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Material degradation and ageing is of particular concern for fossil fuel fired power plant components. New techniques/approaches have been explored in recent years for Residual Life assessment of aged components and material degradation due to different damage mechanism like creep, fatigue, corrosion and erosion etc. Apart from the creep, the high temperature corrosion problem in a fossil fuel fired boiler is a matter of great concern if the fuel contains sulfur, chlorine sodium, potassium and vanadium etc. This paper discusses the material degradation due to high temperature corrosion in different critical components of boiler like water wall, superheater and reheater tubes and also remedial measures to avoid the premature failure. This paper also high lights the Residual Life Assessment (RLA) methodology of the components based on high temperature fireside corrosion. of different critical components of boiler.

Adopting a unique electrical circuit design, here we treat a significant low-cost engineering material (eutectoid steel not containing costly alloying elements) with a high-voltage (100 kV) low-current (150 mA) energy input (energy level exceeding cohesive energy). A distinctive structural evolution is ascertained with treatment duration of only 5 min as an outcome of lamellar fragmentation and matrix supersaturation. This envisages an origin of dispersed nano-sized hard cementite spheroids embedded in nano-thick martensite crystals of stratified-tile-morphology along with distributed α-ferrite regions containing sub-microscopic cementite particles of various shapes. Apart from the conjoint effect of nano-scale dispersion strengthening and martensitic strengthening overhauling the effect of conventional lamellar strengthening on a gross scale; high dislocation density and systematically arranged dislocations of similar sign at incoherent cementite particle-matrix interface provides a unique combination of ultra-high strength (UTS ∼ 1.5 GPa), significantly high specific strength (188 MPa/g cm−3) and large ductility (%Elongation = 20). Therefore, in terms of the adopted synthesis route, structural evolution and mechanical property achieved, a new dimension is hereby added to the next-generation material development so as to meet the ever increasing demand for low-cost structural application. In turn, we elucidate a fundamental conceptualization for the first time which exemplifies disproportionate atomic migration at highly incoherent nano-sized cementite particle-martensite matrix interface in steel under high-voltage low-current energy input, resulting in accumulation of dislocations of similar sign so as to significantly enhance strength along with retention of substantial ductility. [ABSTRACT FROM AUTHOR]