Modelling the development of creep damage: The licon experience

Many plant components are designed for long term operation at high temperature, where they are subjected to creep damage. Development of creep damage in the form of creep cavitation and cracking can be an important sign of expended life, but has been relatively tedious to study in laboratory environment. Consequently, material characteristic signature of creep damage has been mostly obtained from service exposed material from the plant. This is inconvenient particularly for new materials for which no long term testing data or service experience is available. The paper describes the LICON approach to induce service-like creep cavitation damage through multiaxial loading of feature specimens. Examples are shown and discussed for parent and welded 9% chromium steels P91, P92 and E911, as well as for dissimilar welds of 2¼Cr-1Mo (P22). The results demonstrate that unlike the traditional uniaxial testing, the selected approach can produce appropriate creep cavitation damage in high-ductility steels within a reasonable time to characterise new materials and to support in-service inspections.