Remaining life estimation of a service exposed economiser tube

A service exposed (80,000 hr) economiser tube of a 60 MW boiler of a thermal power plant was investigated for the detailed metallurgical assessment necessary for remaining life estimation. The investigation included hot tensile tests, hardness measurement, microscopy and thickness measurement. Analysis revealed that there was no degradation of mechanical properties and microstructural features. The reduction in tube thickness was primarily due to oxidation and corrosion/erosion processes. Taking into account all the experimental data and mechanics aspects of the tube an estimated remaining life of 20,000 hrs was calculated and thus recommended for further use.