Subscribe to our newsletter to receive the latest news and events from TWI:

Subscribe >

CreepTest – Early-stage creep damage detection

CreepTest was a European Framework VII project that was successfully completed in summer 2015. The project developed a field-implementable ultrasonic technique to detect early-stage creep damage in power plant components. This type of damage, known as Type IV, is found in a particular class of material: creep-strength-enhanced ferritic (CSEF) steels.

Examples of this class include grade P91, which has historically been used in large quantities in conventional thermal power plants around the world. Grade P91 has been identified as being highly susceptible to Type IV damage well before the expected end of its life, leading to costly failures and the potential for catastrophic loss of plant and human life.

Importance of early detection

To manage operating costs and prevent catastrophic losses, it is imperative that creep damage is detected early so that decisions regarding component repair or replacement can be made effectively. Current practice in power plants relies on the use of metallographic replication of the component surface and optical analysis under a microscope to establish the presence of creep voids, which indicate damage at an early stage. However, the replication method only gives information of the surface condition of the component; an effective method for volumetric evaluation is being urgently sought around the world.

Verification of signals against sectioning of specimens with creep damage
Verification of signals against sectioning of specimens with creep damage

The ultrasonic technique

CreepTest developed an ultrasonic technique using physical principles and simulations. Specimens were generated in TWI and trials were held on service-exposed components supplied by consortium partner SSE. The validation was completed by sectioning specimens to confirm the presence of early-stage creep voids.

Prototype for field inspection

The technique was encapsulated in a prototype system for field implementation in operating power plants. Its effectiveness was confirmed by additional testing on power plant components.

For further information, please email contactus@twi.co.uk.

Prototype scanner designed for inspecting field exposed component in-situ (top) and superimposition of scan data over area ahead of a crack-top with creep damage
Prototype scanner designed for inspecting field exposed component in-situ (top) and superimposition of scan data over area ahead of a crack-top with creep damage
Media /

Related Insights

View all insights
}