Evaluation of mechanical properties and assessment of residual life of a service-exposed water wall tube

This paper is aimed at investigating the residual life, spanning 32 years, of a service-exposed water wall tube from one of the steam generating boile rs of a thermal power station. The remaining life prediction and safety ass essments were made using destructive accelerated stress rupture and tensile tests at different temperatures, as well as some non-destructive tests. Th ere was no evidence of localised damage in the form of surface cracks, cavi tation or dents in the service-exposed water wall tube. So far as the remai ning life at 425 degrees C is concerned, it is possible to obtain a life gr eater than 100:000 h at the hoop stress level of the service-exposed tube, providing that no localised damage in Ihd form of cracks or dents have been developed. It is recommended that a health check map be carried out after 50,000 h of service exposure. (C) 2000 Elsevier Science Ltd. All rights res erved.