FRACTURE PROPERTIES AND MODES IN CREEP OF P92 CREEP RESISTANT FERRITIC STEEL

摘要

The creep behaviour of P92 steel in as-received condition and after long-term thermal ageing was investigated at 600°C and 650°C using uniaxial tension creep tests. The creep testing was carried out in the power-law creep region. To assess the effect of each damage process on the loss of creep strength, most creep tests were followed by microstructural and fractographic investigations. It was found that creep deformation and fracture are controlled by the same mechanisms. The large Laves phase particles, which coarsened during creep exposure, served as preferential sites for creep cavity nucleation. The fracture data were analysed in terms of Monkman-Grant relationship and the creep damage tolerance factor X.