Journal Published Online: 11 February 2022
Volume 11, Issue 3

Impression Creep Workshop Agreement Activity



Impression creep testing is now an established, small-scale testing technique in which the indentation rate of a rectangular indenter can be converted into an equivalent uniaxial creep strain rate. Its increasing use and practical application to power plants has led to a need for standardization. This paper reports on activity by six laboratories currently using the technique to produce a CEN Workshop Agreement covering this testing methodology. Consensus is being sought on the details of the test itself, both in the form of the original single step test and in the form of the more complex stepped stress test, which can provide data at multiple test conditions in the same specimen. Associated matters being addressed include the standardization of specimen and indenter sizes; a standard methodology for measuring the indentation rate and the creep strain rate, with an appropriate validity check; and an agreement on a pretest rig hysteresis check. A further activity will define a maximum indentation depth, supported by finite element analysis. The agreed impression creep test procedure will be used in an interlaboratory “Round Robin” exercise on selected materials.

Author Information

Brett, S. J.
University of Nottingham, Nottingham, UK
Sun, W.
University of Nottingham, Nottingham, UK
Rantala, J. H.
VTT Technical Research Centre of Finland, Espoo, Finland
Purdy, D.
Electric Power Research Institute, Charlotte, NC, USA
Bridges, A.
Electric Power Research Institute, Charlotte, NC, USA
Eaton-Mckay, J.
Walton House, Warrington, UK
Austin, C.
Walton House, Warrington, UK
Holden, J.
Walton House, Warrington, UK
Clark, A.
Windmill Hill Business Park, Whitehill Way, Swindon, Wiltshire, UK
Kuhn, B.
Forschungszentrum Jülich GmbH Institut für Energie und Klimaforschung (IEK-2) 52425, Jülich, Germany
Omacht, D.
UTMdev s.r.o., Vystavni 198/134, Ostrava-Vitkovice, Czech Republic
Pages: 8
Price: $25.00
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Stock #: MPC20210096
ISSN: 2379-1365
DOI: 10.1520/MPC20210096