Reliability and Safety of the Power Equipment in Respect of Properties Evaluation of Welded Joints Made From New Generation Creep-Resisting Steels

The modernisation of power generation sector has involved the construction of new power units, having supercritical parameters e.g. 580/ 600°C with 280bar, and calculated efficiency of approx. 43%. The new boilers are supercritical ones of capacities 440MW and 840MW. Their investors expect that new creep-resistant steels to be used in order to comply with the operational requirements, as well as to assure the appropriate reliability and safety of the boiler equipment in operation. Authors describe a co-operating process has been made with RAFAKO S.A. the Institute for Ferrous Metallurgy in Gliwice, the Institute of Welding and the Silesian Technical University in Katowice, for several years now, initiating research and development programmes. This paper contains selected information, test results and their evaluation before implementation of the new creep-resistant steels, including evaluation of: - working parameters and temperature conditions of main boiler components, which influence reliability and safety procedures, - base material, welded joints and HAZ structure by means of LM and SEM methods in the welding technology implementation process, - the requested level of mechanical properties, including corrosion mechanisms, - corrosion and creep-resistance results, - loss of service life for selected evaporator and steam superheater components, as crucial elements in evaluation of reliability and safety of boiler equipment.