Innovative development of NDT techniques for the inspection of high-temperature plant components

A Shibli and D Robertson
European Technology Development, Leatherhead, Surrey, UK

Inspection of new high-Cr martensitic steels (ASME P91 and P92) used for higher-output higher-efficiency modern power plant boilers has proved to be problematic when using conventional NDE techniques. This is because creep cavitation damage in these steels develops at a slower rate to start with and with time clusters of nanometer or micron-level cavities quickly join up to turn into cracks, giving rise to the abrupt failure of the component. Thus there is a need to develop new more sensitive NDE techniques that can detect very small levels of creep damage in these materials early in life so that plant can be made safe.

Through ETD’s Group Sponsored Projects (GSPs), supported by international industry from Europe, USA and Japan, a number of NDE techniques have been investigated/developed for creep damage detection and monitoring in pressure equipment used in power and process industry. The techniques investigated/developed have included on-site scanning force microscopy, ultrasonic testing (UT), potential drop, electromagnetic sensors, crystal misorientation and on-site precision hardness testing. The present state of development and their demonstration and use on feature specimens and plant inspection will be discussed.