived much longer. Failure in such materials could be due to oxidation, carburisation in particular for components in petrochemical plants, creep damage and low cycle fatigue in some cases. To achieve high thermal eciency, many components in modern boilers, turbines and nuclear reactors operate at temperatures typically in the range of 500±6008C [2]. It was shown that the remaining life of such components can be analysed from creep and stress rupture properties by de®ning a reference stress such that the component life equals the life of a simple specimen tested at the reference Engineering Failure Analysis 7 (2000) 75±86 1350-6307/00/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S1350-6307(99)00012-6 www.elsevier.com/locate/engfailanal * Corresponding author. Tel.: +91-657-426901; fax: +91-657-426527. E-mail address: asokroy@csnml.renonic.in (A.K. Ray).