TRACK: Safety/Reliability
This paper presents experiences from failure in P11 metallurgy piping because of creep-fatigue interaction. Several cracks were observed in P11 metallurgy piping in superheated steam application at 510 deg C after satisfactory service of 25-30 years. Extensive inspection of the piping systems was carried out. Advanced FEA study was conducted on the piping system to identify susceptible locations for creep related damages. Advanced metallurgical analysis was done to correlate the inspection observations with material degradation. The learnings emphasize on the need to evaluate high temperature piping and piping component for in-service damages based on Creep -Fatigue interaction to establish the impact of residual stresses, subtle fluctuating stresses and thermal induced stresses based on the piping configuration. The results of the evaluation can be used to predict the useful life of piping and piping components of P11 metallurgy exposed to continuous operating temperature of 510 deg C.