Creep and life assessment of engineering components in power plants and process industries

Abstract

Engineering components in thermal power plants such as boiler tubes, headers, main steam pipes, HP, IP and LP cylinders, rotors etc. made of Cr-Mo, Cr-Mo-V steels and in process industries - steam cracker furnace, reformer tubes, process heater tubes etc. made of HP40, IN 519, HK40 alloys operate in a complex environment involving high temperature, pressure and corrosive atmosphere to perform specific functionsfor a minimum specd period of time. During service depending upon the operating conditions, several mechanisms such as creep, fatigue, corrosion, oxidation etc. become operative. Accumulation of microstructural damages in the components due to prolong operation decreases their load bearing capacity thereby limiting the lives of the components.When the load bearing capacity falls below a critical level determined by component geometry and loading, failure occurs.This paper describes some aspects of creep and life assessment technology and a few case studies related to changes in micros tructure due to ageing, creep and remaining life of components in power plants and process industries.