Mechanical property evaluation and remaining life assessment of service-exposed steam pipe of boilers in a thermal power plant

Abstract

This paper is aimed at investigating the residual life of more than eleven years service - exposed main steam pipes of various boilers in a thermal power plant. The remaining life assessment for safety were made using destructive accelerated stress rupture and tensile tests at different temperatures, and some nondestructive tests. There was no evidence of localised damage in the form of surface cracks, cavitation or dents in the service exposed main steam pipes of all the boilers. So far as the remaining life at 823 K is concerned, it is possible to obtain a life of greater than 100000 hours, both at the allowable as well as operating hoop stress levels of the service - exposed pipes, provided no localised damage in the form of cracks or dents has been developed. It is recommended that a health check should be carried out after 50,000 hours of service exposure at 823 K.