Computer-assisted analysis of changes in the microstructure of P92 steel after exposure at elevated temperature

Purpose: The purpose of the work was to analyse the components of X10CrWMoVNb9-2 (P92) steel in initial state and after long-term annealing for up to 100,000 h at 600 and 650°C. Design/methodology/approach: The material for investigation was X10CrWMoVNb9-2 (P92) steel in the form of a Ø160x40mm tube. The images of microstructure were recorded using the scanning electron microscopy. The quantitative analysis of precipitates was carried out using the image analysis system NIKON EPIPHOT200 & LUCIA G v.5.03. Findings: The investigations of microstructure and the quantitative analysis of precipitates in the tested steel in initial state and after long-term annealing allowed the impact of temperature and time on stability of the microstructure of the tested steel to be evaluated. Practical implications: The presented method can be used for evaluation and qualification of structural changes in power station boiler components operating under creep conditions. Originality/value: The presented results of changes in the structure and in the precipitation processes are applied to evaluation of the condition of the elements in further industrial service.